444 A PRACTICAL HANDBOOK OF BRITISH BIRDS. 



have had pink eyes). This plumage is acquired by complete moult 

 July-Sept, and probably Oct. but few moulting examples have been 

 available. 



Nestling. 1st down. — Crown, whole head and under-parts 

 white, triangular patch on vent very pale blue -grey, upper-parts 

 and wings pale blue -grey. Down of crown and chin short but close 

 and rest of down longer and very close. 



2nd down. — Crown and whole head including chin and throat 

 grey like upper -parts which are darker grey than upper -parts in 

 1st down, breast and rest of under-parts white, slightly tinged 

 grey.* 



Juvenile. — Plumage immediately succeeding 2nd down is 

 exactly like that of adults in four white-headed birds with remains 

 of down except that head, neck, and under-parts are pure white or 

 with only a faint tinge of yellowish. No grey-headed examples in 

 this stage are available for examination. 



Measurements and structure. — <J wing 318-330 (one 345) mm., 

 tail 117-134, tarsus 51-56, middle toe with claw 65-74, bill from 

 feathers 38-43 (8 British measured). ? wing 308-340, bill 36-40. 

 Primaries : 1st narrow, about two -thirds longest primary- covert, 2nd 



longest, 3rd 2-12 mm. shorter, 

 4th 16-28 shorter, 5th 36-50 

 shorter ; primaries not emargi- 

 nated but outer web of 2nd con- 

 siderably narrower than in rest, 

 outer secondary shorter than 10th 

 primary and inner about as long 

 as 7th, tips rounded but outer 

 webs rather sharply sloped off. 

 Tail rounded, 14 feathers, tips 

 rounded. Under tail-coverts as 

 long as tail-feathers. Tarsus com- 

 pressed and rather slender. Three toes long, slender and fully webbed, 

 hind-toe almost reduced to its claw ; claws fairly sharp and arched. 

 Bill short, wide at base, tip of upper mandible compressed, decurved 

 and sharply pointed, tip of lower mandible much compressed and 

 sloped off. Nostril tubes elevated, long (rather less than half length 

 of bill), parallel, separated by thin septum, apertures oval and 

 directed forwards. 



Soft parts. — Bill (variable) : nasal tubes brown-black, blue- 

 grey, or yellowish, sometimes mottled blackish, culmen greenish- 



* All the nestlings I have examined have been from Scotland and are 

 as above described. Prof. Koenig, however, states of downy nestlings 

 which he collected in Spitsbergen : "As far as I can make out the light birds 

 have white down and the dark ones dark down. We have not been able to 

 observe, however, that there are differently coloured stages of the down 

 plumage " (in litt. to E. Harte t). Prof. Koenig's specimens may all have 

 been too young to show the second down and if so the nestlings are certainly 

 dimorphic. — H.F.W. 



Bill of the Fulmar Petrel (Fulmarus g. glacialis). 



