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Introduction, has taken place in the model. A more erratic

pattern of population oscillation can be seen in the

simulation under present conditions.

 The same rainfall pattern and the same relationship

between prey fish density and the feeding rate of the birds

that allows the bird population to grow under primitive

conditions causes it to decline under present conditions.

In the primitive simulation, the breeding stock grows from

10,400 birds to 53,000 birds in the 25-yr period. In the

present simulation, the breeding stock, starting with the

same initial conditions, drops to 2,140 birds in the same

period of time. Also shown in Figure 80 is the breeding

record at Corkscrew Swamp Sanctuary, for comparison with

results from the model. Although the model matched reality

in some years, successful breeding occurred more frequently

following drainage than predicted by the model.

 In early simulations of Model III before predator fish

were added, differences in trends of the bird population

under primitive and present conditions were much more

pronounced than those shown in Figure 80; adjustments in

coefficients that prevented a population explosion under

primitive conditions caused extinction under present

conditions. The predator fish compartment appeared to make

the model much more realistic.

 Comparison of model results with breeding history at

the Corkscrew rookery suggests that Wood Storks may have

responded to major changes taking place in their ecosystem