Below is a list of possible challenges. Check all errors that you mentioned in your answer.

Traits other than beak type might affect
natural selection.

It could take many generations to observe
adaptions to a population.

The environment may be complex and hard
to study.

Changes in the environment may occur faster
or slower than changes to the birds

The birds may be interdependent with other
organisms that may change, too.

1. true.2. true.3. true.4. false.5. true.the concept of darwin's theory of evolution involves the idea that there are limited resources in a given living environment and that the organisms which live within have variations in their genetic make up due to random mating. the ones with beneficial genetic variations can express certain traits which give them an upper hand in surviving and reproducing in the said environment compared to ones who may have a more disadvantageous variation in traits. over time, the organisms with an upper hand will survive and reproduce more frequently and pass on their beneficial genes while the others die. the result is evolution, where we observe (usually, but not always) eventually, phenotypic distinct changes.