336 



CORRESPONDENCE. 



A MAGPIE FLOCK. 



■Referring to my remarks on p. 138, might I make it quite clear that 

 when I used the word ' flock ' as apphed to magpies, this word meant only 

 cases where the birds were close together, and not birds which might be 

 visible to an observer looking north, south, east and west, or wide apart ? 

 Although never having to my knowledge spoken to Mr. Fortune, I was of 

 the opinion he used the word in the same meaning. I never intended to 

 suggest that every collection of magpies came together in order to mob a 

 cat — such would have been absurd. When exploring the neighbourhood 

 of that magnificent ruin, Rievaulx Abbey in Yorkshire, in 1903, I 

 witnessed a pair of magpies chasing a wild rabbit as it ran, attacking it 

 (so far as I could see) at the back of its head with their beaks. On seeing 

 me, the birds fled, the rabbit escaping. 



Fred D. Welch, M.R.C.S. 



'DIMORPHIC COLORATION' IN THE CUCKOO. 



What one appreciates (amongst other points) in Mr. Butterfield's 

 ' Romance of the Cuckoo ' is the distinction drawn between ' fact ' and 

 ' speculation ' (p. 130), in which he improves on some writers of mammals, 

 birds, etc. As he refers to ' Dimorphism,' the following may be of interest, 

 in two birds, both young, since his cases are presumably based on northern 

 experience. During the summer of 191 1, when staying at Rudgwick in 

 Sussex, two young birds were caught on a fruit farm owned by Admiral 

 Goodrich ; one by myself in a glass-house into which it wandered after 

 insects (on a Monday), the other by a boy who was weeding, in some netting 

 where it got entangled (the following Wednesday). These were of the 

 same size, caught within thirty yards of each other in the same summer, 

 and yet quite different in coloration, as proved by a long and thorough 

 investigation when in my hands. One was of a darkish grey, the other a 

 rich rufous red. What sex they were I cannot say, as I let both go free 

 after noting their coloration, because they were very frightened after the 

 long examination — cuckoos are useful birds. 



When one comes across cases like the above, and notices Dimorphic 

 Coloration in such mammals as apes, mungooses and wildcats, either within 

 or near the tropical parts of Asia, Africa and South America, they confirm 

 the words ' without such cause being in any way traceable to local in- 

 fluences ' (p. 130, 1. 21). 'Dimorphic Coloration' is of course different 

 from seasonal change. A third young one (rather larger), found about 

 10 days before, gave a very peculiar exhibition of behaviour ; it, also, was 

 rich rufous red. 



There is one other point I should like to confirm, that being the remarks 

 at bottom of p. 93 and top of p. 94. On May 14th of this year (1918), 

 when watching a pair which frequent this locality, one was in a clump of 

 forest-trees calling ' cuckoo ' as loud as it could, the other flew across a 

 field behind my house (within about 70 yards of me) making the bubbling 

 peculiar noise, and ' cuckoo,' one rapidly after the other, the two sounds 

 being repeated alternately about fifteen times each. Fact is more valuable 

 than opinion. I never found cuckoos so frequent in Kent and Sussex as 

 in the west — in Herefordshire. Frederick D. Welch. 



O 



CUCKOOS' EGGS. 



Referring to Mr. E. E. Pettitt's note on page 204 of The Naturalist, 

 for June, I might in the first place state that cuckoos' eggs in this district, 

 and perhaps this may apply to the Pennine Range generally, are, with very 

 few exceptions, true to one type, which approaches that of the skylark 

 more nearly than any other British bird. Indeed, the cuckoo occasionally 

 lays its egg in the nest of this species, at least I have found it once in a nest 

 which was built on a heathy waste. 



