What two things is the simile comparing I think ones the bird but whats the other item or thing?

"But alas! we do like cowbirds and cuckoos, which lay their eggs in nests which other birds have built, and cheer no traveller with their chattering and unmusical notes."

Question

What two things is the simile comparing I think ones the bird but whats the other item or thing?

"But alas! we do like cowbirds and cuckoos, which lay their eggs in nests which other birds have built, and cheer no traveller with their chattering and unmusical notes."

anonymous · Answer

Would they be comparing the two birds?