XIV INTRODUCTION. 



sudden change comes, like a sharp frost, we find 

 birds lying dead under the hedges. This is a proof 

 of their sensitiveness. Some species better able to 

 endure cold, but still averse to it, if they do not 

 die, disappear suddenly, and we are often sur- 

 prised at the extraordinary scarcity of a species 

 one day which on the previous day was plentiful. 

 I have always attributed the cause to sudden change 

 of weather. No doubt the abundance or scarcity 

 of food has some influence upon birds in their 

 migration, but not to the same extent, I conceive, 

 as change of temperature. 



The assistance I have received from various 

 sources, whilst preparing these notes for the press, 

 merits some recognition at my hands. 



To my valued friend, Mr. Frederick Bond, I am 

 particularly indebted for numerous communications 

 respecting the birds of this county, with which, 

 as a sportsman and a naturalist, he has been 

 acquainted for more than thirty years. 



Mr. W. H. Power has furnished me with some 

 interesting information relating more particularly 

 to the neighbourhood of Ealing; and I am indebted 



