Effects of Hurricane Georges on the Resident Avifauna of Maricao State Forest, Puerto Rico

Abstract

Hurricane Georges crossed the island of Puerto Rico on 21-22 September 1998. Maricao State Forest, a montane reserve in southwestern Puerto Rico, was struck by Georges after being spared by hurricanes since 1932. I documented the changes in relative abundance of Maricao resident bird species caused by the impact of the hurricane by comparing baseline mist netting capture rates with data 33 days after the hurricane, and point counts records with data up to 22 months after Georges. Total capture rates increased after the storm (26.8 individuals/net hr pre-hurricane vs. 57.9 individuals/net hr post-hurricane). Capture rates classified according to foraging guilds did not differ, but showed significant increases according to foraging level (canopy vs. understory). Increases in capture rates were related to the displacement of birds into lower forest strata after canopy loss. While most species recorded in point counts declined after Georges (16/21),only the relative abundance of six species differed significantly among years. Just one species (Elfin Woods Warbler, Dendroica angelae) recovered by the end of the study. Two species were not observed after the hurricane, including one of the five most abundant (Ruddy Quail-Dove, Geotrygon montana) and a new species was observed in the study area after the hurricane (White-winged Dove, Zenaida asiatica). Only the population of the Gray Kingbird (Tyrannus dominicensis) remained unchanged throughout the study. Results demonstrated that even common species in montane habitats can be highly susceptible to hurricanes, and thus, long-term monitoring of avian communities at different elevations is needed to understand the effects.