356 BULLETIN 191, UNITED STATES NATIONAL MUSEUM 



cavity, excavated by the birds, in a dead willow stub about 5 feet from 

 the ground. 



A set of six eggs, in the Doe collection in the University of Florida, 

 was also taken by Mr. Pope, on April 4, 1911, in the same locality and 

 similarly located ; the nest was "composed of rabbit fur, and plant down, 

 firmly felted together." 



Eggs. — The eggs in the Thayer collection are short-ovate and only 

 slightly glossy. They are white and are rather well covered, especially 

 about the larger end, with fine dots and small spots of reddish brown, 

 "hazel," and with a few underlying spots of "pale purple-drab." 



The measurements of the above 12 eggs average 14.3 by 11.1 milli- 

 meters; the eggs showing the four extremes measure 15.3 by 11.4, 14.0 

 by 11.5, 13.5 by 11.0, and 15.3 by 10.6 millimeters. 



Plumages. — Young Mexican chickadees, in juvenal plumage, are simi- 

 lar to the adults, but the blacjc of the head is duller, and the plumage is 

 softer, shorter, and less firm. The postjuvenal molt of young birds and 

 the annual postnuptial molt of adults seems to occur mainly in August, 

 beginning late in July and continuing into early September, according 

 to what few molting specimens I have seen. Birds in fall plumage, 

 adults, and young being practically indistinguishable, are slightly more 

 strongly tinged with olive than are the faded spring and summer birds. 



Voice. — Dr. Frank M. Chapman (1898) published the following short 

 note on the voice of the type race, as observed by him at Las Vegas, 

 Veracruz : "The call of this Titmouse is a rapid, vigorous, double- 

 noted whistle repeated three times, and not at all like the notes of Parus 

 atricapillus. In its conversational 'juggling' notes there is, however, a 

 marked similarity to the corresponding notes of that species," 



DISTRIBUTION 



Range. — Highlands of Mexico from Veracruz and Oaxaca, north to 

 southern New Mexico and Arizona; nonmigratory. 



The range of the Mexican chickadee extends north to southern Ari- 

 zona (Mount Lemmon and the Chiricahua Mountains) ; and southern 

 New Mexico (San Luis Mountain). East to southwestern New Mexico 

 (San Luis Mountain and Animas Mountain) ; Puebla (Teziutlan) ; and 

 Veracruz (Orizaba, Los Vigos, and Jalapa). South to central Vera- 

 cruz (Jalapa) ; Oaxaca (La Parada) ; and central Guerrero (Omilteme). 

 West to eastern Guerrero (Omilteme) ; Durango (Cienaga de las 

 Vacas) ; western Chihuahua (Pinos Altos) ; and southeastern Arizona 

 (Mount Lemmon). 



Two forms of this species are recognized but their respective ranges 



