Equality on Earth: Fall equinox is on September 22!

If the Earth was not tilted relative to the Sun, there would be no seasons, no variations, no changes throughout the year. But it is tilted and everything is different. In a few days, on September 22, it will be the Fall Equinox, one of two days on Earth when the lengths of day and night are equal, regardless of where one is on the globe. Whereas you are at the North Pole, at the Equator, or at the South Pole, or simply at 45°N on the Bruce Peninsula, you will experience the same length of day and night. The Fall Equinox is thus a day of equality on Earth, albeit in an astronomical sense. Very rapidly after the Equinox, the tilt in the Earth will bring declining day length North of the Equator and the opposite South of the Equator.

It’s been 3 weeks since the last blog, so I will highlight a few birds and a few days instead of going through every day. September is when we say good-bye to many species, mostly the long-distance migrants (warblers, vireos, hummingbirds). We also welcome the short-distance migrants, like kinglets and sparrows, mostly after mid-September.

On September 1, we detected a Yellow-billed Cuckoo. On September 8, a season high total of 18 warbler species were detected, with quite a few Tennessee, Yellow-rumped, and Blackpoll Warblers as well as American Redstarts. On that day, three species of vireos were also detected: Blue-headed, Philadelphia, and Red-eyed. There were lots of Cedar Waxwing and one Ruby-crowned Kinglet during that busy day.

In the darkness of pre-dawn of September 9, an Eastern Whip-poor-will called across the basin. On September 14, it was overcast with a strong North wind: hearing little calls as we opened nets, I was ready for a sudden arrival of boreal sparrows. And sure enough, on the first net round, we collected 19 White-throated Sparrows (out of 26 birds during that one round). We closed nets shortly afterward as the North wind increased and showers fell on and off during the morning. 

A Red-throated Loon was seen flying and then bobbing in the waves of the bay on September 17. On September 20, a large movement of birds was evident after mid-morning, which was reflected in high numbers of captures, resulting with a season high of 78 birds banded of 18 species, with 42 birds in the 11 o’clock net round, and a total of 43 Yellow-rumped Warblers. There were a lot of Red-breasted Nuthatches and Black-capped Chickadees during that morning but luckily not so much in the nets. Three species of Catharus thrushes were captured that day: Gray-cheeked, Swainson’s, and Hermit! September is the month when the first two move through on their way to northern South America, whereas Hermit Thrush tends to migrate later, mostly in October, as this species doesn’t go as far south (wintering grounds are mostly in southern USA). September 20 was also the day of the first White-crowned Sparrow.