352 BRITISH BIRDS. 



" T. F." gives us the measurements of the two eggs taken 

 by him as about If by If inch (say 41.3x35 mm.) 



Unfortunately, the tests of size and weight do not furnish a 

 safe criterion to distinguish the eggs of the two species, 

 although in many cases it is possible to discriminate with 

 tolerable certainty. The Rev. F. C. R. Jourdain has supplied 

 us with the following notes on the subject. The average size 

 of 100 Hen-Harriers' eggs is 44-7 x 34-9 mm., and the mini- 

 mum 40"5 V 31-5. On the other hand, 83 Montagu's Harriers' 

 average 40'67 x 32'46 mm., but the maxima are 46 x 33*4 

 and 43"3 < 35*2. It will be seen that in extreme cases the 

 measurements overlap considerably, but judging from the 

 breadth (which is by far the more reliable factor) the eggs are 

 more likely to be those of the Hen- Harrier than of the other 

 species. On an average, eggs of Montagu's Harrier Aveigh 

 about 400 mg. less than those of the Hen-Harrier, but here 

 again in extreme cases the data overlap. The measurements 

 of Hen-Harriers' eggs as given in Mr. Dresser's book on the 

 " Eggs of the Birds of Europe," Part I., are decidedly too 

 large, and are probably due to misprints. 



The nestlings, however, afford positive proof. " T. F." 

 examined their primaries and noted that the fifth primaries 

 were not notched (or emarginated) on their outer webs. 

 Messrs. Mouritz and Bentham, unfortunately, did not examine 

 the primaries, which in these species afford infallible charac- 

 teristics for identification. Further, one of the young birds 

 was shot in the neighbourhood by a keeper. The nestlings as 

 described to me by Mr. Bentham and as described in the 

 "Field," were like the young one which was shot, and were 

 typical of Montagu's Harrier in that they were very red on 

 the underparts with but the faintest dark streaks. The bird 

 that was shot is an undoubted Montagu's Harrier. 



Mr. F. C. Selous has most kindly made most exhaustive 

 enquiries on the spot, and through the kindness of Colonel 

 Mark Mayhew he has been enabled to examine minutely the 

 two birds which Colonel Mayhew purchased from the keeper 

 who shot them. There can be no doubt whatever by the test 

 of the primaries as well as by the coloration that the bird 

 shot in March is an adult female Hen-Harrier, and that the 

 bird shot in August is a young Montagu's Harrier. Mr. 

 Selous further finds that Harriers are constantly in the 

 neighbourhood of this nest, both in winter and in summer, and 

 that they have nested there a good many times in the past 

 twenty years. Two of his informants were confident that all 

 these birds were Hen-Harriers, but there can be little doubt, 

 from the information obtained by Mr Selous, that the birds 



