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Eagle Resources - Glossary

The following are terms used by eagle experts when discussing bald eagles and eagle recovery equipment and techniques.

aerie: (eyrie) an eagle's nest

aerial chase: a courtship display of eagles

birds of prey: birds which feed on other animals and have hooked beaks and talons

Cainism: (fratricide) to kill a sibling, a fairly frequent event for eagles

captive breeding: when birds that are not allowed or able to go free are encouraged to lay, incubate, and hatch eggs

carrion: dead animals that are found and eaten by other animals

to cartwheel; cartwheeling: a courtship display where eagles of the opposite sex ascend to a great height, lock talons, plunge toward earth at a high speed, and re-ascend moments before touching ground

to cast; casting: the rejection of bones, feather, and furs of animals which have been eaten; small pellets of such materials are held in the eagle's neck and spit out after digestion

chicks: birds that have not yet grown feathers; birds covered in down

clutch: the eggs laid at one time; the usual clutch for an eagle ranges from one to four with two being the average number of eggs in a clutch

courtship: when male and female eagles attract each other for mating

DDT: a chemical pesticide which was found to be lethal for birds and other life forms

eaglet: a young eagle

egg borrowing: removing eggs from an eagle nest to encourage the mating pair to produce another clutch; the eggs may then be placed in a nest of an infertile eagle pair, incubated by hens, or incubated by machine

egg fostering: placing an egg in the nest of an infertile eagle in the hopes the eggs will be incubated

endangered: a species that is in danger of extinction throughout a significant portion of its range

eyrie: (aerie) an eagle's nest

falconry: a sport which uses eagles to hunt

to fledge; fledging: the process of growing the feathers needed to fly; taking the first flight

fratricide: (Cainism) to kill a sibling, a fairly frequent event for eagles

to hack; hacking: a process that is based on the fact that eagles tend to return to the area of their maiden flight to nest. The term is based on a term taken from the sport of falconry. Defined by the Fish & Wildlife Service, it is taking a bird that is past the critical stage of imprinting on humans, putting it in a nest in a different location, raising that bird until it is able to leave the nest and fly, feed, and hunt on its own

hacking tower: a specially built enclosure to keep eagles protected until they are fledged (have attempted their first flight)

Haliaeetus leucocephalus: Latin or scientific name for the bald eagle

Haliaeetus leucocephalus leucocephalus: The southern bald eagle; Latin or scientific name for the bald eagles nesting below the 40th parallel (the southern portion of the United States)

Haliaeetus leucocephalus alascanus: The northern bald eagle; Latin or scientific name for the bald eagles nesting above the 40th parallel (the northern portion of the United States)

incubate: to keep eggs warm until they hatch

incubator: a machine designed to keep eggs at the correct temperature until they hatch

juvenile: a young eagle; eagle up to the age of maturity, which is typically five years of age

migration: seasonal event when birds leave their usual nesting places in search of warmer climate and more abundant food sources

to molt; molting: to shed feathers

pellets: capsules of undigestable materials

to perch; perching: to sit on a tree branch for either hunting or resting purposes

perchpoles: sticks or thin poles places horizontally outside a hacking tower to assist fledging eagles in their first flight

pesticides: chemicals used to control insects and other pests

plumage: the covering of feathers on a bird

predator: an animal that kills another animal for food

prey: an animal which is hunted for food by another animal

raptors: the group of birds or avians known as birds of prey; birds which feed on other animals and have hooked beaks and talons

recovery regions: geographical areas of the country which have agreed to work together to help restore eagle and other wildlife populations within their regions

to roost; roosting: a period of inactivity like sleeping in human beings

range: the parts of the world where a bird lives

scavenger: an animal that feeds on carrion

talons: claws

thermal: a rising current of warm air, helpful to soaring birds

threatened: a species that is likely to become an endangered species within the foreseeable future throughout all or a signficant portion of its range

wingspan: distance between opposite wingtips when the wings are fully extended