Broad-winged Hawks began their first major push through the area this last week during the passage of the first good cold front of the season, with 1185 counted on 11 September and 7228 counted on 12 September. Temperatures dropped to near freezing to our north the night of the 12th, which seems to be the trigger which always get these birds to move. The flight on the 12th was spectacular, with the kettles out over the lake increasing to over 500 in the late afternoon, and we stayed late that day to watch as some of these birds participated in a “fall-out”, dropping out of the sky to roost in the trees around the ridge. We anticipated a good “lift-off” of birds the next morning as they came out of the trees to begin their migration, and we were not disappointed, with about 350 getting up over the ridge in modest kettles, but unfortunately a southeast wind developed during the late morning, which pushed the kettles further inland, so whatever migration occurred later in the day was not visible to us. Besides Broad-winged Hawks, most other species have been slowly increasing in numbers as well, especially Sharpies and kestrels.
|juvenile Broad-winged Hawk over Hawk Ridge|
|kettle of Broad-winged Hawks over Hawk Ridge|
Every fall there is usually at least one or two days when mass migration events occur. As observers keenly interested in migration, these are the days we live for- when there are birds everywhere, and no observer can possibly even begin to see all the birds flying over. This fall, such a mass migration event occurred on 11 September. Sometimes, these events are not predictable and seem to occur without warning, but the fight on 11 September was easy to predict with the passage of a cold front after a long period of above normal temperatures. Although I have seen many days with greater numbers of birds counted, the thing that made this flight of 6960 non-raptors so amazing was the diversity of birds moving at the same. Many of the early season species such as Cedar Waxwings, Common Nighthawks, Cliff Swallows, and Red-winged Blackbirds were still moving, while later season species such as Rusty Blackbirds, Common Grackles, American Pipits, Lapland Longspurs, Golden and Ruby-crowned Kinglets, Purple Finches and American Robins were all just beginning to move, plus the first big push of Blue Jays, a record count of 107 Rose-breasted Grosbeaks, and the biggest warbler flight of the season including at least 15 species and over 2,000 individuals. The diurnal part of this massive flight began sharply at sunrise, but many of these birds had also been moving before dawn as well. Hundreds of Swainson’s Thrushes were heard flying over well before sunrise, when the night sky was literally ringing with their calls at the rate of 5 per second or more., but since each bird calls multiple times as it flies over, it is impossible to count the number of individuals, though I I believe the number had to be at least 500 Swainson’s Thrushes. A few Gray-cheeked Thrushes and Veeries were heard as well. When faced with such an amazing flight of birds, and knowing that there are thousands and thousands of birds flying that were not seen, sometimes all one can do is just say “wow!” Other highlights this last week have been a family group of three Ross’s Geese seen at the mouth of the Lester River just before sunrise, and a good diversity of sparrows showing up with first big push of White-throated Sparrows, many of which have been seen at the feeding station on the ridge, including Clay-colored, Swamp, Lincoln’s, and White-crowned Sparrows.
|Swainson's Thrush resting in early morning light after nocturnal migration|