1900.] Fatten. — The Natural History of the Riiff. 205 



never varied in confinement. These two conflicting statements 

 are most interesting. I should not lay so much stress on the 

 fact that some Ruffs retai7t the same nuptial plumage. 'Some 

 birds in captivit}^ never even assume theirnuptialplnmageatall. 

 This is due no doubt to captivity affecting their reproductive 

 system. A case in point is that of a Knot^ {Trifiga camitus) at 

 present in the Dublin Zoological Gardens, which throughout, 

 the year has retained its winter plamage. On the contrary I 

 have observed gulls in captivity change from winter to 

 summer plumage with great rapidity. Hence it appears that 

 observations made on plumage changes of birds in captivity 

 hardly gives up a true insight as to what happens in a state of 

 nature. 



Judging from analogies and comparisons, I am inclined to 

 think that the three types of Ruff already described (pp. 200-2) 

 represent three different ages betw^een which slight variations 

 may occur. Those with the yellowish-white frill may be the 

 youngest^ ; for they are the smallest, have the "frill" least 

 developed, and show almost no gloss on the plumage. 



The reddish-brown birds are probably older ; they are, 

 on an average, larger, have longer and better developed 

 " ruffs," and show a moderate amount of gloss on the feathers. 



The oldest birds are likely those which display a pre- 

 dominating amount of black in their feathers. They are the 

 most glossy, and increasing lustre of feathers indicates 

 increasing age. This is seen in many of the Crows, Ducks, 

 Pigeons, Gallinaceous,'and other groups of birds. If comparison 

 helps us we may say that the dark colour in the Limicolae 

 is an indication of age. In some species — notably the Dunlin 

 and Sanderling — the old, and often barren, birds lose much of 

 the buff shading of their summer dress, its place being taken 

 by a greater amount of black feathers. What exact ages these 

 tj'pes may represent it is hard to say. The question requires 

 further investigation, and 1 only throw out ni}^ suggestions in 

 the hope that they may help others to lead to more definite 

 results. 



■• Mr. Bartlett noted the same thing happening many years ago in the 

 London Zoological Gardens. (^See Darwin, " Descent of Man," p. 399). 



^ The young male mentioned by Montagu in Thompson's work had a 

 " frill " of white and chestnut. 



