A stark change of season!

Just before the Equinox, on September 21, the weather decided to emphasize the change of seasons by bringing in very strong South winds, with rain coming in the afternoon. The warm South wind turned around into a colder, stronger, meaner North wind on September 22, Equinox Day, with very heavy rain falling down all day. This stretch of intense weather continued into the morning of September 23. Needless to say, no (or barely any) banding happened during this time and observations were quite limited, as conditions really prevented birdwatching. Birds were also very hard to find, sheltering as much as they could.

Even Bald Eagles sometimes need to perch and rest during windstorms: on September 21, the resident adult pair was perched on the edge of Middle Bluff while two immature eagles were perched more on the middle of Middle Bluff. We also watched the local juvenile Bald Eagle enjoying the easy lift of a strong wind. It is always a good day when one sees five Bald Eagles.

There was still a feel of summer prior to the Equinox with warm and clear weather allowing for full coverage of banding. As mentioned in the last blog, it is not only the weather changing but also the bird species: on September 19, we banded a total of 42 birds of 17 species, with Yellow-rumped Warbler, Golden-crowned Kinglet, and White-throated Sparrow the most numerous. These three species are short-distance migrants, wintering in eastern North America: their migration has just begun.

On the other hand, species like Black-and-White Warbler and Red-eyed Vireo have all passed through, except for the occasional stragglers. The former has not been seen for a few days and was last banded on September 13. A season record high of 91 Black-and-white Warblers were banded this fall at Cabot Head. Banding totals have  fluctuated between a low of nine birds (in 2018) to a high of 37 birds (in 2013). Red-eyed Vireos have also been banded in good numbers this fall, with 128 birds so far, the second-highest after the record of 2005 when 239 Red-eyed Vireos were banded in a fall of a record chokecherry crop. In the previous 19 fall seasons, vireo banding totals have been higher than 100 only in five of them.

It is certainly not easy to tease apart the many possible reasons for changes across the years in a messy Nature, but long-term monitoring like the work BPBO does at the Cabot Head Research Station is essential to at least become aware of these variations. The year 2021 marks a remarkable milestone for BPBO as it is the 20th year of uninterrupted long-term bird migration monitoring at Cabot Head. If funding allows, BPBO will produce a major 20-year report this coming winter, highlighting all the ups and downs of bird migration on the upper Bruce Peninsula. (Donations are of course always welcome, but if you’re eager to see storytelling done with many graphs and tables, please earmark donation to 20-year report)