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Jun
22

Sharpe’s Pygmy Finch

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Also known, as of this latest Supplement to the AOU Check-list, as the Morelet seedeater.

Morelet White-collared Seedeater

The re-split of the white-collared seedeater into the Morelet seedeater and the cinnamon-rumped seedeater will strike many birders as a “no-brainer,” and the NACC’s decision in this case aligns the AOS taxonomy with most other authorities’ treatment of these tiny tanagers. The only thing we’re likely to have trouble with is the spelling of the name of one of the “new” species.

As the NACC points out, both the scientific and English names of the northern bird commemorate the Burgundian natural historian, novelist, and illustrator Pierre Marie Arthur Morelet, active in the mid-nineteenth century in Africa, the Azores, Middle America, and the Caribbean. In 1850, two years after Morelet’s return from Central America, Charles Bonaparte published a new seedeater in his honor — but misspelled the explorer’s name in the species epithet, an error that has never been corrected and likely cannot ever be.

Morelet had collected the first specimens in northern Guatemala in 1847; Bonaparte examined them at the Muséum national d’histoire naturelle shortly thereafter. I understand Bonaparte’s mention here of the MNHN curator Jacques Pucheran as identifying the author of a manuscript name, probably on the specimen label, adopted and then misspelled, or at least not corrected, by Bonaparte. In any event, we are stuck with the error, and with the disparity between the number of consonants in the English name and in the scientific name.

Less than a year after Bonaparte’s publication, John Porter McCown collected two male seedeaters in Brownsville, Texas, the first records of the genus north of Mexico. Now numbers 41295 and 41296 in the collections of the American Museum of Natural History, these birds were at first identified by George N. Lawrence as white-throated seedeaters, a species known only from northeastern South America. In July 1856, Philip Lutley Sclater demurred, suggesting that the individuals Lawrence had described were probably in fact representatives of the Morelet seedeater. Two years later, with at least one of the McCown specimens at hand, Spencer Baird — in an authoritative book written with the assistance of George Lawrence — agreed.

White-collared Seedeater, male, Guatemala

We know today that Sclater and Baird were right, but it took decades for the matter to be settled. In 1888, Richard Bowdler Sharpe determined that the Texas birds were female ruddy seedeaters; in what should have been a sweet piece of poetic justice, Lawrence himself had described that species six years earlier.

In gentlemanly response, Lawrence re-examined other Texas specimens belonging to George Sennett, then on deposit at the American Museum. He was able to dismiss their allocation to the ruddy seedeater, but found at the same time that they were not identical to “the true S. morelleti,” either. He accordingly described the northerly specimens as a new taxon, S. morelleti sharpei, recognizing in the subspecific epithet his “friend, Mr. R.B. Sharpe, as he is the only one to have recognized it as being distinct” from nominate morelleti. 

The source of all that confusion was the dull plumage of males in the northern portions of their range. Generations of birders have been mildly disappointed on seeing their first Texas seedeaters at how far from truly “white-collared” the birds there are. Robert Ridgway, in declining to recognize Lawrence’s sharpei, speculated that “fully adult males have simply not yet been taken” north of Mexico, and that it was just bad luck that we in the US did not get to see the more dramatically marked individuals. The AOU quickly removed sharpei from its list of recognized subspecies.

In 1907, with a wider range of specimens available to him, Joel Asaph Allen figured it out. It was not a case, he wrote, of coincidence, but one of genuine geographic variation:

the adult males of the Texas form do not acquire the broad black pectoral collar and the black back of typical morelleti, and … in consequence … have been considered as … immature.

The differences extended to females as well, and Allen found them sufficient to reinstate Lawrence’s sharpei. The bird variously known in English by such names as the little seedeater, the Sharpe finchlet, and the Sharpe pygmy finch re-entered the AOU Check-list the next year. It is still recognized as a valid subspecies by the most authoritative world lists.

Next time you get to see a Morelet seedeater, remind yourself who Morelet was. But also give a thought or two to those who dedicated so much time to figuring out just what the French naturalist had collected on that day in 1847.

 

 

 

 

 

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