Bird Tracks & Gaits
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.)
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Countershading
Countershading is a common color pattern in animals in which the upper side of the animal is darker than the lower side. This color pattern provides camouflage for the animal when viewed from the side, above or below. The counter shading pattern balances the sunlight on the animal’s back and the shadow beneath the animal so as to blend the animal’s side profile with its surroundings. In addition, when viewed from below, a counter-shaded animal with a light belly blends into the light coming from the sky above. When viewed from above, the darker back of a counter-shaded animal blends into the darker ground colors below. Birds (which spend a considerable amount of time in the air) such as this dark-eyed junco, as well as marine animals often exhibit countershading.
Dark-eyed Juncos Having Second Brood
In New England, Dark-eyed Juncos typically have two broods in a summer. The second-brood nest in the photograph contains the first of probably four or five eggs which are laid one day at a time. The egg lies on a soft lining made from the hair of a White-tailed Deer. Unlike most songbirds, Dark-eyed Juncos build their nests in a wide variety of sites, from the ground up to eight feet high in trees. Often they are in a small cavity on a sloping bank (well hidden by surrounding grass), under a protruding rock or among tree roots. But they’ve also been found under fallen tree trunks, on supports underneath houses on stilts, in barns or lofts between hay bales, in vines on the sides of buildings, on window ledges and light fixtures and in hanging flower pots. It’s not unheard of to find a Dark-eyed Juncos relining the old nest of an American Robin.
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