hard shelled egg

Herring gull Larus argentatus eating a chip from the road in a seaside urban setting

Goldcrest Regulus regulus upside down on some dried twigs showing the yellow head crest clearly

House martin Delichon urbicum coming to feed chicks in a nest under the eaves of a roof, small vignette

Curlew Numenius arquata

Dabchick or Little grebe pair Tachybaptus ruficollis

Stylized diagram of the skeelton of a duck

Stylized diagram of the development of a duck egg from being laid until after hatching Day one yolk held in place with chalaza, germinal disc where fertilized chick starts to grow

Stylized diagram of the development of a duck egg from being laid until after hatching day twelve feathers start to show eye covered with lid claws formed

Stylized diagram of the development of a duck egg from being laid until after hatching Day 27 hatchling squashed inside egg ready to hatch, air cell still shows

Stylized diagram of the development of a duck egg from being laid until after hatching day five embryo separates from the yolk, blood vessel network grows and branchesm eye starts to get a colour.

Stylized diagram of the development of a duck egg from being laid until after hatching day eight blood vessels carry waste and oxygen, eyelids start to cover eye, beak and egg tooth more clear.

Common Goldeneye Bucephala clangula male displaying

Stylized diagram of the development of a duck egg from being laid until after hatching duckling hatching half in half out of shell with prominent egg tooth

Common kingfisher Alcedo atthis with minnow in its beak, perched on a branch

Stylized diagram of the development of a duck egg from being laid until after hatching hatched duckling chick

Common sandpiper Actitis hypoleucos sketch cut to white

Bird bone cross section showing cross bracing for strength and hollow structure

Common wood pigeon Columba palumbus showing pink and green feathers

Stylized diagram of the internal organs and anatomy of a duck within a pen outline

Pencil sketch comparing size of humming bird, ostrich, hen, and elephant bird

Coot Fulica atra

Corncrake Crex crex standing on a large stone looking alert with grass at its feet

Cuckoo Cuculus canorus

Blue tit Parus caeruleus visiting a bird box