SUGGESTIONS FOR CALCULATING NEST SUCCESS

Reports of nesting success that do not take into account the time span of observation for each nest usually understate losses, and sometimes the error can be very large. More than a decade ago I pointed out this problem and proposed a way of dealing with it (Mayfield 1960:192-204; 1961). Since that time many field students have used the method, and it has proved especially helpful in combining fragments of data from many sources, as in the North American Nest-record Program at Cornell University. However, not every published report shows awareness of the problem, and letters of inquiry have shown that some people are deterred from dealing with it because of difficulty with details. Therefore, I offer these further suggestions to simplify the procedure as much as possible.