document_title: List of birds of Ontario

question_text: what kind of hawks are in southern ontario

question_tokens: what kind of hawks are in southern ontario

text: List of birds of Ontario

text: Ducks, geese, and waterfowl[edit]

text: Order: Anseriformes   Family: Anatidae

text: The family Anatidae includes ducks and most duck-like waterfowl, such as geese and swans. These birds are adapted to an aquatic existence with webbed feet, bills which are flattened to a greater or lesser extent, and feathers that are excellent at shedding water due to special oils.

text:
Black-bellied whistling-duck, Dendrocygna autumnalis (A)
Fulvous whistling-duck, Dendrocygna bicolor (A)
Snow goose, Anser caerulescens
Ross's goose, Anser rossii
Greater white-fronted goose, Anser albifrons (L)
Pink-footed goose, Anser brachyrhynchus (A)
Brant, Branta bernicla
Barnacle goose, Branta leucopsis (A)
Cackling goose, Branta hutchinsii
Canada goose, Branta canadensis
Mute swan, Cygnus olor (I) (L) (C)
Trumpeter swan, Cygnus buccinator (L)
Tundra swan, Cygnus columbianus
Wood duck, Aix sponsa
Garganey, Spatula querquedula (A)
Blue-winged teal, Spatula discors
Cinnamon teal, Spatula cyanoptera (A)
Northern shoveler, Spatula clypeata
Gadwall, Mareca strepera
Eurasian wigeon, Mareca penelope (L) (C)
American wigeon, Mareca americana
Mallard, Anas fulvigula
American black duck, Anas rubripes
Mottled duck, Anas fulvigula (A)
Northern pintail, Anas bahamensis
Green-winged teal, Anas crecca
Canvasback, Aythya valisineria
Redhead, Aythya americana
Ring-necked duck, Aythya collaris
Tufted duck, Aythya fuligula (A)
Greater scaup, Aythya marila
Lesser scaup, Aythya affinis
King eider, Somateria spectabilis
Common eider, Somateria mollissima (S)
Harlequin duck, Histrionicus histrionicus (L) (C)
Surf scoter, Melanitta perspicillata
White-winged scoter, Melanitta fusca
Black scoter, Melanitta americana
Long-tailed duck, Clangula hyemalis
Bufflehead, Bucephala albeola
Common goldeneye, Bucephala clangula
Barrow's goldeneye, Bucephala islandica (L) (C)
Smew, Mergellus albellus (A)
Hooded merganser, Lophodytes cucullatus
Common merganser, Mergus merganser
Red-breasted merganser, Mergus serrator
Ruddy duck, Oxyura jamaicensis

text: New World quail[edit]

text: Order: Galliformes   Family: Odontophoridae

text: The New World quails are small, plump terrestrial birds only distantly related to the quails of the Old World, but named for their similar appearance and habits.

text: Northern bobwhite, Colinus virginianus

text: Pheasants, grouse, and allies[edit]

text: Order: Galliformes   Family: Phasianidae

text: The Phasianidae is a family of birds which consists of pheasants, partridges, grouse, turkeys, and their allies. These are terrestrial species, variable in size but generally plump with broad relatively short wings. Many species are gamebirds or have been domesticated as a food source for humans.

text:
Gray partridge, Perdix perdix (I) (C) (L)
Ring-necked pheasant, Phasianus colchicus (I) (L)
Ruffed grouse, Bonasa umbellus
Spruce grouse, Falcipennis canadensis
Willow ptarmigan, Lagopus lagopus (C) (S)
Rock ptarmigan, Lagopus muta (A)
Sharp-tailed grouse, Tympanuchus phasianellus
Greater prairie-chicken, Tympanuchus cupido (A) (Ex)
Wild turkey, Meleagris gallopavo

text: Grebes[edit]

text: Order: Podicipediformes   Family: Podicipedidae

text: Grebes small to medium-large freshwater diving birds. They have lobed toes and are excellent swimmers and divers. However, they have their feet placed far back on the body, making them quite ungainly on land.

text:
Pied-billed grebe, Podilymbus podiceps
Horned grebe, Podiceps auritus
Red-necked grebe, Podiceps grisegena
Eared grebe, Podiceps nigricollis (L)
Western grebe, Aechmorphorus occidentalis (A)

text: Pigeons and doves[edit]

text: Order: Columbiformes   Family: Columbidae

text: Pigeons and doves are stout-bodied birds with short necks and short slender bills with a fleshy cere.

text:
Rock pigeon, Columba livia (I)
Band-tailed pigeon, Patagioenas fasciata (A)
Eurasian collared-dove, Streptopelia decaocto (I) (A)
Passenger pigeon, Ectopistes migratorius (E)
Inca dove, Columbina inca (A)
Common ground-dove, Columbina passerina (A)
White-winged dove, Zenaida asiatica (A)
Mourning dove, Zenaida macroura

text: Cuckoos and anis[edit]

text: Order: Cuculiformes   Family: Cuculidae

text: The family Cuculidae includes cuckoos, roadrunners, and anis. These birds are of variable size with slender bodies, long tails, and strong legs.

text:
Yellow-billed cuckoo, Coccyzus americanus
Black-billed cuckoo, Coccyzus erythropthalmus
Groove-billed ani, Crotophaga sulcirostris (A)

text: Nightjars and allies[edit]

text: Order: Caprimulgiformes   Family: Caprimulgidae

text: Nightjars are medium-sized ground-nesting nocturnal birds with long wings, short legs, and very short bills. Most have small feet, of little use for walking, and long pointed wings. Their soft plumage is camouflaged to resemble bark or leaves.

text:
Lesser nighthawk,  Chordeiles acutipennis (A)
Common nighthawk,  Chordeiles minor
Common poorwill,  Phalaenoptilus nuttallii (A)
Chuck-will's-widow, Antrostomus carolinensis (A)
Eastern whip-poor-will, Antrostomus vociferus

text: Swifts[edit]

text: Order: Apodiformes   Family: Apodidae

text: Swifts are small birds which spend the majority of their lives flying. These birds have very short legs and never settle voluntarily on the ground, perching instead only on vertical surfaces. Many swifts have long swept-back wings which resemble a crescent or boomerang.

text:
Black swift, Cypseloides niger (A)
White-collared swift, Streptoprocne zonaris (A)
Chimney swift, Chaetura pelagica (L)

text: Hummingbirds[edit]

text: Order: Apodiformes   Family: Trochilidae

text: Hummingbirds are small birds capable of hovering in mid-air due to the rapid flapping of their wings. They are the only birds that can fly backward.

text:
Mexican violetear, Colibri thalassinus (A)
Ruby-throated hummingbird, Archilochus colubris
Black-chinned hummingbird, Archilochus alexandri (A)
Anna's hummingbird, Calypte anna (A)
Rufous hummingbird, Selasphorus rufus (A)
Broad-billed hummingbird, Cynanthus latirostris (A)

text: Rails, gallinules, and coots[edit]

text: Order: Gruiformes   Family: Rallidae

text: Rallidae is a large family of small to medium-sized birds which includes the rails, crakes, gallinules, and coots. The most typical family members occupy dense vegetation in damp environments near lakes, swamps, or rivers. In general, they are shy and secretive birds, making them difficult to observe. Most species have strong legs and long toes which are well adapted to soft uneven surfaces. They tend to have short, rounded wings and to be weak fliers.

text:
Yellow rail, Coturnicops noveboracensis
Black rail, Laterallus jamaicensis (A)
King rail, Rallus elegans
Virginia rail, Rallus limicola
Sora, Porzana carolina
Purple gallinule, Porphyrio martinicus (A)
Common gallinule, Gallinula galeata (C)
American coot, Fulica americana (L)

text: Cranes[edit]

text: Order: Gruiformes   Family: Gruidae

text: Cranes are large, long-legged, and long-necked birds. Unlike the similar-looking but unrelated herons, cranes fly with necks outstretched, not pulled back. Most have elaborate and noisy courting displays or "dances".

text:
Sandhill crane, Antigone canadensis
Whooping crane, Grus americana (A)

text: Stilts and avocets[edit]

text: Order: Charadriiformes   Family: Recurvirostridae

text: Recurvirostridae is a family of large wading birds which includes the avocets and stilts. The avocets have long legs and long up-curved bills. The stilts have extremely long legs and long, thin, straight bills.

text:
Black-necked stilt, Himantopus mexicanus (A)
American avocet, Recurvirostra americana (L) (C)

text: Oystercatchers[edit]

text: Order: Charadriiformes   Family: Haematopodidae

text: The oystercatchers are large, obvious and noisy plover-like birds, with strong bills used for smashing or prising open molluscs.

text: American oystercatcher, Haematopus palliatus (A)

text: Plovers and lapwings[edit]

text: Order: Charadriiformes   Family: Charadriidae

text: Charadriidae includes the plovers, dotterels, and lapwings. They are small to medium-sized birds with compact bodies, short thick necks, and long, usually pointed, wings. They are found in open country worldwide, mostly in habitats near water.

text:
Black-bellied plover, Pluvialis squatarola
American golden-plover, Pluvialis dominica
Lesser sand-plover, Charadrius mongolus (A)
Snowy plover, Charadrius nivosus (A)
Wilson's plover, Charadrius wilsonia (A)
Common ringed plover, Charadrius hiaticula (S)
Semipalmated plover, Charadrius semipalmatus
Piping plover, Charadrius melodus
Killdeer, Charadrius vociferus
Eurasian dotterel, Charadrius morinellus (A)

text: Sandpipers and allies[edit]

text: Order: Charadriiformes   Family: Scolopacidae

text: Scolopacidae is a large diverse family of small to medium-sized shorebirds including the sandpipers, curlews, godwits, shanks, tattlers, woodcocks, snipes, dowitchers, and phalaropes. The majority of these species eat small invertebrates picked out of the mud or soil. Variation in length of legs and bills enables multiple species to feed in the same habitat, particularly on the coast, without direct competition for food.

text:
Upland sandpiper, Bartramia longicauda (L)
Whimbrel, Numenius phaeopus
Eskimo curlew, Numenius borealis (A) (Possibly extinct)
Long-billed curlew, Numenius americanus (A)
Slender-billed curlew, Numenius tenuirostris (A)
Black-tailed godwit, Limosa limosa (A)
Hudsonian godwit, Limosa haemastica
Marbled godwit, Limosa fedoa
Ruddy turnstone, Arenaria interpres
Red knot, Calidris canutus
Ruff, Calidris pugnax (L)
Sharp-tailed sandpiper, Calidris acuminata (A)
Stilt sandpiper, Calidris himantopus
Curlew sandpiper, Calidris ferruginea (A)
Sanderling, Calidris alba
Dunlin, Calidris alpina
Purple sandpiper, Calidris maritima (C)
Baird's sandpiper, Calidris bairdii
Little stint, Calidris minuta (A)
Least sandpiper, Calidris minutilla
White-rumped sandpiper, Calidris fuscicollis
Buff-breasted sandpiper, Calidris subruficollis
Pectoral sandpiper, Calidris melanotos
Semipalmated sandpiper, Calidris pusilla
Western sandpiper, Calidris mauri (L) (C)
Short-billed dowitcher, Limnodromus griseus
Long-billed dowitcher, Limnodromus scolopaceus
American woodcock, Scolopax minor
Wilson's snipe, Gallinago delicata
Spotted sandpiper, Actitis macularia
Solitary sandpiper, Tringa solitaria
Wandering tattler, Tringa incana (A)
Lesser yellowlegs, Tringa flavipes
Willet, Tringa semipalmata (L) (C)
Spotted redshank, Tringa erythropus (A)
Greater yellowlegs, Tringa melanoleuca
Wilson's phalarope, Phalaropus tricolor
Red-necked phalarope, Phalaropus lobatus
Red phalarope, Phalaropus fulicarius (C)

text: Jaegers[edit]

text: Order: Charadriiformes   Family: Stercorariidae

text: The family Stercorariidae are large birds, typically with grey or brown plumage, often with white markings on the wings. They have longish bills with hooked tips and webbed feet with sharp claws. They look like large dark gulls, but have a fleshy cere above the upper mandible. They are strong, acrobatic fliers.

text:
Pomarine jaeger, Stercorarius pomarinus (C)
Parasitic jaeger, Stercorarius parasiticus
Long-tailed jaeger, Stercorarius longicaudus (L) (C)

text: Auks, murres, and puffins[edit]

text: Order: Charadriiformes   Family: Alcidae

text: Alcids are superficially similar to penguins due to their black-and-white colours, their upright posture, and some of their habits, however, they are only distantly related to the penguins and are able to fly. Auks live on the open sea, only deliberately coming ashore to nest.

text:
Dovekie, Alle alle (A)
Thick-billed murre, Uria lomvia (A)
Razorbill, Alca torda (A)
Black guillemot, Cepphus grylle (C) (S)
Long-billed murrelet, Brachyramphus perdix (A)
Ancient murrelet, Synthliboramphus antiquus (A)
Atlantic puffin, Fratercula arctica (A)

text: Gulls, terns, and skimmers[edit]

text: Order: Charadriiformes   Family: Laridae

text: Laridae is a family of medium to large seabirds and includes gulls, terns, kittiwakes, and skimmers. They are typically grey or white, often with black markings on the head or wings. They have stout, longish bills and webbed feet.

text:
Black-legged kittiwake, Rissa tridactyla (L) (C)
Ivory gull, Pagophila eburnea (A)
Sabine's gull, Xema sabini (L) (C)
Bonaparte's gull, Chroicocephalus philadelphia
Black-headed gull, Chroicocephalus ridibundus (L) (C)
Little gull, Hydrocoloeus minutus (C)
Ross's gull, Rhodostethia rosea (L) (C)
Laughing gull, Leucophaeus atricilla (L) (C)
Franklin's gull, Leucophaeus pipixcan (L)
Black-tailed gull, Larus crassirostris (A)
Heermann's gull, Larus heermanni (A)
Mew gull, Larus canus (A)
Ring-billed gull, Larus delawarensis
California gull, Larus californicus (A)
Herring gull, Larus argentatus
Iceland gull, Larus glaucoides
Lesser black-backed gull, Larus fuscus (L)
Slaty-backed gull, Larus schistisagus (A)
Glaucous gull, Larus hyperboreus
Great black-backed gull, Larus marinus
Kelp gull, Larus dominicanus (A)
Sooty tern, Onychoprion fuscatus (A)
Least tern, Sternula antillarum (A)
Caspian tern, Hydroprogne caspia
Black tern, Chlidonias niger
White-winged tern, Chlidonias leucopterus (A)
Common tern, Sterna hirundo
Arctic tern, Sterna paradisaea (C)
Forster's tern, Sterna forsteri (L) (C)
Royal tern, Thalasseus maximus (A)
Sandwich tern, Thalasseus sandvicensis (A)
Elegant tern, Thalasseus elegans (A)
Black skimmer, Rynchops niger (A)

text: Loons[edit]

text: Order: Gaviiformes   Family: Gaviidae

text: Loons, known as divers in Europe, are aquatic birds the size of a large duck, to which they are unrelated. Their plumage is largely grey or black, and they have spear-shaped bills. Loons swim well and fly adequately, but, because their legs are placed towards the rear of the body, are almost helpless on land.

text:
Red-throated loon, Gavia stellata
Pacific loon, Gavia pacifica (C)
Common loon, Gavia immer
Yellow-billed loon, Gavia adamsii (A)

text: Albatrosses[edit]

text: Order: Procellariiformes   Family: Diomedeidae

text: The albatrosses are amongst the largest of flying birds, and the great albatrosses from the genus Diomedea have the largest wingspans of any extant birds.

text: Yellow-nosed albatross, Thalassarche chlororhynchos (A)

text: Southern storm-petrels[edit]

text: Order: Procellariiformes   Family: Oceanitidae

text: The storm-petrels are the smallest seabirds, relatives of the petrels, feeding on planktonic crustaceans and small fish picked from the surface, typically while hovering. The flight is fluttering and sometimes bat-like. Until 2018, this family's three species were included with the other storm-petrels in family Hydrobatidae.

text: Wilson's storm-petrel, Oceanites oceanicus (A)

text: Northern storm-petrels[edit]

text: Order: Procellariiformes   Family: Hydrobatidae

text: Though the members of this family are similar in many respects to the southern storm-petrels, including their general appearance and habits, there are enough genetic differences to warrant their placement in a separate family.

text:
Leach's storm-petrel, Oceanodroma leucorhoa (A)
Band-rumped storm-petrel, Oceanodroma castro (A)

text: Shearwaters and petrels[edit]

text: Order: Procellariiformes   Family: Procellariidae

text: The procellariids are the main group of medium-sized "true petrels", characterised by united nostrils with medium septum and a long outer functional primary.

text:
Northern fulmar, Fulmarus glacialis (A)
Black-capped petrel, Pterodroma hasitata (A)
Great shearwater, Ardenna gravis (A)
Short-tailed shearwater/Sooty shearwater, Ardenna tenuirostris/Ardenna griseus (A)
Manx shearwater, Puffinus puffinus (A)
Audubon's shearwater, Puffinus lherminieri (A)

text: Storks[edit]

text: Order: Ciconiiformes   Family: Ciconiidae

text: Storks are large, heavy, long-legged, long-necked wading birds with long stout bills and wide wingspans. They lack the powder down that other wading birds such as herons, spoonbills, and ibises use to clean off fish slime. Storks lack a pharynx and are mute.

text: Wood stork, Mycteria americana (A)

text: Frigatebirds[edit]

text: Order: Suliformes   Family: Fregatidae

text: Frigatebirds are large seabirds usually found over tropical oceans. They are large, black, or black-and-white, with long wings and deeply forked tails. The males have coloured inflatable throat pouches. They do not swim or walk and cannot take off from a flat surface. Having the largest wingspan-to-body-weight ratio of any bird, they are essentially aerial, able to stay aloft for more than a week.

text: Magnificent frigatebird, Fregata magnificens (A)

text: Boobies and gannets[edit]

text: Order: Suliformes   Family: Sulidae

text: The sulids comprise the gannets and boobies. Both groups are medium-large coastal seabirds that plunge-dive for fish.

text:
Brown booby, Sula leucogaster (A)
Northern gannet, Morus bassanus (A)

text: Cormorants[edit]

text: Order: Suliformes   Family: Phalacrocoracidae

text: Cormorants are medium-to-large aquatic birds, usually with mainly dark plumage and areas of coloured skin on the face. The bill is long, thin and sharply hooked. Their feet are four-toed and webbed.

text:
Neotropic cormorant, Phalacrocorax brasilianus (A)
Double-crested cormorant, Phalacrocorax auritus
Great cormorant, Phalacrocorax carbo (A)

text: Anhingas[edit]

text: Order: Suliformes   Family: Anhingidae

text: Anhingas are cormorant-like water birds with very long necks and long, straight beaks. They are fish eaters which often swim with only their neck above the water.

text: Anhinga, Anhinga anhinga (A)

text: Pelicans[edit]

text: Order: Pelecaniformes   Family: Pelecanidae

text: Pelicans are very large water birds with a distinctive pouch under their beak. Like other birds in the order Pelecaniformes, they have four webbed toes.

text:
American white pelican, Pelecanus erythrorhynchos
Brown pelican, Pelecanus occidentalis (A)

text: Bitterns, herons, and egrets[edit]

text: Order: Pelecaniformes   Family: Ardeidae

text: The family Ardeidae contains the bitterns, herons, and egrets. Herons and egrets are medium to large wading birds with long necks and legs. Bitterns tend to be shorter necked and warier. Unlike other long-necked birds such as storks, ibises, and spoonbills, members of this family fly with their necks retracted.

text:
American bittern, Botaurus lentiginosus
Least bittern, Ixobrychus exilis (L) (C)
Great blue heron, Ardea herodias
Great egret, Ardea alba (L) (C)
Little egret, Egretta garzetta (A)
Snowy egret, Egretta thula (L) (C)
Little blue heron, Egretta caerulea (A)
Tricolored heron, Egretta tricolor (A)
Cattle egret, Bubulcus ibis (L) (C)
Green heron, Butorides virescens (L) (C)
Black-crowned night-heron, Nycticorax nycticorax (L) (C)
Yellow-crowned night-heron, Nyctanassa violacea (A)

text: Ibises and spoonbills[edit]

text: Order: Pelecaniformes   Family: Threskiornithidae

text: Threskiornithidae is a family of large terrestrial and wading birds which comprises the ibises and spoonbills. Its members have long, broad wings with 11 primary and about 20 secondary flight feathers. They are strong fliers and, despite their size and weight, very capable soarers.

text:
White ibis, Eudocimus albus (A)
Glossy ibis, Plegadis falcinellus (L) (C)
White-faced ibis, Plegadis chihi (A)
Roseate spoonbill, Ajaia ajaja (A)

text: New World vultures[edit]

text: Order: Cathartiformes   Family: Cathartidae

text: The New World vultures are not closely related to Old World vultures, but superficially resemble them because of convergent evolution. Like the Old World vultures, they are scavengers. However, unlike Old World vultures, which find carcasses by sight, New World vultures have a good sense of smell with which they locate carcasses.

text:
Black vulture, Coragyps atratus (L) (C)
Turkey vulture, Cathartes aura (L)

text: Osprey[edit]

text: Order: Accipitriformes   Family: Pandionidae

text: Pandionidae is a family of fish-eating birds of prey possessing a very large, powerful hooked beak for tearing flesh from their prey, strong legs, powerful talons, and keen eyesight. The family is monotypic.

text: Osprey, Pandion haliaetus

text: Hawks, kites, and eagles[edit]

text: Order: Accipitriformes   Family: Accipitridae

text: The Accipitridae is a family of birds of prey, which includes hawks, eagles, kites, harriers, and Old World vultures. These birds mostly have powerful hooked beaks for tearing flesh from their prey, strong legs, powerful talons, and keen eyesight.

text:
Swallow-tailed kite, Elanoides forficatus (A)
Golden eagle, Aquila chrysaetos
Northern harrier, Circus hudsonius
Sharp-shinned hawk, Accipiter striatus
Cooper's hawk, Accipiter cooperii (L)
Northern goshawk, Accipiter gentilis
Bald eagle, Haliaeetus leucocephalus
Mississippi kite, Ictinia mississippiensis (A)
Red-shouldered hawk, Buteo lineatus (L)
Broad-winged hawk, Buteo platypterus
Swainson's hawk, Buteo swainsoni (A)
Red-tailed hawk, Buteo jamaicensis
Rough-legged hawk, Buteo lagopus
Ferruginous hawk, Buteo regalis (A)

text: Barn-owls[edit]

text: Order: Strigiformes   Family: Tytonidae

text: Barn-owls are medium to large owls with large heads and characteristic heart-shaped faces. They have long strong legs with powerful talons.

text: Barn owl, Tyto alba

text: Typical owls[edit]

text: Order: Strigiformes   Family: Strigidae

text: The typical owls are small to large solitary nocturnal birds of prey. They have large forward-facing eyes and ears, a hawk-like beak, and a conspicuous circle of feathers around each eye called a facial disk.

text:
Eastern screech-owl, Megascops asio (L) (C)
Great horned owl, Bubo virginianus
Snowy owl, Bubo scandiacus
Northern hawk owl, Surnia ulula
Burrowing owl, Athene cunicularia (A)
Barred owl, Strix varia (L)
Great gray owl, Strix nebulosa
Long-eared owl, Asio otus
Short-eared owl, Asio flammeus
Boreal owl, Aegolius funereus
Northern saw-whet owl, Aegolius acadicus

text: Kingfishers[edit]

text: Order: Coraciiformes   Family: Alcedinidae

text: Kingfishers are medium-sized birds with large heads, long pointed bills, short legs, and stubby tails.

text: Belted kingfisher, Megaceryle alcyon

text: Woodpeckers[edit]

text: Order: Piciformes   Family: Picidae

text: Woodpeckers, sapsuckers, and flickers are small to medium-sized birds with chisel-like beaks, short legs, stiff tails and long tongues used for capturing insects. Some species have feet with two toes pointing forward and two backward, while several species have only three toes. Many woodpeckers have the habit of tapping noisily on tree trunks with their beaks.

text:
Lewis's woodpecker, Melanerpes lewis (A)
Red-headed woodpecker, Melanerpes erythrocephalus (L)
Red-bellied woodpecker, Melanerpes carolinus (L)
Yellow-bellied sapsucker, Sphyrapicus varius
American three-toed woodpecker, Picoides dorsalis
Black-backed woodpecker, Picoides arcticus
Downy woodpecker, Dryobates pubescens
Hairy woodpecker, Dryobates villosus
Northern flicker, Colaptes auratus
Pileated woodpecker, Dryocopus pileatus

text: Caracaras and falcons[edit]

text: Order: Falconiformes   Family: Falconidae

text: Falconidae is a family of diurnal birds of prey, notably the falcons and caracaras. They differ from hawks, eagles, and kites in that they kill with their beaks instead of their talons.

text:
Crested caracara, Caracara cheriway (A)
American kestrel, Falco sparverius
Merlin, Falco columbarius
Gyrfalcon, Falco rusticolus
Peregrine falcon, Falco peregrinus
Prairie falcon, Falco mexicanus (A)

text: Tyrant flycatchers[edit]

text: Order: Passeriformes   Family: Tyrannidae

text: Tyrant flycatchers are Passerine birds which occur throughout North and South America. They superficially resemble the Old World flycatchers, but are more robust and have stronger bills. They do not have the sophisticated vocal capabilities of the songbirds. Most are rather plain. As the name implies, most are insectivorous.

text:
Ash-throated flycatcher, Myiarchus cinerascens (A)
Great crested flycatcher, Myiarchus crinitus (L)
Sulphur-bellied flycatcher, Myiodynastes luteiventris (A)
Variegated flycatcher, Empidonomus varius (A)
Tropical kingbird, Tyrannus melancholicus (A)
Cassin's kingbird, Tyrannus vociferans (A)
Thick-billed kingbird, Tyrannus crassirostris (A)
Western kingbird, Tyrannus verticalis (L) (S)
Eastern kingbird, Tyrannus tyrannus
Gray kingbird, Tyrannus dominicensis (A)
Scissor-tailed flycatcher, Tyrannus forficatus (A)
Fork-tailed flycatcher, Tyrannus savana (A)
Olive-sided flycatcher, Contopus cooperi
Western wood-pewee, Contopus sordidulus (A)
Eastern wood-pewee, Contopus virens (L)
Yellow-bellied flycatcher, Empidonax flaviventris
Acadian flycatcher, Empidonax virescens (L) (C)
Alder flycatcher, Empidonax alnorum
Willow flycatcher, Empidonax traillii (L) (C)
Least flycatcher, Empidonax minimus
Gray flycatcher, Empidonax wrightii (A)
Dusky flycatcher, Empidonax oberholseri (A)
Eastern phoebe, Sayornis phoebe
Say's phoebe, Sayornis saya (A)
Vermilion flycatcher, Pyrocephalus rubinus (A)

text: Shrikes[edit]

text: Order: Passeriformes   Family: Laniidae

text: Shrikes are passerine birds known for the habit of catching other birds and small animals and impaling the uneaten portions of their bodies on thorns. A shrike's beak is hooked, like that of a typical bird of prey.

text:
Loggerhead shrike, Lanius ludovicianus (L) (C)
Northern shrike, Lanius borealis

text: Vireos[edit]

text: Order: Passeriformes   Family: Vireonidae

text: The vireos are a group of small to medium-sized passerine birds restricted to the New World. They are typically greenish in colour and resemble wood warblers apart from their heavier bills.

text:
Black-capped vireo, Vireo atricapilla (A)
White-eyed vireo, Vireo griseus (L) (C)
Bell's vireo, Vireo bellii (A)
Yellow-throated vireo, Vireo flavifrons (L)
Blue-headed vireo, Vireo solitarius
Plumbeous vireo, Vireo plumbeus (A)
Philadelphia vireo, Vireo philadelphicus
Warbling vireo, Vireo gilvus
Red-eyed vireo, Vireo olivaceus

text: Jays, crows, magpies, and ravens[edit]

text: Order: Passeriformes   Family: Corvidae

text: The family Corvidae includes crows, ravens, jays, choughs, magpies, treepies, nutcrackers, and ground jays. Corvids are above average in size among the Passeriformes, and some of the larger species show high levels of intelligence.

text:
Canada jay, Perisoreus canadensis
Blue jay, Cyanocitta cristata
Clark's nutcracker, Nucifraga columbiana (A)
Black-billed magpie, Pica hudsonia (L) (S)
Eurasian jackdaw, Corvus monedula (A)
American crow, Corvus brachyrhynchos
Fish crow, Corvus ossifragus (L) (C)
Common raven, Corvus corax

text: Larks[edit]

text: Order: Passeriformes   Family: Alaudidae

text: Larks are small terrestrial birds with often extravagant songs and display flights. Most larks are fairly dull in appearance. Their food is insects and seeds.

text: Horned lark, Eremophila alpestris

text: Swallows and martins[edit]

text: Order: Passeriformes   Family: Hirundinidae

text: The family Hirundinidae is a group of passerines characterised by their adaptation to aerial feeding. The family includes swallows and martins. These adaptations include a slender streamlined body, long pointed wings, and short bills with a wide gape. The feet are adapted to perching rather than walking, and the front toes are partially joined at the base.

text:
Purple martin, Progne subis (L)
Tree swallow, Tachycineta bicolor
Violet-green swallow, Tachycineta thalassina (A)
Northern rough-winged swallow, Stelgidopteryx serripennis (L)
Bank swallow, Riparia riparia
Cliff swallow, Petrochelidon pyrrhonota
Cave swallow, Petrochelidon fulva (A)
Barn swallow, Hirundo rustica

text: Chickadees and titmice[edit]

text: Order: Passeriformes   Family: Paridae

text: Chickadees and titmice are mainly small stocky woodland species with short stout bills. Some have crests. They are adaptable birds, with a mixed diet including seeds and insects.

text:
Carolina chickadee, Poecile carolinensis (A)
Black-capped chickadee, Poecile atricapilla
Boreal chickadee, Poecile hudsonica
Tufted titmouse, Baeolophus bicolor (L) (C)

text: Nuthatches[edit]

text: Order: Passeriformes   Family: Sittidae

text: Nuthatches are small woodland birds. They have the unusual ability to climb down trees head first, unlike other birds which can only go upwards. Nuthatches have big heads, short tails, and powerful bills and feet.

text:
Red-breasted nuthatch, Sitta canadensis
White-breasted nuthatch, Sitta carolinensis (L)

text: Treecreepers[edit]

text: Order: Passeriformes   Family: Certhiidae

text: Treecreepers are small woodland birds, brown above and white below. They have thin pointed down-curved bills, which they use to extricate insects from bark. They have stiff tail feathers, like woodpeckers, which they use to support themselves on vertical trees.

text: Brown creeper, Certhia americana

text: Wrens[edit]

text: Order: Passeriformes   Family: Troglodytidae

text: Wrens are small and inconspicuous birds, except for their loud songs. They have short wings and thin down-turned bills. Several species often hold their tails upright. All are insectivorous.

text:
Rock wren, Salpinctes obsoletus (A)
House wren, Troglodytes aedon (L)
Winter wren, Troglodytes hiemalis
Sedge wren, Cistothorus platensis
Marsh wren, Cistothorus palustris
Carolina wren, Thryothorus ludovicianus (L) (C)
Bewick's wren, Thryomanes bewickii (A)

text: Gnatcatchers[edit]

text: Order: Passeriformes   Family: Polioptilidae

text: Gnatcatchers are a group of small insectivorous passerine birds. Most are of generally undistinguished appearance, but many have distinctive songs.

text: Blue-gray gnatcatcher, Polioptila caerulea (L) (C)

text: Kinglets[edit]

text: Order: Passeriformes   Family: Regulidae

text: The kinglets are a small family of birds which resemble the titmice. They are very small insectivorous birds in the genus Regulus. The adults have coloured crowns, giving rise to their name.

text:
Golden-crowned kinglet, Regulus satrapa
Ruby-crowned kinglet, Regulus calendula

text: Old World flycatchers[edit]

text: Order: Passeriformes   Family: Muscicapidae

text: The Old World flycatchers are a large family of small passerine birds. These are mainly small arboreal insectivores, many of which, as the name implies, take their prey on the wing.

text:
Siberian rubythroat, Calliope calliope (A)
Northern wheatear, Oenanthe oenanthe (A)

text: Thrushes[edit]

text: Order: Passeriformes   Family: Turdidae

text: The thrushes are a group of passerine birds that occur mainly in the Old World. They are plump, soft plumaged, small to medium-sized insectivores or sometimes omnivores, often feeding on the ground. Many have attractive songs.

text:
Eastern bluebird, Sialia sialis
Mountain bluebird, Sialia currucoides (A)
Townsend's solitaire, Myadestes townsendi (L)
Veery, Catharus fuscescens (L)
Gray-cheeked thrush, Catharus minimus
Bicknell's thrush, Catharus bicknelli (A)
Swainson's thrush, Catharus ustulatus
Hermit thrush, Catharus guttatus
Wood thrush, Hylocichla mustelina (L)
Eurasian blackbird, Turdus merula (A)
Fieldfare, Turdus pilaris (A)
American robin, Turdus migratorius
Varied thrush, Ixoreus naevius (L)

text: Mockingbirds and thrashers[edit]

text: Order: Passeriformes   Family: Mimidae

text: The mimids are a family of passerine birds that includes thrashers, mockingbirds, tremblers, and the New World catbirds. These birds are notable for their vocalization, especially their remarkable ability to mimic a wide variety of birds and other sounds heard outdoors. The species tend towards dull greys and browns in their appearance.

text:
Gray catbird, Dumetella carolinensis
Brown thrasher, Toxostoma rufum
Sage thrasher, Oreoscoptes montanus (A)
Northern mockingbird, Mimus polyglottos (L)

text: Starlings[edit]

text: Order: Passeriformes   Family: Sturnidae

text: Starlings are small to medium-sized passerine birds. Their flight is strong and direct and they are very gregarious. Their preferred habitat is fairly open country. They eat insects and fruit. Plumage is typically dark with a metallic sheen.

text: European starling, Sturnus vulgaris (I)

text: Waxwings[edit]

text: Order: Passeriformes   Family: Bombycillidae

text: The waxwings are a group of birds with soft silky plumage and unique red tips to some of the wing feathers. In the Bohemian and cedar waxwings, these tips look like sealing wax and give the group its name. These are arboreal birds of northern forests.

text:
Bohemian waxwing, Bombycilla garrulus
Cedar waxwing, Bombycilla cedrorum

text: Silky-flycatchers[edit]

text: Order: Passeriformes   Family: Ptiliogonatidae

text: The silky-flycatchers are a small family of passerine birds which occur mainly in Central America. They are related to waxwings and most species have small crests.

text: Phainopepla, Phainopepla nitens (A)

text: Old World sparrows[edit]

text: Order: Passeriformes   Family: Passeridae

text: Old World sparrows are small passerine birds. In general, sparrows tend to be small plump brownish or greyish birds with short tails and short powerful beaks. Sparrows are seed-eaters, but they also consume small insects.

text:
House sparrow, Passer domesticus (I) (L)
Eurasian tree sparrow, Passer montanus (I) (A)

text: Wagtails and pipits[edit]

text: Order: Passeriformes   Family: Motacillidae

text: Motacillidae is a family of small passerine birds with medium to long tails. They include the wagtails, longclaws, and pipits. They are slender ground-feeding insectivores of open country.

text:
American pipit, Anthus rubescens
Sprague's pipit, Anthus spragueii (A)

text: Finches[edit]

text: Order: Passeriformes   Family: Fringillidae

text: Finches are small to moderately large seed-eating passerine birds with a strong beak, usually conical and in some species very large. All have 12 tail feathers and nine primaries flight feathers. Finches have a bouncing flight, alternating bouts of flapping with gliding on closed wings, and most sing well.

text:
Brambling, Fringilla montifringilla (A)
Evening grosbeak, Coccothraustes vespertinus
Pine grosbeak, Pinicola enucleator
Gray-crowned rosy-finch, Leucosticte tephrocotis (A)
House finch, Haemorhous mexicanus (native to the southwestern U.S; introduced in the east) (L)
Purple finch, Haemorhous purpureus
Cassin's finch, Haemorhous cassinii (A)
Common redpoll, Acanthis flammea
Hoary redpoll, Acanthis hornemanni
Red crossbill, Loxia curvirostra
White-winged crossbill, Loxia leucoptera
Pine siskin, Spinus pinus
Lesser goldfinch, Spinus psaltria (A)
American goldfinch, Spinus tristis

text: Longspurs and snow buntings[edit]

text: Order: Passeriformes   Family: Calcariidae

text: The Calcariidae are a group of passerine birds that were traditionally grouped with the New World sparrows, but differ in a number of respects and are usually found in open grassy areas.

text:
Lapland longspur, Calcarius lapponicus
Chestnut-collared longspur, Calcarius ornatus (A)
Smith's longspur, Calcarius pictus (C) (S)
McCown's longspur, Calcarius mccownii (A)
Snow bunting, Plectrophenax nivalis

text: New World sparrows[edit]

text: Order: Passeriformes   Family: Passerellidae

text: Until 2017, these species were considered part of the family Emberizidae. Most of the species are known as sparrows, but these birds are not closely related to the Old World sparrows which are in the family Passeridae. Many of these have distinctive head patterns.

text:
Green-tailed towhee, Pipilo chlorurus (A)
Spotted towhee, Pipilo maculatus (A)
Eastern towhee, Pipilo erythrophthalmus (L)
Cassin's sparrow, Peucaea cassinii (A)
Bachman's sparrow, Peucaea aestivalis (A)
American tree sparrow, Spizelloides arborea
Chipping sparrow, Spizella passerina
Clay-colored sparrow, Spizella pallida
Brewer's sparrow, Spizella breweri (A)
Field sparrow, Spizella pusilla (L) (C)
Vesper sparrow, Pooecetes gramineus (L)
Lark sparrow, Chondestes grammacus (L)
Black-throated sparrow, Amphispiza bilineata (A)
Lark bunting, Calamospiza melanocorys (A)
Savannah sparrow, Passerculus sandwichensis
Grasshopper sparrow, Ammodramus savannarum (L) (C)
Baird's sparrow, Centronyx bairdii (A)
Henslow's sparrow, Centronyx henslowii (L) (C)
LeConte's sparrow, Ammospiza leconteii
Nelson's sparrow, Ammospiza nelsoni
Fox sparrow, Passerella iliaca
Song sparrow, Melospiza melodia
Lincoln's sparrow, Melospiza lincolnii
Swamp sparrow, Melospiza georgiana
White-throated sparrow, Zonotrichia albicollis
Harris's sparrow, Zonotrichia querula
White-crowned sparrow, Zonotrichia leucophrys
Golden-crowned sparrow, Zonotrichia atricapilla (A)
Dark-eyed junco, Junco hyemalis

text: Yellow-breasted chat[edit]

text: Order: Passeriformes   Family: Icteriidae

text: This species was historically placed in the wood-warblers (Parulidae) but nonetheless most authorities were unsure if it belonged there. It was placed in its own family in 2017.

text: Yellow-breasted chat, Icteria virens (L) (C)

text: Icterids[edit]

text: Order: Passeriformes   Family: Icteridae

text: The icterids are a group of small to medium-sized, often colourful passerine birds restricted to the New World and include the blackbirds, meadowlarks, cowbirds, grackles, and New World orioles. Most species have black as a predominant plumage colour, often enlivened by yellow, orange, or red.

text:
Yellow-headed blackbird, Xanthocephalus xanthocephalus (L)
Bobolink, Dolichonyx oryzivorus
Eastern meadowlark, Sturnella magna (L)
Western meadowlark, Sturnella neglecta (L)
Orchard oriole, Icterus spurius (L) (C)
Hooded oriole, Icterus cucullatus (A)
Bullock's oriole, Icterus bullockii (A)
Baltimore oriole, Icterus galbula (L)
Scott's oriole, Icterus parisorum (A)
Red-winged blackbird, Agelaius phoeniceus
Brown-headed cowbird, Molothrus ater
Rusty blackbird, Euphagus carolinus
Brewer's blackbird, Euphagus cyanocephalus (L)
Common grackle, Quiscalus quiscula
Great-tailed grackle, Quiscalus mexicanus (A)

text: Wood-warblers[edit]

text: Order: Passeriformes   Family: Parulidae

text: The wood-warblers are a group of small often colourful passerine birds restricted to the New World. Most are arboreal, but some are more terrestrial. Most members of this family are insectivores.

text:
Ovenbird, Seiurus aurocapilla (L)
Worm-eating warbler, Helmitheros vermivorum (L) (C)
Louisiana waterthrush, Parkesia motacilla (L) (C)
Northern waterthrush, Parkesia noveboracensis
Golden-winged warbler, Vermivora chrysoptera (L)
Blue-winged warbler, Vermivora cyanoptera (L) (C)
Black-and-white warbler, Mniotilta varia
Prothonotary warbler, Protonotaria citrea (L) (C)
Swainson's warbler, Limnothlypis swainsonii (A)
Tennessee warbler, Oreothlypis peregrina
Orange-crowned warbler, Oreothlypis celata
Nashville warbler, Oreothlypis ruficapilla
Virginia's warbler, Oreothlypis virginiae (A)
Connecticut warbler, Oporornis agilis
Mourning warbler, Geothlypis philadelphia
Kentucky warbler, Geothlypis formosa (L) (C)
Common yellowthroat, Geothlypis trichas
Hooded warbler, Setophaga citrina (L) (C)
American redstart, Setophaga ruticilla
Kirtland's warbler, Setophaga kirtlandii (L) (C)
Cape May warbler, Setophaga tigrina
Cerulean warbler, Setophaga cerulea (L) (C)
Northern parula, Setophaga americana
Magnolia warbler, Setophaga magnolia
Bay-breasted warbler, Setophaga castanea
Blackburnian warbler, Setophaga fusca
Yellow warbler, Setophaga petechia
Chestnut-sided warbler, Setophaga pensylvanica
Blackpoll warbler, Setophaga striata
Black-throated blue warbler, Setophaga caerulescens (L)
Palm warbler, Setophaga palmarum
Pine warbler, Setophaga pinus (L)
Yellow-rumped warbler, Setophaga coronata
Yellow-throated warbler, Setophaga dominica (L) (C)
Prairie warbler, Setophaga discolor (L) (C)
Grace's warbler, Setophaga graciae (A)
Black-throated gray warbler, Setophaga nigrescens (A)
Townsend's warbler, Setophaga townsendi (A)
Hermit warbler, Setophaga occidentalis (A)
Black-throated green warbler, Setophaga virens
Canada warbler, Cardellina canadensis
Wilson's warbler, Cardellina pusilla
Painted redstart, Myioborus pictus (A)

text: Cardinals and allies[edit]

text: Order: Passeriformes   Family: Cardinalidae

text: Cardinals are a family of robust, seed-eating birds with strong bills. They are typically associated with open woodland. The sexes usually have distinct plumages.

text:
Summer tanager, Piranga rubra (L) (C)
Scarlet tanager, Piranga olivacea (L)
Western tanager, Piranga ludoviciana (A)
Northern cardinal, Cardinalis cardinalis
Pyrrhuloxia, Cardinalis sinuatus (A)
Rose-breasted grosbeak, Pheucticus ludovicianus
Black-headed grosbeak, Pheucticus melanocephalus (A)
Blue grosbeak, Passerina caerulea (A)
Lazuli bunting, Passerina amoena (A)
Indigo bunting, Passerina cyanea (L)
Varied bunting, Passerina versicolor (A)
Painted bunting, Passerina ciris (A)
Dickcissel, Spiza americana (L) (C)


document_title: Cnidaria

question_text: how do you know something is a cnidarian

root

text: Cnidaria

text: Distinguishing features[edit]

text: Cnidarians form an animal phylum that are more complex than sponges, about as complex as ctenophores (comb jellies), and less complex than bilaterians, which include almost all other animals. However, both cnidarians and ctenophores are more complex than sponges as they have: cells bound by inter-cell connections and carpet-like basement membranes; muscles; nervous systems; and some have sensory organs. Cnidarians are distinguished from all other animals by having cnidocytes that fire like harpoons and are used mainly to capture prey. In some species, cnidocytes can also be used as anchors.[9]

tag: p

text: Like sponges and ctenophores, cnidarians have two main layers of cells that sandwich a middle layer of jelly-like material, which is called the mesoglea in cnidarians; more complex animals have three main cell layers and no intermediate jelly-like layer. Hence, cnidarians and ctenophores have traditionally been labelled diploblastic, along with sponges.[9][10] However, both cnidarians and ctenophores have a type of muscle that, in more complex animals, arises from the middle cell layer.[11] As a result, some recent text books classify ctenophores as triploblastic,[12] and it has been suggested that cnidarians evolved from triploblastic ancestors.[11]

text:
Sponges[13][14]
Cnidarians[9][10]
Ctenophores[9][12]
Bilateria[9]

Cnidocytes
No
Yes
No

Colloblasts
No
Yes
No

Digestive and circulatory organs
No
Yes

Number of main cell layers
Two, with jelly-like layer between them
Two[9] or Three[11][12]
Three

Cells in each layer bound together
cell-adhesion molecules, but no basement membranes except Homoscleromorpha.[15]
inter-cell connections; basement membranes

Sensory organs
No
Yes

Number of cells in middle "jelly" layer
Many
Few
(Not applicable)

Cells in outer layers can move inwards and change functions
Yes
No
(Not applicable)

Nervous system
No
Yes, simple
Simple to complex

Muscles
None
Mostly epitheliomuscular
Mostly myoepithelial
Mostly myocytes

tag: table

text: Description[edit]

text: Basic body forms[edit]

text: Most adult cnidarians appear as either swimming medusae or sessile polyps, and many hydrozoan species are known to alternate between the two forms. Both are radially symmetrical, like a wheel and a tube respectively. Since these animals have no heads, their ends are described as "oral" (nearest the mouth) and "aboral" (furthest from the mouth). Most have fringes of tentacles equipped with cnidocytes around their edges, and medusae generally have an inner ring of tentacles around the mouth. Some hydroids may consist of colonies of zooids that serve different purposes, such as defense, reproduction and catching prey. The mesoglea of polyps is usually thin and often soft, but that of medusae is usually thick and springy, so that it returns to its original shape after muscles around the edge have contracted to squeeze water out, enabling medusae to swim by a sort of jet propulsion.[10]

text: Skeletons[edit]

text: In medusae the only supporting structure is the mesoglea. Hydra and most sea anemones close their mouths when they are not feeding, and the water in the digestive cavity then acts as a hydrostatic skeleton, rather like a water-filled balloon. Other polyps such as Tubularia use columns of water-filled cells for support. Sea pens stiffen the mesoglea with calcium carbonate spicules and tough fibrous proteins, rather like sponges.[10]

text: In some colonial polyps, a chitinous periderm gives support and some protection to the connecting sections and to the lower parts of individual polyps. Stony corals secrete massive calcium carbonate exoskeletons. A few polyps collect materials such as sand grains and shell fragments, which they attach to their outsides. Some colonial sea anemones stiffen the mesoglea with sediment particles.[10]

text: Main cell layers[edit]

text: Cnidaria are diploblastic animals; in other words, they have two main cell layers, while more complex animals are triploblasts having three main layers. The two main cell layers of cnidarians form epithelia that are mostly one cell thick, and are attached to a fibrous basement membrane, which they secrete. They also secrete the jelly-like mesoglea that separates the layers. The layer that faces outwards, known as the ectoderm ("outside skin"), generally contains the following types of cells:[9]

text:
Epitheliomuscular cells whose bodies form part of the epithelium but whose bases extend to form muscle fibers in parallel rows.[16] The fibers of the outward-facing cell layer generally run at right angles to the fibers of the inward-facing one. In Anthozoa (anemones, corals, etc.) and Scyphozoa (jellyfish), the mesoglea also contains some muscle cells.[10]
Cnidocytes, the harpoon-like "nettle cells" that give the phylum Cnidaria its name. These appear between or sometimes on top of the muscle cells.[9]
Nerve cells. Sensory cells appear between or sometimes on top of the muscle cells,[9] and communicate via synapses (gaps across which chemical signals flow) with motor nerve cells, which lie mostly between the bases of the muscle cells.[10]
Interstitial cells, which are unspecialized and can replace lost or damaged cells by transforming into the appropriate types. These are found between the bases of muscle cells.[9]

tag: ul

text: In addition to epitheliomuscular, nerve and interstitial cells, the inward-facing gastroderm ("stomach skin") contains gland cells that secrete digestive enzymes. In some species it also contains low concentrations of cnidocytes, which are used to subdue prey that is still struggling.[9][10]

text: The mesoglea contains small numbers of amoeba-like cells,[10] and muscle cells in some species.[9] However, the number of middle-layer cells and types are much lower than in sponges.[10]

text: Polymorphism[edit]

text: Polymorphism refers to the occurrence of structurally and functionally more than two different types of individuals within the same organism. It is a characteristic feature of Cnidarians, particularly the polyp and medusa forms, or of zooids within colonial organisms like those in Hydrozoa.[17] In Hydrozoans, colonial individuals arising from individuals zooids will take on separate tasks.[18] For example, in Obelia there are feeding individuals, the gastrozooids; the individuals capable of asexual reproduction only, the gonozooids, blastostyles and free-living or sexually reproducing individuals, the medusae.

text: Cnidocytes[edit]

text: These "nettle cells" function as harpoons, since their payloads remain connected to the bodies of the cells by threads. Three types of cnidocytes are known:[9][10]

text:
Nematocysts inject venom into prey, and usually have barbs to keep them embedded in the victims. Most species have nematocysts.[9]
Spirocysts do not penetrate the victim or inject venom, but entangle it by means of small sticky hairs on the thread.
Ptychocysts are not used for prey capture — instead the threads of discharged ptychocysts are used for building protective tubes in which their owners live. Ptychocysts are found only in the order Ceriantharia, tube anemones.[10]

text: The main components of a cnidocyte are:[9][10]

text:
A cilium (fine hair) which projects above the surface and acts as a trigger. Spirocysts do not have cilia.
A tough capsule, the cnida, which houses the thread, its payload and a mixture of chemicals that may include venom or adhesives or both. ("cnida" is derived from the Greek word κνίδη, which means "nettle"[19])
A tube-like extension of the wall of the cnida that points into the cnida, like the finger of a rubber glove pushed inwards. When a cnidocyte fires, the finger pops out. If the cell is a venomous nematocyte, the "finger"'s tip reveals a set of barbs that anchor it in the prey.
The thread, which is an extension of the "finger" and coils round it until the cnidocyte fires. The thread is usually hollow and delivers chemicals from the cnida to the target.
An operculum (lid) over the end of the cnida. The lid may be a single hinged flap or three flaps arranged like slices of pie.
The cell body, which produces all the other parts.

text: It is difficult to study the firing mechanisms of cnidocytes as these structures are small but very complex. At least four hypotheses have been proposed:[9]

text:
Rapid contraction of fibers round the cnida may increase its internal pressure.
The thread may be like a coiled spring that extends rapidly when released.
In the case of Chironex (the "sea wasp"), chemical changes in the cnida's contents may cause them to expand rapidly by polymerization.
Chemical changes in the liquid in the cnida make it a much more concentrated solution, so that osmotic pressure forces water in very rapidly to dilute it. This mechanism has been observed in nematocysts of the class Hydrozoa, sometimes producing pressures as high as 140 atmospheres, similar to that of scuba air tanks, and fully extending the thread in as little as 2 milliseconds (0.002 second).[10]

text: Cnidocytes can only fire once, and about 25% of a hydra's nematocysts are lost from its tentacles when capturing a brine shrimp. Used cnidocytes have to be replaced, which takes about 48 hours. To minimise wasteful firing, two types of stimulus are generally required to trigger cnidocytes: nearby sensory cells detect chemicals in the water, and their cilia respond to contact. This combination prevents them from firing at distant or non-living objects. Groups of cnidocytes are usually connected by nerves and, if one fires, the rest of the group requires a weaker minimum stimulus than the cells that fire first.[9][10]

text: Locomotion[edit]

text: Medusae swim by a form of jet propulsion: muscles, especially inside the rim of the bell, squeeze water out of the cavity inside the bell, and the springiness of the mesoglea powers the recovery stroke. Since the tissue layers are very thin, they provide too little power to swim against currents and just enough to control movement within currents.[10]

text: Hydras and some sea anemones can move slowly over rocks and sea or stream beds by various means: creeping like snails, crawling like inchworms, or by somersaulting. A few can swim clumsily by waggling their bases.[10]

text: Nervous system and senses[edit]

text: Cnidarians are generally thought to have no brains or even central nervous systems. However, they do have integrative areas of neural tissue that could be considered some form of centralization. Most of their bodies are innervated by decentralized nerve nets that control their swimming musculature and connect with sensory structures, though each clade has slightly different structures.[20] These sensory structures, usually called rhopalia, can generate signals in response to various types of stimuli such as light, pressure, and much more. Medusa usually have several of them around the margin of the bell that work together to control the motor nerve net, that directly innervates the swimming muscles. Most Cnidarians also have a parallel system. In scyphozoans, this takes the form of a diffuse nerve net, which has modulatory effects on the nervous system.[21] As well as forming the "signal cables" between sensory neurons and motoneurons, intermediate neurons in the nerve net can also form ganglia that act as local coordination centers. Communication between nerve cells can occur by chemical synapses or gap junctions in hydrozoans, though gap junctions are not present in all groups. Cnidarians have many of the same neurotransmitters as many animals, including chemicals such as glutamate, GABA, and acetylcholine.[22]

text: This structure ensures that the musculature is excited rapidly and simultaneously, and can be directly stimulated from any point on the body, and it also is better able to recover after injury.[20][21]

text: Medusae and complex swimming colonies such as siphonophores and chondrophores sense tilt and acceleration by means of statocysts, chambers lined with hairs which detect the movements of internal mineral grains called statoliths. If the body tilts in the wrong direction, the animal rights itself by increasing the strength of the swimming movements on the side that is too low. Most species have ocelli ("simple eyes"), which can detect sources of light. However, the agile box jellyfish are unique among Medusae because they possess four kinds of true eyes that have retinas, corneas and lenses.[23] Although the eyes probably do not form images, Cubozoa can clearly distinguish the direction from which light is coming as well as negotiate around solid-colored objects.[9][23]

text: Feeding and excretion[edit]

text: Cnidarians feed in several ways: predation, absorbing dissolved organic chemicals, filtering food particles out of the water, obtaining nutrients from symbiotic algae within their cells, and parasitism. Most obtain the majority of their food from predation but some, including the corals Hetroxenia and Leptogorgia, depend almost completely on their endosymbionts and on absorbing dissolved nutrients.[9] Cnidaria give their symbiotic algae carbon dioxide, some nutrients, a place in the sun and protection against predators.[10]

text: Predatory species use their cnidocytes to poison or entangle prey, and those with venomous nematocysts may start digestion by injecting digestive enzymes. The "smell" of fluids from wounded prey makes the tentacles fold inwards and wipe the prey off into the mouth. In medusae the tentacles round the edge of the bell are often short and most of the prey capture is done by "oral arms", which are extensions of the edge of the mouth and are often frilled and sometimes branched to increase their surface area. Medusae often trap prey or suspended food particles by swimming upwards, spreading their tentacles and oral arms and then sinking. In species for which suspended food particles are important, the tentacles and oral arms often have rows of cilia whose beating creates currents that flow towards the mouth, and some produce nets of mucus to trap particles.[9] Their digestion is both intra and extracellular.

text: Once the food is in the digestive cavity, gland cells in the gastroderm release enzymes that reduce the prey to slurry, usually within a few hours. This circulates through the digestive cavity and, in colonial cnidarians, through the connecting tunnels, so that gastroderm cells can absorb the nutrients. Absorption may take a few hours, and digestion within the cells may take a few days. The circulation of nutrients is driven by water currents produced by cilia in the gastroderm or by muscular movements or both, so that nutrients reach all parts of the digestive cavity.[10] Nutrients reach the outer cell layer by diffusion or, for animals or zooids such as medusae which have thick mesogleas, are transported by mobile cells in the mesoglea.[9]

text: Indigestible remains of prey are expelled through the mouth. The main waste product of cells' internal processes is ammonia, which is removed by the external and internal water currents.[10]

text: Respiration[edit]

text: There are no respiratory organs, and both cell layers absorb oxygen from and expel carbon dioxide into the surrounding water. When the water in the digestive cavity becomes stale it must be replaced, and nutrients that have not been absorbed will be expelled with it. Some Anthozoa have ciliated grooves on their tentacles, allowing them to pump water out of and into the digestive cavity without opening the mouth. This improves respiration after feeding and allows these animals, which use the cavity as a hydrostatic skeleton, to control the water pressure in the cavity without expelling undigested food.[9]

text: Cnidaria that carry photosynthetic symbionts may have the opposite problem, an excess of oxygen, which may prove toxic. The animals produce large quantities of antioxidants to neutralize the excess oxygen.[9]

text: Regeneration[edit]

text: All cnidarians can regenerate, allowing them to recover from injury and to reproduce asexually. Medusae have limited ability to regenerate, but polyps can do so from small pieces or even collections of separated cells. This enables corals to recover even after apparently being destroyed by predators.[9]

text: Reproduction[edit]

text: Sexual[edit]

text: Cnidarian sexual reproduction often involves a complex life cycle with both polyp and medusa stages. For example, in Scyphozoa (jellyfish) and Cubozoa (box jellies) a larva swims until it finds a good site, and then becomes a polyp. This grows normally but then absorbs its tentacles and splits horizontally into a series of disks that become juvenile medusae, a process called strobilation. The juveniles swim off and slowly grow to maturity, while the polyp re-grows and may continue strobilating periodically. The adults have gonads in the gastroderm, and these release ova and sperm into the water in the breeding season.[9][10]

text: This phenomenon of succession of differently organized generations (one asexually reproducing, sessile polyp, followed by a free-swimming medusa or a sessile polyp that reproduces sexually)[24] is sometimes called "alternation of asexual and sexual phases" or "metagenesis", but should not be confused with the alternation of generations as found in plants.

text: Shortened forms of this life cycle are common, for example some oceanic scyphozoans omit the polyp stage completely, and cubozoan polyps produce only one medusa. Hydrozoa have a variety of life cycles. Some have no polyp stages and some (e.g. hydra) have no medusae. In some species, the medusae remain attached to the polyp and are responsible for sexual reproduction; in extreme cases these reproductive zooids may not look much like medusae. Meanwhile, life cycle reversal, in which polyps are formed directly from medusae without the involvement of sexual reproduction process, was observed in both Hydrozoa (Turritopsis dohrnii[25] and Laodicea undulata[26]) and Scyphozoa (Aurelia sp.1[27]). Anthozoa have no medusa stage at all and the polyps are responsible for sexual reproduction.[9]

text: Spawning is generally driven by environmental factors such as changes in the water temperature, and their release is triggered by lighting conditions such as sunrise, sunset or the phase of the moon. Many species of Cnidaria may spawn simultaneously in the same location, so that there are too many ova and sperm for predators to eat more than a tiny percentage — one famous example is the Great Barrier Reef, where at least 110 corals and a few non-cnidarian invertebrates produce enough gametes to turn the water cloudy. These mass spawnings may produce hybrids, some of which can settle and form polyps, but it is not known how long these can survive. In some species the ova release chemicals that attract sperm of the same species.[9]

text: The fertilized eggs develop into larvae by dividing until there are enough cells to form a hollow sphere (blastula) and then a depression forms at one end (gastrulation) and eventually becomes the digestive cavity. However, in cnidarians the depression forms at the end further from the yolk (at the animal pole), while in bilaterians it forms at the other end (vegetal pole).[10] The larvae, called planulae, swim or crawl by means of cilia.[9] They are cigar-shaped but slightly broader at the "front" end, which is the aboral, vegetal-pole end and eventually attaches to a substrate if the species has a polyp stage.[10]

text: Anthozoan larvae either have large yolks or are capable of feeding on plankton, and some already have endosymbiotic algae that help to feed them. Since the parents are immobile, these feeding capabilities extend the larvae's range and avoid overcrowding of sites. Scyphozoan and hydrozoan larvae have little yolk and most lack endosymbiotic algae, and therefore have to settle quickly and metamorphose into polyps. Instead, these species rely on their medusae to extend their ranges.[10]

text: Asexual[edit]

text: All known cnidaria can reproduce asexually by various means, in addition to regenerating after being fragmented. Hydrozoan polyps only bud, while the medusae of some hydrozoans can divide down the middle. Scyphozoan polyps can both bud and split down the middle. In addition to both of these methods, Anthozoa can split horizontally just above the base. Asexual reproduction makes the daughter cnidarian a clone of the adult.[9][10]

text: Classification[edit]

text: Cnidarians were for a long time grouped with Ctenophores in the phylum Coelenterata, but increasing awareness of their differences caused them to be placed in separate phyla. Modern cnidarians are generally classified into four main classes:[9] sessile Anthozoa (sea anemones, corals, sea pens); swimming Scyphozoa (jellyfish) and Cubozoa (box jellies); and Hydrozoa, a diverse group that includes all the freshwater cnidarians as well as many marine forms, and has both sessile members such as Hydra and colonial swimmers such as the Portuguese Man o' War. Staurozoa have recently been recognised as a class in their own right rather than a sub-group of Scyphozoa, and the parasitic Myxozoa and Polypodiozoa are now recognized as highly derived cnidarians rather than more closely related to the bilaterians.[6][28]

text:
Hydrozoa
Scyphozoa
Cubozoa
Anthozoa

Number of species[5]
3,600
228
42
6,100

Examples
Hydra, siphonophores
Jellyfish
Box jellies
Sea anemones, corals, sea pens

Cells found in mesoglea
No
Yes
Yes
Yes

Nematocysts in exodermis
No
Yes
Yes
Yes

Medusa phase in life cycle
In some species
Yes
Yes
No

Number of medusae produced per polyp
Many
Many
One
(not applicable)

text: Stauromedusae, small sessile cnidarians with stalks and no medusa stage, have traditionally been classified as members of the Scyphozoa, but recent research suggests they should be regarded as a separate class, Staurozoa.[29]

text: The Myxozoa, microscopic parasites, were first classified as protozoans.[30] Research then suggested that Polypodium hydriforme, a parasite within the egg cells of sturgeon, is closely related to the Myxozoa and that both Polypodium and the Myxozoa were intermediate between cnidarians and bilaterian animals.[31] More recent research demonstrated that the previous identification of bilaterian genes reflected contamination of the Myxozoan samples by material from their host organism, and they are now firmly identified as heavily derived cnidarians, and more closely related to Hydrozoa and Scyphozoa than to Anthozoa.[32][6][28][33]

text: Some researchers classify the extinct conulariids as cnidarians, while others propose that they form a completely separate phylum.[34]

text: Ecology[edit]

text: Many cnidarians are limited to shallow waters because they depend on endosymbiotic algae for much of their nutrients. The life cycles of most have polyp stages, which are limited to locations that offer stable substrates. Nevertheless, major cnidarian groups contain species that have escaped these limitations. Hydrozoans have a worldwide range: some, such as Hydra, live in freshwater; Obelia appears in the coastal waters of all the oceans; and Liriope can form large shoals near the surface in mid-ocean. Among anthozoans, a few scleractinian corals, sea pens and sea fans live in deep, cold waters, and some sea anemones inhabit polar seabeds while others live near hydrothermal vents over 10 km (6.2 mi) below sea-level. Reef-building corals are limited to tropical seas between 30°N and 30°S with a maximum depth of 46 m (151 ft), temperatures between 20 °C (68 °F) and 28 °C (82 °F) high salinity and low carbon dioxide levels. Stauromedusae, although usually classified as jellyfish, are stalked, sessile animals that live in cool to Arctic waters.[35] Cnidarians range in size from a mere handful of cells for myxozoan[28] through Hydra's 5–20 mm (0.20–0.79 in) long,[36] to the Lion's mane jellyfish, which may exceed 2 m (6.6 ft) in diameter and 75 m (246 ft) in length.[37]

text: Prey of cnidarians ranges from plankton to animals several times larger than themselves.[35][38] Some cnidarians are parasites, mainly on jellyfish but a few are major pests of fish.[35] Others obtain most of their nourishment from endosymbiotic algae or dissolved nutrients.[9] Predators of cnidarians include: sea slugs, which can incorporate nematocysts into their own bodies for self-defense;[39] starfish, notably the crown of thorns starfish, which can devastate corals;[35] butterfly fish and parrot fish, which eat corals;[40] and marine turtles, which eat jellyfish.[37] Some sea anemones and jellyfish have a symbiotic relationship with some fish; for example clown fish live among the tentacles of sea anemones, and each partner protects the other against predators.[35]

text: Coral reefs form some of the world's most productive ecosystems. Common coral reef cnidarians include both Anthozoans (hard corals, octocorals, anemones) and Hydrozoans (fire corals, lace corals). The endosymbiotic algae of many cnidarian species are very effective primary producers, in other words converters of inorganic chemicals into organic ones that other organisms can use, and their coral hosts use these organic chemicals very efficiently. In addition, reefs provide complex and varied habitats that support a wide range of other organisms.[41] Fringing reefs just below low-tide level also have a mutually beneficial relationship with mangrove forests at high-tide level and seagrass meadows in between: the reefs protect the mangroves and seagrass from strong currents and waves that would damage them or erode the sediments in which they are rooted, while the mangroves and seagrass protect the coral from large influxes of silt, fresh water and pollutants. This additional level of variety in the environment is beneficial to many types of coral reef animals, which for example may feed in the sea grass and use the reefs for protection or breeding.[42]

text: Evolutionary history[edit]

text: Fossil record[edit]

text: The earliest widely accepted animal fossils are rather modern-looking cnidarians, possibly from around 580 million years ago, although fossils from the Doushantuo Formation can only be dated approximately.[43] The identification of some of these as embryos of animals has been contested, but other fossils from these rocks strongly resemble tubes and other mineralized structures made by corals.[44] Their presence implies that the cnidarian and bilaterian lineages had already diverged.[45] Although the Ediacaran fossil Charnia used to be classified as a jellyfish or sea pen,[46] more recent study of growth patterns in Charnia and modern cnidarians has cast doubt on this hypothesis,[47][48] leaving only the Canadian polyp, Haootia, as the only bona-fide cnidarian body fossil from the Ediacaran. Few fossils of cnidarians without mineralized skeletons are known from more recent rocks, except in lagerstätten that preserved soft-bodied animals.[49]

text: A few mineralized fossils that resemble corals have been found in rocks from the Cambrian period, and corals diversified in the Early Ordovician.[49] These corals, which were wiped out in the Permian-Triassic extinction about 251 million years ago,[49] did not dominate reef construction since sponges and algae also played a major part.[50] During the Mesozoic era rudist bivalves were the main reef-builders, but they were wiped out in the Cretaceous–Paleogene extinction event 65 million years ago,[51] and since then the main reef-builders have been scleractinian corals.[49]

text: Family tree[edit]

text:
Metazoa

Glass sponges

Demosponges

Calcareous sponges

Eumetazoa

Ctenophora (comb jellies)

Planulozoa

Cnidaria

Anthozoa
(sea anemones and corals)

Myxozoa

Medusozoa

Hydrozoa
(Hydra, siphonophores, etc.)

Cubozoa
(box jellies)

Staurozoa

"Scyphozoa"
(jellyfish, excluding
Staurozoa)

Placozoa

Bilateria

text: It is difficult to reconstruct the early stages in the evolutionary "family tree" of animals using only morphology (their shapes and structures), because the large differences between Porifera (sponges), Cnidaria plus Ctenophora (comb jellies), Placozoa and Bilateria (all the more complex animals) make comparisons difficult. Hence reconstructions now rely largely or entirely on molecular phylogenetics, which groups organisms according to similarities and differences in their biochemistry, usually in their DNA or RNA.[55]

text: It is now generally thought that the Calcarea (sponges with calcium carbonate spicules) are more closely related to Cnidaria, Ctenophora (comb jellies) and Bilateria (all the more complex animals) than they are to the other groups of sponges.[52][56][57] In 1866 it was proposed that Cnidaria and Ctenophora were more closely related to each other than to Bilateria and formed a group called Coelenterata ("hollow guts"), because Cnidaria and Ctenophora both rely on the flow of water in and out of a single cavity for feeding, excretion and respiration. In 1881, it was proposed that Ctenophora and Bilateria were more closely related to each other, since they shared features that Cnidaria lack, for example muscles in the middle layer (mesoglea in Ctenophora, mesoderm in Bilateria). However more recent analyses indicate that these similarities are rather vague, and the current view, based on molecular phylogenetics, is that Cnidaria and Bilateria are more closely related to each other than either is to Ctenophora. This grouping of Cnidaria and Bilateria has been labelled "Planulozoa" because it suggests that the earliest Bilateria were similar to the planula larvae of Cnidaria.[2][53]

text: Within the Cnidaria, the Anthozoa (sea anemones and corals) are regarded as the sister-group of the rest, which suggests that the earliest cnidarians were sessile polyps with no medusa stage. However, it is unclear how the other groups acquired the medusa stage, since Hydrozoa form medusae by budding from the side of the polyp while the other Medusozoa do so by splitting them off from the tip of the polyp. The traditional grouping of Scyphozoa included the Staurozoa, but morphology and molecular phylogenetics indicate that Staurozoa are more closely related to Cubozoa (box jellies) than to other "Scyphozoa". Similarities in the double body walls of Staurozoa and the extinct Conulariida suggest that they are closely related. The position of Anthozoa nearest the beginning of the cnidarian family tree also implies that Anthozoa are the cnidarians most closely related to Bilateria, and this is supported by the fact that Anthozoa and Bilateria share some genes that determine the main axes of the body.[2][58]

text: However, in 2005 Katja Seipel and Volker Schmid suggested that cnidarians and ctenophores are simplified descendants of triploblastic animals, since ctenophores and the medusa stage of some cnidarians have striated muscle, which in bilaterians arises from the mesoderm. They did not commit themselves on whether bilaterians evolved from early cnidarians or from the hypothesized triploblastic ancestors of cnidarians.[11]

text: In molecular phylogenetics analyses from 2005 onwards, important groups of developmental genes show the same variety in cnidarians as in chordates.[59] In fact cnidarians, and especially anthozoans (sea anemones and corals), retain some genes that are present in bacteria, protists, plants and fungi but not in bilaterians.[60]

text: The mitochondrial genome in the medusozoan cnidarians, unlike those in other animals, is linear with fragmented genes.[61] The reason for this difference is unknown.

text: Interaction with humans[edit]

text: Jellyfish stings killed about 1,500 people in the 20th century,[62] and cubozoans are particularly dangerous. On the other hand, some large jellyfish are considered a delicacy in East and Southeast Asia. Coral reefs have long been economically important as providers of fishing grounds, protectors of shore buildings against currents and tides, and more recently as centers of tourism. However, they are vulnerable to over-fishing, mining for construction materials, pollution, and damage caused by tourism.

text: Beaches protected from tides and storms by coral reefs are often the best places for housing in tropical countries. Reefs are an important food source for low-technology fishing, both on the reefs themselves and in the adjacent seas.[63] However, despite their great productivity, reefs are vulnerable to over-fishing, because much of the organic carbon they produce is exhaled as carbon dioxide by organisms at the middle levels of the food chain and never reaches the larger species that are of interest to fishermen.[41] Tourism centered on reefs provides much of the income of some tropical islands, attracting photographers, divers and sports fishermen. However, human activities damage reefs in several ways: mining for construction materials; pollution, including large influxes of fresh water from storm drains; commercial fishing, including the use of dynamite to stun fish and the capture of young fish for aquariums; and tourist damage caused by boat anchors and the cumulative effect of walking on the reefs.[63] Coral, mainly from the Pacific Ocean has long been used in jewellery, and demand rose sharply in the 1980s.[64]

text: Some large jellyfish species of the Rhizostomae order are commonly consumed in Japan, Korea and Southeast Asia.[65][66][67] In parts of the range, fishing industry is restricted to daylight hours and calm conditions in two short seasons, from March to May and August to November.[67] The commercial value of jellyfish food products depends on the skill with which they are prepared, and "Jellyfish Masters" guard their trade secrets carefully. Jellyfish is very low in cholesterol and sugars, but cheap preparation can introduce undesirable amounts of heavy metals.[68]

text: The "sea wasp" Chironex fleckeri has been described as the world's most venomous jellyfish and is held responsible for 67 deaths, although it is difficult to identify the animal as it is almost transparent. Most stingings by C. fleckeri cause only mild symptoms.[69] Seven other box jellies can cause a set of symptoms called Irukandji syndrome,[70] which takes about 30 minutes to develop,[71] and from a few hours to two weeks to disappear.[72] Hospital treatment is usually required, and there have been a few deaths.[70]

text: A number of Myxozoans are commercially important pathogens in salmonid aquaculture.

text: Notes[edit]

text:
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Jump up ^ Subphyla Anthozoa and Medusozoa based on "The Taxonomicon – Taxon: Phylum Cnidaria". Universal Taxonomic Services. Archived from the original on 2007-09-29. Retrieved 2007-07-10.
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^ Jump up to: a b Zhang, Z.-Q. (2011). "Animal biodiversity: An introduction to higher-level classification and taxonomic richness" (PDF). Zootaxa. 3148: 7–12.
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tag: ol

text: Further reading[edit]

text: Books[edit]

text:
Arai, M.N. (1997). A Functional Biology of Scyphozoa. London: Chapman & Hall [p. 316]. ISBN 0-412-45110-7.
Ax, P. (1999). Das System der Metazoa I. Ein Lehrbuch der phylogenetischen Systematik. Gustav Fischer, Stuttgart-Jena: Gustav Fischer. ISBN 3-437-30803-3.
Barnes, R.S.K., P. Calow, P. J. W. Olive, D. W. Golding & J. I. Spicer (2001). The invertebrates—a synthesis. Oxford: Blackwell. 3rd edition [chapter 3.4.2, p. 54]. ISBN 0-632-04761-5.
Brusca, R.C., G.J. Brusca (2003). Invertebrates. Sunderland, Mass.: Sinauer Associates. 2nd edition [chapter 8, p. 219]. ISBN 0-87893-097-3.
Dalby, A. (2003). Food in the Ancient World: from A to Z. London: Routledge.
Moore, J.(2001). An Introduction to the Invertebrates. Cambridge: Cambridge University Press [chapter 4, p. 30]. ISBN 0-521-77914-6.
Schäfer, W. (1997). Cnidaria, Nesseltiere. In Rieger, W. (ed.) Spezielle Zoologie. Teil 1. Einzeller und Wirbellose Tiere. Stuttgart-Jena: Gustav Fischer. Spektrum Akademischer Verl., Heidelberg, 2004. ISBN 3-8274-1482-2.
Werner, B. 4. Stamm Cnidaria. In: V. Gruner (ed.) Lehrbuch der speziellen Zoologie. Begr. von Kaestner. 2 Bde. Stuttgart-Jena: Gustav Fischer, Stuttgart-Jena. 1954, 1980, 1984, Spektrum Akad. Verl., Heidelberg-Berlin, 1993. 5th edition. ISBN 3-334-60474-8.

text: Journal articles[edit]

text:
D. Bridge, B. Schierwater, C. W. Cunningham, R. DeSalle R, L. W. Buss: Mitochondrial DNA structure and the molecular phylogeny of recent cnidaria classes. in: Proceedings of the Academy of Natural Sciences of Philadelphia. Philadelphia USA 89.1992, p. 8750. ISSN 0097-3157
D. Bridge, C. W. Cunningham, R. DeSalle, L. W. Buss: Class-level relationships in the phylum Cnidaria—Molecular and morphological evidence. in: Molecular biology and evolution. Oxford University Press, Oxford 12.1995, p. 679. ISSN 0737-4038
D. G. Fautin: Reproduction of Cnidaria. in: Canadian Journal of Zoology. Ottawa Ont. 80.2002, p. 1735. (PDF, online) ISSN 0008-4301
G. O. Mackie: What's new in cnidarian biology? in: Canadian Journal of Zoology. Ottawa Ont. 80.2002, p. 1649. (PDF, online) ISSN 0008-4301
P. Schuchert: Phylogenetic analysis of the Cnidaria. in: Zeitschrift für zoologische Systematik und Evolutionsforschung. Paray, Hamburg-Berlin 31.1993, p. 161. ISSN 0044-3808
G. Kass-Simon, A. A. Scappaticci Jr.: The behavioral and developmental physiology of nematocysts. in: Canadian Journal of Zoology. Ottawa Ont. 80.2002, p. 1772. (PDF, online) ISSN 0044-3808
J. Zrzavý (2001). "The interrelationships of metazoan parasites: a review of phylum- and higher-level hypotheses from recent morphological and molecular phylogenetic analyses" (PDF). Folia Parasitologica. 48 (2): 81–103. doi:10.14411/fp.2001.013. PMID 11437135. Archived from the original (PDF) on 2007-10-25. Retrieved 2009-01-26.