NEWLY- OBSERVED HABIT IN THE BLACKCAP WARBLER. 169 



black, Blackbirds, Turdus merula, shortly followed by old females, 

 and later by young of the previous spring, the rear being brought 

 up by the halt and lame, — birds of all ages, in defective plumage, 

 having lost part of their tail or some of the primary wing- 

 feathers, some toes, or even a whole foot. This order by age and 

 sex is maintained with unfailing precision by all species during 

 their respective periods of autumn and spring migration. Heligo- 

 land being in fact an unequalled " Vogelwarte" — bird observatory 

 — the seasonal movements of birds pass before the observer in their 

 original purity ; no birds, either old or young, reside here to raise 

 any doubt as to whether the individuals seen by observers are 

 natives of the place or passengers. 



Finally, I may remark that the 'Vogelwarte Helgoland' is 

 not, as would appear from Mr. Seebohni's repeated allusions to 

 the same in the ' Zoologist ' and the * Ibis,' a mere enumeration 

 of the birds observed and obtained on the island, the section of 

 the book relating to these birds being of merely secondary import ; 

 the principal part of the work consisting of observations on 

 migration, which are divided into nine chapters, viz. : — Migration 

 in general ; Direction ; Height and speed of migratory flight ; 

 Succession as to age and sex; Meteorological influences on mi- 

 gration ; Exceptional occurrences ; What induces birds to start 

 on migration ; and What guides them during the same. 



ON A NEWLY-OBSERVED HABIT IN THE BLACKCAP 



WARBLER. 



By John Lowe, M.D., F.L.S. 



A singular habit of the Blackcap, Sylvia atricapilla, which I 

 have noticed during the present spring may be worth recording, 

 if, as I suppose, no previous note has been published on the 

 subject. 



In the garden of the Martinnez Hotel, Orotava, Teneriffe, 

 are some large bushes of Hibiscus Africanus, which are covered 

 with their brilliant scarlet blossoms. Being only ten or twelve 

 feet distant from the balcony, one can see everything that passes 

 in them with great facility. They are the favourite resort of the 

 Blackcap Warblers, which come there to feed, taking but little 



