In Some Colonial, Ground-Nesting Gulls, Young Birds Sometimes Leave Their

question 10

Essay

In some colonial, ground-nesting gulls, young birds sometimes leave their natal nests if they have been poorly fed. On occasion, these chicks move to the nests of adults that aren't their parents. Researchers found the following:
Gull chicks that abandoned their natal nests weighed much less on average for chicks their age.
If, however, gull chicks were adopted by nonrelatives, they weighed more on average than unadopted gull chicks.
Adopted chicks are more likely to survive than chicks that remained in natal nests that failed to supply enough food.
Parents that adopted nonrelative chicks lost 0.5 chicks of their own on average.
Less than 10 percent of adult gulls take in a nonrelative chick.
Explain why gull parents might be willing to adopt the offspring of other gulls?

---

Definitions:

Auricle

The external, visible part of the ear that captures sound waves and directs them into the ear canal; also known as the pinna.

Pinna

The outer part of the ear that captures sound waves and directs them into the ear canal.

Rinne Test

is a hearing test that compares air conduction to bone conduction of sound, used to differentiate between types of hearing loss.

Bone Conduction

The transmission of sound vibrations through the bones of the skull to the inner ear, bypassing the outer and middle ear.