324 THE ZOOLOGIST. 



Whinchat, May 2nd Morecambe Bay. 



Wood- Wren, May 4th Bingley. 



-Beed- Warbler, May 8th Keighley. 



:|: Spotted and *Pied Flycatcher, 



May 8th Bolton Wood. 



Swift, May 10th Barden Tower, Wharfedale. 



Fieldfare, May 10th (last seen)... Bingley. 



Nightjar, May 18th Goit Stock Valley, Bingley. 



As to those species against which an asterisk is placed it cannot be taken as 

 absolutely certain whether the dates of first appearance as observed by us 

 were coincident with their arrival ; but as to the remainder, the dates as 

 specified we have every reason to believe indicate their actual arrival. 

 Neither the Chiffchaff nor Stonechat breeds in this neighbourhood, or. if so, 

 but rarely (although both occur occasionally on migration), which is a 

 curious feature in their economy, especially when taken in connection with 

 their habits as stated in most manuals on ornithology. We should be 

 extremely obliged to any of your readers who would forward notes to 

 supply material for the better working out of the distribution of these two 

 species, stating particulars uuder the following heads, viz. : — Altitudinal 

 range, whether well wooded, and, if so, what species of tree predominates, 

 and whether of young or old growth ; relative abundance or otherwise of 

 allied species, such as Wheatear, Whinchat, Wood-Wren, and Willow- 

 Warbler ; or do they occur on migration only, as in this district, or breed ? 

 It may be said iu passing that this district is well wooded, the trees chiefly 

 oak, birch, and beech, the former predominating ; it has an extensive 

 altitudinal range (400-1300 ft.), most of which, over 1000 ft., consists of 

 moorland. — E. P. Butterfield (Wilsden, near Bradford). 



Songs of Birds affected by Temperature. — In the April number, 

 Mr. H. S. Daveuport takes me to task for my conclusions on this point. 

 No doubt the sentence he quotes is too strongly expressed ; in fact, a modi- 

 fying word had slipped out of my type-written copy in that particular 

 sentence. But the experience of years makes me feel sure that tempera- 

 ture as such does not seriously affect the singing of most birds. This 

 morning, for example, in a very cold wind from W.N.W., there was far 

 more singing going on in the osier-bed, where I watch the Marsh- Warbler, 

 than there was in the warm weather of a fortnight ago. So, too, birds will 

 sing in severe cold, if the air is clear, as it usually is in the hardest frosts. 

 But they will cease singing in cold rain, in snow, or in depressing chilly 

 fogs ; this at least is my experience. A low temperature often invigorates 

 the human frame, if not continued too long ; and so long as the birds can 

 find food and get some amount of sun, they seem brisk and lively, and will 

 sing up to noon in great cold. In the later hours of a winter day I hardly 

 ever hear any but the Robin and Wren. The following is one of many 



