148 BRITISH BIRDS. [vol. vii. 



LETTER. 



ON INCUBATION. 



To the Editors of British Birds. 



Sirs, — In the article on Incubation, by Mr. Eric B. Dunlop {antea, 

 p. 109), the writer says : " Another bird which rears few young 

 compared to the number of eggs it lays is the Great-crested Grebe. 

 Four or five eggs are very frequently deposited, but it is not usual 

 for more than two young to be brought to maturity. Mr. Edward 

 Tristram suggests . . . that when the first one or two chicks are 

 hatched the parents at once leave the nest with them, regardless 

 of the remaining eggs which have not hatched out." 



During the past five years there is no bird which I have watched 

 and photographed more than the Great-crested Grebe, and during 

 this time I have had not less than fifty nests Tinder observation, and 

 my experience is that in the great majority of cases four young are 

 reared where five eggs are laid, and three when the nest contains 

 only three eggs. It is commonly thought that this Grebe only rears 

 two young, and this idea has no doubt been brought about through 

 the habits of the birds. When the first two young leave the shells 

 the male bird almost invariably takes care of them, and they are 

 led away from the nest, but the hen remains sitting on the other 

 eggs until the one egg hatches, if there should be only one left, or 

 if there are three, she will sit until two more eggs hatch. Then she 

 will desert the fifth egg, and take her two young out on to the lake, 

 but she does not interfere with the male bird. Each parent bird 

 will look after its two young until they are about a month or six weeks 

 old ; after that time they will be seen together, but if alarmed in any 

 way the young will quickly swim towards their respective parents, 

 and if not too large, hide under their wings, when the birds dive and 

 carry the young to a place of safety. 



On the lakes where I have observed these Grebes, I have been 

 surprised to find that there are so many pairs which do not nest. 

 During the past summer there were over forty pairs, but although 

 the whole of the suitable nesting-parts were most carefully searched, 

 I found that only fifteen of these pairs were nesting, and it is interesting 

 to know that in one comer of the largest lake there was quite a colony 

 of nests : seven containing eggs were found on a piece of reed- covered 

 water about ten yards square. This is a thing I have never seen before, 

 for usually they resent other birds of their own species coming to 

 their particular portion of the lake. 



Those pairs which did not nest were, as late as the middle of July, 

 still going through their curious courting exercises, that is, facing 

 each other, with necks extended, frills open, and crests raised, and 

 at short intervals almost touching beaks and giving the head a peculiar 

 shake. If another Grebe came near them, the male immediately 

 placed himself in fighting attitude. Oliver G. Pike. 



WiNCHMORE Hill, Middlesex, September 5th, 1913. 



[The Great-crested Grebe breeds in large colonies on some of the 

 bigger sheets of water on the Continent, and small colonies have been 

 met with occasionally in the British Isles, as for example in the West 

 of Ireland, where Mr. J. Henderson found several pairs breeding 

 close together; cf. also Yarrell, 4th ed., IV., p. 118. Seebohm {History 

 of British Birds, III., p. 456) describes the large colonies on the Lantow 

 See and Garda See in Pomerania, and numerous other instances are 

 quoted in the Neuer Nanmann, XIT., p. 73. — F. C. R. Jourdain.] 



