This stability has been proposed to require active maintenance by auditory feedback, as song gradually deteriorates after deafening in adult birds. Leonardo and Konishi distorted auditory feedback ...

The difference between these birds becomes clear when you compare the adult males. Purple finches are a deep cranberry or raspberry color on most of their body. Male house finches are more orange ...

In flight, wings appear translucent. Adult: one molt per year, but fresh fall adults look very different from summer birds. On freshly molted birds, black plumage has white spots all over ...

The attractive Cassin’s finch of the montane west is slightly larger and longer winged than the similar purple finch, which it occasionally overlaps with during winter. It is often seen in small ...