CUCKOW 121 



stadt, who says {Zoolog. Garteu, 1866, pp. 374, 375) that through a 

 telescope he watched a CuckoAv as she laid her egg on a bank, and 

 then conveyed the egg in her bill to a Wagtail's nest. Cuckows 

 too have been not unfrequently shot as they were carrying a 

 Cuckow's egg, presumably their own, in their bill,^ and this has 

 probably given rise to the vulgar, but seemingly groundless, belief 

 that they suck the eggs of other kinds of birds. More than this, 

 Rowley, who had much experience of Cuckows, declared {Ihis, 

 1865, p. 186) his opinion to be that traces of violence and of a 

 scuffle between the intruder and the owners of the nest at the time 

 of introducing the egg often appear, whence we are led to suppose 

 that the Cuckow ordinarily, when inserting her egg, excites the 

 fury (already stimulated by her Hawk-like appearance) of the 

 OAvners of the nest by turning out one or more of the eggs that 

 may be already laid therein, and thus induces the dupe to brood all 

 the more readily and more strongly what is left to her. Of the 

 assertion that the Cuckow herself takes any interest in the future 

 welfare of the egg she has foisted on her victim, or of its product, 

 there is no evidence worth a moment's attention. 



But a much more curious assertion has also been made, and one 

 that at first sight appears so incomprehensible as to cause little 

 surprise at the neglect it long encountered, ^lian, who flourished 

 in the second century, declared {De Nat. Anim. III. xxx.) that the 

 Cuckow laid eggs in the nests of those birds only that produced 

 eggs like her own — a statement which is of course far too general ; 

 but in 1767 currency was given to it by Salerne (L'hist. Nat. Ois. 

 p. 42), who was, however, hardly a believer in it ; and it is to the 

 effect, as he was told by an inhabitant of Sologne, that the egg of 

 a Cuckow resembles in colour that of the eggs normally laid by the 

 kind of bird in whose nest it is placed. In 1853 the same notion 

 was prominently and independently brought forward by Dr. 

 Baldamus (Naumannia, 1853, pp. 307-325), and in time became 

 known to English ornithologists, most of whom were sceptical as to 

 its truth, as well they might be, since no likeness whatever is 

 ordinarily apparent in the very familiar case of the blue-green egg 

 of the Hedge-Sparrow and that of the Cuckow, which is so often 

 found beside it.^ Dr. Baldamus based his notion on a series of eggs 

 in his cabinet,^ a selection from which he figured (op. cit. 1854, pi. v.) 



^ The earliest instance of this in the British Islands seems to be that 

 reported by Thompson {B. Irel. iii. p. 472) ; another was recorded in 1851 

 {Zool. p. 3145) ; but Le Vaillant seems to have been the first to discover the fact 

 in a South African species {Ois. d'Afr. v. pp. 47, 48), and untrustworthy witness 

 as he was, in this case he seems to have spoken truly. 



- An instance to the contrary was recorded by Mr. A. C. Smith {Zoologist, 1873, 

 p. 3516) on Mr. Brine's authority, and a few others have since been observed. 



^ This series was seen in 1861 by the writer. 



