Have you ever noticed those bunches of old leaves and twigs up in the trees? Until recently, like most people, I had no idea what they were. Then I was enlightened by my wife, who drew my attention to them; and my daughter, who works at the Kortright Centre, knew what they were. There are many of them in the ravine. They are called dreys. The word does not appear in my Gage’s Canadian dictionary and is evidently rare. Here is a photo of a drey near the Bathurst St bridge:
Dreys are squirrel nests. They are built of twigs, dry leaves and grass (and no doubt bits of plastic too), typically in the fork of a tall tree, but also sometimes hanging precariously in the branches. Inside they form a hollow sphere about a foot or more in diameter, lined with finer materials such as grass, moss, leaves, shredded bark and pine needles (thanks to Wikipedia for these details). They may have one or two entrances, the second one used as an emergency exit. They need constant maintenance to keep them waterproof.
Apparently, squirrels prefer to nest in tree holes, which are much safer from predators, especially if the entrance is small enough to keep raccoons out. But there are often too many squirrels for the available tree holes, so the dreys provide overflow capacity.
Next time you are walking through the ravine, watch out for the dreys!
Below this post is an example of why I dislike Tumblr: my finger slipped while I was typing the title and the unfinished post was prematurely posted!