A foxy conundrum: investigating the disappearing red foxes in Russia

Families of red foxes have been disappearing from Kronotsky Nature Biosphere Reserve​ in Russia.

ZSL’s resident wildlife vet in the country, Misha Goncharuk, tells us about this animal mystery he is helping to investigate:

The Kamchatka Peninsula is one of the most picturesque places on Earth with its magnificent volcanoes, geysers, and absolutely wild, primal nature. It's somewhere I've always wanted to visit and now my dream has come true. 

For the last four years, the Russian Academy of Sciences (RAS) has been conducting a red fox behavioural study in Kronotsky Nature Biosphere Reserve. While the species is not endangered, observations during the last two years have shown a mysterious decrease in populations.

All seven of the previously studied families within the population have disappeared, causing understandable alarm within the Reserve’s administration.  

Could mass migration or infectious disease exposure be at play? Unfortunately nobody knows due to the short field seasons of this study, but that’s what I went to investigate. 

Kronotsky Reserve is, without a doubt, one of the most beautiful but inaccessible places in the world, meaning the only way to access the study site was by helicopter. 

The Reserve, and the flora and fauna within, are under the protection of UNESCO as a World Heritage Site. UNESCO has a very limited number of conservation activities each year and in 2016 decided to help our country investigate why these foxes are vanishing from the site.

As a result, we decided to try and find out whether a disease pathogen is responsible for their disappearance by collecting and inspecting blood samples from red foxes in the area. 

If a disease was the reason for the disappearance of foxes, the blood samples collected would show specific antibodies for said disease when analysed in the laboratory. 

The list of diseases of interest included rabies and canine distemper virus, to name but a few.

Staff from the RAS sought a wildlife veterinarian to help with fox-trapping and collecting samples. I was recommended to join the investigation as a veterinarian who has experience in scientific biomedical trapping of carnivores by my colleague and mutual friend Katya Blidchenko.

Since ZSL has already been doing this type of work for years in Lazovsky State Nature Reserve, I was absolutely thrilled to accept this offer! I believe that this unique opportunity was a gift of fate as I left Primorsky Kray (where ZSL is based in Russia) for Kamchatka exactly on my birthday.

After arriving in the main city, Petropavlovsk-Kamchatsky, and once the weather had improved, I was transported by helicopter to Kronotsky Reserve.

The closest distance our helicopter could land to the trapping site was 70km away, so we had to trek for a further three days before reaching our destination. It was the most interesting field walk that I’ve ever done: magnificent volcanoes, wild brown bears and generally the unbelievable nature of Kamchatka.  It was worth all of the hard hiking!

I worked closely with RAS scientist Anna Yachmennicova.  All of the foxes on the trapping site are known to her as she has observed them for a long time. Of these, there were six foxes (three breeding pairs) that we needed to capture.

Generally, trapping foxes is difficult because they are smart - but not in Kamchatka. Two of the foxes live near the main ranger station in the area and were sitting in our cages the next morning after traps were set and rigged up. First pair - success! All procedures were performed and all samples taken.

After that, we travelled to an area 30km away from ranger station by boat. These foxes near the ocean were much smarter. They entered our traps, but did not take the bait or trigger the trap door mechanism. 

We spent two weeks there and captured only one vixen (female fox) on our third and final try. 

In total, we captured three foxes in two different areas. Even this small number of animals can bring us closer to understanding the true reason for the population decline in red foxes in Kronotsky Biosphere Nature Reserve. 

I was very happy to see that despite political differences, people from different organizations from different countries are still able to find a compromise and work collaboratively on wildlife conservation!

Now, we are looking for a good laboratory to test our samples, hopefully we will have the results later this year. Watch this space for the results of the study.

• Read more blogs on our conservation work
• Find out how you can help us protect declining populations
• Learn about some of the threats facing wildlife