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It is probable that, with few exceptions, the vast majority of the rej)reseu- 

 tatives of our English avi- fauna, such as are generally considered habitual residents — 

 the young, invariably; the old, irregularly — leave the British Islands in the autumn, 

 their place being taken by others — not necessarily of the same species — coming 

 from more northern latitudes, or from districts in Europe, where, on the approach 

 of winter, the conditions of locality and food supply are found less favourable to 

 existence. These immigrants, on the approach of spring, leave, moving back to 

 the continent on the same lines, but in the reverse direction to those traversed in 

 the autumn. At this same period also, there is a great return of the autumn migrants 

 from the continent to their nesting quarters in England. The great numbers of 

 Corvus Comix which winter in our eastern counties in England, do not move doMii 

 from Scotland and the north, but cross directty from Clermany by an east to 

 west route. 



Of the enormous immigration which arrives on the east coast of England in 

 the autumn, either to winter in these islands, or merely on passage across the 

 country' a small proportion only ajjpear to return by the sa.me routes. The spring 

 returns made by lighthouses and light-ships, show that Dirds then move in the same 

 lines as in the autumn, but in the reverse direction. These return travellers do not. 

 however, represent anything like a tithe of the visible migrants, which, week by 

 week, and mouth by month, at the latter season move in one broad stream on to 

 our shores. 



Without attempting in this treatise to enter into the subject of the general 

 causes which influence the periodical movement of birds, we can only say that 

 migration, using that word in its widest sense, cannot possibly be explained by 

 any-one theory, or set of facts ; it is a complex, many-sided and deeply involved 

 movement, arising from a great diversity of causes and effects, acting and re-acting 

 on each other, but all working to the same end. 



When all has been said, our knowledge is very restricted: and we have yet 

 very much to learn about the path of the bird in the air. We know that, with 

 adverse conditions against them — cyelouic periods in October and November, with a 

 sea swejjt by winds cruel and pitiless, in fog and rain, sleet and snow — a great 

 wave of migration is bearing down upon our east coast. This wave has a front 

 of hundreds of miles, and runs east to west. It is made up of strangely contrasting 

 species — both day and night feeders — there are curlew, woodcock, short-eared owls, 

 grey crows, redwings, ringousels, blackbirds, thrushes, redbreasts, larks, starlings. 

 golden-crested wrens, and a host of others. All these brought together and impelled 

 forwards by an instinct and necessity common to all alike, and which is sufficient 

 to land them sometime between midnight and 5 a. m. on the east coast of 

 Great Britain. 



The units, which make up this vast and varied concourse, move in parallel 

 lines across the intervening waters, coming from an infinite number of starting 

 points widely apart. It is by no means improbable that they may have been hours 

 on the wing before approaching the North Sea, coming in one unbroken and self- 

 dependent flight over land and water. 



It is easy to r;nderstand how birds with their acute vision, and migrating in 

 the daytime, could discern Heligoland from the nearest coast to the east — only forty 

 miles away — and from Heligoland be able to see the loom of land at Borkum, and 

 then Ter Schelling, and the southuard trend of the European coast-line. But. in the 

 night, when birds most migrate, these landmarks would be invisible, and in the 

 great sea passage of 360 miles from E. to W., between Heligoland and England, 

 there are no landmarks to give even the general direction. There is the light of 



