Light Pollution

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Following our initial research (2011 - 2015) quantifying Wedge-tailed Shearwater fallout along a coastal highway in the southeastern shore of Oahu, we have undertaken a 4-year study to compare seabird fallout before and after the switch from yellow high-pressure sodium (HPS) bulbs to white light-emitting diode (LED) highway lights.

It is our hope that this research will increase the understanding and public awareness about shearwater fallout and possible mitigation efforts aimed at reducing mortality.

A Wedge-tailed Shearwater chick, grounded along the Kalaniana'ole Highway, in Waimanalo town, rescued during a road survey.


To this end, we completed the following activities during four years (2016 - 2019):

(i) surveyed a 16-km section of the Kalaniana'ole Highway, from Hawaii Kai to Olomana Golf Course, using standardized methods to map shearwater fallout during the fledging season (November 1 - December 21),

(ii) marked and resighted randomly-selected carcasses at daily intervals to quantify potential biases in the road surveys due to carcass loss by scavenging and washout, and

(iii) disseminated the study results via our project web-site, our facebook site, scientific presentations and public seminars.

Figure 1. The 16-km survey, spanning from the Olomana Golf Course (north), through Waimanalo town, to Hawaii Kai (south). The map shows the location of the Manana shearwater colony and of the Sea Life Park rehabilitation center.


Between 2016 and 2019, we conducted 68 strandardized road surveys during the fledging season and documented 90 grounded wedge-tailed shearwaters.

There average number of grounded shearwaters per year, was similar:

before (25.8 +/- 23.1 S.D., median = 16, range = 11 - 60)


after (22.5 +/- 16.7 S.D., median = 18.5, range = 7 - 46)

the switch in highway lighting, from HPS to LED lights.


Figure 2. Annual wedge-tailed shearwater fallout during years with HPS (orange) and LED (blue) highway lighting, showing the mean (dashed lines) and S.D.s (error bars).


After four years of surveys following the shift from HPS to LED lights, we cannot detect a significant change in the magnitude of wedge-tailed shearwater fallout in our study area.

Yet, because there is substantial inter-annual variability, an in-depth statistical analysis is underway to assess the influence of the highway lights, in the context of other potential environmental drivers, like the moon cycle and the speed and direction of the prevailing wind during the fledging season.


To learn about the latest results, link to the abstract, provided below:



Pacific Seabird Group Conference (2020)

Jennifer Urmston, K. David Hyrenbach, Susan Carstenn, & Keith Swindle



You can also view a public outreach presentation on this research:




Pelagicos Contact

David Hyrenbach


Other Pelagicos People

Jenn Urmston



Keith Swindle

US Fish and Wildlife Service
Office of Law Enforcement
3375 Koapaka St., Ste. B-296, Honolulu, HI 96819

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