To study and conserve the Newell’s Shearwater, Hawaiian Petrel, and Band-rumped Storm-Petrel, the Kauaʻi Endangered Seabird Recovery Project uses a number of different research and survey methodologies every year. Several of these are outlined below.
The first step in conserving a species is to understand where they are. In the rugged terrain of Kauaʻi this represents a serious challenge, as for the most part the birds nest at high elevations in dense native forests or on sheer cliff faces that drop thousands of feet. Locating the birds is not easy! To do this requires intensive survey work at night or in the early morning at specific times of the year, when the birds are most active and vocal. KESRP staff use a combination of techniques to locate the birds, including recording their calls, mapping the location of calling intensity and actual nest sites, and using high tech gear such as thermal imaging cameras and night vision goggles to see them in the darkness. This has allowed us to plot their distribution throughout Kauaʻi where survey work has been undertaken. To date over 400 auditory surveys have been conducted by KESRP at locations throughout the island, and more are scheduled each year in areas still to be explored.
The view through night vision goggles - a critical aspect of auditory survey work (Photo Andre F. Raine)
Because shearwaters and petrels come to their colonies at night and nest in hard to reach locations, charting population trends is particularly difficult. This is where radar comes into play. By surveying with surveillance radar from 15 fixed locations around the coast we can track the number of birds moving from the sea to inland breeding colonies. Using several standard criteria (such as speed and timing of movement) it is possible to separate out our target species and get an idea of number of birds moving over our survey sites per hour. Comparing this data with previous years then gives us an idea of how populations are changing over time.
View of a radar screen showing the complex imagery used to identify seabirds passing over fixed sites at night (Photo by Andre F. Raine)
Protecting endangered species requires a number of different management techniques, from predator control to ungulate exclusion, habitat management to controlling man-made threats. Understanding how populations respond to these changes is critical as it allows us to ascertain how successful our management techniques are. To this end, KESRP monitors on an annual basis a number of known Newell’s Shearwater and Hawaiian Petrel breeding burrows in several remote locations (such as Hono o Na Pali NAR and Upper Limahuli Preserve), collecting data on fledging success rates, reasons for failure and site fidelity. Burrows are monitored using burrow scopes, remote cameras and other technologies that decrease the amount of direct contact needed with the burrow itself. Adults and juvenile birds are also banded to allow for a more detailed understanding of individual survival rates and site fidelity.
Monitoring nest sites, such as this Hawaiian Petrel burrow, allows us to understand the success of management techniques (Photo by Andre F. Raine)
Protecting the Newell’s Shearwater, Hawaiian Petrel, and Band-rumped Storm-Petrel requires us to understand not only what the birds are doing on land, but also what they are doing at sea. Tracking seabirds to their key feeding grounds, or ascertaining where their main wintering grounds lie, are critical aspects to their future survival. To do this, KESRP research staff have started attaching minute tracking tags to both Newell’s Shearwater and Hawaiian Petrel in an effort to chart their dispersal at sea. Through the use of geolocators, data loggers, and satellite tags we can start to understand not only where these fantastic birds go, but also what potential threats await them.
Minute devices, such as this Lotek LAT2900-1 geolocator, allow us to track seabirds at sea (Photo by Trevor Joyce)
Additional seabird surveys
As well as working on the three endangered seabirds, KESRP also undertakes additional survey work on other seabird species. This ranges from direct counts of nesting Laysan and Black-footed Albatross on the island of Lehua to Wedge-tailed Shearwater banding and monitoring of nesting colonies at sites on Kauaʻi. As well as giving us more information on these other seabird species, studying more common species such as the Wedge-tailed Shearwater can serve as a proxy for understanding the impact of different management techniques on the endangered seabirds for which KESRP is predominantly focused.