Table 3 continued.


 (




 Wood Storks feed in proportion to
 fish density rather than fish bio-
 mass. Fish density controls the
 flow of fish to the birds.



 Bird breeding is stimulated by an
 abundance of food, which is reflec-
 ted in the individual weights of
 the birds. Bird biomass divided by
 bird number yields average weight,
 which, by means of a comparator
 operator, is compared with a breed-
 ing weight threshold to determine
 whether or not breeding will occur.
 Average weight rising above the
 threshold value switches on the
pathway from bird biomass to bird
number to initiate breeding activity.