THE EAGLE-OWL. 79 



wing-coverts are of even more loose and downy structure than in 

 Snowy Owl. Whole upper -parts and under-parts darkish-buff 

 barred brown, tarsi and toes uniform buff. 



First winter. — Like adults. The juvenile body -feathers and 

 greater, median and lesser wing-coverts commence to moult before 

 wing- and tail-feathers are grown but moult is often not finished 

 until December. Wing- and tail-feathers and primary-coverts 

 are not moulted. 



Measurements and structure. — $ wing 420-470 mm., tail 220-285, 

 tarsus 65-80, bill from base of feathers 40^7 (12 measured). 

 $ wing 450^95 mm. Primaries : 3rd and 4th longest, 2nd usually 

 as long but sometimes 5-15 mm. shorter, 1st 30-60 shorter, 5th 

 20-30 shorter ; 2nd to 4th emarginated on outer webs ; outer 

 edge of 1st primary with longer and more curved serrations than 

 in Snowy Owl but not so long comparatively as in Long-eared 

 and Tawny Owls, some very short serrations on emarginated portion 

 of 2nd to 4th primaries, outer edge of outer " bastard " wing- 

 feather also serrated. Outer secondary about equal to 10th 

 primary, rest becoming longer and longest about equal to 1st 

 primary, tips rounded. Tail slightly rounded, 12 feathers, tips 

 rounded. Under tail -coverts about three-fourths as long as tail- 

 feathers. Rest of structure as Snowy Owl. 



Soft parts. — Bill and claws black ; iris orange. 



Characters and allied forms. — B. b. hispanus (Spain) ground- 

 colour is paler and less tawny especially on under-parts ; B. b. 

 ruthenus (south-east Russia, Asia Minor) has ground-colour much 

 as last but black streaks on back of head and hind -neck are narrower 

 and barring on sides of breast and flanks very prominent ; B. b. 

 turcomanus (Transcaspia, Turkestan) is very much like B.b. ruthenus 

 but usually with less black markings and rather paler sandy and 

 less tawny ground-colour ; B. b. sibiricus (western Siberia) is 

 paler than any of above (ground-colour of under-parts creamy- 

 white) and has very large bill and foot and longer wing ; B. b. 

 aharonii (western Palestine and Jordan Valley) is much like B. b. 

 ruthenus but is smaller ; B. b. ascalaphus (north Africa and 

 Palestine) differs from all forms above in having feathers of sides 

 of upper-breast with well-defined wavy brown-black cross bars 

 and rounded white subterminal spots on each side of black-brown 

 central streak which is extended laterally across tip of feathers ; 

 B. b. desertorum is much paler than last and appears to inhabit 

 desert country of north Africa and eastern Palestine, but distribu- 

 tion and differences require further investigation ; B. b. nikolskii 

 (western Persia), B. b. yenisseinsis (middle Yenesei), B. b.jakutensis 

 (Jakutsk province) have been separated but have not been seen 

 by me, while there are several other forms in eastern Asia. Very 

 large size and long " horns " distinguish Eagle -Owl from other 

 British species. 



