Labor Day and the beginning of September are often seen as the beginning of the fall season despite the fact the autumnal equinox is not until weeks later (September 23 this year). However, many of our birds agree with this assessment as well. You can find migrant passerines beginning to disperse and even some moving south in July. Shorebirds can be found on the way to wintering quarters in terrific numbers in “fall” migration in the middle of what we think of as a hot summer day. Raptors including many species of hawks, accipiters, falcons, eagles, vultures and more start to move to the south in considerable numbers in September along the Atlantic Coast.
As the days get shorter and the air gets cooler the hawk watchers among us need to begin to monitor the weather even more closely. What we want to find are cold fronts passing through the region followed by strong high pressures providing west, northwest and north winds of a moderate intensity under sunny skies with, optimally, some light cirrus clouds. As the sun heats the ground this warm air rises creating columns of thermals that help keep raptors aloft. Winds from the cooperative directions noted above help to push them south or east to the Atlantic Coast or along ridge lines. This makes their journey swift and all the more effortless.
Broad-winged Hawk kettle
Having patches of wispy clouds overhead makes the hawk watching much easier for humans! As the day warms the raptors will get higher and higher in the sky, disappearing into the depths of the blue around midday if they have no backdrop. You can still find some, certainly, but it requires a lot of intensive staring and scoping or you will only see the handful coming by at low levels.
What are we looking for in September? The massive push of Broad-winged Hawks is usually the highlight with thousands of birds being seen at prime locations mid-month if the conditions align correctly. A few local residents (me being one of them) started a hawk watch at Boothe Memorial Park in Stratford, Connecticut several years ago. We have had several very memorable days in this handful of years, some being historic for the Northeast, with only opportunistic watching including one with 8,234 raptors, 8,041 of them Broad-wings, on September 16, 2011. We will soon see if this year provides such a show! I’ll be writing more soon about specific watch days this fall from our site in Stratford.
Scott Kruitbosch
Conservation & Outreach Coordinator
