OXFORD UNIVERSITY 
                 DEPARTMENT OF ZOOLOGY AND COMPARATIVE ANATOMY 
 
                                       28th                     Address:
UNIVERSITY MUSEUM 
                                               Sept                   OXFORD

                                       Sept                     70leo..:
OXFORD 4 ,61 
BUREAU OF ANIMAL POPULATION                                     Telegrams:
MUS. OXFORD 
 
 
                      A Census Method for British Partridges. 
 
 
 
                      A census method I have recently been working on with
par- 
         tridges may interest you as I do not see in your book that you have

         used the same method with quail, although it might be applicable.

 
                     The principle is this; one knows by searching in the
spring 
         the approximate number of nests on the area of estate, say one thous-

         and acres, then at the beginning of August, (in the case of Hnglish
par- 
         tridges), when the young birds will all flyvwhen the covey is flushed,

         I go round and count the number of young and old birds seen during
the 
         course of several walks, recording both coveys and old birds wvhose
young 
         or nests have perished.   Of course one does not see anything like
the 
         total population owing to the amount of standing corn and other
cover, 
         but in the course of several walks, it is usually possible to count
50% 
         of the probable stock on the ground; one then has figures showing
a 
         sample of the production of young birds per old bird.   Supposing
one 
         hundred nests were known to be on the ground in the spring, and
the 
         August counts gave one hundred old birds and four hundred young
birds, 
         then the calculation of the whole stock is very simplebased upon
the 
         fact that it one hundred old birds produce four hundred young; two

         hundred old birds (i.e. nesting stock), will produce eight hundred
young: 
  VLt;;i plus two hundred old, equals one thousand birds. 
 
                     I find this sort of census is very useful because it
enables 
         one to know how many birds ought to be shot in the fall in order
to 
         leave a sufficient nesting stock.   At the same time of course one
gets 
         useful figures of the average covey size, and the mortality among
young 
         birds.   In bad seasons in England, the proportion of young birds
to 
         old is often less than one urouhgQbird to one old in the fall. 
 
 
 
 
 
 
                                                        A.D. Middleton. 
 
                  7 
         triax-41