Newell’s shearwater population modeling for Habitat Conservation Plan and Recovery Planning

Abstract

The Newell’s shearwater (Puffinus auricularis newelli), an IUCN and ESA listed species, faces terrestrial threats from predation, fallout (attraction to artificial lights) and collision with powerlines. Various indices suggest the population has declined by ~75% in the past two decades. Population modeling is required for Habitat Conservation Plan (HCP) and Recovery Planning to consider the benefits of existing and proposed management actions to the Kauai population. Population scenarios modeled here included a) stable, realistic and optimal growth; b) threats of predation, fallout and powerline collision; and c) management actions of minimizing fallout and powerline mortality, the Save Our Shearwater rescue program, predator control, predator eradication and chick translocation. The growth rate (lambda) produced in our worst case threat scenario for all threats (0.906) fell within the range of annual change suggested by ornithological radar data from 1993- 2010 using only Newell’s shearwater traffic (0.899), and Save Our Shearwater data of Newell’s shearwater fledglings from 1988-2009 (0.905).