4000 n 



JAN FEB 



MAR 



?DS AND VEGETATION (1)/ 

 s 1' ' 



APR MAY JUN JUL AUG SEP 



OCT 



NOV DEC 



Figure 38. Monthly changes in trophic composition of bird communities 



(based on major food source) sampled by four wildlife survey 

 routes, 1977. 



157 



