was computed from the formula n™ +t° C* where t is the number of 
standard errors for a 95 percent ~p* probability of occurrence 
(roughly 2, but varying according to the size of each sample), C is 
the coefficient of variation, and p is 10 (the percent of sampling 
error allowed). | 
Table 1.--Number of stops required to obtain snipe population 
. within a sampling error of 10 Socaent 
; Morning Evening 
Length of Stop : Coefficient ; Number : Coefficient ; Number 
in Minutes ¢ of Variation : of Stops : of Variation : of Stops 
: : : : 7 
1 : 18.8% : Ly ¢ 35.3% : Sh 
: : : e 
2 ¢ 16.7 : 12 e 33-3 t 55 
2 2 : 2 
3 : 12.9 : 2 26. t 39 
$ : : 2 
Ty : 9.1 2 k : 22.2 2 33 
: : : 2 
5 : 0 * 1 : 2h.7 : i? 

_As shown in Table 1, a single stop of five minutes during the 
morning peak should be sufficient to record the total number of winnow- 
ing males at any location when this number is in the vicinity of three 
males. If the number of pairs at a given stop is considerably larger 
than this a longer listening period would be called for; data for this 
condition are not yet available. The number of stops necessary to 
obtain a reliable count during the evening winnowing period appears 
to be prohibitive. 
In cases where it is convenient to cover a transect route on 
several mornings, the Length of each stop can be adjusted to the 
length of the route in order that the entire winnowing period may be 
utilized. For instance, if the route contains five stops one mile 
apart, two minutes could be allotted for driving betweenstops and 
four minutes for listening at each stop; Table 1 indicates that four 
trips wuld be necessary to obtain sufficient data from each stop. 
Similarly, if the route contained seven stops one-half mile apart, 
three minutes could be spent at each stop, but it would require seven 
trips to obtain the required data. Since four stops could be completed 
in a single morning by spending five minutes at each one, this method: 
appears to be more practical for general use than a transect with mre 
stops of shorter duration. Further research on the transect method may 
reveal that this will be an important tool in detecting annual changes 
in abundance, but until enough data have been assembled to permit 
statistical analysis, the optimum number of trips per route and minutes 
per stop cannot be determined. | 
49 
