70 FIELD GUIDE A pocket-sized book that helps the reader to identify different birds. FLEDGE To leave the nest. FLIGHT FEATHERS The long feathers that make up a bird’s wings and are used to fly. They can be grouped into primary feathers (on the outer wing) and secondary feathers (on the inner wing). FLOCK A group of birds flying or feeding together. GIZZARD The muscular chamber in a bird’s stomach, where food material is ground up into a pulp. HABITAT The type of environment where a bird is normally found, such as wetland, forest, or grassland. HATCHING The process by which a baby bird breaks out of its egg by chipping its way through the shell with the tiny egg tooth on its beak. ALULA A group of feathers on the leading edge of a bird’s wing that prevents it from stalling as it slows down. BARBS Tiny side branches off a feather shaft that make up a bird’s feather. BINOCULAR VISION The area of sight in which the fields of vision of both eyes overlap. Binocular vision enables birds to judge distances accurately. BODY FEATHERS (OR CONTOUR) The small, overlapping feathers on a bird’s head and body that give it a streamlined shape. BREED To find a partner, mate, build a nest, lay eggs, and raise chicks. BREEDING SEASON The time of year when birds mate, build nests, lay eggs, and raise their chicks. CAMOUFLAGE The colour and patterning of a bird’s feathers and eggs that match its surroundings and make it hard to see. CLUTCH The total number of eggs that is incubated by a parent bird or a pair of birds at any one time. COLONY A large group of birds that live together in one place to breed or roost, or the place in which they live. COURTSHIP The behaviour of birds when finding partners before mating. It may take the form of special movements, dancing, or songs. COVERTS Groups of small feathers that cover the base of the main flight feathers. DABBLING The way a duck feeds, by opening and shutting its beak while skimming it across the surface of the water. DISPLAY A conspicuous pattern of movements or colourful plumage used to communicate with other birds of the same species, especially in courtship or when threatened. DISTRIBUTION All the areas in which a bird is seen regularly. DOWN FEATHERS Very soft, fine feathers that trap air close to a bird’s body and help to keep it warm. EGG TOOTH A small structure on the tip of a chick’s upper bill, which it uses to crack open the eggshell when hatching. The egg tooth drops off soon after hatching. EXTINCTION The process by which living things, such as the dodo, die out completely and no longer exist. Body feather Clutch of eggs A gannet colony Blue tit nestlings Duckling hatching