Walking through a cloud of Monarchs!

The past week brought us some remarkable weather, with a succession of intense thunderstorms during the weekend, finally breaking the heat wave, and ushering in stable conditions of clear skies, light North wind and perfect temperatures. We can feel the first hints of fall in the crispness of dawn and coolness of night but the sun is still strong and warm during the day: Goldilocks would be happy!

On August 28, a dark ominous western horizon greeted us at dawn, accompanied with a very strong South wind: it was clear that a storm was brewing. We nonetheless opened the few nets not impacted by the wind while keeping an eye on the radar. As the light dimmed and the clouds got closer, we decided to close the nets after only an hour. Shortly afterwards, an intense thunderstorm moved through Cabot Head. The sky cleared later in the morning but the wind stayed too strong to open nets again. We spent the rest of the day watching mixed flocks of migrants moving through, as well as numerous Monarch butterflies arriving from Georgian Bay in seemingly endless streams. Bay-breasted Warbler was the most abundant species, with an estimated total of 50 birds, an unheard number for Cabot Head in any given day in fall (or spring, for that matter). Ten other species of warblers were also detected that morning, albeit in much smaller numbers, with boreal forest specialists like Tennessee, Cape May and Blackburnian Warblers.

The following day, August 29, started like a repeat with strong South wind and dark clouds, a few nets open for an hour before closing them in a hurry while the sky opened up. The first drops started to fall as we were closing the first net but a few minutes later we were thoroughly soaked under an intense downpour. It was intense but short lived: both rain and wind ended quickly, allowing us to open all the nets for the rest of the morning. In that remaining time, we banded a total of 27 birds of 10 species, including 11 Bay-breasted Warblers. It is the highest daily banding total for this species ever: from 2002 to 2020, all daily banding totals have been from one to three Bay-Breasted Warblers, except for three days with totals of 6, 8, and 9 birds. It seems possible that many Bay-breasted Warblers seen the day before in high numbers stayed around. On August 29, another storm rolled in during the evening: please check the pictures on Instagram and Facebook.

During these stormy days, dozens and dozens of Monarchs roosted and stayed at Cabot Head in numbers I have rarely seen before. They favoured branches of trees lining the road to the station at the end of our regular net checks. We were walking through clouds of Monarchs, an orange fluttering of wings, seemingly fragile and insignificant, but actually ready for their incredible migration to the high forests of Oyamel firs in the central highlands of Mexico. When the contrary winds stopped, when the unsettled air blew away, when dawn came clear on a North wind, they left us, resuming their journey on a wing and a butterfly prayer.

After the storms, we have indeed entered a period of clear skies, light North wind, cool nights: perfect conditions for winged migrants, either scaly or feathery. Many, if not most, of the birds blocked at Cabot Head by the bad weather have now departed, reflected in low numbers of birds seen and captured. The calls of Black-caped Chickadees very often alert us for the few waves of birds rippling through the trees, mixing up species in a fun diversity of Vireos, Warblers, Nuthatches, aforementioned Chickadees and sometimes flycatchers. It is then a game of hide-and-seek with birds appearing and disappearing between leaves, providing frustrating brief glimpses, challenging our observation skills: like a jigsaw puzzle missing many pieces, one needs to build a complete picture from a bit of a tail, a fraction of a wing, some belly. A fun game to play, very different from the full view of resplendent plumages in the bare branches of spring: Fall migration, the best thing after Spring migration!

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