February 17, 2021 - North side
February 17, 2021 (Wednesday), 12:45pm - 2:15pm
Coverage: Jones parking lot to second stop sign
42 dead newts, 0 juveniles.
Other roadkill: None noticed
Weather: Cool, low 60s, mostly sunny, no rain in a while.
Traffic: 24 cars; 9 parked cars; 7 bikes; 2 quarry trucks; 7 pedestrians
After the previous crew encountered 379 over the weekend, I almost feel guilty (yet glad) for having so few to log. The newts must have made a big push to finally get out there all at once with the last rain. I wonder if the next wave we see will mostly be on the reservoir side of the road, as they start returning to their summer sites.
Almost all of the newts were crispy, many quite adhered to the road.
@merav, Flag #77 was still on the side of the road from the last experiment, and it appears that the corresponding newt was still on the road. May be a juvenile, and still looked similar to how they did in my original photo, so pretty easy to tell. I removed both flag and newt and put the flag with the rest, near flag 17.
Echoing @karangattu, I did have some time to ponder between newt encounters. While no closer to understanding my purpose in life, I did wonder what would happen if MidPen created multiple ponds along that bottom edge of Sierra Azul, a bit up from the road, but close enough to (maybe/hopefully) tempt a lot of downward-migrating newts to breed in them instead. It sounds like they have a strong tendency to return to the same breeding pond year after year, so it may take a while for them to establish in the new ponds. Once they did though, later generations would return there, potentially reducing their dependency on the reservoir. End of thought experiment...
Comments
@newtpatrol, I've had the same thought about creating vernal ponds for the newts on Sierra Azul property so they wouldn't have to cross the road. I think it's a great idea. I proposed this idea to Julie Anderson at Midpen and she dismissed the idea, saying the newts wouldn't use the ponds because, as you say, they are genetically programmed to return to the site of their birth. Let's ask @tyap for her opinion.
There is an old cement water cistern along Priest Rock Trail that fills with water this time of year. There are breeding newts in that water cistern, so at least some newts are able to adapt to a new "vernal pond."
One thought about how few newts there were on the road... I've seen over and over again that there are very few newts on the road when there is frost on the rooftops. In other words, they don't come out in great numbers when the temperature drops below a certain point. The low for 2/17/21 was 39.4 F. I vaguely remember reading about the cutoff temp being 42 F or thereabouts, but I can't find the reference paper. However, our data support this theory, too. This would explain the crispiness of the corpses as well.
I wonder if that's feasable. One way to help the newts adapt to these new habitats would be to relocate eggs to the new ponds. Especially from places that don't hold water long enough for the larvae to develop, such as the little pool at the limekiln trailhead, that had mating newts last week.
Just today I found a reference from the National Weather Service that said ground temps can be several degrees colder than air temps, so there might be frost on the ground (requiring 32F or below) even when the reported temps are in the high 30's. Use this link for more info:
https://www.weather.gov/source/zhu/ZHU_Training_Page/fog_stuff/Dew_Frost/Dew_Frost.htm#:~:text=Q%3A%20Can%20frost%20occur%20at,dropped%20to%20the%20freezing%20mark.
Relocating eggs sounds like a useful strategy. I wonder at what point they get "programmed" with the natal pond location. California Herps says "This homing behavior has not been explained, but experiments show that it involves a sense of their body position, but it could also involve the sense of smell or a form of celestial navigation." A quick study search found this paper that says that moving them during egg or larval stage is best for ensuring that they imprint the new pond: https://www.jstor.org/stable/43442521
I'd love to see that experiment happen. Even just one pond in a high-mortality area, which would be really interesting to study. Given how many newts there are migrating, it probably wouldn't be easy/possible to determine how much of an effect it had on overall road crossing and mortality (unless some got tagged at Lexington and found to shift to the new pond), but it could at least provide a refuge to keep the population going.
As for frost, I've definitely seen that phenomenon in my yard.
It was nice to encounter a couple of live newts at Mount Madonna yesterday. Interestingly, I drove past Uvas reservoir and did not notice (at least from a drive-by perspective) squished newts, as was obvious at Guadalupe on Hicks.
Thanks for sharing that info, @newtpatrol! I'm on the hope rollercoaster again, hoping that there's some way to save these newts.
Add a Comment