Inexorably, the days are getting shorter, the nights cooler, the sky emptier. Little by little, we are saying goodbye to the forest gems who enliven our woods with their songs and brilliant plumage. Migration of the wood warblers is now but a trickle; the first departures are well on their way to warmer climes filled with delicious food to sustain them over the winter months until returning to our region to take advantage of the abundant insect crop.
On August 23, we captured a moulting adult female Bay-breasted Warbler, a boreal forest species, the first sign of the fall exodus. It is a species that does not breed on the Bruce Peninsula, unlike quite a few other warbler species. So, undoubtedly, it was in the process of migrating! A few days later, on August 27, two other species of the boreal forest made their appearance: a male Wilson’s Warbler, observed briefly, and two Cape May Warblers, one observed and one in the net.
Two days later, August 29, a sudden but short shower caused birds to pause their journey and take shelter. Fortunately for us, some were captured in our nets and we had a good haul of a very diverse mix of warblers. We ended up with a total of ten species of warblers on that day; some potentially local, some from far away, but all on the move. They were: Nashville, Magnolia, Myrtle (a subspecies of Yellow-rumped), Black-throated Green, Black-and-white, Mourning, Wilson’s, and Canada Warblers, as well as American Redstart and Common Yellowthroat. On that same day, we also caught the first Swainson’s Thrush of the fall. The following day, it was the first Veery.
After the excitement of the first Black Vulture at Cabot Head, seen again on August 23, we had the excitement of the second ever Carolina Wren! On the morning of August 31, we captured a young individual of this sedentary but expanding species. It breeds in Ontario mostly along the edge of Lakes Erie and Ontario. It is a species vulnerable to harsh winters, so its northward march will often be halted by a severe winter. The first ever Carolina Wren – a juvenile as well – at Cabot Head was banded on September 4, 2012.
We have also witnessed, in these last days of August, sustained movements of Monarch butterflies in substantial numbers! Even though we do not do any standardized monitoring of Monarchs, their numbers seem up this year, which is heartening.
On the evening of August 28, as we went for a walk, we were treated to a sky filled with Common Nighthawks! We were near the gate and the extensive wetland and lake on the East side of Middle Bluff, with dusk slowly deepening, when all of a sudden, Common Nighthawks started streaming by in the previously empty sky. Dozens of them flying together, low and high, far and near. It was difficult to count them accurately but we estimated at least 100 individuals were gathering and hunting in the sky, as big clouds moved in on the western horizon. We eagerly watched again the following evenings, hoping for a repeat performance, but seems it was a one evening event that we had been so fortunate to witness.