GPS Data loggers

Despite many studies on yellow-eyed penguins we know little about their habits at sea. Interpretation of the species population dynamics, and consequently conservation measures, are primarily based on what can be observed on land. Today with the aid of modern satellite technology, studying penguin behaviour at sea through miniature GPS logging devices attached to their backs has opened a new window of opportunity to examine all aspects of the penguins’ biology.

These GPS-loggers are manufactured by a German company, earth&OCEAN Technologies who are the only manufacturers able to make these to the required specifications. The Trust purchased three of these at an approximate cost of $15000 (funded by part of the 2002 Contact Energy ‘Community Conservation Challenge’ donation).

The loggers record the penguins’ dive depths at given intervals (usually 1 second) as well as their geographical position after each dive. The average battery life of a GPS-logger is approximately 3 days, so only short-term attachment will be conducted. The devices are attached using adhesive cloth tape, allowing for easy detachment without causing any damage to the penguin’s plumage.

In collaboration with the University of Otago’s Zoology Department and the Department of Conservation’ Southland Conservancy, the Trust attached these loggers on yellow-eyed penguins during periods of this year’s breeding season. These devices allowed us to record a bird’s geographic position as well as its dive behaviour. Trialled on three birds at Bushy Beach near Oamaru last year by PhD student Thomas Mattern (pictured right), the results showed a ‘map’ of travel where the penguins appear to use underwater landmarks to guide them to the best foraging areas. We now wish to know if this is the same for the Stewart Island population where there are different oceanographic environments to that off the Otago coastline. Yellow-eyed penguins breed mainly along the northern and north-eastern coast of Stewart Island where the shelf is located more than 100km off-shore resulting in a wide shelf area compared to the North Otago shallow and narrow continental shelf which is less than 50km off-shore. This research will be carried out in 2005.

By studying the foraging behaviour of yellow-eyed penguins breeding at locations with different oceanographic features, we may shed light on a greatly unknown component of their biology and will help to better construe this species’ population status and to develop customised management strategies for the species’ different habitats.

Related posts:

• Feeding
• Foraging
• YEP Reproductive Study
• Stewart Island Census 1999-2000