194 THE ZOOLOGIST. 



party of about a dozen would descend, but it was more usual 

 for about two-thirds of the party to break their journey in 

 this way. 



When the migration was active and the stream almost con- 

 tinuous, not many minutes elapsed before the Rock accommodated 

 half a hundred birds, and as the wind and rain abated and the 

 migrants rose and resumed their journey, they, as they circum- 

 vented the lantern (an interesting sight in daylight), appeared 

 to form quite a good-sized flock, which, if appearing at night, 

 might have been designated as a small " rush " of Pipits. Here 

 again we see that the so-called "rush " was really an assemblage 

 temporarily held up by temporary stress of weather. But in 

 regard to nocturnal migrants, there is this difference to note — 

 that, if overtaken by a " squall," the birds, instead of swooping 

 down to the Rock, would, in all probability, on approaching the 

 lantern, endeavour to obtain shelter to leeward, but becoming 

 confused by the glare of the rays flashing across them, would 

 sooner or later be carried to windward, and then of a sudden crash 

 in against the glass. This " incidental strike " is very character- 

 istic in rough weather, especially when birds have been trying to 

 forge their way in a head-wind. As mentioned elsewhere,* they 

 are usually hurled against the glass, and clouds of feathers are 

 seen issuing from their backs or breasts. With a rebound they 

 leave the glass immediately, and, borne away by the wind 

 lifeless or fatally wounded, drop on the Rock or into its sur- 

 rounding waters. 



Before leaving this part of the subject, I may say that there 

 is good reason for believing that birds of prey, when on migration 

 (especially when near the land or an island whence they can 

 bear off their quarry), may cause disorder and even hold up 

 several parties of small birds on diurnal migration. During my 

 last visit to the Tuskar Light- Station I saw many Merlin 

 Falcons, some passing, others alighting on the Rock, and when 

 they were about I have seen Pipits wildly excited ; on one 

 occasion one of these little birds suddenly descended and alighted 

 close beside me panic-stricken. Almost immediately I perceived 



" :: Vide " Grasshopper-Warblers on Migration observed at the Tuskar 

 Lighthouse," 'Irish Naturalist,' vol. xxi., August, 1912, p. 140; also vide 

 "The Dartford Warbler in Ireland," 'Irish Times,' Dec. 26th, 1912, p. 5. 



