BIRDS. 



337 



Pagophila eburnea (Phipps). Ivory Gull. 



Rare. Very occasional visitant. 



Mr. J. G-. Millais mentions having procured one on the tidal part 

 of Tay (Froc. Perth. Soc. of Nat. Sciences, vol. i. p. 182). 



Larus ridibundus, L. Black-headed Gull. 



Common. Resident. Breeds. Increasing in numbers. 



Generally distributed throughout the whole area, where suitable 

 localities for nesting purposes are to be found. 



A large colony recently formed at the White Mire of Methven — 

 having some years ago deserted that same spot owing to some land 

 improvements which were carried out — has again begun to occupy it. 

 This Gull has greatly increased about Loch Tay and elsewhere, by 

 1902 (D. Dewar, iii lit., 27th November 1902) ; but they cannot be 

 really considered as abundant there yet. 



It is not common about Rannoch (Godfrey, 1902). But one seen 

 at Loch Rannoch, and one at Loch Eigheach, on 23rd April 1902 

 (Godfrey). 



" The Gull Loch " in the Sidlaw Hills bears upon its bosom 

 three floating islands with a large colony of these birds — needless 

 to say, the beau-ideal locality for a colony of Black-headed Gulls. 



Individuals are ' seen passing along the length of Glen Ogle to 

 and fro and about Lochearnhead, and also along the Balvaig river 

 (Forth), and along the burn which runs to join the Edenchip 

 water which flows into Loch Earn. But I am not aware of any 

 prominent breeding place immediately in the neighbourhood, except 

 on the Forth side. 



There are colonies as well in the north-east of our district, but 

 it is almost unnecessary to enter into particulars, unless it be to draw 

 attention to the fact that there are too many for the best balance of 

 natural laws, and there would be little harm in having their numbers 

 thinned down. They eat up a power of insect life that would support 

 many other equalty innocent birds ! Birds seem to me to cease to 

 be innocent when they become aggressive to weaker and equally 

 attractive species. Superabundance recoils even upon the species 

 itself at times ; and I have undoubted proofs that at one surcharged 

 colony of Black-headed Gulls, many died from pure starvation and 

 lack of insect food at the time of the nesting operations in an 

 adjoining area (Forth). Both old and young died, and so weak 



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