DR. BUREAU ON THE PARTRIDGE. 215 



The Moult of the Secondaries. 



This is accomplished with similar regularity, but is 

 not synchronous with that of the primaries. It takes 

 place in two groups — an internal and external — simul- 

 taneously. The internal group consists of the third 

 to the fifteenth, and the external of the first and second. 

 The former is moulted from without inwards and the 

 latter from within outwards. The third (first of internal 

 group) is shed while the seventh primary is growing, 

 or at the time of the fall of the sixth (say on the 45th- 

 50th day). The second is dropped about the same time 

 as the fourth primary, and the first a little before the 

 fall of the third primary. 



The Moult of the Tail. 



The tail of the juvenile plumage is full grown (49-5 1mm.) 

 at an age of thirty -nine days, and when widely spread, 

 shows a slight median indentation with a still slighter 

 lateral indentation on each side, thus forming a scalloped 

 outline, which is further accentuated by the two upper 

 tail-coverts covering the two middle rectrices, which 

 by their great length and shape simulate tail-feathers 

 Though the moult takes place with great regularity from 

 within outwards, it does not coincide with the fall and 

 growth of the primaries. 



The tail has hardly become full-grown before the six 

 feathers on either side of the middle line are rapidly 

 dropped in pairs, the eighth, seventh and sixth falling 

 almost simultaneously. Nothing is left on either side, 

 except the two most external feathers, which project 

 markedly and give the bird a characteristic " swallow- 

 tailed " appearance which lasts until a little after the 

 loss of the sixth primary (say from the 4:0th to the 50th 

 day). 



On the 4:1th day the six or seven new tail-feathers 

 that are growing on either side of the middle line 

 measure about 25mm. By the time the fifth primary has 

 dropped {55th day) the most external tail-feather has 

 usually been shed also, while the rest of the tail has 

 gone on growing and has a characteristic arched shape. 

 By the 01th day the middle feathers are full-grow^n 



