hatching: The parents start incubating the eggs as soon
as the first egg is laid. This produces a staggered hatching of several
days between the first and last chicks. If the food is in short supply,
the youngest - and therefore smallest - chicks will die, but some of
the clutch will survive.
A yearly list of bird species by the National Audubon Society of those
species believed to be declining in numbers.
Cache: The storage of food items for later
retrieval and use.
Camouflage: the colors and patterns animals have that help them
blend in with their habitat. Camouflage helps prey hide from predators
and it allows predators to sneak up on their prey without being seen.
Carrion: Prey animals found dead.
Clutch: The number of eggs laid by a female
Conifers: Trees that are evergreen and
have cones: pines, spruces, junipers and firs.
Convergent evolution: The development
of similar features in unrelated species when they live in similar environments.
Example: the talons and hooked bill of owls and hawks.
Crepuscular: Active during the dawn
and dusk hours, as opposed to strictly nocturnal or diurnal.
Crop: The expandable pouch in the esophagus
of some birds. It is a temporary food storage that allows its owner
to eat very rapidly. Hawks and eagles have crops.
Diurnal: When animals are active during
Ectoparasite: Parasites on the outside
of the body such as lice.
Extinction: When a kind of plant or animal has all died. This
is a natural process that is happening very, very rapidly today because
of changes humans have made in the environment.
Facial disk: A saucer-shaped
disk of movable feathers around the eyes of owls that direct light to
its eyes and sound to its ears.
Imprint: The normal attachment of a young
bird to its parents. This usually occurs during a very short time period
after the chick opens its eyes and is able to focus. Now the chick knows
what species it is, who to trust and who to mate with when it gets older.
Incubation: When birds sit on eggs
and hatch them by the warmth of their body.
Kettle: A term used to describe a group
of hawks flying in circles in thermals or updrafts.
Mantle: To spread its wings and tail over
the food to hide it while eating.
Molt: The yearly process during which raptors
lose their old feathers and replace them with new ones. Molting in small
and medium-sized raptors takes several months. Larger birds such as
vultures and eagles may take several years to replace their entire set
Morph: Differences in plumage as a result
of genetically controlled color phases (morphs) in individuals of a
species. These differences are not related to age or season of the year.
Nocturnal: When animals are active at
Nomadic: The movement in which a population
shifts from site to site between seasons in a relatively unpredictable
manner. Short-eared owls migrate to sites where rodent populations are
Opportunists: With birds of prey
it means that they will hunt what ever prey comes along. They do not
wait for just one type of prey.
Pellet: Also called a casting. The regurgitated
(spit-up) remains of undigested fur, feathers and bones that are produced
by raptors after a meal.
Pesticide: A chemical poison (such as
now-outlawed DDT) that is used to kill insect pests. Usually these chemicals
get into food chains/food webs and kill other animals.
Scavenger: A carnivore that feeds upon
animals that are already dead.
Symbiosis: A permanent relationship
between two different species. The relationship in which both of the
species benefits is called mutualism. Ravens finding a dead animal can't
open up the carcass so they call wolves to open it and feed, the ravens
Symmetrical: Regularly shaped or able
to be divided into similar parts.
Synchronous hatching: Incubation
doesn't start until all the eggs are laid. All the eggs will hatch at
the same time, some cases within an hour of each other. An available
food supply is not a problem to these species.
Territory: The area in which bird lives
and defends. A bird's song is one of the ways it stakes out and defends
Thermal: The rising body of warm air.
Some soaring birds use this elevator to gain height without flapping
Third eyelid: An "extra" eyelid that birds use to
cover and protect their eyes when capturing prey or diving very fast.
: A habitat in Northern Canada and Northern
Alaska that is covered with low-lying vegetation like mosses, lichens,
grasses and small shrubs.