150 BIRDS DECEIVED BY WEATHER. [p ART II. 



egg is deposited quite tally with the one above 

 mentioned. From the similarity of the Hydro- 

 campa potamogeta's arrangements (described by 

 Reaumur see Rennie's Insect Architecture^. 154. 

 Murray, 1857) I should however conclude that 

 the one in question was of that family. The Cater- 

 pillar, indeed, appeared to me thicker than I 

 should expect to find that of a ffydrocampa, 

 but my eyes may have thus far deceived me. 



From the mistakes which birds occasionally 

 make with regard to the time of incubation, it 

 would appear that their instinct affords them no 

 other guide to the approach of summer, than that 

 of the increasing warmth of the temperature. A 

 remarkable proof of this occurred in the winter 

 of 1857-8, when two of the chimnies of a house 

 in the Isle of Wight, where I was staying at the 

 time, were between Christmas and New Year's 

 Day blocked up by Jackdaws' nests, which must 

 have been constructed then, as the chimnies had 

 been swept less than a fortnight before. The 

 birds were indeed, I believe, actually seen carry- 

 ing in materials. In these nests, besides the quan- 

 tity of sticks and rubbish of which they usually 

 consist, the jackdaws had taken the odd fancy to 

 insert some pieces of glass, whether for use or 



