Friday, January 23, 2009
The Red-shouldered Hawk is not a common bird in Carlisle, in any season. It used to be a very common hawk across the eastern half of North America and as far west as Texas, but early in the 20th century it was hunted and shot. Its eggs were often taken by egg collectors in the late 1800s and early 1900s. It also suffered decline due to egg-shell thinning in the years of DDT use from 1945 to 1972. Throughout all this time, forest fragmentation has skewed conditions in favor of the larger, more aggressive Red-tailed Hawk.
Name: The Red-shouldered Hawk is Buteo lineatus where Buteo is from the Latin for hawk and lineatus means striped, probably referring to the black and white striped flight feathers and the bands on the tail.
Hawks: Most of the birds around here that we call hawks fall into one of two groups: the Accipiters or the Buteos. Accipiters include Cooper’s Hawk, the Sharp-shinned Hawk, and the Northern Goshawk. They are more slender than the Buteos and have comparatively long legs, long thin toes, and long tails. They have excellent maneuverability, which allows them to chase their prey (mainly birds) through the trees. The Buteos are chunkier shorter-tailed birds and include the Broad-winged Hawk, the Red-shouldered Hawk, and the Red-tailed Hawk (most common of the three in Carlisle). Buteos hunt in a manner more like a human hunter in a deer blind. They choose a likely spot and then use the sit-and-wait technique.
Recent sighting: On January 11 and again on January 12, a Red-shouldered Hawk visited Jean Keskulla’s yard on Concord Street. It perched in a tree where it could watch the bird feeder. Other birds, aware of its presence, were scolding it, which seemed to bother it not at all. It waited and watched for about two hours, probably hoping for some small rodent to come to the feeder. It was too cold for the chipmunks to be out and the red squirrels were not around either. Jean did not see it take any prey but she did report a subsequent ‘parade of predators.’ On the day after the Red-shouldered Hawk had left, a Sharp-shinned Hawk made an appearance and also a fox.
Other Carlisle sightings: The Red-shouldered Hawk first turned up in the Carlisle Christmas Bird Count (CBC) in 1988 and at least one was counted in each of the years from 1997 to 2002. The most recent entry in the CBC was one in 2007. We have one confirmed instance of the bird breeding in Carlisle. Here is Ken Harte’s account: “In 2001, a pair of Red-shouldered Hawks nested about 35 feet up in the crotch of a red oak on the north side of Kibby Place. I had been seeing them since early March eyeing our chickens and discovered the nest on March 29. The eggs hatched in early May, and on June 18 the last of three young left the nest. Adults and young stayed in the neighborhood through July, and I watched one of the adults catch a chipmunk under my feeder. They disappeared in August, but one juvenile was considerate enough to reappear off Russell Street on December 30 for the Christmas Bird Count.”
Distinguishing characteristics: There are three types of Red-shouldered Hawk that live in different parts of the country. The California type is the most richly colored and the Florida type is the palest. Ours is the Eastern type and the colors are between the rich and pale extremes. All three have the red shoulders for which the bird is named, but this is not a good field characteristic. You will more likely notice the ‘red’ or rather tawny orange breast with orange bars, the black and white checkered wings, and the striped tail with several narrow white bands. The broad-winged hawk has only a single broad white band across its tail. In flight, the Red-shouldered Hawk shows a pale crescent-shaped patch near the tip of the wing. The wing span is around 40 inches. Jean considers the Red-shouldered to be the prettiest of our hawks, and Wayne Petersen, director of the Important Bird Areas program for Mass Audubon, finds few raptors “more colorful, more confiding, and more winsome than the Red-shouldered Hawk”.
Prey: Petersen’s view would not be shared by small mammals, snakes, frogs, and many birds. Examination of stomach contents of 220 Red-shouldered Hawks at the turn of the 20th century showed the most common prey by far to be mice and other small mammals, which were present in 142 of the subjects. Next most common was 92 occurrences of insects. Despite the Red-shouldered’s reputation for taking domestic chickens, only three had eaten poultry although 12 had eaten birds. The rest of the menu included frogs, snakes, spiders, crawfish, fish, and earthworms.
References: The Sibley Guide to Birds and The Sibley Guide to Bird Life and Behavior, both by David Allen Sibley; “Red-shouldered Reveries,” an article by Wayne Petersen published in the quarterly journal of the Massachusetts Audubon Society, Autumn 2007; Birds That Hunt and are Hunted by Neltje Blanchan; Cornell Lab of Ornithology at www.birds.cornell.edu (search for red-shouldered), Carlisle CBC and nesting data from Ken Harte.
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