Project Results

HPU graduate Jennifer Urmston has published the first chapter of her MS thesis.  Working with U.S.F.W.S. special agent Keith Swindle and her HPU advisor (Dr. David Hyrenbach), Jenn analyzed 8 years (2012–2019) of observations of road-killed shearwaters along the Kalanianaʻole Highway on Oʻahu to compare mortality before (2012–15) and after (2016–19) a transition in highway lighting from unshielded high-pressure sodium (HPS) to full-cutoff light-emitting diode (LED) streetlights.  Altogether, the interaction between moon illumination and wind speed was the most important predictor, suggesting that more shearwaters are grounded during nights with low moon and strong winds. The lack of an increase in mortality after the change from HPS to shielded LED streetlights suggests the new streetlights did not worsen the light pollution impacts on wedge-tailed shearwaters on Southeast Oʻahu. 

Download the open-access paper by clicking here.

About This Project

Wedge-tailed Shearwater chicks are attracted to lights and grounded due to collisions with utility wires / posts and hit by cars. Since 2011, we have surveyed a coastal highway during fledging (Nov-Dec) and have documented grounded shearwaters. We will use this 5-year baseline to test if deaths increase or decrease after the installation of new highway LED lights. This study will reveal whether the lights being replaced throughout Hawaii will impact these native seabirds.

Ask the Scientists

What is the context of this research?

Wedge-tailed Shearwaters breed on islets along the windward coast of O'ahu. Fledging birds are attracted to lights, grounded due to collisions with utility wires, and hit by cars.

Since 2011, we have documented shearwater fallout along a 16-km stretch of a coastal highway during the fledging season (Nov-Dec). Fallout peaked in 2011 (128 birds), and declined after managers stopped illuminating the Waimanalo park at night (2012-15 mean = 25.7 birds +/- 23.1 S.D.).

In July 2016, the Department of Transportation replaced the orange sodium highway lights with white LEDs to decrease energy consumption. We will test that these new high-intensity lights do not increase shearwater fallout, by comparing our 2012-15 baseline data with standardized surveys during the 2016 fledging season.

What is the significance of this project?

The Wedge-tailed Shearwater is a seabird protected by State of Hawai'i and Federal statutes in the U.S. The species is susceptible to introduced predators and collisions with human structures.

Our research seeks to raise awareness of the plight of fledging shearwaters and to motivate actions to minimize light pollution impacts on this species. In 2012, working with State of Hawai'i wildlife managers, we managed to turn off the lights of the Waimanalo beach park, an action that lead to an 80% reduction in fallout.

We are concerned about the installation of high-intensity highway lights in July 2016. We will test that the newly-installed LEDs do not increase shearwater mortality by comparing the 2016 fallout rates with standardized surveys from the last 4 years (2012-15).

What are the goals of the project?

Our overarching goal is to increase public awareness about wedge-tailed shearwater fallout and to stimulate mitigation actions aimed at reducing the mortality of fledging birds.

More specifically, we will complete the following activities:

- survey a 16-km section of the Kalaniana'ole Hwy, using the same standardized methods used since 2011 to document and map shearwater fallout during the 2016 fledging period,

- mark and resight randomly-selected carcasses at daily intervals to quantify potential biases in the road surveys due to loss by scavenging and rain, and

- disseminate our study results to wildlife managers and the public via social media, a scientific presentation at the Hawaii Conservation Alliance Conference and a public seminar at HPU.