I've read that birds such as crows and blue jays often mimic other bird species calls. There seems to be evidence that birds do learn and react to other bird species calls, specifically when they relate to danger. What I'm curious about is what advantages do birds gain when they imitate other species calls?
There are a number of reasons birds will mimic other birds mostly for deception, but not always.
Impressing a mate: Songs are a large part of bird courtship behavior, and a more varied song that includes different mimicked tones can help attract a better mate. Because mimicked tones are learned, a bird with more vocal variety is demonstrating its intelligence, ability to survive, and other characteristics a mate would find desirable.
Safeguarding Food: Using a hawk or owl call, or the sound of a cat, dog, or other predator, is an effective way for a bird mimic to claim a food source. When it utters such a call, birds monopolizing feeders or nearby bushes, trees, or other feeding spots may scatter, letting the mimic take advantage of a less crowded food source.
Defending Territory: Songs are crucial for many birds to claim territory, and adding mimicked tones into the song can demonstrate the resident bird's strength. Extra sounds may also trick other interested birds into believing that there are far more birds in the region than there actually are. The newcomers may then simply move along rather than challenge the resident mimic bird.
Social Acceptance: Baby birds learn many songs from their families and other birds of their species, and if mimicked sounds are included, young birds will learn them as part of their initial repertoire. This helps birds fit in with their flocks, which will also help them eventually defend their own territories and attract mates. Many pet birds that mimic speech are doing so for social acceptance, as they consider humans to be their flock.Bird to bird mimicry I have personal experience with one of these where a Blue Jay would come to our feeder imitating the screech of a hawk and all the other birds would scatter so he/her had the feeder to themselves.