302 PROCEEDINGS OF THE NATIONAL MUSEUM vol.93 



MIMUS POLYGLOTTOS LEUCOPTERUS (Vigors) : Western Mockingbird 



Orpheus leucopterus Vigoes, The zoology of Captain Beechey's voyage, 1839, 

 p. 17 (Monterey, Calif.). 



In the sand dune area near the coast at El Conejo, Carriker found 

 mockingbirds common, but we did not note them elsewhere in the 

 area that we covered, except that I saw one from the train near La 

 Piedra between Alvarado and Veracruz on April 16, also in the 

 coastal area but farther north. Carriker secured a series of ten birds 

 on February 10 and 12 and May 15. On the last date he observed 

 that they were nesting. 



The specimens secured are of more than ordinary interest. Cur- 

 rently it has been held that Mimus polyglottos as a species, when 

 compared with M. gilvus, is marked by white primary coverts, exten- 

 sive white on the basal portions of the inner primaries, and by having 

 the outer rectrix white except occasionally when there is a blackish 

 margin on the outer web. In Mimus gilvus as a species the primary 

 coverts have been said to be black, the bases of the primaries without 

 white, and the outer rectrix with the base extensively black. Actually 

 the subspecies Mimus gilvus gracilis often has considerable white on 

 the inner webs of the primaries at the base. Also, in Mimus poly- 

 glottos polyglottos an occasional individual has extensive black mark- 

 ings across the center of the outer rectrix. We have two female birds 

 from Hornbeak, Tenn. (No. 351105), and Jacksonville, Fla. (No. 

 54867), that show this character. A female of M. p. leucopterus 

 from Fort Verde, Ariz. (No. 235964), shows the same marking to a 

 less extent. It appears then that the color of the primary coverts is 

 the most definite character separating the two species though here 

 there is occasional black tipping in polyglottos. It may be noted that 

 gilvus is always grayer and that its bill is somewhat more slender. 

 The two are close but sufficiently different to warrant maintenance 

 as distinct specific groups. 



The two species polyglottos and gilvus meet across the Isthmus of 

 Tehuantepec, where they merit careful study. We have in the 

 National Museum from the city of Tehuantepec a skin of M. g. 

 gracilis taken on October 29, 1869, and one of M. p. leucopterus on 

 February 12, 1904. Similarly, from Puerto Mexico (Coatzacoalcos), 

 Veracruz, there is a series of M. g. gracilis taken on April 13 to 15, 

 1896, and January 27, 1904, and one leucopterus dated January 28, 

 1904. 



At the point of junction through this region the two species appar- 

 ently hybridize at times. From El Conejo we have one male (No. 

 360063) with the black tail markings of gilvus and the white primary 

 coverts of polyglottos, and another of the same sex (No. 360059) that 

 displays a slight tendency in this direction, as the inner web of the 



