Feed on

By: Ethan Woodis, OMMP Field Crew Leader

Nesting season for the Marbled Murrelet is upon us! That means the Oregon Marbled Murrelet Project’s Coastal Telemetry crews are back on the coast. With the weather clearing up and the whales moving North, the tourist season on the Oregon Coast is in full force. For many people, seeing us on the coast with our radio telemetry gear pointed at the ocean can be a strange sight. For the record, we are not looking for, tracking or listening to whales, sharks or extraterrestrials. We are, also, not photographers, meteorologists or seismologists. And finally, our phone service is just as bad as everyone else’s on the coast and we are not using our antenna to boost the signal. What we are doing is using a radio telemetry receiver and a Yagi antenna to listen for Marbled Murrelets that have been tagged with a radio telemetry transmitter. If the bird with the attached transmitter is close enough to the receiver (within about three kilometers), the receiver will pick up the transmitted signal and start beeping. By listening for these beeps, recording where we are when we hear them and taking a bearing with a compass in the direction that the signal is being received, we are able to determine where the tagged murrelet is on the water. This will help us to understand the foraging habits of Marbled Murrelets on the Oregon Coast which will help us to better understand how we can help to protect this extremely unique species.

Photography by Ethan Woodis


That’s how and why we are using radio telemetry but what exactly is radio telemetry? Radio telemetry was the first real-time method of tracking individual animals over a long distance. In the field of wildlife research this has made it possible for researchers to track and study wildlife much more efficiently. The transmitters we use are VHF (Very High Frequency) tags. In the electromagnetic spectrum, VHF tags transmit between 30 and 300 MHz. More common uses of VHF are television, FM radio, armature two way land radio and Air Traffic Control to name a few. Some people may have seen radio collars on deer, wolves or other large animals. These are also VHF tags but they are much larger than what we put on murrelets. The larger the transmitter the longer the battery will live. That means in only a few months our transmitters will die. The tags fall of the bird during their fall molt and it can have a new one put on the following breeding season. Within the short lifespan of our tags we are able to learn where these birds forage and where they nest. As this is a very cryptic bird, this work would be impossible without the use of radio telemetry tags.

Photography by Jim Rivers


So, when you see us waiving our antennae toward the ocean seemingly oblivious to the Gray Whale calf foraging just off the rocks, you now know what we are searching for and how we are searching for it. Marbled Murrelets are an extreme difficult animal to study but with technology, lots of patience and even more coffee we are slowly unraveling the mysteries of these magnificent birds.

Photography by Holly Todaro

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One Response to “Radio Telemetry”

  1. Greetings To Jenn Guerrero & All the OMMP Field Crew! Also:Jim, Kim, Dan, & Matt!
    The research you are conducting, coordinating, and communicating is EPIC!
    I so support your efforts! I had the honor to meet and learn of your Program through your Field Crew Leader, Ethan Woodis, who was kind enough to take a moment in time and share his purpose of utilizing the radio telemetry gear & yagi antenna in locating a tagged Marbled Murrelet that was a fatality due to our local eagle parents feeding their eaglet. It was the highlight of my day to learn of your research efforts! Wanted to take a moment to share the eaglet fledged right in front of my observation @ 10:39 am Sunday, July 8th! …. Confirmation of Life goes on!
    Keep up the great work! Carry the torch of educating us, your public cheerleaders!

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