Male Common Grackles have started to arrive on their northeastern breeding grounds (females will arrive in another week or so), having migrated from southern U.S. Common Grackles typically migrate in large flocks containing hundreds of birds, not all grackles. Red-winged Blackbirds, Brown-headed Cowbirds, European Starlings and occasionally American Robins can be found alongside Common Grackles in these migrating flocks. In the early 1990’s, magnetic material was found in the heads and necks of Common Grackles, indicating that the geomagnetic field may play a role in their migratory navigation.
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Just a dusting of snow can reveal the patterns of tracks that different birds leave, and that pattern tells you how a bird moves (walks/hops). Frequently this knowledge can narrow down the possible species that made the tracks. In general, smaller birds tend to hop and larger birds frequently walk. This may be a result of conserving energy — short-legged birds move farther in a single hop than they do taking several steps, whereas it is more economical for larger birds, with longer strides, to move one leg at a time. In addition, birds that spend time on the ground foraging for food are more apt to walk, placing one foot in front of the other, much as humans do. Mourning doves, ducks, pigeons, and wild turkeys all leave “chains” of tracks, alternating feet as they walk. Birds that live mostly in trees and bushes tend to hop from one spot to another, even when they are on the ground, leaving paired tracks. Sparrows, including juncos, as well as finches frequently move in this way. There’s no hard and set rule, as some birds do both –American robins, ravens, crows and blackbirds are as likely to walk as they are to hop! (Photo shows tracks of Mourning Dove on bottom walking towards the left; Dark-eyed Junco above, hopping towards the right.)
Although the common grackle, a member of the blackbird family, is the bane of many corn growers as well as a threat to songbirds trying to raise young (grackles eat other birds’ eggs and nestlings), it is quite a colorful bird, with its pale yellow eyes and iridescent purple plumage. Grackles have already begun nesting and defending their territory, as can be seen from the stance of the bird in this image. This “bill-up display” is a position assumed when a male is being approached on its territory by another male. It moves its head upwards so that its bill is almost vertical, signaling to the approaching grackle that it would be in its best interest to depart.