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Petrels Research
View
images of southern giant petrels being tagged.
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Attaching Transmitters
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Dan's journal. |
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What: Donna Patterson is studying southern giant petrels of the Palmer region. She wants to know how the petrel population is changing over time and what factors influence it.
Why: Petrels are scavengers as well as predators. Along with skuas, leopard seals and orcas they are at the top of the food chain of the Antarctic Peninsula, exerting an important influence on all of the organisms below it. These petrels are in decline almost everywhere around the Antarctic apart from the Palmer region. Patterson hopes research on this exception to the continental trend could help explain what�s happening to giant petrels throughout Antarctica.
How: Patterson does a complete census of petrels in the Palmer region. She does a much more careful survey of 32 nesting sites on Humble Island, where she monitors egg and chick health (by examining, weighing and measuring eggs and chicks) during the entire breeding season. She considers the reproduction process as a good indicator of the health of her subjects. Patterson monitors where adults forage for food with satellite "tags," or radio transmitters. The tags transmit signals every minute eleven hours a day (full-time transmission would use up too much battery power). Satellites flying overhead receive the signals of the birds (it takes at least two satellites receiving the same signal to determine a location). These signals are relayed by other satellites to a ground station in France, where a computer calculates the positions of the birds to within 300 feet. Patterson gets the information once a day by email.
Chronology of Patterson's research
Glossary of petrel terms
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