Natural History 433 



ing the other where it is more suitable. The scales on the toes are 

 often suggestively reptilian in appearance, and when there are 

 also feathers about the toes they grow not on the scales but from 

 between the scales from between the other scales we may indeed 

 say to emphasise the point. 



Plumage Coloration 



The feathers of many birds are richly coloured, and even 

 those of sober hue may be very beautifully marked. In some 

 cases the colours may be due to actual pigment; but in others, 

 especially blues and greens, the minute physical structure of the 

 feathers is responsible and wonderful effects of iridescence are 

 produced. 



Brilliance of plumage is often associated with the mating 

 season, but this is far from being a general rule. In some instances 

 the male has a special breeding plumage, and sometimes both sexes 

 have this, examples of each kind being found among the Plovers. 

 In other cases the male has brilliant plumage for most of the year, 

 like the Mallard, while his mate is always dull. In many species, 

 on the other hand, the sexes are alike and have a similar appear- 

 ance all the year round; this permanent plumage may be dull- 

 coloured as in the Song-Thrush or Curlew wonderfully 

 beautiful birds, nevertheless or brilliant as in the Kingfisher. 

 Most birds that have a permanent bright plumage, however, are 

 dull in their first year, as is the case with the afterwards splendidly 

 iridescent Starling, but in some cases, such as the Kingfishers and 

 the Parrots, the gorgeous plumes have appeared before the birds 

 leave the nest. One other kind of change must also be mentioned, 

 namely, the seasonal changes of the Ptarmigan, which is white 

 during the season of snow and of duller appearance when its 

 native hills are brown once more. 



Courtship and Mating 



Some of the most interesting habits of birds are those as- 

 sociated with the mating season. In many cases there are curious 



