198 MR. A. H. KVANS UN THE 



the same bird, which shews a partiality for Robins' uests (3 out 

 of 4). 



The third and fourth series are exhibited for the same purpose ; 

 in the third the egg is again remarkable, in the fourth Hedge- 

 SpaiTows are the favourite hosts. 



The fifth series includes reddish or greyish eggs, of a type not 

 uncommon along four or five miles of the Cam. The preference 

 here is for the nests of Sedge- or Reed-Warblers, and the simi- 

 larity of coloration may shew tlie range in their case of kindred 

 birds. The specimens were taken by Messrs. Richmond, Mills 

 and myself : where two occurred in the same nest, they were 

 clearly the produce of difterent hens. 



The single egg next to these was laid in a Pied-Wagtail's nest 

 after the young had flown, the sole instance in my experience. 



With regard to the choice of foster parents, it should be noted 

 that in the latter part of May and in June there is often little 

 real choice, especially on the moors. The Cuckoo must take what 

 she can get, and individual hens seem to have a restricted range, 

 if we are to judge by the eggs. Ihey appear to be somewhat 

 lazy birds, which follow the " line of least resistance," choosing 

 Reed- and Sedge- Warbleis for hosts on rivers and lakes, Hedge- 

 Sparrows, Robins, Wagtails and the like in lanes and ga.rdens, 

 Pipits on moors and commons, with a decided preference for a 

 small, comfortably lined nest. No one would look for Cuckoo's 

 eggs in a dense wood, or low down in a thick hedge or pile of 

 sticks, where Hedge-Sparrows often breed. 



An examination of the dates on which the specimens exhibited 

 were taken shews a still more important fact, namely, that the 

 identical hen returns for several years in succession to the same 

 grounds or even to the same copse. Here we have definite proof, 

 as opposed to assumption. This fact is not only made evident 

 by the eggs from Histon Manor, but by the two very remai'kable 

 series from the collections of Dr. Norman Ticehurst and Mr. 

 J. L. Bonhote. 



In the first series, where the Cuckoo's egg resembles tha.t of 

 a Spotted Flycatcher, the foster parent was invariably a Pied- 

 Wagtail. The nests were in pollard Willows between Grant- 

 Chester and Waterbeach, a range of some eight miles. An egix, 

 less richly coloured, also taken near Waterbeach, about ten years 

 earlier, is sufiiciently near the types to justify the conclusion 

 that kindred birds occurred there before the dates on the rest of 

 the series. 



The second series of large grey eggs with uniform small stipples 

 came from a clay-pit near Waterbeach, and, as in the last case, 

 were found annually for several years in Sedge- or Reed- Warblers' 

 nests. Here, again, I exhibit a similar, though greener, egg taken 

 many years later, which a])parently shews kinship in the bird 

 which laid it. Be this as it may, the dates of the main series 

 prove the annual return of a hen bird to the very same spot. 



The number of eggs of the foster parent allowed to remain 



