For the Birds Radio Program: Smith's Longspurs
Lifer! Laura and Paula finally got their bird, which turns out to be “polygynandrous,” with one of the highest rates of copulation of all birds.
One of the greatest thrills of birding is seeing a brand new bird—one you’ve never before seen in your life in the wild. Adding birds to my life list was fast and easy when I started birding. In 1975, I saw 120 lifers, and in 1976, 100 more. But it’s a sport of diminishing returns. Every time you add one, that’s one fewer lifer out there to add in the future.
Of course, going to new places always opens up new opportunities. I added fully 334 species the first time I went to Costa Rica. But the second time I went, I added only 28 more. If birding is in some ways a hobby of diminishing returns, at this point every new addition for me is all the more precious. When I headed down to Arkansas last month, I was of course hoping against hope to see one particular new bird, an Ivory-billed Woodpecker, which I didn’t see. But I did add one lifer—a bird I knew I’d see if I went to one place, because they’re quite reliable in Arkansas in winter—a Smith’s Longspur. I asked people on the Arkansas birding listserv before I went, and was told I could easily find one at the Stuttgart Municipal Airport. So early on the trip, on January 5, Paula, Photon, and I headed there.
The Stuttgart Municipal Airport is a tiny place with clean, well-maintained runways and a small building with a friendly staff. It was a completely different experience than trying to catch a glimpse of a Snowy Owl at the Duluth Airport post 9/11, where police and security people instantly chase away anyone with binoculars or a scope. When we arrived at the Stuttgart Airport, there was a guy in his upper teens or early 20s on duty. He wasn’t familiar with the bird but told us where he thought birders were going to see it, by heading to one side of the runway, and he sent us right out there.
The wind was gusting to well over 30 and viewing was tricky. Though we found plenty of Savannah Sparrows and Lapland Longspurs, we didn’t see a single Smith’s. We were naturally disappointed, but decided to try again, closer to the end of the trip.
This time the man on duty was the airport manager, who was just as friendly but more experienced and knowledgeable than the boy we’d spoken to on the earlier venture. He told us exactly where the birds would be, and encouraged us to drive out and park near some old hangars to make our search even easier. Sure enough, we came upon a whole flock of Smith’s Longspurs.
They’re fairly nondescript sparrow-like birds, still in winter plumage so lacking the cool facial markings they assume in breeding plumage, but are pretty easy to identify, with white outer tail feathers and a buffy underside. It was windy again but we got great looks at a few, as well as seeing a group of 20 or 30 fly right over our heads.
I was thrilled to see this new species, but nowhere near as thrilled as when I started reading about it. It turns out that Smith’s Longspurs are the kind of birds that would make great guests on some steamy, seamy TV talk show. Unlike the majority of songbirds, Smith’s Longspurs are polygynandrous. Each female mates with two or more males for a single clutch of eggs, at the same time that each male mates with two or more females. Males are not territorial, but instead compete for fertilizations by mating frequently in order to displace or dilute sperm from other males. Over a period of one week in June, a female Smith’s Longspur will mate over 350 times on average. This is one of the highest copulation rates of any bird. Males appear well equipped to service them. Their testes are about double the mass of those of their close relative, the monogamous Lapland Longspur. As expected from their mating behavior, most Smith’s Longspur broods contain chicks of mixed paternity. At such nests, two or more males may assist females in feeding nestlings. The advantages of extra-male help in raising offspring may partly explain why female Smith’s Longspurs mate with more than one male. It’s interesting that the system is so well developed in this one species, when so very many songbirds, including their close relatives, are far more monogamous.
I suppose that humans who mate with a great many partners often sign hotel books with the name “Smith,” but Audubon named this species in honor of his friend Gideon B. Smith of Baltimore. Of course, Audubon didn’t know about the species’ mating habits, which weren’t understood until the 1990s. Smith’s Longspurs may be promiscuous, but apparently they’ve been very discreet about it.