New Technology for Monitoring Island Foxes

Monitoring island fox survival is vital to protecting the vulnerable and small populations on six separate Channel Islands. (Current island fox status)

 

Checking for the individual radio signals from 50–60 individual island foxes across an entire island every two weeks, can require many staff hours. Reducing staffing hours would make island-fox monitoring less expensive?

Enter a new technology referred to as "Digipeater." The collar pictured above is one of the 10 new Digipeater radio collars funded by FIF and fitted on Santa Cruz Island foxes this summer. While the collar size is similar to VHF radio-tracking collars, the new collars weigh slightly less and have an additional ability: they interact with stationary digital repeating antennae in the field. 

Multiple times a day, receivers on the antenna scan for fox-collar signals. When a signal is picked up, it's relayed from one antennae to another until it reaches a base station. The base station transmits information directly to biologists. A biologist doesn't have to be in the field to know that all collared island foxes are active and well.

If an island fox goes for a number of days without being picked up by the automated system, biologists can go into the field looking for the signal from that specific fox.

 

The U.S. Navy on San Clement Island has been using Digipeaters for several years. Last summer during a wildfire that burned across a third of the island, biologists were restricted from going into the field. As the low-burning wildfire spread, the Digipeaters continued to collect status information on island foxes. From a safe location biologists could detect island fox activity and survival. No collared island foxes died in the wildfire. 

 

This Santa Cruz Island fox was fitted with a "Digipeater" collar in July. Her new collar reports in daily and requires less in-person labor. It's a win-win for monitoring island foxes.

These collars are possible, because of donors like you. 

Digipeater collars are $350 each and are made locally in Southern California. 

Fox Foto Friday - Where's M152?

Remember this face from last year? M152 is a male fox on the eastern side of Santa Rosa Island. 

This year he was not counted during the annual count and health checks in his area. But don't fear... M152 is doing well. We know he is still in his territory and going about his daily life because he is wearing a radio-tracking collar.

This demonstrates the importance of having two ways to monitor island foxes. 

Annual counts and health checks allow biologists to check the health and well-being of individual animals while they have them in-hand. This provides a snapshot of the population's health as a group at a specific time.

Radio-tracking collars enable the monitoring of individual foxes throughout the year. Their movements in an area can be tracked and if something happens to them, their radio collar reports to  biologists.

M152 did not come into a capture cage this year. Perhaps he was finding plenty of food because of the normal rainfall this spring and saw no reason to enter a capture cage. Perhaps when he came across a capture cage, another fox was already in it.

M152 is a pretty wily fox. We think he is approximately 5–6 years old. In that time he's only been captured twice: in 2014 and last year in 2018. ID micro-chips make is possible for each island fox to be tracked as an individual.

We're sorry that the biologists didn't have a chance to weigh him, check his health, and take a whisker sample this summer. It would have been great to compare to his last health check.

But other foxes did get examined and their stories are important too.

What Has Arrived at Channel Islands National Park?

 Radio collars!

Five new radio collars

still in the wrapper

and 

Six refurbished radio collars

all rebuilt and ready to go back on island foxes!

...have arrived at Channel Islands National Park. These radio-telemetry collars will be fitted on island foxes in the next few months as biological technicians count island foxes and check their health.

Your donations funded these radio collars!

Look closely, this island fox is wearing a radio collar

Foxes with worn collars will be giving them up for refurbishing or new batteries. You have funded fourteen more of these collars to go from the field to the workshop for refitting. More on Refurbished Radio Collars

Radio collars offer a frontline of defense for monitoring and protecting island foxes.