MOVEMENTS OF LONDON BIRDS 143 



for several centuries to drive out his fellow tenants, 

 would have made peace with them and found 

 some more profitable outlet for his superabundant 

 energies. Possibly the introduction of a few 

 feathered policemen owls, or magpies, or 

 sparrow hawks would have the effect of 

 making him a less quarrelsome neighbour. 



In autumn and in spring a variety of summer 

 visitants, mostly warblers, pass through London, 

 delaying a little in its green spaces. In Sep- 

 tember we are hardly cognisant of these small 

 strangers within our gates, all but one or two 

 being silent at that season. In April and May, 

 in many of the parks, we may hear the chiff- 

 chaff, willow-wren, blackcap, sedge-warbler, the 

 whitethroat, occasionally the cuckoo, and a few 

 other rarer species, but they sing little, and soon 

 leave us to seek better breeding-sites than the 

 inner parks offer. 



While some of our birds, as we have seen, 

 forsake us at the approach of cold weather, 

 some for a short period, others to remain away 

 until the following spring, a small contrary 

 movement of birds into London is going on. 

 These winterers with us come not in battalions 



