Happy World Migratory Bird Day!
April Bird of the Month: American Crow
The American Crow (Corvus brachyrhynchos) is a large, intelligent bird found in most of North America. (Many other species of crow are found all over the world). They live in families of up to 15 individuals that contain young from five different years. Their flight style is unique— a patient, rhythmic flapping that is rarely broken up with glides. They eat almost anything, including worms, insects, small animals, seeds, and fruit as well as carrion and chicks they rob from other nests. Despite their tendency to eat roadkill, the American Crow is not specialized to be a scavenger, and carrion makes up only a very small part of their diet. Their beaks, though large, are incapable of tearing open the flesh of even a gray squirrel, so they rely on other animals to open a carcass before being able to eat. Crows don’t regularly visit feeders, but can be attracted to yards by peanuts, compost, garbage, or pet food left outside.
Crows are crafty foragers, sometimes stealing from other animals by following them to food sources. A group of crows was once seen distracting a river otter to take their fish! Crows also make and use tools— an act that illustrates their incredible intelligence. They have a highly complex language system of croaks and calls used to communicate anything from greetings to danger. They are capable of recognizing not only each other, but human faces as well. They remember, for instance, the farmer who has shot at them (danger) or the child who leaves peanuts out for them (friend), all the while communicating about these people to each other! The oldest recorded wild American Crow was at least 16 years old. A captive crow in New York lived to be 59 years old!
May Bird of the Month: Indigo Bunting
Image from Cornell Lab of Ornithology
The Indigo Bunting (Passerina cyanea) can be found in New England in midsummer along rural roads, where they often sing from telephone lines or wooded edges for hours on end. The all-blue male Indigo Bunting sings with cheerful gusto and looks like a scrap of sky with wings. In fall, their mostly brown plumage can make them tricky to identify, but tinges of blue in their wings or tail act as a giveaway. Females are mostly brown all year round. They eat insects and small seeds from plants like thistle. Indigo Buntings migrate at night, using the stars for guidance. The birds possess an internal clock that enables them to continually adjust their angle of orientation to a star, even as that star moves through the night sky! They learn their songs as youngsters not from their fathers but from nearby males, sharing a “song neighborhood”. A local song may persist up to 20 years, gradually changing as new singers add novel variations! Like all other blue birds, Indigo Buntings lack blue pigment. Their jewel-like color comes instead from microscopic structures in the feathers that refract and reflect blue light, much like the airborne particles that cause the sky to look blue. Plumage does contain the pigment melanin, whose brown-black hue you can see if you hold a blue feather up so the light comes from behind it, instead of toward it.
Image from Cornell Lab of Ornithology