30 September 2024
Yesterday afternoon a black tern (Chlidonias niger) made Allegheny County’s Rare Bird Alert when it was spotted at the main pond at Imperial. Immediately I thought of the black terns I’ve seen during spring migration at the Great Lakes with gorgeous black heads and bellies.
But black terns are not black at this time of year. I didn’t know this until we saw them from the beach at Chipiona, Spain on the WINGS Spain in Autumn tour.
In early September their bellies and faces turn white, like this one in Chipiona in early September 2024.
As time passes they become even paler. If you happened to see the black tern at Imperial yesterday it would look more like this.
Black terns live in both the New and Old Worlds. The North American subspecies (C. n. surinamensis) spends the winter on the coasts of Central and South America. The Eurasian subspecies (C. n. niger) migrates across the Mediterranean and the Atlantic coast to Africa.
They don’t look like “black” terns in non-breeding plumage. This group was filmed in January 2018, probably in Africa.