170 BRITISH BIRDS. 



usual clutch being two, but some had three and a few only 

 one egg. The keeper marks every egg of this species with an 

 indelible pencil, so as to render them useless to egg-stealers, 

 and their number this year was 498, as compared with a little 

 over half that number last year. The young of this species 

 are very hard to find, as the colony is situated among the 

 thick herbage of the rag-wort, and we only succeeded in 

 marking 42. On this date young Black-headed Gulls 

 were running and flying about in thousands, being mobbed 

 unmercifully and sometimes killed when they trespassed 

 among the eggs of the Common Tern, and many eggs had yet 

 to hatch. Upon one of our visits a Cuckoo also was having 

 a very bad time of it. The mortality among the young 

 Gulls is enormous, although the ground here is clean as com- 

 pared with another gullery in Lancashire where the ground 

 is very foul and wet, but the mortality far less, starvation 

 and the gape-worm being the main causes of death among 

 them. 



The mortality among the young Common Terns is also fairly 

 high, but not a fraction of what it is among the Gulls, but a 

 remarkable fact is that there seems scarcely any mortality 

 among the young of the Sandwich Tern. 



A pair of Peregrines were preying upon the Common 

 Terns, at whose advent or crossing every voice was hushed, 

 although the Falcons were often invisible to the human eye ; 

 those birds on the ground rising, and those high in air falling 

 towards the earth and scattering in all directions. On the 

 other hand, the Gulls do not seem to mind a Hawk much, 

 but rise in great consternation when a Heron passes overhead. 



On our second visit on July 23rd, not a single Sandwich 

 Tern or Gull remained, notwithstanding the number of eggs 

 of the latter unhatched on June 20th, all of which were now 

 also gone ; but Common Terns were in great abundance, and 

 in all stages of development, some were even flying. So easy 

 were they to find that we rung 279 in two hours, and then 

 had to stop owing to our supply of rings having become 

 exhausted. Many eggs had yet to hatch, and some birds 

 were still laying — possibly second broods. 



On July 30th they were much scarcer and harder to find, 

 but we succeeded in marking 297, but on August 10th, our 

 next visit, we only marked 74, and less on every 

 succeeding day, viz., on August 13th, 17th, 18th and 26th, 

 when I marked 46, 30, 13 and 3, respectively, most of the 

 old birds also having left on the last date. 



There were a few cripples met with among the Common 

 Terns, perhaps 20 or 25, the chief deformity being a stiff 



