Here is a quote about from my grandfather Dr. J. Murray Speirs’ Birds of Ontario (1985):
Green-winged Teal females at rest on the water are often indistinguishable from female Blue-wings. Both have a green “speculum” (a green marking on the wing which is not always shown).
This morning at Humber Bay, we saw this very small duck among a group of Mallards.
I’m calling it a Blue-winged because, in my experience, Green-winged are usually is shallow muddy water not deeper water as this was.
Bird Species list: red-necked grebe, mute swan, double-crested cormorant, great blue heron, great egret, Canada goose, mallard, gadwall, wood duck, American wigeon, blue-winged teal, hooded merganser, northern harrier, ring-billed gull, herring gull, belted kingfisher, eastern phoebe, black-capped chickadee, golden-crowned kinglet, yellow-rumped warbler, house sparrow, common grackle, red-winged blackbird, northern cardinal, American goldfinch, white-throated sparrow, song sparrow. (27 species)
O suns and skies and flowers of June,
Count all your boasts together,
Love loveth best of all the year
October’s bright blue weather. – Helen Hunt Jackson (1830–85)