THE NEED FOR A BIRD CENSUS 23 
repressive measures should be instituted with regard to other 
species. 
It is obvious that bird counts, such as are here suggested, 
will only furnish approximate figures, but if the counts were 
repeated year by year, they could scarcely fail to provide 
data which would form, from almost any standpoint, a most 
useful and valuable basis upon which to work, 
It is interesting and important to note that such studies 
have in practice afforded very valuable evidence of the 
relative abundance of different species. They have shown 
that the average bird population can be largely increased ; 
that there are wide variations in the numbers of birds in 
different areas, and that these variations fluctuate from year 
to year; that in certain areas there are far too few birds on 
farm land, and that their numbers can be increased with a 
little care. Moreover, such counts have materially helped in 
determining what effect present legislation has upon the 
increase of game and insectivorous birds. 
So far as I know, no bird census has ever been attempted 
for the British Isles, but in other countries, particularly the 
United States, a number of statistical studies have been 
made, the most important being that commenced in 1914, 
and still being continued. Surely if it is feasible to obtain 
valuable results in a country of over three and a half million 
square miles, it should be possible to do so on a comparatively 
small area of 121,000 square miles, such as the British Isles. 
On the lines laid down by Professor S. A. Forbes and the 
late Mr Wells W. Cooke, such a statistical study is quite 
possible. 
In the United States the method adopted has been to 
obtain a large series of bird counts, taken during the breeding 
season, in order to ascertain the number of pairs of birds 
breeding within definite areas. Some selected area or areas, 
fairly representative of the average character of the country 
in a particular neighbourhood, are taken, the area being not 
less than a quarter of a square mile or larger than double that 
size. The recorder is required to furnish the number of pairs 
of birds actually nesting within the selected area, not birds 
feeding therein only. 
