The Spring Migration brings a Bird Rarely Seen on Cape Cod
In this week's Bird Report, Mark Faherty tells us about a newly-arrived stranger to the shores of Provincetown.
While the return of warblers and tanagers and other brightly colored spring migrants tend to dominate the thoughts and dreams of birders this time of year, sometimes a bird turns up that makes us forget all about them. Such an oddity was found recently by Peter Flood, one of the three birders who spend so much time watching seabirds in Provincetown that I have dubbed them the “Race Point Bird Observatory.” On Sunday, Peter watched as a graceful and unfamiliar seabird floated in to Race Point to roost among the more pedestrian Common and Roseate Terns. He soon realized this striking black bird with the sharply contrasting white wings and tail was a White-winged Tern, a super-rare Eurasian vagrant. Delicately built, but deceptively tough, this bird came a long way to rest his wings on our shorelines.
Breeding from southeastern Europe through Central Asia and spends the winter in Africa, White-winged Tern should not have been on any sane birders list of possibilities for a spring day on Cape Cod. But we birders aren't generally sane, and we live to expect the unexpected. When the hardest of the hard core birders get together, the conversation inevitably turns to fantasies about what absurd rarity from some far-flung corner of the globe they might see that day.
If it sticks around, this tern is one of those rarities that will have birders all over the country booking flights – the kind of bird that can single-handedly- or single wingedly - bring a pulse of economic activity to the region during an otherwise slow shoulder season.
White-winged Terns are closely related to our North American Black Tern, an uncommon but more expected migrant on Cape Cod, mainly in fall. While Cape Codders might expect that all terns nest on ocean beaches like ours do, both our Black Terns and White-winged Terns breed in freshwater marshes in the interior of continents. So somewhere in a reedy marsh in Eastern Poland or maybe Russia, there’s probably another White-winged Tern wondering where her mate is. Some suspect bird vagrancy is largely due to male birds who refuse to stop and ask for directions, but I haven’t seen anything in the scientific literature to confirm this.
The only other birders to see it were, as you would expect, the other two members of the Race Point Bird Observatory, Blair Nikula and Steve Arena, who both were birding different parts of the beach that day. The bird ultimately ended up roosting among hundreds of terns and gulls at Hatches Harbor. Both Hatches Harbor and Race Point are important resting areas for recently arrived terns and other seabirds, who are vulnerable to repeated flushing by vehicles, dogs, and beach walkers. So when you visit these gorgeous spots, do these exhausted migrants a favor and give them some room so they can rest those tired wings.
I think of a bird like this as the physical embodiment of the magic of birding. It arrived seemingly out of nowhere, and will soon disappear as mysteriously as it arrived. What brought it here? A storm? A ship? An insatiable wanderlust gone awry? Who knows? Birds have wings. You don’t know when, and you don’t know where, but unexpected birds can turn up just about anywhere. And if you are one of the lucky ones to be in the right place at the right time to find that super rarity, that’s pure magic.
Click here for photos of the White-winged Tern taken by Peter Flood.
Mark Faherty is Science Coordinator at Mass Audubon's Wellfleet Bay Wildlife Sanctuary.