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394 Recent Ornithological Publications . 
Dr. Davy plausibly suggests that the thickness of egg-shells 
bears a proportion to the weight of the parent bird, and to the 
time of incubation. This last point, however, is one on which 
we really have little authentic information, and we beg leave to 
suggest its consideration to some of our brethren who busy 
themselves only with British birds as a means of improving their 
“ shining hours." 
Sir Oswald Mosley’s f Natural History of Tutbury’ (London, 
1863) contains, amongst other ornithological notices by Mr. 
Edwin Brown, an account of the occurrence at Chellaston, near 
Derby, in May 1859, of a male example of the “ Red-eyed Fly¬ 
catcher" (Vireosylvia olivacea ) of North America. This is believed 
to be the first recorded instance of the occurrence of this bird as a 
straggler in Europe. A nicely executed coloured lithograph of 
the bird (drawn by Mr. Wolf) is given. Mr. Brown gives an 
extract from Mr. Gosse’s notes on “ this species ’’ as occurring 
in Jamaica. This is rather unfortunate, as the Jamaican bird 
is, as is now well known to naturalists, a distinct species—the 
Vireosylvia altiloqua (VieilL). 
The ‘ Proceedings of the Natural History Society of Dublin’* 
contains frequent notices of the occurrence of rarer birds in Ire¬ 
land, principally from the pen of Mr. Bobert Warren, jun. Mr. 
Warren has paid much attention to the four species of Skua 
(Stercorarius) which occur on the Irish coast. Professor Kina- 
han, in some remarks on one of Mr. Warren’s papers, conceives 
that the following conclusions have been established by Mr. 
Warren’s observations upon these birds: — 
1st. The Common Skua (S. catarrhactes) is a southern species, 
and a regular visitant in summer and autumn, following the 
shoals of mackerel and herrings into our bays, the British Isles 
being nearly its northern limit; the species breeding annually in 
the Orkneys, though not as yet known to breed in Ireland. 
2nd. That the three other species, viz. Buffon’s (or the Long¬ 
tailed) Skua, Richardson’s Skua, and the Pomarine Skua, 
all occur as annual migrants—an annual migration of these 
* 3 vols., and part 1. vol. iv. Dublin, 1864. 
