A report on the Ontbirds hotline made me hop to attention recently.

Margaret Bain had seen 250 red-necked grebes in the bay off Thickson's Woods Nature Reserve in Whitby that day. Two hundred fifty! I feel lucky to see a handful of these excellent divers as they migrate northwestward in spring, toward shield and prairie lakes where they nest.

Grebes look somewhat like ducks, with smaller heads and longer necks. Like diving ducks, they feed underwater on whatever small animals are to be found -- fish, crustaceans, larvae of diving beetles and other insects. Instead of webbed feet, they have lobed toes to power their swimming.

Like loons, their legs are situated well back on their bodies, making them graceful in the water and awkward on land. That's why, like loons, they place their nests, plant material piled on top of floating vegetation, right next to open water, where they can dive to safety if approached by danger. A wonderful spot for a baby bird to sleep, gently rocked by the rippling waves.

Mostly a dusky grey where they winter just offshore along the Atlantic coast, Ontario's largest grebes acquire a black cap, white cheek patch and rich cinnamon neck in breeding plumage, hence their name. They carry on courtship as they migrate, solidifying strong pair bonds by performing elaborate dances together, including running across the water like penguins, side by side.

Red-necked grebes normally pass through Durham Region in April and early May. They sometimes gather in great numbers on favourite shallow bays of lakes, waiting for a south wind before they move on, flying at night.

Two days after Margaret Bain's sighting, I managed to get down to the shore of that exact same bay with my scope. The sun was sinking in the west and the slanting rays lit up the ruddy necks of several loose flocks of what were not, in fact, red-breasted mergansers, often the commonest waterfowl there in spring. No, they were red-necked grebes, a dozen here, another dozen there, a handful splashing over the water together, trying to take off in flight. I must've seen a hundred all told, likely more than I've ever seen together in my life.

I'll file that thrilling scene in my memory, alongside mental pictures I have of a summer day in northern Saskatchewan. My husband and I were on a canoe trip there, paddling down a small river, when we saw a bird quietly slip off her floating nest in a calm reedy section at a bend near a lake. Red-necked grebe!

The same day I saw my grebes in Lake Ontario last week, 130 more were counted offshore Second Marsh in Oshawa.

To hear and report other great bird sightings, now that migration is in full swing, check the Durham Region Field Naturalists hotline, faithfully managed by Rayfield Pye: 905-576-2738.