576 THE ZOOLOGIST. 



laying, the eggs to be laid are easily distinguished, as there is a sudden 

 break off in size from the rest, not a gradual decrease. I have tried a good 

 many experiments myself, and have never known a bird continue laying an 

 egg a day beyond the normal number ; but have always found that the bird 

 continued laying up to its normal number, and that there was then an 

 interval of a few days (during which, I suppose, the birds paired again) 

 before the next lot was begun. For instance, in the case of a Starling 

 which I experimented upon, there was an interval of five days between the 

 two sets of eggs which it laid. I may mention that a good number of the 

 birds experimented on deserted the nests. It would have been interesting if 

 Mr. Alderson had noticed whether the eggs were fertilized, but I suppose 

 they could not have been so. — Bernard Riviere (Finchley Road, London). 



Hours at which some Birds Sing.— In « The Zoologist' (p. 472), Mr. 

 Riviere touches on a very large subject, which occasionally attracts atten- 

 tion from observers, but which is yet far from having had an exhaustive 

 treatment accorded to it. The hours at which birds begin to sing differ 

 according to the season of the year and according to locality ; they are also 

 influenced in some other way, perhaps by weather conditions, as the same 

 species occasionally show a marked difference of time in the hours at 

 which they begin to sing on corresponding dates of different years. Mr. 

 Riviere neglects to give the particular date in April, and thus deprives his 

 note of the value it would otherwise have. In Shetland, during midsummer, 

 no real darkness covers the land, and in consequence great activity prevails 

 by night as well as by day. Larks and Wheatears sing at the hour of 

 midnight, and the former has a long spell of uninterrupted song. Gulls 

 of several species, Snipe, Arctic Terns, and other species of birds, make 

 little difference between night and day, and are ever watchful for and ready 

 to meet any night intruder on their haunts long before he comes near their 

 home. Further south, in the Forth area, for instance, we cannot boast an 

 absence of darkness in summer, and we find that bird-life in the main 

 enjoys a temporary halt every night. Yet even here many species of birds, 

 such as Coot, Little Grebe, Heron, Peeweep, Curlew, Redshank, &c, pay 

 little regard to the succession of day and night. At dawn of day the 

 songsters break forth one by one in song, till the whole grove or moorland 

 rings with their melody. The Lark is the species in this neighbourhood that 

 hails the day, but in the woodlands, where Larks are absent, Blackbird and 

 Thrush generally rival each other in breaking the silence of night. Few 

 things are more interesting to the field-naturalist, or more delightful to 

 him, than the music of the grove, when it succeeds the dismal period of 

 waiting on in the stillness and darkness of night. For several hours he 

 has had little to attract his attention save the hooting and shrieking of 

 Owls, the plaint of the Peeweep, or it may be the terrific yell of a Heron, 



