3o British Birds, with their Nests and Eggs. 



In September the young birds undergo a moult after which the " upper parts of 

 the head and nape are variegated with black and white. The forepart aud sides of the 

 neck with all the lower parts pure white ; as are the head, neck and rump, but 

 most of the feathers there have a crescent at the tip. The forepart of the 

 back, the scapulars, the smaller wing-coverts, are light greyish-blue, with 

 similar black bars ; the secondary coverts unspotted and toward the end white ; 

 the secondaries white with an oblong dark grey mark toward the end, the pri- 

 maries and their coverts of a darker grey on the outer and a great part of the 

 inner webs. The tail feathers pale grey, shaded with darker toward the end, 

 where they are margined with white " (Macgillivray). In their habits the Sandwich 

 Terns differ very little from the species we have already described. Their food 

 consists of fish-fry ; sometimes of shell-fish and small fishes, especially of the 

 sand eels ( Ammodytes tobianus) which live buried in the sand but rise to the 

 surface often quite suddenly in great shoals, and when attacked dive as suddenly 

 to the bottom, again seeking safety in the sand. The Sandwich Tern is almost 

 constantly on the wing, on the outlook for food and every little while uttering 

 a harsh and grating cry audible a long way off. The Sandwich Tern, when 

 its eye catches sight of its prey, dashes down perpendicularly into the water, 

 though rarely immersing its whole body, whence it emerges in a few moments 

 successful. If the object of its attack should move away from the surface the 

 Tern will with a quick and easy evolution recover itself, and instead of striking 

 the water, will sail over the spot and ascend again into the air. When shot 

 on the wing it falls gyrating to the ground, reminding one much of the "tumbling" 

 performed by many species of Rhipidura, due, as Sir William Jardine long 

 ago pointed out, to the small, light bodies being greatly supported by the long 

 tail and expansive wings. 



Sandwich Terns make their appearance in Heligoland, according to the 

 observations of the patriarchal ornithologist of the island, Herr Gatke, " during the 

 second half of April and until the middle of May, when they may be seen chasing 

 one another about, in pairs, in the bright sunshine, at heights of from five 

 hundred to a thousand feet, amid frequent utterance of their loud shrill cries, 

 often, indeed, their calls alone are audible from heights to which the eye vainly 

 endeavours to penetrate. These are undoubtedly breeding pairs from the coasts of 

 Sleswich-Holstein and East Frisia, which rejoicing in their recent union, thus 

 gaily disport themselves, but a few minutes being required to take them back 

 to their home. 



" Somewhat later the same birds are met with in much larger numbers. 

 They then come in swarms very close to the Sand-island, dipping incessantly down 



