THE SOOTY TERN. 71& 



rather coarse. Whole upper -parts, sides of head, and sides of neck 

 speckled grey-white and grey-black with varying amount of buff, 

 latter, usually confined to tips of down, is often absent ; upper part 

 of throat as upper -parts but rest of under -parts white. 



Juvenile. — Whole upper -parts black-brown, feathers of crown 

 with very narrow pale buff tips (sometimes so narrow as to be 

 scarcely noticeable, and soon becoming worn), those of upper- 

 mantle with slightly broader but still very narrow tips, those of 

 lower -mantle, back, rump, and upper tail-coverts broader and 

 those of scapulars still broader and whiter ; under -parts brown 

 often washed ashy and becoming greyer by wear, round vent 

 greyish -white, under tail-coverts blackish-grey, feathers tipped 

 buff-brown ; under wing-coverts and axillaries blackish-grey, 

 feathers fringed ash ; tail-feathers brown-black, inner webs browner,, 

 extreme tips with small buffish -white spot ; primaries as adult ;. 

 secondaries as adult but inner webs white only at base and innermost 

 feathers tipped white as wing-coverts ; greater and median coverts 

 tipped buffish-white ; lesser only very narrowly fringed bumsh-white. 



First winter. — Fore-head and lores brown-black, feathers 

 fringed grey giving a hoary appearance ; crown brown -black ; mantle 

 and back same but feathers edged white ; under-parts grey-brown 

 more hoary than juvenile ; lesser and median coverts brown-black ; 

 rest of plumage as juvenile. The juvenile body-feathers and some 

 median and lesser wing-coverts are moulted in winter (Dec.) but 

 not wings and tail. N.B. — Very few 1st winter birds available and 

 none fully moulted. Subsequent plumages are uncertain owing to 

 want of material but apparently next moult is complete and takes 

 place in 1st summer after which bird becomes like adult but usually 

 has some sprinkling of white on fore-part of crown and lores, some 

 feathers of mantle very narrowly edged white, sometimes some 

 brown-tipped feathers on under-parts and outer tail-feathers with 

 dusky outer webs with some grey -white at tip. 



Measurements and structure. — £ wing 275-310 mm., tail : outer 

 feather 157-173, central 71-86, tarsus 22-25, bill from feathers 

 39-48 (14 Atlantic birds measured but in all except four outer tail- 

 feathers broken and not measured). $ wing 272-290, tail : outer 

 158-180, central 72-78. Primaries : 1st narrow, pointed, and 

 about half primary-coverts, 2nd longest, 3rd 2-12 mm. shorter, 

 4th 20-30 shorter, 5th 42-53 shorter. Tips of secondaries more 

 pointed than in Sandwich Tern and inner feathers shorter, equalling 

 9th primary. Other structure similar to Sandwich Tern but bill 

 proportionately broader at base. 



Soft parts. — Bill, legs, and feet black ; iris dark brown. 



Characters and allied forms. — A number of forms have been 

 described (S. f. crissalis Pacific coast America, S. f. oahuensis 

 Hawaia, 8. f. serrata New Caledonia, S. f. infuscata East Indies, and 

 others) but the characters ascribed do not seem constant except in 

 birds from N. Pacific which have rather more grey on under-parts 



