eggs and nests

Question 1

albumen

Answer 1

makes up roughly 2/3 of the mass of an egg made up of protein and water, acts as the primary water source for the embryo

Question 2

urovaginal junction

Answer 2

location where females collect and store sperm until an egg is ready to be laid; some species may have sperm selection

Question 3

amnion

Answer 3

fluid contained in the egg surrounding the embryo which is connected directly to the yolk

Question 4

chorion

Answer 4

connects with the allantoic sac via the chorioallantoic membrane for gas exchange

Question 5

allantoic sac

Answer 5

connects with the chorion and also serves to hold waste

Question 6

yolk

Answer 6

connects directly to the embryo; layered with white yolk produced at night and yellow yolk produced during the day; size is dependent on development, larger in precocial and smaller in altricial

Question 7

energy use during development

Answer 7

steadily increases in early development, plateaus late in development and spikes just before hatching for the strength to break out of the egg

Question 8

egg tooth

Answer 8

hard structure on the beak used to crack open the egg via upward motion of the head, falls off after hatching

Question 9

hatching muscle

Answer 9

large muscle on the back of the neck aids in the neck movement used for hatching, absorbed by the body after hatching

Question 10

precocial

Answer 10

birds hatch with eyes open and downy feathers; leave the nest within a few minutes-2 days; longer incubation time with fewer offspring
ex: brush turkeys and rails

Question 11

semi precocial

Answer 11

hatch with eyes open and downy feathers; capable of leaving the nest soon after hatching but stay close to continue to be fed by the parents; can often walk or swim; those with increased predation pressure leave sooner
ex: gulls and terns

Question 12

semi altricial

Answer 12

hatch with eyes closed and covered in down; incapable of leaving the nest ; must be fed by the parents
ex: hawks, owls, herons

Question 13

altricial

Answer 13

hatch with eyes closed and little to no down; cannot leave the nest and must be fed by parents
ex: all passerines

Question 14

ground nesters

Answer 14

tend to be precocial

Question 15

elevated nesters

Answer 15

tend to be most altricial

Question 16

mound builders

Answer 16

use a depression filled with organic material like leaves to lay the eggs on top of, the leaves generate heat while breaking down to incubate the eggs, the whole nest is covered with breathable material such as sand or dirt; highly precocial offspring

Question 17

nest type

Answer 17

consistent among a species, many species all use a particular kind of tree or branch

Question 18

metabolic savings

Answer 18

metabolic rate is often lower in the nest due to warmth

Question 19

methods of incubation

Answer 19

in 50% of birds both parents incubate; female only incubation is more common than male only; some species sneak into the nest to reduce predation; species with lower predation risks visit the nest more often