218 THE ZOOLOGIST. 



It is not an easy matter to distinguish between a stunned 

 bird which had recovered consciousness and a fatigued bird. 

 When seen at break of day both appear listless, very tame, 

 and move about with their feathers puffed out. A bird with 

 a broken wing at once attracts attention as it tumbles and 

 flutters over the inequalities of the rugged rock-surface. When 

 pursued it generally disappears by crouching in a crevice, where 

 it will remain until dislodged by a stick or even the hand. When 

 a post-mortem examination is made on the body of the stunned 

 bird there is, as a rule, some cerebral or cranial lesion ;* in 

 fatigued birds there is usually no indication of damage of the 

 head due to contact with the glass. Objective evidence such as 

 this, even though not obtained till after death, is valuable. In 

 regard to the occurrence on the Rock at dawn of tame and list- 

 less migrants, the evidence that they descended to the Rock at 

 the close of a nocturnal migration becomes all the more con- 

 vincing if the same species were seen at the lantern or in the rays 

 prior to daybreak. This is a particularly important point to note 

 in the case of birds which very seldom alight on the Rock in 

 daylight unless associated with a nocturnal passage. I may 

 mention three common species — the Song-Thrush, Goldcrest, 

 Corn-Crake — which figured prominently at the lantern, and 

 whose occasional appearance on the Rock at dawn invariably 

 followed their advent at the lantern. 



Few birds that had been hurdled against the lantern-glass 

 by the wind were observed alive on the Rock ; most of them 

 fluttered or were carried into the sea. On September 19th, 

 1912, however, I examined a Song-Thrush which Mr. Power 

 captured alive on the Rock at 7.30 a.m. The wind during the 

 previous night blew with the force of a fresh breeze. This bird had 

 lost a considerable number of feathers from the lower region of 

 the abdomen and right flank. Elsewhere the plumage was good, 

 nor was there any sign of moult. It may be well to state that, 

 as many birds are found migrating during an active moult, it is 

 necessary, when a specimen is captured on the Rock in daytime, 

 to arrange carefully any feathers which may have been ruffled, 

 and at the same time to note whether many feathers are missing, 



■'■'■ Birds which strike very hard often show in addition lesions of the orbit, 

 eyeball, and spinal cord. 



