108 STUDIES IN BIRD-MIGRATION 



the Twite population of the island is to be reckoned 

 in thousands. Early in the season they are to be found 

 everywhere, especially on the face of cliffs where seed- 

 bearing plants flourish. Later, after the corn is cut 

 and garnered, they gather together, form immense 

 flocks, and frequent the stubbles. The extraordinary 

 abundance of this species adds much to the difficulties 

 of detecting and identifying immigrants, especially the 

 Finches and Buntings, which on arrival usually join the 

 ranks of the Twite armies, where they become to all 

 intents and purposes effaced. On this account this 

 cheery little bird becomes in the autumn a veritable 

 curse to the bird-observer. A diminution in their 

 numbers takes place late in the autumn. The return of 

 the autumn emigrants takes place in early spring, and 

 many were noted as arrivals on 28th February and 15th 

 March 19 10. The arrivals observed at this season prob- 

 ably include birds on passage — migrants whose appear- 

 ance it has been impossible to detect in the autumn. 



AcANTiiis RUFESCENS, Lesser Redpoll. — A male cap- 

 tured on I St May 1906, is the only occurrence known ; but 

 the species has several times been recorded for Shetland. 



AcANTHis LiNARiA, Mealy Redpoll. — Redpolls are 

 not infrequent visitors in the autumn, and in some 

 seasons are extremely abundant ; but unless examples 

 are obtained, it is usually quite impossible to say to 

 which of the several races of Redpoll they belong. 



It is probable that the typical form under notice 

 is the most frequent of all, and of it specimens 

 have been captured in March, April, and May — dates 

 varying from 3rd of March to 2nd of June. Others, 

 possibly of this race, have been seen as late as i6th 

 June. 



