Wednesday, June 15, 2011

Whimbrel in Duluth

(Transcript of today's For the Birds)

This spring’s weather has disrupted a lot of birds. A woman in my own neighborhood called me this week to tell me that her chickadees had finally abandoned their nest and 7 eggs—she’d been incubating them for over a month before she finally gave up. There is a fairly good chance that one or two eggs in a clutch can be infertile, but for all the eggs to fail means there probably was an issue with the weather. The cold, late spring meant that male chickadees probably didn’t have an easy time searching out enough food for themselves and their mate, so the female probably had to spend too much time off the eggs for the embryos to develop.

After witnessing one of the biggest Fox Sparrow migrations ever, at least in my area, we had a surprisingly pitiful migration of White-throated and White-crowned Sparrows, and bird song in my neighborhood has seemed subdued ever since the Fox Sparrows moved on. It’s hard to know whether large numbers of birds were killed in the storms and tornadoes this spring—some birds seem to be migrating still. There were still Red-throated Loons being seen along Park Point in Duluth the first week of June, and one Whimbrel was still hanging out at the ball fields in Park Point on June 14.

Whimbrels are larger than most songbirds, but smaller than crows and much more delicately built. They’re softly mottled and streaked, with very dark stripes running lengthwise along the crown. Their most conspicuous mark is the long bill, which curves downward. Their generic name, Numenius, is Greek for “new moon,” in reference to the curved bill.

The Duluth Whimbrel has been confusing a lot of people, particularly because it’s hanging out on the soccer field where it crosses paths with a lot of non-birders. When people look it up in their bird books, they’re even more puzzled because field guide range maps don’t show them migrating in the Great Lakes area. The vast bulk of Whimbrels migrate along the coasts, some making a nonstop Atlantic flight of up to 2,500 miles from southern Canada or New England to South America. But individuals do take an over-land route and we see Whimbrels in the western Lake Superior area every year during migration. Mid-June sightings aren’t so common. Unlike most shorebirds, Whimbrels are monogamous, both sexes sharing incubation duties and then brooding and feeding the chicks. The breeding season is very concentrated and short on their tundra breeding grounds, so it’s doubtful this poor straggler will make it up there to breed this year.

The reason this individual is sticking around will never be known, but we can speculate. Whimbrels winter along the Gulf of Mexico, where they are adept at catching and eating marine invertebrates, especially crabs. This bird may be suffering neurological or physical problems from eating contaminated food in the Gulf this winter, or it may have been disoriented by hitting a bad storm, or it may simply have been delayed by cold weather. Whatever brought it there, the bird is moseying about in the open for everyone to see, but he’s just not talking.