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their ancestral homes appear to be different, they mingle freely 

 in many localities, as, for example, in the North of Scotland, 

 where the lecturer has taken eggs from a nest occupied by a pair 

 of birds, the one a hoodie, the other a carrion crow ; nor is this 

 inter-breeding by any means rare. But the result of such inter- 

 breeding is rarely distinguishable from one or other of the parents, 

 although one would have expected the offspring always to show 

 character intermediate between the two forms. 



(Immediately after the lecture it was pointed out by Mr. 

 Langton that the Arctic Skuas afforded another and even better 

 example of the peculiarity observed in the offspring of the two 

 forms of crows. The two forms of the Arctic Skua are well 

 known, and are so distinct that they were for long considered to 

 belong to distinct species. Both forms occur together, and 

 constantly inter-breed. Yet the offspring retain one or other of 

 the original forms, and are very rarely, if ever, intermediate in 

 plumage between their parents). This is equally the case with 

 the bridled and common Guillemot. 



The lecturer then instanced two groups of birds where the 

 plumage offered but a slight criterion of the distinctness of allied 

 species. Chiffchaffs, willow warblers, wood wrens, and lesser 

 "whitethroat s, differ widely in their habits, their nests, and their notes. 

 In fact, in a state of nature they cannot be mistaken for one another. 

 Yet but few naturalists can distinguish the birds at a glance when 

 ■dead, while the females are almost indistinguishable by their 

 plumage. Similarly, though in a less degree, the three species of 

 snipe, being exhibited side by side, showed a very close series of 

 resemblances of plumage, though the birds are so widely different 

 in their habits, as well as in size. 



The most interesting group of the abnormal or irregular 

 variants was exemplified by a male Marsh harrier, showing in 

 some of the wing feathers the same soft grey colour which is in 

 all cases assumed by the adult males of the other two British species 

 of hari'iers. As mentioned above, the females of the Hen 

 harrier (and of the closely allied Montagues harrier) are brown 

 birds, while their consorts are of a uniform slatey grey colour. The 

 two sexes of the Marsh harrier on the other hand are usually 

 alike, blackish-brown, with a white pate and nape. But the males 

 in rare cases show a partial approxinjation to the grey colour of 

 their cousins, most usually in some of the wing feathers and very 

 rarely indeed in the tail or elsewhere. 



Other abnormal variations were stated to fall generally into 

 one of these groups, in one of which (as in the case of the town 



