Winter Range of Oklahoma's Hybrid Orioles
Winter Range of Oklahoma’s Hybrid Orioles
A few years ago the writer reported on oddly plumaged orioles from Oklahoma which he believed to be hybrids between Baltimore and Bullock orioles, Icterus galbula and Icterus bullockii (Auk, 55, 1938: 1-6). Recently, while examining the Baltimore Orioles in the collection of the American Museum of Natural History, he came upon three more of these hybrids, all highly plumaged males from Guatemala. The most obviously intermediate of the three is very much like iigure 2 in the color plate illustrating the Oklahoma birds, the principal difference being that in the Guatemala bird the corners of the tail are orange rather than yellow, and the white tipping of the greater coverts is a little less extensive. This bird (no. 398609) was taken at San Lucas, Guatemala, on December 26, 1927; it was probably in its winter hotie (see Griscom, Bull. Am. Mus. Nat. Hist., 64, 1932:390). The other two (nos. 398601 and 398597) were taken at San Lucas, November 16, 1926, and at Panajachel, October 14, 1926. They are closer to galbda than to bullockii, but the paleness of the middle coverts, the extensive white tipping of the greater coverts, and a tendency to dusky tipping of the outer rectrices reveal their bullockii blood. Close examination of all Central and South American specimens in our museums will doubtless reveal further examples of these hybrids, and it would be interesting to discover where most of them winter.
George Miesch Sutton
Cornell University, Ithaca, New York, October 20, 1941