1910-1911.] Bird Migration in Solway. 297 



our everyday walks in the depths of winter as they are in the 

 height of summer, the facts of observation show us that the 

 individual birds of each species, so seen, are constantly migra- 

 tory. That is to say, all the individuals of such a species as, 

 for example, the Eobin, shift their quarters a few leagues 

 north, or south, at the migration seasons. It will thus happen 

 that at the northernmost limit of the distribution of such a 

 species, no birds of that species will be found in winter, while 

 similarly, at the southern limits of its range, no birds of the 

 species will be found in summer. 



Let me take another bird, the Willow-Warbler, whose merry 

 little tinkling song forms so large and rich a proportion of the 

 music that sounds so sweetly during May and June. This 

 species leaves the British Islands entirely in September, and 

 remains away for more than six months. Not only does the 

 Willow-Warbler leave the British Islands, but, with the excep- 

 tion of a few stragglers remaining in Southern Spain and in 

 Sicily, he leaves the entire continent of Europe also, to winter 

 far inland towards equatorial Africa. This long journey of 

 over 2000 miles that is undertaken by these delicate-looking 

 birds when scarcely three months old is a very striking thing, 

 and could it be thoroughly explained, the whole of the vast 

 and varied facts of migration would need no further eluci- 

 dation. 



Well, these Willow-Warblers have spent their six months 

 or so in that great wilderness of tropic woodlands that we now 

 know to exist beyond the Sahara desert. The temperature is 

 high, food abundant, and shelter from the scorching sun by 

 day and the drenching dews by night easily obtainable. But 

 by-and-bye an irresistible longing for home sets in. Some- 

 thing has set the little birds thinking of the place where first 

 they saw the light. Something tells them that, far away in 

 the cold misty north, the leaves are expanding on the trees, 

 and that the wild-flowers are springing up in the recesses of 

 the copsewood. And so, with simultaneous impulse, these 

 winged migrants fly off in haste, crossing country after country, 

 where we with our short-sighted ideas would think these tiny 

 wanderers might find peace and plenty. They halt not, on 

 they come, and morning after morning in early May we see 

 our feathered friends of the previous autumn back again, 



