BIRDS OF THE RAVENGLASS GULLERY. 171 
A high death-rate always obtains among young birds, but the 
Common Terns were subject to an extraordinary mortality. I 
Saw many dead nestlings on the breeding-grounds prior to July 
11th, but on that date their bodies might have been counted by 
hundreds. I cannot account for this exceptional death-roll, but 
if it was caused by an epidemic the nestlings alone were affected, 
for no dead adults were to be seen. 
When visiting the chief breeding-grounds of the Common 
Tern a curious habit, which is common to other Terns, was 
frequently forced upon my notice. Suddenly, without apparent 
reason, the clamour of all the birds over a wide area would 
cease; the babel of many voices was succeeded by an uncanny 
hush as those birds which were sitting or standing beside their 
brooding mates, actuated by a common impulse, rose, and, join- 
ing those which were hovering in the air above them, swept in a 
close grey mob low over the ground to the verge of the dunes. 
In a few seconds the birds returned and distributed themselves 
over the nesting-ground again, and the weird silence gave place 
once more to the customary hubbub.* 
Single birds often fished in the harbour, and as the tide was 
falling one or two were generally to be seen capturing Sprats in 
the pool of a fish-garth near the mouth of the Ksk. At times 
the birds would pack in a close flock above a shoal of fish at the 
river mouth. Whenever a bird made a successful plunge and 
rose with what looked like a small Sprat its bill, it would make 
off towards the sandhills, whence others were coming to join in 
the hunt. When fishing this bird often utters a sharp ‘‘ kitt, 
kitt,’ and sometimes ‘“‘kierie,” notes very different from the 
‘pierre’? and ‘‘pee-rah”’ of alarm. In feeding the young bird 
the parent sometimes alights on the ground beside it, and at 
others hovers immediately above it, and puts the fish into its 
gaping mouth. 
When fishing the Common Tern hovers at a height of from 
ten to fifteen feet above the water, with rapidly vibrating wings, 
tail depressed and fanned out, and bill pointing downwards. 
Then it plunges obliquely forward, headlong to the water, some- 
times submerging itself entirely, sometimes all but the wings, 
** For an account of a similar habit in the Arctic Tern, see Zool. 1906, 
p. 96. 
