Bibliographical Notice. 335 



chapter we have an evolutionary sketch of the orders of birds, 

 which could only come after prolonged attending of the mind there- 

 unto, and the pedigrees suggested are made, to our thinking, very 

 much more valuable by the insertion of a genealogical tree. This 

 useful device cannot do harm when an author is so careful to insist 

 upon uncertainties as Mr. Pycraft always is. 



From the distributional chapter, which is almost too condensed, 

 we may select the note that the Penguins seem to be the only group 

 of importance with a southern origin, and the protagonists of tbe 

 north will also be pleased to find Mr. Pycraft's adherence to the 

 view that Trogons, Parrots, and Struthiou3 birds are northern 

 forms which have spread southwards. The chapter on migration 

 does not seem to us so strong as the others ; thus the movements of 

 Swallows in particular are taken to illustrate the conclusion that 

 the normal migration is due north and south, and an attempt is 

 made to correlate a wide migratory range with prolific reproduc- 

 tivity on the one hand, and catholicity of appetite on the other. 

 As one would expect, the chapter on inter-relations is fascinating, 

 and we may refer to an instance given to show that the Cuckoo 

 keeps careful watch on birds likely to prove suitable victims. " A 

 young Cuckoo was found in the nest of a Pied Wagtail which had 

 built in a flower-pot containing a plant trained over an intricate 

 trellis-work, leaving but small interspaces just big enough to allow 

 the passage of so small a bird, and this flower-pot, it is to be noted 

 was placed in a greenhouse. Thus, then, the Cuckoo must have 

 watched the Wagtails collecting nesting materials, and have watched 

 their destination. Then, having deposited its egg on the ground 

 somewhere in the vicinity, it must have picked it up and gone 

 straight to the flower-pot, thrust in its head, and dropped the egg 

 into the nest." But is Mr. Pycraft pulling the reader's leg when he 

 says of the commensalism of Petrels and Hatteria that the Petrel 

 seems generally to live on the left, the " lizard " on the right side of 

 the burrow ? 



The mode of treatment followed by the author in the section of 

 the book that deals with family affairs seems to us peculiarly happy 

 and successful. The chapters abound in significant facts, winch 

 are utilized with good judgment. Song is not necessarily correlated 

 with happiness : " the most famous singer of all, for example, the 

 Nightingale, will sing when alarmed, or under the emotion of a 

 great shock, as when its nest and eggs are destroyed, or when 

 roused from sleep by some sudden alarm." The theory that imita- 

 tion plays an important part in the construction of the nest is dis- 

 missed, though it is rather the absence of evidence in favour of the 

 theory than anything against it that is urged. The whiteness of 

 some eggs is primitive, and in other cases secondarily derived : and 

 a very interesting state of affairs is illustrated by the British Puffin, 

 whose eggs are found to be thinly covered over with a layer of 

 white over a coloured surface. It is suggested that birds that nest 

 in holes have white eggs, not because they took to holes to hide 

 their conspicuous eggs, but because " in such dimly lighted places 

 coloured eggs, from their low refractive power, would run grave 



