VOL. xm] LETTER. 167 



the field will be able to appreciate his patience and dogged perseverance. 

 Unfortunately however his work has added nothing new to our know- 

 ledge on this very interesting problem. The artificial conditions 

 brought about by the systematic taking of the eggs entirely destroy the 

 value of the results obtained. 



Mr. Chance says, " Had I not taken the first laid eggs of the Cuckoo, 

 she would certainly not have had opportunity to lay such a large 

 series." Exactly ! the clutch is abnormal since the conditions were 

 rendered abnormal. 



Having seen this remarkable series I have no hesitation in confirming 

 that the eggs are the produce of the same bird, or jointly the produce 

 of birds closely related, e.g., mother and offspring or possibly a sister. 



Cuckoos would naturally have a better opportunity to become 

 parasitic on a common species like the Meadow- Pipit, than on a rarer 

 one like the Grasshopper-Warbler, or the Nightingale, better facilities 

 being offered because several nests are often in one comparatively 

 small area, and the breeding-range of the Cuckoo is very limited. 



The taking of first nests of the Meadow-Pipit would cause second 

 nests to be available for the Cuckoo in about ten days ; and in all 

 probability if second nests were disturbed third nests would become 

 available in a further ten days ; for from experience I have found 

 that ten days is sufficient time for a bird of this species to build the 

 nest and lay eggs after its last nest was disturbed. Hence the Cuckoo 

 had nests available for roughly 30 days ; thus artificial conditions 

 were created. Mr. Chance estimates the number of Meadow- Pipits 

 at not more than ten pairs. If this was so some of them must have had 

 late first nests, or they must have attempted to breed a fourth time. 



There is, as far as I am aware, no concrete evidence to prove Prof. 

 Newton's theory that the type of egg is perpetuated by the offspring.* 



Though I have met with certain evidence which would in a measure 

 support this, it would be premature to assume that such is the case, 

 but one would naturally expect that it is so. 



Mr. Chance informs us that he spent over one hundred hours on this 

 small common. The actual time between the first and last laying of 

 this particular Cuckoo occupied about 1,176 hours, i.e., from May i8th 

 to July 5th. How can he be sure of what happened in 1,076 hours ? 

 The possibility of a second Cuckoo {i.e., of an offspring) must not be 

 lightly dismissed, and it can hardly be bearing in mind that most 

 Cuckoos' eggs are deposited with the fosterer at daybreak. Of this 

 I have the most undeniable evidence. 



Cuckoo's eggs are sometimes found alone in nests. If the foster- 

 parent only had one egg and this was removed by the Cuckoo on its first 

 visit, the absence of a foster parent's egg is accounted for. I only 

 possess certain knowledge of one case where the Cuckoo's egg was 

 deposited before those of the fosterer. This was in a Hedge-Sparrow's 

 nest. About 5 a.m. the latter was empty ; a Cuckoo was seen to visit 

 the nest just after inspection and she deposited her egg. 



The method of depositing the egg was settled, at least to my satis- 

 faction, by Mr. A. H. Meiklejohn and is fully recorded in the Zoologist, 

 1900, pp. 262-4, fh^ sgg being swallowed and then regurgitated. The 

 value of this note should not be overlooked, Mr. Meiklejohn being a 

 most careful observer. We must also bear in mind that Cuckoos have 

 been found with broken eggs in the gullet. That the egg is deposited 

 by the claw I do not think has ever been seriously accepted. 

 Croydon, Sept. 13^^, 1919. P. F. Bunyard. 



* " And it can hardly be questioned that the egg of the daughter would more or 

 less resemble those of the mother." — Diet, of Birds, p. 123. 



