46 



MIGBATION. 



A ccidental 

 visitors. 



More nume- 

 rous than 

 supposed. 



Palmen's 

 rly-lines. 



Each species 

 has its own 

 rlv-lines. 



short before the journey is completed l , or never migrate at all, remaining the whcle year in 

 their winter-quarters 2 . As in autumn, the cripples bring up the rear. 



It is not an uncommon thing for birds to lose their way on migration. The list of 

 British birds contains a long catalogue of accidental visitors, most of which are migratory 

 birds which now and then take the wrong turning, get into the wrong stream of migration, 

 and make their appearance in our islands as strangers from far distant lands — some from 

 Siberia, others from Southern Europe, and not unfrequently, especially amongst the group 

 of birds of which this volume treats, from North America. Of these unexpected visitors 

 who have lost their way, by far the greater number are birds of the year on their first 

 journey to unknown winter-quarters. It is not to be wondered at that little birds so 

 absolutely inexperienced should often lose their way and find themselves in strange winter- 

 quarters. 



The wonder is that so few birds do go astray, but probably many more than we have 

 any idea of take the wrong turning. No doubt most of them winter with us or pass on 

 further south without being discovered. Very few accidental visitors to our shores are 

 caught. It is only on the island of Heligoland that an approximate estimate can be formed 

 of the number of accidental visitors that occur on migration ; and even there a comparatively 

 small proportion of the strangers are caught or even seen. In the opinion of the veteran 

 ornithologist who has kept watch on this lonely island for nearly half a century, and 

 chronicled the visits of such extraordinary and unlikely guests, that for some years ornitho- 

 logists suspected that they were the victims of a hoax — in Mr. Gatke's opinion the birds 

 which have passed over the island of Heligoland without being identified are even more 

 extraordinary and interesting than those which adorn the walls of his studio. 



There has been much disputing amongst ornithologists as to the routes, or "fly-lines " 

 as the Americans aptly call them, of migratory birds. Dr. Palmen wrote a very interesting 

 work on the " Zugstrassen der Vogel," in which he attempted to map out the fly-lines of a 

 score of birds breeding in the high north and wintering in the far south. He further 

 attempted to classify their routes ; but as his researches only apply to so small a proportion 

 of migrants, his classification has little or no practical value. It is impossible to lay down 

 any system of routes that can be applied to migratory birds as a whole. Each species has 

 its own system of fly-lines, which continually cross those of other species, sometimes at 

 right angles ; and it not unfrequently happens that two species use the same route for some 

 distance ; but whilst one species may be travelling from east to west, the other may be 

 migrating from west to east at the same season of the year. The Sedge-Warblers {Acro- 

 cephalus phragmitis) and the Willow- Wrens (Phylloscopus trochilus), which breed in the 

 valley of the Yenesay, probably all winter in South Africa ; whilst the Black-headed Buntings 

 (Emberiza melanocephala) and the Rose-coloured Starlings {Pastor roseus), which breed 

 from Italy to the Crimea, all winter in India. 



z - Seebohm, ' Ibis,' 1879, p. 162. 



2 Seebohm, ' British Birds,' iii. p. 97. 



