Gray Fox Report: March 2024

Gray Fox (Urocyon cinereoargenteus townsendi)

In 2022, we had two gray foxes occupying the region from Matadero Creek, over to the Regional Water Quality Control Plant. Throughout this territory they prayed on woodrats, jack rabbits and cottontail rabbits, insects and when in season fruits, thus significantly helping to keep the ecosystem in balance. They control stomach problems by eating a particular kind of grass that grows at the baylands and elsewhere. Recently, there has been a decline in the number of gray foxes from two to zero due to canine distemper. Distemper is a virus that attacks the neurological system, the gastrointestinal system, and the respiratory system all at the same time. In addition to distemper, these foxes can also suffer from parvovirus, heartworm and in rare instances rabies. (Source)

Raccoon (Procyon lotor)

During 2022, the population of raccoons at the Regional Water Quality Control Plant (RWQCP) was robust with both male and female raccoons and their young, often called cubs. In early 2022, I counted a total adult and cub population of 37 raccoons of all ages. From time to time, the number passing my trail cameras varied slightly because some of the raccoons had a range that extended to the golf course and to Matadero Creek. In early 2023 I saw a gradual decline in the number of raccoons around the RWQCP until today there is only a single raccoon occupying this territory. Viral diseases in raccoons include rabies, canine distemper, raccoon parvovirus, infectious canine hepatitis, and pseudorabies. (Source) 

The raccoon population at Matadero Creek has been on a steady decline over a period from early 2023 to the present. Down in the overflow channel along the creek, between channel markers #14 and #15, there is a distinct odor of a decaying animal. Given the “size” of the odor it’s likely a raccoon. As well, there are two young raccoons. When they first appeared along the creek, mama raccoon taught them survival, but over the past three months, she has not been with them as they forage alone. She likely died from canine distemper as that is the deadliest of all the viruses that raccoons can get. 

Striped Skunk (Mephitis mephitis)

The baylands never really had a very large population of striped skunks, but in the early days, well before 2022, in one area behind the RWQCP, there were numerous skunks living in a region that I called Skunk Hill. More recently in 2024, Animal Control picked up a skunk from near the RWQCP. Presently, I have seen only one skunk and when it passes my camera its tail is hung low and the skunk rather shuffles along indicating that the skunk is not well. Viruses include Canine Hepatitis, Canine Distemper, Intestinal Roundworms, Leptospirosis, and Rabies. (Source)

A common thread runs through these three populations: Canine distemper. And if we return to the CDFW’s veterinarian’s comment that it appears to be endemic, then maybe here in the Baylands distemper is simply a part of the landscape. Regarding the skunk and raccoon populations, according to Animal Control, “…we suspected canine distemper as well. We’ve had about a dozen calls for skunks recently in the Byxbee [Park] area with signs of distemper.” 

In Part 2 of this examination, we will see how such die-out’s impact on the Palo Alto Baylands Nature Preserve. Scientifically, it’s called a tropic cascade.