MAY. 77 



on guard. Darting from one to the other in a maze 

 of curves and flashes, he soon sends the whole gang 

 of marauders loafing away. 



DELAYED MIGRANTS. 



May 15. Whether caused by icebergs or not, the 

 persistent north and east winds of spring continued 

 to be very unfavourable to the migration of birds. 

 Turtle-doves, however, managed to reach their homes 

 even on the east coast by the loth or nth, when 

 there was, indeed, a temporary mitigation of the 

 wind ; but, besides being birds of extremely powerful 

 flight, they are not dependent upon flying insects for 

 their food, like house-martins and swifts, flycatchers 

 and nightjars. To these birds cold winds from the 

 east or north mean starvation, so they wisely hold 

 back from the bleak regions where they were born. 

 Not that the insect-eating birds which wander twice 

 a year between Africa and, say, Norfolk, have much 

 freedom of choice in the dates of their departure or 

 arrival. They go when they must, and come home 

 when they can. The cold north winds of autumn 

 take them south, and the warm south winds of spring 

 bring them back again. When south winds blow in 

 autumn they stay very late, and when north winds 

 blow in spring they arrive very late, because they 

 cannot help it. 



PROVIDENCE AND EVOLUTION. 

 At first sight it seems a fortunate coincidence 

 that the same cold winds which sweep away the 

 insects that should feed the birds also save the birds 



