oikonos

Exploring Albatross Movements
Satellite Tag Information

How do Satellite Tags work?

Introduction

Essentially these are radio transmitters that transmit a signal that can be detected by polar orbiting satellites. Depending largely on the number of signals received from an individual tag by a satellite in any given overpass, locations with different levels of accuracy can be assigned.

At the current time, all satellite tags that are commercially available function through the Argos system. Argos lets you locate any platform equipped with a suitable transmitter, anywhere in the world, to within 150 to 1000 meters (using Doppler effect). The Argos receivers are carried on-board NOAA series satellites on polar, sun-synchronous, circular orbits at 850 km altitude, providing full global coverage.

More detailed Information:

Argos system overview

How Argos works

Applications

Satellite Technology can be used to track a sailing race and the far-ranging voyages of albatross:

Tracking a Sailing Race

Tracking Albatross

Biologists wait for Albatross on RV Phocoena, August 2004

Sue safely holds a Black-footed Albatros, named Manako, by protecting his wings. Note the tag attached to his back feathers with waterproof tape. The antenna transmits a signal to the Argos satellite receivers.

To save battery power, the transmitters are turned on with a magnet when ready to be used. The "chirper" is a tool to use in the field to make sure the transmitter is ON.

Manako resting on the water after release.

We learned from the number on a leg band that Monako hatched on Midway Atoll in 2000 and genetic analysis of a few drops of blood told us he is a male.

Link to a map of his voyage in 2004

Who builds the Albatross Transmitters ?

Sirtrack, an engineering group in New Zealand, designs and manufactures the satellite tags we use to track albatross.

How does the tag affect the bird ?

Great care is taken to ensure the safety of each albatross. Biologists must consider the weight, drag, and attachment method used. The Kiwisat 202 satellite tag weighs 54 grams, below the 3% weight ratio estimated to negatively affect bird flight. Black-footed Albatross often eat squid that weigh more than 100 grams. The tag is attached with waterproof tape to several feathers on the back of the bird. The tag will fall off in approximately 90 days when the bird replaces its back feathers (moults) or the tape wears off. This attachment method has been approved by the U.S. Fish & Wildlife Service.

How can Satellite Tracking Help Albatross ?

Across the North Pacific, longline fisheries impact the Black-footed Albatross. The birds are attracted to the squid used as bait and the discards thrown into the sea. When attempting to feed on the bait, they can get hooked, causing entanglement and drowning. Based on predicted population declines ascribed to longline fisheries bycatch, the International Union for the Conservation of Nature recently raised the species status to "endangered".

Effective measures which can virtually eliminate albatross deaths in longline fisheries are being applied in the Alaska and Hawaii fisheries. However, little is known about the at-sea movements of these far-ranging birds in the Northeast Pacific, where they can meet with other fisheries. With satellite tracking, we can follow individuals and learn where they spend time and overlap with specific fisheries. With this information, we can work with fisheries managers to reduce bycatch mortality.