A grebe (pronounced "greeb"), on Picket Lake in May of last year.

Some of you more astute birders, may recognize this as a Western grebe Aechmophorus occidentalis.

Just a few years back, this would have been considered a "dark phase" Western grebe. The "light phase" of the species, which is rarer, at least around here, would look identical except the white on the face went higher up, above the eye. You could find both colour types together. Most folks just assumed these were colour variations of the same bird, sort of like skin or hair colour in humans.

We were wrong.

Don't know the specifics, but somewhere along the way, some observant folks noticed that the dark phases always mated with the darks, and the lights with the lights. And that the elaborate courtship dances, which involve a lot of running alongside each other on top of the water, were different between the dark and light phases.

And in recent years, it was finally settled. What we were unable to readily distinguish was apparently quite obvious to the birds.

They're two different species.

The "light" version is now known as "Clark's grebe", Aechmophorus clarkii.

And I've yet to identify one. So don't be surprised if I spend a lot of time staring at apparently identical birds out on the water.

The white faces are hard to pick out.