137 



so many meteorological factors, that completely successful results 

 in this direction are extremely rare." 



Marsh Sandpiper. — Breeds from Hungary eastwards. A single 

 example obtained May 7th, 1862; an early date for this species 

 to have lost its partner. 



Black-winged Stilt. — Breeds throughout Southern Europe ; 

 said to have been formerly well known to Heligolanders, an 

 example seen June 25th, 1879, by Jan Aeuckens. 



From the above list it will be seen that the majority of these 

 so-called south-eastern species have occurred on Heligoland only 

 once in fifty years. Further, that so far from being confined to 

 the south east, many, on the contrary, breed both in Northern 

 Africa and throughout the countries bordering the Mediterranean 

 in Europe. Some are again resident species and others have 

 occurred at such early dates as to throw great doubt on the 

 supposition that they have taken up the migratory flight anew 

 owing to the loss of their nesting partners. Under the circum- 

 stances it seems idle to attempt to prove that these irregular 

 occurrences are due to the influence of definite laws. It is far 

 more reasonable to suppose the majority have simply over-shot 

 the mark in their eagerness to reach their breeding grounds. No 

 doubt the sense of direction, or whatever we like to call the 

 means by which migrants find their way, varies greatly in 

 individuals and in odd cases is altogether deficient. Or, again, 

 single individuals may frequently attach themselves to migratory 

 flocks of other species wintering in the same locality but travelling 

 to different breeding grounds, and so get carried out of their 

 proper track. The most recent capture of the Pine Grosbeak 

 in England occurred in the Midlands during an unusually strong 

 migration of Fieldfares, a flock of which it had, no doubt, joined, 

 though properly speaking it is not a trae migrant. Strong 

 winds also, at times, exert a certain influence on the appearance 

 of these erratic wanderers. 



In the light of the foregoing evidence, it will hardly be worth 

 while to discuss the cases of species from Northern Africa or 

 Western Europe, which have occurred on Heligoland. According 

 to Herr Gatke, birds in the latter locality have a great disinclina- 

 tion to migrate to the east. It is difficult to say to what species 

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