THE SOUTHWARD FLIGHT 105 



months is its whole sojourn in this country. It seems 

 probable that its early departure is due to the diminishing 

 supply of insects at the lofty levels where it prefers to feed. 

 By the beginning of August the nights are already growing 

 far longer and more dewy than they were in June ; and the 

 period when Britain is habitable for the swift seems to lie 

 within six or seven weeks on either side of Midsummer Day. 



As September goes by, we gradually miss several birds 

 from their accustomed haunts, if we keep a careful daily watch. 

 Some warm day in 

 the garden we notice 

 that the spotted fly- 

 catcher is no longer 

 perched in its favour- 

 ite position on the 

 tennis - post or the 

 corner of the porch ; 

 and in the evening 

 twilight we miss the 

 nightjar flitting noise- 

 lessly down the clearing in the copse. Both these birds are 

 late-comers, and obey the same general rule as the swift in 

 being quick to go. For them too, with their need for an 

 abundant insect diet, the English climate sets an early term 

 of departure. But still we can hardly feel that the summer 

 birds are really leaving us, so long as the days are full of 

 sunshine, and the empty places are so few as compared with 

 any week in the quiet time since June. 



By October there is no mistaking that the southward 

 migration is in full swing. It is most visible in the case of 

 the swallows and their kindred, which migrate by day. The 

 concourses of swallows and martins on roofs and telegraph 

 wires are not only larger than when they first began in 



f\ : 



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NIGHTJAR 



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