Hawaiian Petrel Monitoring Protocol: Pacific Island Network

Hu, Darcy; Ackerman, Gail; Bailey, Cathleen; Duffy, David; Schneider, David

Seabirds are a conspicuous component of both marine and oceanic island terrestrial ecosystems and perform important functions. They are top predators and transfer nutrients from ocean to land (Ellis et al. 2006). Because seabirds exploit marine resources through a variety of feeding methods, they are important ecological indicators of marine environmental health (Thompson and Hamer 2000). In the National Park Service’s Pacific Island Network (PACN), seabirds nest and roost in a variety of environments, from coastal shores to alpine regions. Here, too, they are indicators of ecosystem integrity. Seabird communities face a variety of threats, including predation by introduced mammals, habitat destruction, avian disease, human disturbance at or near colonies, and competition for food with the fishing industry. To address a need for population assessment of the endangered Hawaiian petrel (Pterodroma sandwichensis), or 'ua'u, PACN has identified seabirds as an important Vital Sign and has developed a program designed to monitor specific species within this group through replicated surveys. The Hawaiian Petrel Monitoring Protocol will be implemented in two national parks: Hawai'i Volcanoes National Park (HAVO) on Hawai'i Island, and Haleakalā National Park (HALE) on Maui. The implementation of this protocol will not be carried out by the PACN Inventory and Monitoring (I&M) Program due to limited staff and funding. Instead, each park’s Resource Management Division will provide financial support to implement the protocol and conduct annual Hawaiian petrel monitoring. This protocol addresses one monitoring question with three objectives: (1) what is the annual nest density and reproductive (fledgling) success in known Hawaiian petrel colonies, (2) what are the long-term trends in colony distribution and density monitored in approximate 5-year intervals, and (3) are these affected by predator control? The first goal of monitoring is to obtain unbiased estimates of Hawaiian petrel nest density and reproductive (fledging) success from known colonies in HAVO and HALE in order to detect changes in colony growth or decline. The second goal of monitoring is to periodically (approximately every five years) obtain unbiased estimates of nest density from potential Hawaiian petrel habitat. This information can be used to assess changes in density and distribution of subcolonies across the landscape. The third goal is to estimate nest density and fledging success in areas undergoing different management regimes to assess effectiveness of management. Benchmark levels of these estimates could serve as warnings of the need for modified management or further investigation of these colonies. The focal areas that will be monitored include known Hawaiian petrel colonies on Mauna Loa, HAVO, and on the western rim of Haleakalā Crater, HALE. Additional monitoring within these parks may occur as time and funds allow. For example, additional sampling sites within suitable habitat may be surveyed at HAVO and HALE to search for new Hawaiian petrel burrows.

Hawaiian Petrel Monitoring Protocol: Pacific Island Network

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