UJ 



< 



SO 



10^ 



< 



? 10= 



10' 



10^ 



Observer 2 

 V = 92 +0.35X 



Observer 3 

 y = 68 +0.53X 



10* 



10^ 



10' 



NUMBER OF NESTS 



Figure 12. Aerial estimation of adults vs. nest counts at 1 1 Massachusetts colonies, 1 and 6 June 1977. 

 Least squares regression equations are given for each of two observers. 



46 



