170 The hish Naturalist. September, 



my return to Sheffield, I hope to send a note to the Irish 

 Naturalist as an addendum to this paper. If the gizzards 

 prove to be empty the evidence will be overwhelming that 

 the birds had travelled some distance, and an interesting 

 question will arise as to whether an immigration or an 

 emigration was going on. On the other hand, if the gizzards 

 contain food it may be inferred that an emigratory move- 

 ment may have been taking place, the birds having procured 

 food just before leaving the part of the mainland of Ireland 

 in the vicinity of the Tuskar light -station ; but still we 

 cannot necessarily conclude that the birds had travelled but 

 a short distance, a conclusion much more easily arrived at in 

 the case of grain -feeding birds, ^.g., Finches, whose diet is only 

 found on the mainland. But flies and other insects which 

 frequent maritime beaches and rock -islands, and which form 

 the staple food of the Rock-Pipit, could doubtless have been 

 procured as the birds sojourned on the rock ere they were 

 captured. And yet these Pipits may have come some 

 distance. In support of such a view I recall the result of my 

 examination of the gizzards of numbers of Wrens which I 

 procured on the Tuskar Rock, where, it may be remembered, 

 that from the same phase of migration (vernal) " the gizzards 

 of the birds taken at the lantern were quite empty, while 

 those of the birds secured on the rock in the day-time con- 

 tained, in varying amounts, some insect remains, pointing 

 to the fact that the birds managed to procure something to 

 eat as they perambulated on the rock from daybreak until 

 they were collected."^ Had I secured a few of my Rock- 

 Pipits from the Tuskar lantern, I anticipate that their 

 gizzards would also have been empty. Finally, it should be 

 remembered that, like the Wrens, so also the Rock-Pipits 

 which I observed at the Tuskar light -station signified by 

 their presence that a particular phase of migration was also 

 taking place, here autumnal, and lasting just a month. 



Tuskar Lighthouse, 

 Co. Wexford. 



^ " Wrens on Migration observed at the Tuskar Rock and Light- 

 house." Irish Naturalist, vol. xxi., July, 19 12, p. 130. 



