The cold front that rained and blew its way through the region Thursday night may be just what the doctor ordered for boosting the magnificent annual passage of thousands of hawks around the northwest corner of Lake Erie.
These annual autumnal migrations, principally of broad-winged hawks in terms of numbers, are an internationally recognized natural phenomenon.
Timing of the major movements by species varies somewhat from year to year, but the peak period for movement of the greatest numbers of birds of prey, or raptors, generally occurs in mid-September.
On Sept. 17, 1998, for example, a record 517,000 hawks soared past two sites, and on Sept. 18, 2006, some 131,000 hawks and other raptors soared overhead.
The watch sites are along the shore at Lake Erie Metropark and Pointe Mouillee State Game Area about 15 miles northeast of Monroe, near the mouth of the Detroit River. Annually between Sept. 1 and Nov. 30, trained observers maintain the sites, scanning the skies along the mouth of a four-mile-wide migratory funnel.
Through mid week, before the cold front, more than 5,500 raptors had passed over the metropark site, some 4,000 of them broad-winged hawks and about 1,000 of them sharp-shinned hawks.
The annual observation now is known as the Detroit River Hawk Watch and its management has been turned over by the founding organization, Southeastern Michigan Raptor Research, to the Detroit River International Wildlife Refuge and its friends associate, the International Wildlife Refuge Alliance. Daily updates are available by visiting online at drhawkwatch.org, then clicking on “count data” and “hawkcount.”
No fewer than 15 species of raptors might be represented during the fall migrations.
These birds include such families as hawks, eagles, falcons, owls, and vultures.
These noteworthy passages are rooted in geography and weather. Ideal passage conditions form on the back side of a cold front, with clear skies and moderate northerly wind to help push the migrations.
As birds of prey head south from summer breeding grounds in eastern Canada, their flights run into Lake Erie on the south and Lake Huron and Lake St. Clair on the west.
Swirling updrafts of sun-warmed air known as thermal layers are favored by raptors but do not form over water, so birds heading southwest are funneled along the north shore of Lake Erie toward the Detroit River mouth where they cross into southeast Michigan and disperse southward toward their wintering grounds.
Another watch site, the Holiday Beach Migration Observatory near Amherstburg, Ont., now in its 37th season, lies across the Detroit River mouth from Lake Erie Metropark.
Through Friday morning some 6,500 raptors had passed over that site so far this month, including more than 3,300 broadwings and more than 2,200 sharpshins.
At Holiday Beach another volunteer group also watches hawks and keeps records, which can be viewed at the observatory's Web site, hbmo.org.
In conjunction with the hawk observations, celebrations are in order.
The 21th annual HawkFest, a celebration of raptors and the autumn passages, is under way this weekend at Lake Erie Metropark's Marshland Museum grounds. Hours Sunday are 10 a.m. to 5 p.m.
Featured events include environmental presentations on hawks, a live raptor rehabilitation program, and programs on the flight of hawks and the recovery of bald eagles.
Games and crafts for children also are planned, along with an optics display, exhibits, raffle, and prizes.
A Hawks Feast breakfast is set for 9 a.m. Sunday. Call the metropark for other details, 734-379-5020 extension 6836 or visit online at metroparks.com.
The annual Festival of Hawks at Holiday Beach got under way last weekend and continues this weekend with a series of events from 9 a.m. to 3 p.m.
These include nature displays and workshops, equipment displays, songbird banding demonstrations, hawk banding, monarch tagging, and hawk identification, and dragonfly migration walks.
Daily times and event details are available on the HBMO Web site.
The observatory lies within the Holiday Beach Conservation Area, 40 minutes from the Ambassador Bridge at Detroit/Windsor.
For details call 519-736-3772 or visit the HBMO Web site.
Contact Steve Pollick at:firstname.lastname@example.org 419-724-6068.
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