ative of distribution. With other methods of recovery, this may not 
be so. A large number of birds are taken each year in muskrat traps. 
A heavy recovery in one area and a lesser one in another may not be 
indicative of a difference in the movement of birds. This difference 
could have resulted because the trapping season was open during migra- 
tion in one area, but closed in another. Then too, the method of 
trapping in one area could account for the difference. 
Hickey (1951) has ably presented the case with mallard band- 
ings and concluded that bait trapping injected a bias by "conditioning" 
the birds for the particular banding area involved. Hickey feels that 
a correction factor can be worked out for individual banding stations 
to remove bias introduced by "conditioning." In some instances this 
may be possible but in others, coastal areas, for instance, where 
migrant and wintering populations are involved it seems that the prob- 
lem would be hopelessly complicated by variables. 
We have gone into some detail on certain factors or biases 
affecting the distribution of banding recoveries. Wherever possible 
we should eliminate or segregate the data likely to cause great dis- 
tortions. Definitions of terms and classifications of data that have 
been used in this report and those that have not, are as follows: 
l. The seasons of fall, winter, and spring are 
regarded as follows: 
Fall - June to January (through shooting season). 
Winter - January and February. 
Spring - March, April, and May. 
2. Definition of recoveries: 
Local - taken within 50 miles of the banding station. 
Direct - Banded during the period June to December, 
and taken anytime during this same period or during 
the following January. 
Indirect — Recoveries in subsequent seasons, after 
the bird has had a chance to go through at least one 
intervening season of movement from the time of banding. 
Another cause of difficulty in interpreting banding data is 
the lack of consistency in the various banding operations. Not only 
_ were many important bandings completed long before the present era of 
widespread, heavy shooting, and short split seasons, but many stations 
were not operated continuously. 
