FALCO. 949 
a’, Two outer quills with inner webs emarginated near tip; first quill shorter than 
fourth. 
b'. Tarsus not decidedly longer than middle toe; basal segment of toes covered 
with small hexagonal or roundish scales. 
Adult males: Bluish gray above, with blackish shaft-streaks; hind- 
neck spotted or mixed with whitish and buffy or ochraceous; quills 
dusky ; tail crossed by a greater or less number of blackish bands, 
and tipped with whitish; lower parts whitish, buffy, or light rusty, 
striped with brownish or dusky. Adult females: Brownish above, 
the tail usually with a greater or less number of lighter (usually 
narrow) bands; top of head streaked with blackish, and feathers of 
back and rump with shaft-streaks of the same; lower parts much as 
in the male, but without rusty tinge. Young (both sexes) : Much like 
adult female, but darker, or else much tinged above with ochraceous 
orrusty. (Subgenus Msalon Kavp.) 
c'. Middle tail-feathers of adult male crossed by about six imperfect, mostly 
concealed, blackish bands, besides the broad and continuous subter- 
minal one; that of adult female and young crossed by about eight 
light bands, including terminal band. Adult male with closed tail 
showing one black band, this a broad subterminal one; inner web 
of longest quill with about ten white spots; hind-neck, breast, and — 
sides more deeply rusty than thighs; dark markings on breast 
linear, and streaks on cheeks crowded into a distinct “mustache”; 
length about 11.00, wing 7.60-8.00, tail 5.10-5.30, culmen .45-.50, 
tarsus 1.35-1.45, middle toe 1.15. Adult female: Tail with about 
eight narrow pale bands (more on lateral feathers), the first two 
or three concealed, however, by upper coverts; upper parts usually 
much spotted with a lighter tint than ground-color; length about 
12.00-14.00, wing 8.60-9.00, tail 6.00-6.30, culmen .52-.55, tarsus 
1.45-1.47, middle toe 1.20-1.25. Young: Similar to adult female, 
but more or less tinged with rusty, the lighter spots on upper parts 
more distinct. Hab. Europe, etc.; accidental in Greenland. 
358.1. F. zesalon Tunst. Merlin. 
c. Middle tail-feathers of adult male crossed by not more than four black- 
ish bands besides the broad subterminal one, that of female and 
young never with more than six light bands, including terminal one. 
Adult males with closed tail showing more than one black band; 
inner web of longest quill with less than ten white spots; hind-neck, 
breast, and sides less tinged with rusty than thighs; markings on 
breast broad, stripe-like, and streaks on cheeks not crowded into a 
distinct “mustache.” 
d', Middle tail-feathers with not more (altogether) than four blackish 
: or five lighter bands; outer webs of quills mostly destitute of 
1 Falco esalon Tunst., Orn. Brit. 1771, 1. 
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