LESSER BLACK-BACKED GULL. 217 



first and third week in April, but in Norfolk have noticed 

 steady northward passage early in May. 



The Lesser Black-back joins the Herring-Gull in its watchful 

 and sustained flights behind steamers, remaining on the wing 

 for hours, also in the frenzied raids on shoals of fish, when the 

 water is churned by the plunging and superficial dives of the 

 excited birds, and the air rings with their cries ; it is an 

 equally useful scavenger in rivers and harbours. It is as 

 omnivorous as the commoner bird, but its reputation, like its 

 back, is blacker ; so emphatically did the game-preserver 

 accuse it of egg robbery that it was excepted from the pro- 

 tection given to most other gulls. At its nesting colonies the 

 disembowelled corpses of Puffins and Shearwaters prove it as 

 murderous as its larger relative ; certainly on Puffin Island I 

 have seen more bodies in the Black-back colony than on 

 Herring-Gull ground. It delights, too, in a large carcase, only 

 yielding its place to the Greater Black-back. Its manner of 

 flight, its pose on land, and its habit of perching on an elevation 

 agree with the Herring-Gull, but its calls differ slightly. The 

 loud ky-eoh, as it sounds to me, and the angry hakak-ak^ or 

 wow-ow-ow, when it swoops with a rush toward the head of an 

 intruder, sound more ferocious than the usual wails of the 

 Herring-Gull ; but both birds have a wailing mew and an 

 irate bark. The normal ow or owch is deeper and more 

 melancholy than the call of the other bird. 



Though I have found odd pairs of Lessers nesting with 

 Herring- Gulls, it usually keeps in a colony by itself. Loud 

 though the clamour is when a colony of the latter bird is in- 

 vaded, the medley of angry voices and the frequent threatening 

 swoop of an anxious parent is more marked on Black-back 

 ground. The bird may be slighter in build and weaker in bill 

 than the Herring-Gull, but, in my experience, it is much bolder. 

 Grassy islands and marshes are more usual nesting sites than 

 steep cliffs. The nests vary in size and construction, but 



