

ZOOLOGY. 



NOTES ON THE BIEDS OF THE BASDT OP THE TAY 



AND ITS TEIBUTAEIES. 



By Colonel H. M. DRUMMOND HAY, C.M.Z.S., B.O.U., &c. 



{Contimted from p. 115.) 



53. MoTACiLLA Yarrelli, Gould. (Pied Wagtail.) 



COMMON throughout the whole district. Some years, how- 

 ever, it is much more abundant than others. The partial 

 migration of these birds seems a puzzle : many remain all winter, 

 except in very severe weather, notwithstanding that a very exten- 

 sive migration takes place every autumn, when large bodies leave 

 this country and cross over to the Continent, with a correspond- 

 ing return in the spring, as is well authenticated. On our own 

 shores, at the mouth of the Tay, at the end of August or begin- 

 ning of September, large numbers may be seen all day long 

 steadily moving along the coast southwards, in small trips and 

 companies, along with the Wheatear. It is difficult, therefore, to 

 explain why some should remain behind. Even in the unusual, 

 severe winter of 1878-79, when the Tay was frozen over, and the 

 feeding-grounds on its banks one mass of ice, the Wagtails were 

 seen as late as the loth of December, and so starved that they 

 greedily devoured bread when offered (a most unnatural food). 

 Could these birds have been caught, as it were, by the sudden 

 arrival of winter, and become so enervated and weakened as to 

 be unable to proceed further south ? It would be difficult other- 

 wise to account for their late stay. Mr Cordeaux remarks, in his 

 ' Birds of the Humber District,' " that the gradual increased area 

 placed under turnip cultivation of late years, has supplied for 

 these birds, and kindred species, a source of winter food previ- 

 ously unattainable, and offers inducements to them to brave even 

 the severest winters; " and further adds, " that owing to the almost 



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