Red-tailed Hawk Winter Population in New England
Red-tailed Hawks are “partial migrants” – some are migratory and some are not. Most Red-tails living and breeding in the northern portion of the species’ range (southern Canada and northern United States) migrate to more southerly locations for the winter and are absent for three to five months. However, some are year-round residents, remaining near their breeding territories even in severe winters with extensive snow cover. In northern New England the Red-tailed Hawk winter population consists of breeding birds that don’t migrate as well as Canadian birds that migrate south for the winter months. (Photo: juvenile Red-tailed Hawk)
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Birds Molting Old Feathers And Growing In New Ones
With birds, molting refers to the loss of old, worn feathers and the growth of new ones. A molt can involve all of the bird’s feathers (complete molt), or just some of them (such as wing or tail feathers – a partial molt). Most birds have a complete molt once a year (chickadees, hummingbirds, owls, etc.), or one complete molt and a partial molt before the breeding season (buntings, tanagers, warblers, etc.), or two complete molts per year (Bobolinks, Marsh Wrens).
Complete molts often occur in late summer and early fall, after the breeding season is over. When you think about it, the timing of this “prebasic” or “postnuptial” molt makes a great deal of sense. Growing new feathers takes an inordinate amount of energy; food is plentiful now, the demands of breeding are over and for many birds, migration isn’t quite under way. It is the perfect time to look for molted feathers on the ground. (Photo: molted Red-tailed Hawk tail feather)
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Wing Prints In The Snow
Rarely have I had the good fortune to come upon a predator dining on its prey, but in this case, luck was with me. Seconds after I spotted a Red-tailed Hawk on the ground working on something it noticed me and flew away, perching within sight so as to keep an eye on its recent kill. This sighting eliminated some of the mystery of the story written in the snow. Wing prints would have revealed that the predator was airborne, and the wingspread might have narrowed the list of potential hawks/owls that it could have been, but determining the species would have been challenging without a sighting.
Although smaller rodents (voles, mice, etc.) make up a greater percentage of a Red-tail’s diet than larger ones, Gray Squirrels (whose remains are visible and were still warm) are consumed. The large numbers of Gray Squirrels on roadsides last fall reflected a booming population which most likely has provided ample food for many predators this winter, including this hawk. Interestingly, fur from the tail had been removed prior to the bird’s directing its attention to the internal organs of the squirrel. A quick retreat by this curious naturalist hopefully allowed the Red-tail to return to its meal.
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A True Mystery Photo
A discovery recently brought to my attention has stumped this naturalist. What you are looking at is a collection of Flying Squirrel tails lying within a 30-square-foot patch of ground adjacent to a stand of Eastern Hemlocks. For several days in succession, additional tails appeared each morning, eventually totaling 20 or more.
Flying Squirrels, both Northern and Southern, are part of many animals’ diet. Among the documented predators are Great Horned Owls, Barred Owls, Screech Owls, Northern Goshawks, Red-tailed Hawks, Martens, River Otters, Weasels, Fishers, Red Foxes and Bobcat. Many of these animals can gain access to the trees where the Flying Squirrels reside. Others take advantage of squirrels foraging on the ground.
The puzzling part of this mystery is the large number of tails. In cold weather (usually in winter, but we’ve had below-freezing nights recently), Flying Squirrels huddle together in tree cavities in an attempt to provide themselves with added warmth. Did a foraging Fisher discover a communal den? How did it manage to capture so many squirrels? Did the survivors remain in the same cavity, only to be captured in subsequent nights? So many questions that this naturalist cannot answer. Perhaps a reader can! (Thanks to John Quimby and Michael O’Donnell, who kindly shared their fascinating discovery with me.)
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Red-tailed Hawks Building & Refurbishing Nests
Red-tailed Hawks are on eggs, or soon will be. Whether their nest is in the canopy, on a building ledge, transmission tower or elsewhere, it usually has a commanding view of the surrounding area and unobstructed access from above.
Both members of a pair share in nest site selection, which is often in mixed woods adjacent to open fields. They build their nest together, working most diligently in the morning, and construction is completed within four to seven days. If a nest is re-used, which it often is, it is refurbished with sticks and greenery. Red-tails are very wary during this nest-preparation period and may discontinue nest-building if humans are detected, so should you come upon a nest during this stage, best to remove yourself quickly.
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Great Horned Owls Incubating Eggs
Great Horned Owls are said to have the widest range of nest sites of any bird in North or South America. Like other owls and falcons, this raptor does not build its own nest, but rather relies heavily on abandoned stick nests of diurnal birds of prey. Red-tailed Hawk nests are often usurped, as well as those of Bald Eagles, crows, ravens and herons. Nests may be lined with shreds of bark, leaves, downy feathers from the owl’s breast, fur of prey and trampled pellets. In addition to bird nests, Great Horned Owls also raise their one to four nestlings (usually two) in tree cavities and snags, on cliffs, in deserted buildings, in squirrel nests and even on the ground.
The female Great Horned Owl does all the incubating; the male delivers prey to her at intervals throughout the night. These early nesters have incubated eggs successfully when outside temperatures have been as low as -27°F. Hopefully warmer temperatures will welcome the newly hatched owlets in about a month. (photo: mostly hidden Great Horned Owl in Great Blue Heron nest)
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Overwintering Red-tailed Hawks
Red-tailed hawks are “partial migrants” — some individuals are migratory, and others are not. Many Red-tails living in the northern portion of the species’ range in southern Canada and northern United States migrate to more southerly locations for the winter. A few northern birds, however, remain on their breeding territories even in the most severe winters.
Overwintering Red-tailed Hawks are generally easy to spot, as they often perch on dead trees overlooking open fields and on telephone poles next to highways, where they watch for prey. Mice, voles, squirrels, snowshoe hares and an occasional bird make up most of their diet. If you notice the coloration of a Red-tailed Hawk’s tail, it will tell you whether the bird is a juvenile or adult. Adults have rufous tails; juveniles have barred, brownish tails. Seconds after this photograph was taken this juvenile Red-tailed Hawk killed and consumed an American Crow while being mobbed by more than 50 other crows.
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Young Beavers Out and About
Most beavers are born between May and early July, weighing one pound and measuring a foot long. They are fully furred, their eyes and ears are open and they know how to swim. Even so, they don’t usually venture out of the lodge for the first month or so. Initially their fur isn’t water-repellent, but by three to four weeks of age, the young beavers’ anal glands, used in greasing their fur, are functional. When the kits weigh seven or eight pounds, they start to leave the lodge regularly to explore their pond and feed with their parents and older siblings.
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Common Raven Defends Nesting Territory
Common ravens are known for their aerial acrobatics, often doing rolls and somersaults and other amazing tricks. According to Cornell Lab of Ornithology, one bird was seen flying upside down for more than a half-mile. Young birds are fond of playing games with sticks, repeatedly dropping them and then diving to catch them in mid-air. The pictured raven, however, was much too busy to be doing cartwheels in the sky. It has a nest with eggs nearby, and during its morning patrol encountered a red-tailed hawk which it drove out of sight in a matter of seconds. Although small mammals make up most of a red-tail’s diet, they are known to also prey on smaller birds, including defenseless nestlings, which the ravens will have in the next few weeks. (Because of the angle, the 24-inch-long, 53-inch-wingspread raven looks disproportionally larger than the 19-inch-long, 49-inch wingspread red-tail.)
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