of taking an Ornithological Census. 193 
unvaried notes of the Chiff-chaff are as commonly heard as the 
joyous song of the Willow Wren,, while, in the parish in which 
I am writing, the latter bird outnumbers the former by many 
hundreds to one; or why, again, in some of the northern coun¬ 
ties the Wood Warbler is nearly as numerous as the Willow Wren, 
while here it is not more common than the Chiff-chaff? Of 
course the ready reply is, “ Oh, it is owing to the difference 
in the habits of the species, and in the character of the locality.” 
But this is really no answer; for immediately I rejoin, what are 
those differences ? and, at present, I have no means of gratifying 
my curiosity on this point. Nor will, I suspect, a satisfactory an¬ 
swer be found until we have reliable information not only as to 
the approximate proportion which the species I have named bear 
to each other in different districts, but also as to the relative 
abundance of other species which influence their existence. This 
opens a wide region for inquiry, wherein not only the student of 
other branches of zoology, but also the botanist and the geolo¬ 
gist must help us ornithologists, and accordingly the object of 
my communication to the Linnean Society is to invite such 
assistance. 
I regret extremely that among Mr. Wolley’s papers I can find 
few memorandums or suggestions bearing on the subject, and 
yet I know that towards the close of his life it occupied his 
thoughts not inconsiderably. He first acquainted me with his 
idea in a letter from Ormoga in (Eland, dated June 7, 1356, in 
which he stated, that at the meeting of Scandinavian naturalists, 
which he was then about to attend, he should like to “ give 
some account of the British birds, of which so little is known 
on the Continent beyond the bare list.” He wished to begin 
“ by naming the birds which are commonest in England and 
most characteristic of our bird-fauna;” above all, “ to be able to 
represent by numbers the relative abundance of each species: 
throughout Great Britain put a Sparrow at 1,000,000, and an 
Osprey at 1, what will be the intermediate figures ? ” As may 
be readily imagined, I was unable to supply him with any facts 
that he could use, and consequently his design was abandoned, 
but, as I trust, only to be taken up and completed some day by 
the numerous ornithologists of this country. However, I had 
