David and I had a nice surprise today in the form of a text message from John West, saying that he had just found a Least Tern at Rotary Park! This being a state bird for both of us, we rushed down to the sweltering beach (113 F) and were happy to see the little elf still there.
Least Tern is one of several species that presumably wander to Arizona from populations along the upper Gulf of California, but are much more regular in central and southeastern Arizona than here in the LCRV. I believe there are fewer than 10 records.
I haven’t spent much time with Least Terns, especially in recent years, so it was fun to watch and study this bird. It was still quite young, with a bit of brown remaining on the scapulars and pale tips to some of the wing coverts. When it spread its wings, the white triangle on the inner wing formed from bright white outer secondaries and greater coverts and inner primaries contrasted with the rest of the wing, forming a shadow of a dark “M” pattern. Most striking, of course, was the diminutive size. A rare Snowy Plover was on the beach with it; the two were about the same size, but I would guess the Snowy Plover was heavier. The Least Tern was dwarfed by Forster’s Terns and Killdeer, and it may as well have been a speck of sand next to a Caspian Tern.
The light wasn’t great, but I took a video of the bird loafing on the beach. (I recommend changing the quality to high def.) Check out the size comparison with a diminutive Snowy Plover!
John got some great photos before we arrived, but David got some too.