64 FALCONID^. 



the type specimen with a series of B. calurus. Capt. Bendire agrees with this 

 determination. 



Buteo costaricensis would appear to be the small form of Eed-tailed Buzzard resident 

 throughout Central America. It has a white chest-patch, instead of a rufous one, and 

 the upper surface is uniformly coloured, the head being of the same dark chocolate- 

 brown as the back, though occasionally rufous or grey-headed examples are seen. 

 The throat is white, with a few narrow dark stripes, and the abdominal patch is 

 rufous, without many dark spots ; the thighs are decidedly rufous, especially in the 

 more southern examples. 



It must be stated, however, that intermediate specimens of all the above-named races 

 are to be found in the collection of the British Museum, and that a series, when laid 

 out for examination, shows nearly every possible link of intergradation between all the 

 above-mentioned forms. 



5. Buteo socorroeusis. 



Buteo borealis, var. montanus (nee Nutt), Grayson, Proe. Bost. Soc. N. H. xiv. p. 301 \ 

 Buteo borealis, var. costaricensis (nee Ridgw.), Lawr. Mem. Bost. Soc. N. H. ii. p. 302 °. 

 Buteo borealis socorroensis, Ridgw. Pr. U. S. Nat. Mus. iii. pp. 194, 220 ' ; Towns, op. cit. xiii, 



p. 135*. 

 Buteo socorroerisis, Gurney, List Dium. Birds of Prey, p. 66°. 



cJ ad. B. caluro similiB, sed pedibus valde crassioribus ; gastraeo magis concolore, pallide cinnamomeo ; abdomine 

 et corporis lateribus minus distincte fusco notatis ; tibiis satufife vinascenti-cLnnamomeis, vinaceo-fulvo 

 vix transfasciatis. Long. tot. 20-0, alae 15-25, caudse 8*0, culm. I'O, tarsi 3-20. (Descr. maris e MSS. 

 R. Eidgway.) 



2 ad. man similis. Long. tot. 22-50, alae 16-50, caudse 8-75, culm. 1-18, tarsi 3-65 (^teste Eidgway). 



Eab. SocoEEO Island {Grayson ^'^^, Townsend^). 



We have not seen an example of the Red-tailed Buzzard of Socorro, and in answer 

 to our enquiries as to its distinctive characters, Prof. Eidgway has very kindly sent us 

 the following note : — 



" Adults {sexes alike in coloration). Similar to B. calurus, but with much larger and 

 stouter feet; underparts more uniformly pale cinnamomeous — cinnamon-rufous (see 

 my ' Nomenclature of Colours ') or vinaceous-cinnamon — than in most nearly similar 

 examples of B. h. calurus, vrith dusky markings on the sides and abdomen much smaller 

 and fewer ; thighs deep vinaceous-cinnamon, indistinctly barred with paler (vinaceous- 

 buff) ; longer scapulars blotched with vinaceous-cinnamon. s . Length (skin) 20 inches • 

 wing 15-25 ; tail 8"00 ; culmen 1-00 ; tarsus 3-20 ; middle toe 1-62. $ . Length (skin) 

 22-50 inches; wing 16-50; tail 8-75; culmen 1-18 ; tarsus 3-65; middle toe 1-90." 



The late Colonel Grayson, who first discovered this Buzzard on Socorro, says that it 

 is a common resident on the island, breeding there and subsisting on land-crabs. The 

 bird's claws become much blunted from their frequent contact with the shells of these 

 Crustacea ^. 



