Words On Birds by Steve Grinley
Autumn is Hawk Migration Time
September 14, 2019
By Steve Grinley
September and October are prime months for the fall hawk migration in New England, and I realized that it has been a number of years since I’ve discussed hawk identification, so I thought you may want to read again about the different species of hawks that you might see migrating overhead this time of year:
As the midday sun warms the earth on cool autumn days, the warm air rises into thermals on which hawks use to glide their way south. River valleys and mountain ridges provide thermal paths along which hawks migrate. In this area, the Merrimack Valley provides good thermals for migrating raptors. Behind the Page School in West Newbury is one of the more popular spots for hawk watchers in this area. It provides a panoramic view of the Merrimack Valley and you can watch hawks as they approach from the north. Old Town Hill in Newbury is another vantage point, or you may find your own favorite knoll to view the hawk flight.
Within an hour or so drive are Mount Wachusett and Mount Watatic in central Massachusetts and Mount Agamenticus in southern Maine. A little further drive is Mount Modnadnock in western New Hampshire. These are popular spots where regular (often, daily) hawk watching vigils are held in the fall where you can visit and even join in on a hawk watch.
Identifying hawks can sometimes be difficult, even for experienced birders. Plumage differences between males and females and among juveniles give the most experienced hawk watchers problems. A good spotting scope helps distinguish field marks when birds are soaring at great heights. However, a good pair of binoculars and sometimes even the naked eye can distinguish many hawk species. With a little practice, and the aid of a field guide, hawk watching can be a fun way to spend an Autumn day!
Most hawks can be identified into one of three groups: buteos, accipiters and falcons. Buteos are large hawks with broad wings and short rounded tails. Accipiters are generally smaller than buteos with rounded wings and long tails. Falcons have pointed wings and long tails.
The red-tailed hawk is probably the most familiar buteo. They are the common roadside hawk that you see sitting in a tree along Routes 95 or 495 and even along the Plum Island Turnpike. They usually have a white chest with a dark band across the belly. Its red tail is present in adult birds, but juvenile red-tails have brown tails. Though most red-tailed hawks are migratory, many are permanent residents and spend the winters here as well.
The most plentiful of the migrating buteos in the east is the broad-winged hawk. Broad-wings are smaller that red-tails with wide light and dark bands across the tail. Broadwings migrates by the thousands through Massachusetts and sometimes kettles of several hundred can be spotted on a good autumn day at popular hawk watch sites. Red-shouldered hawks and the larger rough-legged hawk are less numerous but often make appearances among the other migrating buteos.
Of the three common accipiters, the smallest is the sharp-shinned hawk. The wing beat pattern of “flap, flap, sail” is characteristic of accipiters (though other hawks do that occasionally too). The Cooper’s and sharp-shinned hawks are nearly identical in color patterns with the sharpy usually the smaller of the two with a square tail. The long, rounded tail of the cooper’s hawk helps distinguish it. Female hawks are usually larger than males so a female sharp-shinned can be as large as a male Cooper’s, making identification tricky. These two are also the most frequent hawks raiding bird feeders as 90% of their diet is birds. The goshawk is the largest, and less common, accipiter. It is crow size, and appears very light underneath.
Of the three eastern falcons the largest and fastest is the peregrine falcon which can reach speeds in excess of 60 mph with a strong tail wind or when diving for a duck or pigeon. The American kestrel is the most plentiful of the falcons during migration. Adult kestrels are identified by their small size, rusty coloration on their back and tail and light color underneath. The merlin is small like the kestrel but striped underneath with a noticeable white tip to the tail and a white line over the eyes. All three of these falcon species sport dark “sideburns”.
Several large migrating raptors don’t fall into these three groups. Harriers, once called marsh hawks, have long wings and tail and a white rump patch. The much larger turkey vulture with its five foot wingspan, has a long tail and dark two-tone wings held in a dihedral.
Another large raptor, the osprey, soars with a “crook” in the wing and its strong white and brown coloration is distinctive. Though we now have resident bald eagles in our area, you may be also be lucky enough to catch sight of our national symbol in migration, soaring on flat seven to eight foot wingspan with slightly upturned “fingers” at their tips, as they glide overhead.
Happy hawk watching!
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