Modelación matemática del consumo de presas y el flujo de energía asociado a la reproducción de Rostrhamus sociabilis (Aves, Falconiformes)

Abstract

Mathematical model of prey consumption and energy flow associated with breeding in Rostrhamus sociabilis (Aves, Falconiformes)
The snail kite (Rostrhamus sociabilis) is a bird of prey that has permanent populations and is fairly common in Cuba. It is classified as High Concern in the North American Water Bird Conservation Plan, partially due to a highly specialized diet, preying only on water snail of the genus i>Pomacea. In the current paper we developed a mathematical model in Stella software to analyze consumption and mobilization of energy during reproduction of this species. The model was calibrated with reproductive parameters determined in a nesting colony of the Great Wetland of North Ciego de Ávila, Cuba. Variables included in the basic model were adults, eggs and nestling morphometry, behavioral aspects, trophic elements and other reproductive parameters; some were measured in the field and the rest were taken from literature sources. The main outcomes of the model were: energy consumption per individual, daily and total season consumption, and the number of prey it represented. To test the model we simulated the behaviour of a 100–nest colony that resulted in the production of an average of 158 ± 7.1 eggs and between 106 and 125 nestlings. Daily adult energy consumption was estimated between 110.32 and 118.47 kcal, which can be achieved by consuming around 28 snails each day. A colony of this size has an estimated requirement of 1,893,103 kcal of total energy per season, driven by 5,933 ± 59 kg of snail biomass, equivalent to between 419 and 552 thousand snails in three and half months. Sensitivity analysis of the model showed that the variables that most influenced energy consumption were those related to reproductive success, adult body size and flying behavior. The resulting model will allow to simulate and assess the potential impact of future habitat modifications on the species breeding.