Distilling Professional Opinion to Gauge Vulnerability of Guam Avifauna to Brown Treesnake Predation

Authors

Robert M. McElderry, Research Corporation of the University of Guam
Eben H. Paxton, Hawaii National Park
Andre V. Nguyen, University of Hawaii at Hilo
Shane R. Siers, USDA National Wildlife Research Center

Date of this Version

7-8-2021

Citation

McElderry RM, Paxton EH, Nguyen AV and Siers SR (2021) Distilling Professional Opinion to Gauge Vulnerability of Guam Avifauna to Brown Treesnake Predation. Front. Conserv. Sci. 2:683964. doi: 10.3389/fcosc.2021.683964

Comments

OPEN ACCESS

Abstract

The avifauna of Guam was devastated by the introduction of the Brown Treesnake, and the restoration of native birds would need to address the problem with eradication or suppression of BTS. With eradication of the snake unlikely in the near term, and suppression capabilities limited to specific finite areas, key information for reintroductions is how low BTS abundance will likely need to be for each bird species to be re-established based on their vulnerability to BTS predation. Here, we estimate vulnerability, which can no longer be measured directly, so biologists who are familiar with one or more of seven Guam birds were surveyed to obtain their knowledge and produce quantitative vulnerability estimates. As is typical of birds adapted to islands devoid of predators, respondents judged that our focal species exhibit few predator avoidance and tolerance traits, leaving body size as the prime determinant of vulnerability. Respondent opinion also holds that any behavior that reduces the likelihood of an encounter by BTS, e.g., roosting/nesting in palm crowns, cavity nesting, and in particular urban dwelling, substantially reduces vulnerability. Our results can help inform species-specific decisions about when it may be safe to consider the release of birds on Guam depending on the relative vulnerability of each species to predation by BTS.