120 STUDIES IN BIRD-MIGRATION 



In spring the migrants are chiefly observed following 

 the plough ; but in autumn their favourite resorts are 

 the few beaches, where they capture the flies which 

 abound in the belt of seaweed which fringes high- 

 water mark. 



MoTACiLLA BOARULA, Grey Wagtail. — There are as 

 yet only five known instances of the occurrence of. this 

 species— all in spring, and, with one exception, of single 

 birds. In one instance two appeared. This species can 

 only, it is thought, be regarded as a straggler beyond its 

 accustomed range, since it has no summer haunts in 

 Northern Europe, being there, as in Fair Isle, a rare 

 visitor only. The date's of these visits are as follows : 

 nth, i8th, and 20th April, and 17th and 21st May. 



MoTACiLLA RAVI, Yellow Wagtail. — This is another 

 bird whose visits to Fair Isle have carried it beyond 

 the range of its usual habitats, which do not extend 

 beyond the southern half of the Scottish mainland. It 

 has occurred on four occasions, all in spring : an adult 

 male on 8th May 1906 ; a male on nth May 1908 ; two 

 on 23 rd April 1909 ; and one on 27 th April 1909. 

 The specimen obtained on nth May 1908 was an 

 abnormally pale one. 



MoTACiLLA FLAVA, Blue-headed Wagtail — Four of 

 these birds appeared on i8th May 1908, and an adult 

 male was captured and sent to me.^ It had been 

 previously recorded for both the Orkney and Shetland 

 groups, but the occurrences of this species and of the 

 hitherto much overlooked M. thunbergi ( = M. borealis) 



' On the 14th of May 1910, and again on the i8th and 19th, adult 

 males appeared, and for several days came under the notice of the Duchess 

 of Bedford and myself. These birds haunted the grasslands, and showed 

 a strong predilection for the company of cattle. 



