Despite persistent cool mornings and alternating sunny and cloudy days, nine of eleven telemetered rattlesnakes have left their winter shelters and the remaining two have been basking regularly and will undoubtedly be on the move soon. We have also been finding plenty of new rattlesnakes basking and now have 27 animals processed and marked with colored paint in the rattles, in addition to the eleven with radios.
As I have already described, Female 41 was one of the first to leave her hibernation site and was soon joined by Male 49, a snake marked last season but not telemetered. Male 49 and Female 41 remained in close proximity at the same location from 16 February until 20 March and, although they were occasionally coiled in contact with one another, I never saw the male courting her. Male 49 followed when Female 41 moved more than 50 meters between 20 and 24 March but there has still been no witnessed courtship. However, the grass is very thick at their new location, making her hard to see and him impossible to spot if he’s not with her (and I don’t want to step on him… they’re very fragile!).
On 22 March, I came across Female 55, another animal processed last year and released without a transmitter, basking alone at the edge of a large log. But when I returned on 24 March, she had company: an unmarked (no paint in the rattle) male on top of her, jerking, chin-rubbing, and tongue-flicking – typical courtship behavior (you can view a 2015 clip of Female 41 with another male here).
We can expect the females to hunt for the next two-to-three months, after which pregnant females will retreat to their favorite gestation shelters to thermoregulate until their kids are born around the first of September. Non-pregnant females will continue to hunt through the summer. Males will spend most of their time looking for receptive females until late May/early June, after which they, too, will hunt full-time for voles and ground squirrel pups until courtship resumes in late summer.
After a couple of false starts during warm periods in mid and late February, a new series of cool storms kept the Effie Yeaw Nature Center rattlesnakes immobile through the first half of March. On days with a little sunshine, both telemetered and other rattlesnakes were frequently found basking at the entrance to their shelters but they did not venture away from them. Natural selection tends to remove animals from the gene pool that wander too early and get caught in a late-season freeze. As if to demonstrate that it was cool temperature and not the rain that was keeping them inactive, several rattlesnakes were found lying out in the rain on days when the temperature was in the high 60s, despite the clouds.
While the rattlesnakes continued to bask on sunny days, none of the telemetered animals moved between 29 February and 17 March. Then today, I discovered that 7 of the 9 telemetered rattlesnakes had left their shelters and moved significant distances in the past two days.
I haven’t seen courtship yet. Female 41 and Male 49 hung out together for a month (16 February through 15 March) but they were only rarely touching one another and were usually coiled a couple of feet apart with no courtship observed. She is now hunting several dozen yards away and Male 49, without a transmitter, has disappeared.
The important message, however, is that rattlesnakes are on the move and encounters between people and rattlesnakes will increase immediately. Unfortunately, I have already seen photos of a rattlesnake bite from a few days ago in the foothills. Watching carefully where you put your hands and unprotected feet and leaving snakes alone when you encounter them would prevent almost all bites. If you must walk in vegetation or rocks where you cannot be sure what you’re stepping on, wear high-top shoes or boots that cover your feet and ankles. Of course, boots that cover some of your calf are better but most accidental snakebites (where the person is not intentionally interacting with the snake) are to the ankle and below.
Remember, you can’t save all the cute animals, eat all the tasty ones, kill all the ones that scare you, and have a functional ecosystem, too!
After some limited basking by a couple of telemetered rattlesnakes and short movements by Female 41 and Male 49 two weeks ago, the return of cool cloudy weather sent these animals underground again. Then, despite several days of sunny weather last week, the rattlesnakes remained cool and out of sight – with the exception of Male 49. While Female 41 stayed underground and cold, he napped most afternoons in the sun just a couple feet away.
But yesterday, everything changed. Males 37 and 38 who spent the winter near the top of the bluff had moved down; one was out of sight under a log and the other was in an ambush coil in the grass under a small fig tree.
A rapidly pulsing transmitter told me before I arrived that my underweight geriatric Male 40 had survived another winter and was in the sun at his winter shelter.
Female 41 was in the sun with Male 49 laying partly on top of her, although I saw no active courtship during my brief visit.
Other telemetered snakes had moved short distances but were out of sight when I was there yesterday. But in my travels, I also sighted five unmarked rattlesnakes basking, including a beautiful little female sporting a food bolus about the size of a vole – so she has already fed successfully.
So for the next three months or so, females will be trying to eat as much as they can to nourish their next brood while males will be wandering all over the place (and hunting less) in search of receptive females. It is during this time that male rattlesnakes tend to turn up in yards and on trails, producing interactions with people.
Remember that rattlesnakes want nothing to do with something the size of a person. Leave them alone and they will be happy to avoid you, too!