Animals use various strategies to survive winter
By Kathryn Reed
Animals have a way of knowing when to prepare for winter, but if winter doesn’t come, it can be a problem.
Those that use camouflage as a tactic from hiding from their predators are having a hard time of it in the Sierra this year because their white coat is standing out against the brown landscape instead of blending in with the snow.
Will Richardson, co-founder and co-executive director of the Tahoe Institute for Natural Science, spoke at the Tahoe Area Sierra Club meeting Jan. 22 about winter wildlife survival strategies.
In Lake Tahoe he said five species turn white in winter – two types of rabbits, long and short tail weasel, and the white-tailed ptarmigan.
“Winter presents a lot of challenges for any organism,” Richardson told the crowd of more than 60 people.
Key problems are shelter and food. Animals can choose to leave for the winter, tough it out or lower their metabolism so they can sleep through most of the winter.
Migration is common for birds. But insects and some mammals choose this option, too. Many birds head for the tropics. Millions land in Central and South America.
“What happens when you lose an acre of rain forest? What happens here?” Richardson asked rhetorically.
Facultative migration is a shorter migration; maybe just to the Carson Valley or Central Valley.
A sure sign that animals are confused by the weather this year is a barn swallow was spotted in Tahoe City this month. Richardson said he doesn’t know of any time when any species of swallow has been seen in the basin in January.
Mountain quail walk out of the basin every year. The same goes for deer.
Waterfowl tend to stay in Tahoe through the winter. And they attract eagles. Richardson said this is a big year for eagles; with 15 spotted during the Christmas bird count.
Snakes do what’s called hibernaculum. This means they all are huddled together in the quest to have a consistent temperature.
Frogs have one of the more unusual winter rituals. The Sierra chorus frogs are what Tahoe has the most of. When they touch an ice crystal their body starts to shutdown and their organs freeze.
“They are able to freeze solid. They have no heart, no brain function,” Richardson said.
He showed a video of a similar species of frog to what is in the basin that depicted the freezing process as well as the thaw-warming in the spring. Scientists still aren’t sure how this is possible.
Putting on a winter coat as well as extra weight are other ways animals survive winter. Feathers are a great insulator.
Richardson said no matter what strategy animals employ, preparation is critical – especially to have enough food stored.
I’m so sorry to have missed Will’s presentation (I ‘miscalendared’ it and showed up on the 23rd) as it would have added immensely to the 3 1/2 hour tour taken with the renowned Illustrator/Naturalist John Muir Laws of S.F’s CA Academy of Sciences. . .a tour taken in our own Van Sickle Park during the Sierra Nevada Alliance Conference a few months ago. . .
As I was able to restart a relationship with Jack during his visit to Tahoe, I am hoping to do the same with Will very soon, as more of the populace needs to know of and pay attention to our wildlife and their needs, in a time where us humans are not too trustworthy with the way we’re doing things. . .
Therefore, knowing of the changes in their habitats and lifestyles (what we’re now calling “adaptation” in our own survival modes) will help us understand better the reasons why change is becoming paramount – as most now know the story of the ‘canary-in-the-coal-mine’, never realizing that that concern could reach them, as it has now.
Habitats are changing both in latitude, longitude, and at various elevations, and their survival is intricately tied to our own, so I can certainly applaud Will’s presentation, even if I wasn’t fortunate enough to put it on the calendar correctly – there isn’t yet a category of “too much information” for knowing other species and their needs. . .