Waterthrushes and Gummy Bears

vieill type of Louisiana waterthrusy

Waterthrush identification and misidentification can lay bare some strong emotions. In a recent online discussion of the value of the color of the supercilium, one of North America’s best birders was moved to this outburst:

the first individual to propose [that character as a useful distinction] should be covered in honey and gummy bears and thrown to a ravaging class of preschoolers to receive their just deserts.

As soon as I’d stopped laughing out loud, I silently congratulated Cameron for knowing the phrase “just deserts” (and spelling it right!), and then, inevitably, started to wonder: just who might that sticky-fated “first individual” have been?

Pl enl 752 labeled tachetée

This particular ID chestnut turns out to be older than I’d expected. I knew that Roger Tory Peterson had used the color of the supercilium to distinguish the two species as early as the first Field Guide of 1934, and it was an easy matter to confirm that in this he was following the great Ralph Hoffman, who had written a quarter of a century before — in italics — that the Louisiana was to “be distinguished by the pure white line over the eye,” the same part of the bird “buffy in a strong light” in the northern waterthrush.

We have to go back another sixty years beyond that, though, to find what I believe is the first authoritative statement of the importance of supercilium color in identifying the waterthrushes. In 1858, Spencer Baird and his colleagues at the Smithsonian informed their readers that the Louisiana waterthrush was “readily distinguished” from its more widespread congener by its large bill and by the fact that

the stripe over the eye, besides being more conspicuous, is, with the underparts, of a decided white, instead of brownish yellow,

as in the northern. Baird, Brewer, and Ridgway would reaffirm this “field mark” in their influential History of North American Birds, published in 1874, this time reinforcing its validity in the accompanying color plate.

Ridgway 1874 waterthrushes

Before 1858, every published source seems to have relied on bill and tarsus measurements to distinguish the two species. And so the famous trio — the Nestor of American ornithology, the father of American oology, and the great cataloguer of American birds — appears to be responsible for promulgating the notion that the color of the eye stripe is sufficient to separate the brown-crowned members of the genus Parkesia. 

There we have it. Break out the honey, prepare the gummy bears, rally the preschoolers!

More about the tangled history of these species to come — 

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A July Fourth First

William Palmer

On Independence Day 1890, William Palmer, taxidermist and exhibits technician at the Smithsonian’s National Museum of Natural History, was collecting for the museum on St. Paul Island in the Pribilofs. One of the birds that fell to his gun that fateful day was Cuculus cuckoo, the first of its genus ever to be taken in North America. Palmer and Stejneger published the bird in the Auk as a specimen of Cuculus canorus telephonus, the common cuckoo of the Far East.

It took forty years for another Cuculus to meet up with an Alaskan collector. In the summer of 1930, “an Eskimo” secured a female common cuckoo on St. Lawrence Island; that bird, too, made its way into the collections of the National Museum, where Herbert Friedmann and J.H. Riley identified it as of the subspecies bakeri.

Friedmann and Riley also took the time to re-examine Palmer’s cuckoo. It turned out not to be a common cuckoo at all, but an oriental cuckoo. 

Gould, Oriental Cuckoo

Palmer died in April 1921, but Stejneger could still be consulted: he agreed that the St. Paul bird was in fact optatus, and the correction was made in the next, fourth edition of the AOU Check-list.

Cuculus, AOU 4

But the first Old World cuckoo for the New World had lain misidentified in its drawer for four decades. Or rather in its drawers. Good preparator that he was, Palmer had skinned the bird and skeletonized the carcass. The identification of the skin was corrected — but the trunk skeleton still appears in the Smithsonian‘s database as belonging to a common cuckoo.

Two for the price of one, I guess.

I am not inclined to believe that the cuckoo Palmer claims to have seen on June 13, 1890, was the individual he would shoot three weeks later — or even that that earlier bird can be identified. 


Nighthawks: An Identification Trick

Those of us in the east and midwest really have only one Chordeiles to worry about most of the time, the Common Nighthawk. In the deserts of the southwest, however, a second species, the Lesser Nighthawk, flies into the identification ointment.

Everybody knows the subtle plumage distinctions (though beware Henry’s Nighthawk!) and the differences in wing shape and vocalizations — but this time of year there’s another trick.

Common Nighthawks molt their flight feathers on the wintering grounds, far south of the US. Adult Lessers, in contrast, are shedding primaries this month, resulting in strange (but symmetrical) gaps and patches in the outer wing, as shown by the blurry bird in the photo. Neat, huh?

The 2013 ABA Bird of the Year
The 2013 ABA Bird of the Year