86 WHITE-WINGED PIED WAGTAIL. 



Length of male sent me by Mr. Tristram, seven inches and two fifths; 

 of female six inches and seven tenths. From carpal joint to tip three 

 inches and a half; tail three inches and three fifths; beak from gape 

 seven tenths of an inch. Breadth of lower mandible at gape one fifth of 

 an inch; tarsus one inch. 



The Wagtails form a group of birds always interesting to the 

 naturalist. They are among the most beautiful and elegant of the 

 feathered tribes, and there are few people who have not watched their 

 graceful movements among our rocky streams without pleasure. 



They are also interesting studies to the philosophic naturalist — for 

 they present him with some puzzling problems as to the distinction 

 between species and variety and race. "Natural selection" has been 

 busy with the group, and without however shewing any tendency to 

 develop a Pelican or a Balceniceps rex out of the delicate Wagtail, 

 it has given to one a darker head, and to another a gayer coat, 

 which I doubt not will in that extensive future which we are told 

 to expect, have their due influence over the deluded eyes of the weaker 

 Wagtail sex. 



There are eight European Wagtails described by authors, five of 

 which are observed in England. Degland however has reduced this 

 eight to four. He leaves out M. lugubris, Pallas, as of uncertain 

 occurrence in Europe, and he considers M. yarrelli, with which it is 

 thought identical by authors, as a variety of our White Wagtail, the 

 Motacilla alba of Linnaeus. 



M. cinereo-capilla of Savi, M. melanocepliala and M. Jlaveola, (Ray's 

 Wagtail,) are considered by both Degland and Schlegel, to be races 

 or varieties of M. Jlava, (our Grey-headed Wagtail.) 



Mr. Tristram writes me word that he cannot satisfy himself of the 

 specific distinction of M. Jlava from M. cinereocephala, and that he can 

 shew every intermediate gradation between M. Jlaveola and M. melano- 

 cepliala. 



This subject is very well treated by Dr. Zander in "Naumannia," 

 1858, Part 3, p. 239. Dr. Zander considers that all European Wag- 

 tails are varieties of M. alba, M. boarula, M. citreola, and 31. jlava, 

 Linnseus. He says he considers much of the difficulty arises from the 

 fact that the intermediate varieties are not so frequently seen as the 

 so-called species. He describes how perplexing are the changes pro- 

 duced by a substitution of black or yellow for grey, or by the passing 

 of grey into grey yellow. "The grey goes through all shades till it 

 comes to the clearest black, and the eye stripe becomes less, until 

 hardly seen." He also thinks that the various colours in the females 



