FALCO. 251 



8.80-9.10 (8.95), tail 5.70-6.30 (5.92), culmen .55-.60, tarsus 

 1.30-1.40, middle toe 1.15-1.25. Young (both sexes) : Similar to 

 adult female, but more decidedly buffy below, and upper parts 

 more or less tinged with rusty. Egg (single specimen) 1.52 X 

 1.22, buify white, handsomely marbled and irregularly spotted 

 with maddei'-brown. Sab. Interior of North America, breed- 

 ing from Rocky Mountains of Colorado (?) northward, and 

 straggling west to Pacific coast ; south, in winter, to Texas and 

 Arizona (probably into Mexico). 



358. F. richardsonii Eidgw. Richardson's Merlin. 

 b^. Tarsus decidedly longer than middle toe ; basal phalanx of toes with trans- 

 verse scutellse. 

 c^ Bill robust, the length of the cere on top equal to about one-third 

 the culmen ; transverse scutellffi on basal phalanx of toes large 

 and almost uninterrupted ; second and third quills longest, first 

 equal to or shorter than fourth ; sexes essentially alike in color, 

 and young not very diff"erent from adults ; size medium (wing more 

 than 9.00). (Subgenus Rhynchofalco Eidgw.) 



Adult : Above plain bluish gray or plumbeous, the secondaries 

 broadly tipped with whitish ; tail darker towards end, tipped 

 with white, and crossed by about eight narrow bands of the 

 same ; a broad stripe behind eye, middle of ear-coverts, with 

 entire chin, throat, and chest, immaculate white, the postocular 

 stripe changing to orange-rufous on occiput, where the two of 

 opposite sides are confluent ; sides and flanks slaty blackish, 

 narrowly barred with white ; thighs and lower tail-coverts 

 light rufous, or rusty ochraceous. Young : Similar to adult, 

 but colors duller, the gray above less bluish, rufous or ochra- 

 ceous of thighs, etc., paler, the chest more or less buffy and 

 striped with dusky. Male : Length about 15 00, wing 9.20- 

 10.70, tail 6.30-8.00. culmen .60-.68, tarsus 1.70-1.85, middle 

 toe 1.35-1.50. Female: Length about 17.00-18.00, wing 11.00- 

 11.60, tail 7.80-8.80, culmen .71-.80, .tarsus 1.80-2.00, middle toe 

 1.55-1.70. Nest on low trees or bushes (usually yuccas or 

 cacti). Eggs 2-4(?), 1.78 X L57, dull white or buflPy white, 

 thickly speckled and irregularly spotted with vandyke-brown. 

 Hab. Tropical America in general (except West Indies), north 

 to southern Texas and I^ew Mexico. 



359. F. fusco-ccerulescens Vieill. Aplomado Falcon. 

 c^ Bill small, the length of the cere on top less than one-fourth the chord 

 of the culmen ; transverse scutellse interrupted at extreme lower 

 part of tarsus and extreme base of toes ; tarsus much longer than 

 middle toe (without claw) ; sexes very different in color, and young 

 of both sexes (in American species) essentially like adults. Nest in 

 holes, usually in dead trees. Eggs 2-5, 1.45, or less, X 1-16, or less, 



