BIRDS OF ARGENTINA, PARAGUAY, URUGUAY, AND CHILE 89 



With this in mind, the following brief synopsis of my findings as to 

 the valid forms and their distribution will be clear. 



CATHARTES AURA AURA (Linnaeus). 



Vultur aura Linnaeus, Syst. Nat., ed. 10, vol. 1, 1758, p. 86. (State of 

 Vera Cruz, Mexico."*) 



The typical form of the turke}^ vulture has the wing coverts dis- 

 tinctly margined with brown like C. a. se2)te7ifrionalis, but is smaller 

 as the measurements of the wing range from 475 to 510 mm. It 

 ranges from Panama (Empire, Fort Lorenzo) northward into Mex- 

 ico, and in the West Indies. Swann'^^ has described the bird from 

 Cozumel Island as C. a. insularis. From the description this is ap- 

 parently similar in size to au7'a (wing 470-505 mm.), but is said to 

 be darker. As Cozumel Island lies only 15 miles from the main- 

 land, I am inclined to consider this as doubtfully distinct (no speci- 

 mens are at hand), and for the present a synonym of aura, espe- 

 cially since there is some variation in degree of blackness in that 

 form. The type of Gathartes hurrovianus Cassin^* has been ex- 

 amined by Nelson and pronounced identical with aura. 



CATHARTES AURA SEPTENTRIONALIS Wied. 



Cathartes septentt-ionali-s "NVied, Reise Nord-America, vol. 1, 1839, p. 162. 

 (Near New Harmony, Indiana.) 



The northern turkey vulture is similar in color to typical aura, 

 but is larger, with a wing ranging from 520 to 553 mm. It ranges 

 from the northern part of the Mexican table-land north through the 

 United States into southern Canada. The southern limit attained 

 by this form in Mexico is uncertain, 



CATHARTES AURA RUFICOLLIS Spix. 



Cathartes ruficollis Spix, Avium Spec. Nov. Brasiliam, vol. 1, 1824, p. 2. 

 (Interior of Bahia and Piauhy.) 



The turkey vulture of eastern and northern South America is 

 similar in size to typical aura, as the wing ranges from 495 to 

 510 mm., but differs in blacker color and in restriction of the brown 

 edgings on the wing coverts. It ranges from Paraguay (probably 

 from northern Argentina and Uruguay) north through Brazil into 

 the Guianas and Venezuela. The applicability of the name ruficollis 

 to the red-headed turkey vulture is discussed under the account of 

 the yellow-headed vulture. Hellmayr ^'^ has stated that Spix's type 

 of ruficollis was no longer extant, and referred the name to aura 

 with a query. I think there can be no valid reason for not recog- 



*^Type locality fixed by Nelson, Proc. Biol. Soc. Washington, vol. IS, Apr. 18, 1905, 

 p. 124. 



««Syii. Accipitres, ed. 2, pt. 1, Sept. 28, 1921, p. 3. 



" Proc. Acad. Nat. Sci., Philadelphia, vol. 2, 1845, p. 212. 



s^Abhandl. K. Bayerischen Akad. Wiss., II Klass. vol. 22, pt. 2, 1906, p. 567. 



