PS 11-130 - Introduced game birds as seed dispersers in Hawaiian forests

Monday, August 7, 2017
Exhibit Hall, Oregon Convention Center
Samuel B. Case1, Jinelle H. Sperry2 and Corey E. Tarwater1, (1)Zoology and Physiology, University of Wyoming, Laramie, WY, (2)Engineer Research and Development Center, Champaign, IL

In the last century, several game bird species (Galliformes) have been introduced to the Hawaiian Islands for recreational hunting. Among these species, the Kalij Pheasant (Lophura leucomelanos) and Erckel’s Francolin (Pternistis erckelii) are unique for their widespread establishment in forest habitat. Although both species are frugivorous, little is known about their role as seed dispersers in Hawaiian forest ecosystems. These game birds might offer conservation benefits by consuming and dispersing native seeds. Alternatively, they may have a negative effect on native plants by dispersing nonnative plants at higher frequencies or acting as seed predators of native plants. As a part of the Hawaii VINE project, we are investigating seed dispersal of these two species in the Wai’anae Range of O’ahu. Thus far, we have collected data on game bird diet, abundance, distribution, and behavior at three different forested sites varying in rainfall, elevation, and plant communities. To determine extent of frugivory, we conducted behavioral observations, deployed camera traps on fruiting plants, and identified seeds within fecal samples. We measured abundance and distribution of birds using line transect surveys. For each detection during surveys and observations, we recorded group size, age (juvenile/adult), and sex of individuals.


Our preliminary data suggests that both game bird species are common across our sites and are likely dispersing seeds. We observed game birds feeding on fruit of both native and nonnative plant species, including video evidence of Erckel’s Francolins feeding on fruit of two federally listed endangered species, Solanum sandwicense and Delissea waianaeensis. Game birds foraged low (less than 1.5 m above the ground). Fecal samples frequently contained seeds of common nonnative invasive species. Group size varied for both species. Kalij Pheasant groups contained an average of 1.87 ± 0.12 (mean ± standard error [SE]) individuals and ranged from 1-5 birds (n = 61 detections). Erckel’s Francolin groups contained an average of 1.64 ± 0.19 (mean ± SE) individuals and ranged from 1-5 birds (n = 36 detections). Larger groups of Erckel's Francolin (>2 individuals) consisted of offspring, while all detected Kalij Pheasants were adults and larger groups varied in their sex ratios. Female pheasants were twice as likely to be solitary compared to males, but this was not true for francolins. These results are a first step in understanding the role of introduced game birds in seed dispersal networks and their potential impacts on native plant communities.