northeast-flora-and-fauna

Here's a Black-capped Chickadee . Or is it a Carolina Chickadee ? It's awfully hard to say. In most of the country the issue is decided quickly by knowing where you are. The further south you go, the more likely it is that a bird looking like this is a Carolina Chickadee, and the further north you go, they more likely you are to encounter a Black-capped Chickadee. This article describing the differences shows that I live awfully close to the "hybrid zone", the area in the middle where the chickadees could be Black-cappeds, Carolinas, or hybrids. Skilled birders can recognize the song and call differences between the 2 species ... but near the hybrid zone this is of limited usefulness since each species can learn to make the other's sounds. A Black-capped Chickadee that grows up around Carolina Chickadees might well speak Carolina Chickadee-ese, and vice versa. Or it might be "bilingual". Of course, the hybrid zone isn't fixed in stone. An especially...