THE FORK-TAILED PETREL. ai ? 



Eastern Scotland than elsewhere in the British Isles. The sufferers from the 

 untoward accidents of the autumn months are chiefly birds of the year, but not 

 exclusively so. In September, 1891, a great number of Fork-tailed Petrels were 

 driven upon the N.W. coast of England. I personally examined upwards of six- 

 teen individuals procured inland or in the vicinity of the coast ; these were adult 

 birds and were deep in moult, a circumstance which perhaps re-acted unfavourably 

 upon their staying powers. But the majority of the Forked-tailed Petrels 

 which are picked up dead, or captured alive but worn out by their long abstin- 

 ence from food inland, prove to be birds of the year. October is the month 

 in which they occur most numerously. Many are taken between November and 

 February, but captures between the end of February and the beginning of 

 September are exceptional. 



The great irruption of Fork-tailed Petrels to Ireland in 1891 occurred 

 between the ayth of September and the middle of October. Mr. Williams, 

 of Dublin received no fewer than twenty-seven for preservation at that time, and 

 his birds, like those which I examined in the North-west of England, proved to 

 be deep in moult, as well as much emaciated. 



The adult male of the Fork-tailed Petrel is greyish black above when in 

 fresh plumage, and, if in fine condition should possess a steel-blue glint upon 

 the feathers of the upper surface ; the forehead is rather paler ; the greater and 

 median wing-coverts are pale sooty brown ; the longer tail-coverts are white with 

 dark shafts, the shorter coverts sooty with white margins ; the rectrices are sooty 

 with the basal portion of the shafts white ; the breast is sooty brown ; the under 

 tail-coverts are white at the base. The total length of my specimens varies from 

 seven and a half to eight and a half inches. I can find no external differences 

 between the sexes, but young birds of the year appear to be distinguished in autumn 

 by the pale margins of their wing-coverts. The plumage of this Petrel becomes dull 

 and faded at the end of the breeding season. The colours of the soft parts do not 

 vary, the irides being constantly dark brown, and the bill and feet uniform black. 

 The nestling in down is covered with long and delicate flakes of the softest possible 

 down, not "sooty" in colour as has been stated but of a delicate grey hue. In 

 July and August 1895, ^ received two freshly skinned Petrels in down from St. 

 Kilda. The bills of these tiny creatures were prominent, and exactly similar in 

 external form to the mandibles of the adult. One of these specimens had been 

 ruined by the discharge of oil ejected by the bird, but the other was in good 

 condition, and proved a welcome addition to our series of British Birds in the 

 Carlisle Museum. 



VOL. VI 



2 I 



