NOTES AND QUERIES. 391 



Greaves, under the head of " Nidification of the Whitethroat," remarks 

 that it would " require a great amount of observation to definitely 

 decide whether one sex only in this or any other species is concerned 

 with nest building." My own observations favour the view that the 

 female is chiefly concerned in nest building — in some species I should 

 say the nest is built exclusively by the female ; as to which sex 

 determines the nesting site, it would be difficult to decide, but from -i 

 my own limited observation, I think the fmnater" ,>(vv>'*^ 



This summer three eggs were brought to me which had been p-^ 

 taken out of three different nests as the eggs of the Linnet, but I 

 found they were from the nests of the Twite. On making enquiries 

 I found that about a dozen nests had been found within a very 

 limited area. In this district there seems to be a local race of this 

 species, which builds its nest on the ground amongst mat-grass 

 (Nardus) and bracken (Pteris), and is much more social in its habits 

 than the one which builds in the heather. A pair of House-Martins 

 here commenced to build their nest on June 1st last, and fledged on 

 July 23rd — fifty-three days — and at present (Sept. 11th) have a 

 second brood, which in all probability will leave the nest in a day or 

 two, thus covering another period of fifty-three days. I think it 

 must have been over a month ago since the first brood left this 

 neighbourhood, presumably on migration. It might here be remarked 

 that this species incurs great risk in having a second brood in this 

 upland district. In some years it must tax the resources of the 

 parents to provide the means of subsistence for their second brood, 

 and occasionally, it is to be feared, the young must be starved to 

 death. It is somewhat singular that the House-Martin is more 

 habitually double-brooded than many of our resident species, but 

 this is an undoubted fact. — E. P. Butterfield (Bank House, Wils- 

 den, Bradford). 



One of the Causes of our Rare Birds disappearing. — I have just 

 received a post-card from Leeds, asking if I had any duplicate eggs to 

 dispose of by exchange or sale, the writer stating he was ready to deal 

 either way, as he had a large stock of eggs of nearly all the British 

 List ; among other rare specimens, he had ten eggs of Golden Eagles 

 and fifty of Ospreys, thus showing plainly why the Golden Eagles and 

 Ospreys of Scotland are so steadily vanishing. If these dealers were 

 not so well paid by silly collectors who pose as naturalists, our rarer 

 birds would be allowed to rear their young in peace and safety, but 

 while this craze for egg-collecting, and especially the demand for full 

 clutches, exists, our poor birds will eventually disappear. I replied 



