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DR. L. BUREAU'S WORK ON THE PARTRIDGE. 



In a volume* of 124 pages illustrated with 35 plates, 

 many of them half tone blocks taken from actual 

 specimens, Dr. Bureau describes his work on the deter- 

 mination of age in the Partridge (Perdix cinerea), which, 

 as he tells us, is the result of eleven years methodical 

 observation in the field, preceded by years of preparatory 

 study. 



The method of the determination of a young bird's age 

 is based upon the moult of the primaries of the juvenile 

 plumage, which begins before the end of the fourth week 

 and lasts to the end of the fourth month, i.e. to the 

 middle or end of October or even, for later broods, until 

 the beginning of November. After this and up to the 

 age of fifteen or sixteen months, it is still possible to 

 say whether a bird is young or old by means of the first 

 two primaries, which are not replaced at the first moult 

 but are retained until the end of the second moult in 

 the bird's second September or October. The extremity 

 of these feathers is pointed, whereas that of those that 

 replace them is more rounded. This is of course a method 

 of telling young birds from old ones well known to sports- 

 men, though perhaps the reason (viz : that these are 

 juvenile plumage feathers retained until the bird is over 

 a year old) is not so generally realized. The main points 

 in the moult upon which the determination of age is 

 based are as follows : — 



1. The absolute regularity with which the primaries 

 of both wings are moulted from within outwards, 

 i.e. from ten to three. 



2. Each primary is dropped at a certain age, or, in 

 other words, when the one internal to it has attained 

 a certain length, which is constant for each feather. 



3. The daily growth of each new feather is fairly 

 constant although not the same for each one. It 

 may be taken as fairly accurate that this rate is 

 a little greater during the earlier days of growth, 



V Age des Perdrix. 1. La Perdrix grise. Par le Dr. Louis Bureau, 

 Directeur du Museum d'Histoire Naturelle de Nantes, Foreign Member 

 of the B.O.U. Williams and Norgate, 14, Henrietta Street, Co vent 

 Garden, London, W.C. 8vo., 124 pp., 35 figures. 



