Even though San Diego County seems like paradise with our four climate zones (beach, foothills, mountains, deserts), it’s really quite harsh when considering our big temperature swings and lack of rain most of the year. That being said, San Diego has an amazing number of species and plants, birds, reptiles, amphibians, mammals and bugs, especially in our backcountry areas. Everywhere you look, there are species that have adapted to live in a specific niche. One example of these adapted species are ringtails.

Ringtails (Bassariscus astutus) are omnivores specialized for life among steep rocky habitats or high in palm trees among palm oases. One might not think they would be anywhere near a road, but they often are found as roadkill in places like near Buckman Springs where I-8 passes some cliffs. Another spot is on State Route 67 by Mount Woodson—at a bottleneck between two patches of ideal habitat—where ringtails have been killed repeatedly while trying to negotiate heavy traffic.

Roadkill is one of the ways by which habitat fragmentation is translated into a species’ decline. Scientists from The Nat have teamed up with the San Diego Zoo to capture ringtails and equip them with a GPS collar in orer to better understand the ringtail’s movements and their risk in these areas.

Ringtails are small and furry like a domestic cat, but long and slender like a weasel, and they are most active at night. Their distinctive black and white banded tails provide camouflage and balance as they skitter over boulders and along low tree branches. It’s almost impossible to observe ringtails unless you use remote cameras, and they are even harder to live trap. Once sought for its fur, the ringtail is now listed by the California Department of Fish and Game as a fully protected species.

Biologists from the Museum and the Zoo have found that strawberry jam is the best bait to bring the critters running. Once the animals are fitted with a GPS collar, scientists can track their progress from back at the Museum. They download the GPS data points to their computers along with video footage from the cameras.

With these data, biologists may determine how far do individual animals travel in a given area. Are the roads running next to their area actually in the middle of ringtail territories? Or are they avoided? Biologists refer to that as “habitat fragmentation” and it’s a tough problem to solve. The goal is to identify ways to keep the animals off the road to prevent the deaths so ringtail communities do not become isolated from one another. As always, genetic diversity is very important for healthy populations.

This study, which is still in progress, will allow biologists and land managers to gain a better understanding of the ringtail’s space-use patterns in Southern California and potentially make changes to the roadway that will decrease the number killed on roads. As humans continue to encroach on the habitat where many of these species live, we must better understand how to avoid impacting their complex ecosystem. 

Learn more about our ringtails in the San Diego County Mammal Atlas, published by the San Diego Natural History Museum, and the San Diego Zoo Institute for Conservation Research.

Posted by The Nat on March 6, 2020