THE ROSEATE TERN. 707 



dark grey lesser coverts forming a narrower line and not so dark, 

 primaries with inner edge of white extended right up to tip. 



First winter. — Like adult winter but wings and tail as juvenile. 

 N.B. — Very few examined and none in moult. Summer. — Like 

 adult winter but fore -head purer white, fore -part of crown with 

 more hoary appearance and less streaked, outer webs of outer tail- 

 feathers (except outermost which are white) rather darker, grey of 

 secondaries and lesser coverts rather darker. Only one moulting 

 examined, this completing (June), some tail-feathers growing and 

 wings new. 



Measurements and structure. — g wing 223-236 mm., tail : outer 

 feather 140-205, central 60-70, depth of fork 75-135, tarsus 19-21, 

 bill from feathers 37-40 (12 measured). $ wing 218-233, tail : outer 

 150-190, central 60-68, fork 85-125. Juvenile wing 207-225, tail : 

 outer 110-120, central 65-66, fork 45-54. Primaries : 1st narrow, 

 pointed and about two -thirds primary-coverts, 2nd longest, 3rd 

 10-14 mm. shorter, 4th 26-32 shorter, 5th 44-50 shorter. Rest of 

 structure as Common Tern but tail much longer in proportion to 

 wings and outer tail-feathers more sharply tapered with finer point 

 both in juvenile and adult. 



Soft parts. — Bill (winter and juv.) black, (ad. summer) com- 

 mencing end May base becomes red-vermilion extending to half 

 upper and third lower mandible ; legs and feet (winter) orange-red, 

 (ad. summer) red-vermilion, (juv.) pale orange-red ; iris dark brown 

 (Bureau). 



Characters and allied forms. — S. d. korustes (Ceylon, Andaman 

 Is., Tenasserim) is rather smaller ; S. d. bangsi (Seychelles, Malay 

 Peninsula, S. China, New Guinea) is stated to have whole bill red 

 in summer ; S. d. gracilis (Australia) is stated to have longer and 

 finer bill, but this appears very variable. Distinguished from 

 Common and Arctic Terns at all ages by white outer web of outer 

 tail-feather, shorter wing, white inner edge of outer primaries 

 extended to tips as well as other differences described above. 



Field -characters. — Adult has upper-parts paler grey, and outer 

 tail-feathers longer than in Common or Arctic, whilst breast is 

 suffused with rose-pink, (N.B. — In breeding season breast of 

 Sandwich Tern is salmon-pink and that of Common Tern often has 

 a vinaceous-grey tinge), and bill is black, but these characters are 

 only apparent in favourable positions and good light, and apart 

 from colour of bill do not apply to immature birds. Might extremely 

 buoyant, wings being neither raised nor depressed to same extent 

 as in Common and Arctic. Cries very characteristic ; call -note 

 " tchu-ick " ; alarm -note a loud guttural " aach." 



Breeding-habits. — Usually found breeding among colonies of 

 other Terns, preferably on rocky islets, but at times also on shingle- 

 banks on shore. Nest. — Practically none, eggs usually laid in 

 natural hollow in rock. Eggs. — Two, but often one only (evidence 

 of three in British Isles unsatisfactory), elongated and rather 



