Shearwaters at Freeman Seabird Preserve Oahu Harrison Pravder Hokulea Program Washington University in St Louis INTRODUCTION Conservation Climate A staggering 340 out of the United States 1500 endangered species call ID: 178218
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Keeping Common Birds Common: Breeding Patterns of Wedge-tailed Shearwaters at Freeman Seabird Preserve, O`ahuHarrison PravderHokule`a Program, Washington University in St. Louis
INTRODUCTION
Conservation Climate
A staggering 340 out of the United States’ 1500 endangered species call
Hawai`i home. These species are protected under the Endangered Species Act (ESA). Under the act, species at risk for extinction are targeted for revival. The ESA consumes much of the US Government’s allocated funds for conservation activity, thereby directing funds away from common species, species that are crucial for sustained ecosystem stability.
Wedge-tailed Shearwater
The Wedge-tailed Shearwater (Puffinus pacificus) (also known as a wedgie) is a medium-sized petrel native to the Hawaiian archipelago. With an estimated population of 5.2 million individuals worldwide, wedgies range throughout the tropical Indian and Pacific Oceans. Despite being greatly affected by introduced predators and human habitat interference, wedgies are not considered at risk under the ESA, and thus are not given much attention to by conservationists. They are, however, protected under the Migratory Bird Treaty Act, an act that discourages human disruption of migratory bird activities. Nonetheless, human activity (via habitat destruction and other means) has lead to an ongoing global wedgie population decrease of unknown rate. Freeman Seabird Preserve (FSP) The last breeding ground for wedgies on the south shore of O`ahu, FSP is a preserve that was established by the Hawai`i Audubon Society in 2008 after a generous donation. Efforts to improve breeding conditions for wedgies have had great success. My WorkMy work focused on monitoring wedge-tailed shearwaters at FSP and evaluating regional population threats through necropsies. My monitoring efforts strove to document WTSH nesting and fledging success on the preserve and to identify local threats to the colony. In the necropsies, I examined all parts of the deceased seabirds and evaluated several organs for external abnormalities, such as plastics and toxins.
DISCUSSION
Breeding Information
A bimodal distribution was observed for egg laying with two peaks arising on June 21st and 24th (Julian days 172 and 175).The June 24th peak coincided with a full moon.Mean=July 22, Median=July 21WTSH ObservationsThe colony continues to expand the number of breeding pairs.Many birds nesting in “artificial homes”.Few birds nesting in native vegetation (5 Birds).Nesting in ʻohai, ʻilima papa, and naio.Necropsy FindingsPlastics seen in all birds mostly in the form of fishing line.Predatory ActivityPredatory activity observed from cats and humans.People seen walking barefoot through the preserve towards the ocean.
ACKNOWLEDGMENTS
I would like to express my sincere thanks to Dr. K. David Hyrenbach for his thorough guidance and generosity throughout my time in Hawai`i. I would also like to thank Anu Hittle without whom the Hokule`a program would not exist and for all of the great experiences I enjoyed because of her leadership. Additionally, I would also like to thank Dr. Tiffany Knight for her support throughout the process. Funding was provided by the WU Environmental Studies Program, WU Office of Undergraduate Research, and WU Career Center.
FREEMAN SEABIRD PRESERVE
★
METHODOLOGY
Bird Monitoring
I went to the Freeman Seabird Preserve on a
nearly daily basis to inspect the nests.
I looked for:
Eggs
Adults with eggs
Adults without eggs
A Bushnell® 8MP motion-activated
camera was set up at different locations
around the preserve each day. Photos
and/or videos were taken and analyzed.
Necropsies
I performed necropsies at the Oceanic Institute (Waimanalo, HI) on a weekly basis. Three WTSH were necropsied. Samples were taken for pollutants, and the stomachs were analyzed for plastics.
CONCLUSIONS
Work is needed to assess all species, not just those that are threatened/endangered.
This study contributes to increasing our knowledge base of one common species; more work is needed to study other species
.
We need to ensure that common species remain common, for without common species, the ecosystem would suffer drastically due to loss of essential ecosystem services.
It is more cost-efficient in the long term to protect species that can be preserved, rather than bring back deprived species.
Several measures can be taken to protect
all
species:
Limit invasive predators
Protect native habitat
Limit human exposure
Priorities must be set to maximize each
dollar spent.There are trade-offs in every conservation action. With limited funds, we need to maximize the overall benefit.Public outreach efforts are necessary to educate the community of conservation issues and to inform the public of their role in this ongoing issue.
RESULTS/OBSERVATIONS
A Siamese house cat seen at the Freeman Seabird Preserve during the day.
A cat seen visiting the Freeman Seabird Preserve at night.
Night activity at the Freeman Seabird Preserve.
*Note: All pictures taken with Bushnell® 8MP Motion-Activated Camera
NUMBER OF NEW EGGS LAID
CUMULATIVE NUMBER OF EGGS LAID