Table 5. Stochastic growth rates for six models projected over 20 yrs. Subscripts reflect different factors in the model (Sj = juvenile survival (age 0–2), S3-6 = annual survival for birds age 3–6 yrs, Sa = adult survival (age 7+ yrs), Pa = mean number of young fledged per pair, λ = intrinsic rate of increase, t = time in yrs). Effect is calculated as the difference in a scenario’s growth rate relative to the Gannet Islands baseline growth rate.
‡ Fox predation reduced annual productivity from 0.390–0.306 (see text for explanation). § Productivity (0.698 when foxes absent, 0.615 when present) for the Gannet Islands 1980–2002. |Change in lambda for each scenario relative to the baseline. |