It was with a bit of a heavy heart a week ago this morning that I watched my favorite EYNC rattlesnake, Male 37, glide into a hollow log… this time without a transmitter.
Denise and I arrived at Effie Yeaw late on Tuesday, 10 April, and unloaded the boxes of equipment and supplies we would need to remove surgically-implanted transmitters from a dozen rattlesnakes. EYNC’s Executive Director, Torey Byington, had consented to allowing us to take over part of the EYNC kitchen and the wonderful staff graciously shared their lunch room with a make-shift surgical suite for the next few days.
I wanted to allow the telemetered rattlesnakes to hibernate with their transmitters one last winter to complete my 2017 data with verified winter den locations. Plus, because their immune systems and their ability to heal wounds slow down considerably when they’re cold, I routinely avoid surgeries just before hibernation. Thus, I was committed to returning this spring to remove the transmitters.
I was worried about the weather as we prepared for the drive from Arizona. While mid-April is usually warm and the rattlesnakes are very active (females hunting for food and males hunting for females), recent weather had been cloudy with unseasonably cool temperatures and the forecast was for more of the same. Yet, the naturalists at the Nature Center were telling me that visitors had been reporting rattlesnake sightings on the occasional sunny days, so we stuck with the original plan and hoped for the best. We were not disappointed.
Even though it was overcast, cool and breezy, Denise and I headed out into the preserve Wednesday morning to capture as many of the telemetered rattlesnakes as possible. While I usually use only a snake hook and put captured rattlesnakes in a cloth bag, many escape capture with the hook and getting an unhappy rattlesnake safely into a cloth bag is not a quick process. So, for this effort, we used a clamp stick (photo below) and put the snakes in plastic buckets. Grabbing them with the clamp stick is more stressful for some of the snakes but prevents most escapes and putting them in a bucket is quick, easy and safe.
Despite the cool cloudy weather, we were relieved to have nine of the rattle-snakes in buckets by early afternoon!
However, Males 36 and 37 were inaccessible inside hollow logs and, not surprisingly, we had no radio signal from Female 80. Her signal vanished last summer after she ventured into the residential area at the top of the bluff. Her transmitter might have failed prematurely, she could have been carried far away by a hawk or owl, or a homeowner could have destroyed her and her transmitter… we’ll just never know for sure.
Over Thursday and Friday, I completed surgeries on six of the animals. Males 36 and 37 remained inaccessible inside their respective logs on Thursday but Friday dawned clear and sunny and my hopes of capturing them was high. After a couple early surgeries to allow things to warm up outside, I went out again to look for them – and it became apparent why they were hidden and not moving.
As I approached the log where Male 36 had been sheltered, a smaller chocolate brown unmarked (not previously captured) female rattlesnake was coiled in the sun at the open end of the log. Using a mirror to reflect sunlight into the log, I could see Male 36 coiled in the shadow behind the female. Now things became clear… Male 36 was not moving around because he had already found a female and was hanging out with her! I had an idea: I gently lifted the female away from the log and moved her a hundred feet or so away. Within a few minutes, Male 36 was sniffing around where she had been laying. Ten minutes later, enough of him was protruding from the log for me to capture him. One down and one to go!
The sun was also shining on the log where Male 37 had been. But this time I found Male 37 outside the log, on top of and courting another unmarked female. I captured him and, after a pang of guilt, took his female too.
By the end of a long day Saturday that included the last five surgeries, all the transmitters had been successfully removed, nine rattlesnakes had been released and our equipment was repacked for the drive home. Males 36 and 37 were the last two surgeries Saturday night and needed to recover overnight before release.
So, on our way out of town early the next morning, we released the two males. Male 36 glided back into the same log where I had captured him; I saw no sign of the female I had moved. Finally, I released Male 37 into his hollow log followed by the female he had been courting.
My last act was to leave my EYNC keys behind in an envelope, turn out the lights and lock the door. The field work is done but much data analysis, DNA analysis and writing remains. I will be forever grateful for the support and encouragement of many people and several organizations.
Acknowledgements
Recently retired EYNC Executive Director Paul Tebbel initially invited me to study rattlesnakes at EYNC. Over the past four-plus years, Paul and the entire staff and cadre of volunteers at the Nature Center were encouraging, supportive and genuinely interested in what I was doing. Torey, the new ED, has been wonderful, as well. The ARNHA board of directors consented to my study, trusted me that it could be done safely, and several board members took a personal interest in my work. Mary Maret, Resource Specialist for Sacramento County Regional Parks, facilitated the necessary county permits and was personally very supportive. Laura Patterson at California Department of Fish and Wildlife expertly managed issuance of my Scientific Collecting Permits. Rulon Clark added me to his laboratory group at San Diego State University as an adjunct researcher, allowing my field work to be approved by SDSU’s Institutional Animal Care and Use Committee – an essential detail needed to publish results in reputable scientific journals. Finally, Fred Andreka and Holohil Systems have been providing me with small dependable surgically-implantable radio transmitters for nearly twenty years and Holohil’s John Edwards has provided amazing customer service.
Thank you to everyone, including the countless EYNC visitors who stopped to talk and ask questions on the trails, many of whom seemed to walk away with an altered opinion of rattlesnakes!