Bird-Life in London. 251 



this case, and certainly they can have taken no 

 part in ousting the flycatchers, yet the diminution 

 in numbers and final extinction of the martins and 

 flycatchers were practically simultaneous. It is a 

 noteworthy fact that martins nested in the heart of 

 London in Gilbert White's time, for he wrote: 

 (t They even affect the close air of London. And 

 L have not only seen them nesting in the Borough, 

 but even in the Strand and Fleet-street ; but then 

 it was obvious from the dinginess of their aspect 

 that their feathers partook of the filth of that sooty 

 atmosphere." Yet sparrows were, no doubt, rela- 

 tively as numerous and quite as mischievous in the 

 London of Gilbert White's time as they are in our 

 own. After weighing all the evidence, we cannot 

 help feeling that the case against the sparrow must 

 be dismissed with the Scotch verdict " not proven." 

 Wandering cats, no doubt, do enormous injury to 

 birds in London, and may possibly have interfered 

 with the fly-catchers, but they cannot have affected 

 the martins. Our theory, the value of which we 

 leave entomologists to decide, is that the extinction 

 of the birds in question is caused by the state of the 

 atmosphere, and the general change of condition 

 due to altered surroundings which have destroyed 

 much of the insect life on which they feed. The 

 effect of the atmosphere is shown in the fact 

 that rose culture, for which the district of Ken- 

 sington was once famous, is now practically impos- 

 sible even in the largest gardens, and, roughly 

 speaking, it may be taken as true that in the 



