The last couple of years in late September/early October, I've noticed monarch butterflies flying, one after another, past our living room window. Then I noticed them in parks, flying just above our heads. While driving on a major thoroughfare stopped at a light, I notice a few flying at car-roof level, in traffic, dipping and flopping in air, struggling and driven by something.
All were heading south. I've seen so many by now, it's remarkable.
Since then I've learned that my locale, and thousands of others across North America, are along the yearly monarch migration route. We must be in the thick of it now, as just two days ago, I counted five flying by in a span of two minutes, all at heights approximately 10-40 feet above ground.
From the Michoacan Reforestation Fund site, I learned that:
"Monarch butterflies born in Canada and the United States begin their southward migration in the fall. Those west of the Rockies head for various sites in California, while those east of the Rocky Mountains fly all the way to Mexico. Some fly as many as 2,800 miles. There is emerging evidence that some Western monarchs reach Mexico as well. They start out one by one, but soon are joined by tens, then scores, hundreds, thousands and tens of thousands of fellow monarchs. Roosting together at night in trees and feasting on nectar from favorite flowers, they build their fat reserves as they head toward Mexico, a place which they have never been before."
Total fascination! I've got my camera at the ready.