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 Red-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 etimples 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 socorroensis. 
Buteo borealis, var. montanus (nec Nutt.), Grayson, Proc. Bost. Soc. N. H. xiv. p. 301°. 
Buteo borealis, var. costaricensis (nec 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 socorroensis, Gurney, List Diurn. Birds of Prey, p. 66’. 
gad. B.caluro similis, sed pedibus valde crassioribus ; gastro magis concolore, pallide cinnamomeo ; abdomine 
et corporis lateribus minus distincte fusco notatis; tibiis saturate vinascenti-cinnamomeis, vinaceo-fulvo 
vix transfasciatis. Long. tot. 20°0, alee 15°25, caudee 8°0, culm. 1:0, tarsi 3°20. (Descr. maris e MSS. 
R. Ridgway.) 
9 ad, mari similis. Long. tot. 22-50, ale 16°50, caude 8°75, culm. 1°18, tarsi 3°65 (teste Ridgway). 
Hab. Socorro Istanp (Grayson ! 23, 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. Ridgway 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. b. calurus, with 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. ¢. Length (skin) 20 inches; 
wing 15°25 ; tail8°00; culmen 1:00; tarsus 3:20; middle toe 1°62. 9. 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 }, 
