While out for a jog the other day, I spotted two birds flitting along the trees on the Don Trail at Beachwood.
they looked like they were the size of chickadees with the colour of a nuthatch, but muted. i watched on skirt through the trees, making a strange sound. i heard a second one returning the call, but I didn't see it clearly.
went home and took a look at some pictures and I'm relatively certain they were blue-gray gnatcatchers. i couldn't ID an eye ring, but the call, size and colour lead me to think that its what I saw.
anyways, for those who frequent the area (and if you don't, i don't really suggest using the trail this year....construction's making it a mess), keep your eyes open.