Slow Down! Save the Butterflies and the Bears
If you’ve been driving around the park lately, you’ll see yellow caution signs on them with red bears. These mark places where bears have been hit by cars, which as far as I know is the leading cause of death to the parks bears.
Currently, there is a major population explosion of California Tortoise Shell butterflies, a relatively uncommon species in most years. They are being killed by the thousands by cars, but at 25mph they tend to flow over the car. Please slow down if you see tons of butterflies. Here’s the announcement:
Once again, we are experiencing an irruption in the population of the
butterfly, the California Tortoise Shell (Nymphalis californica) along El
Portal Road between Windy Point, to down past Yosemite View Lodge. This
beautiful orange and brown butterfly is being killed by vehicles in the
thousands in this area. While complete avoidance of hitting butterflies is
not possible, the carnage can be substantially reduced if drivers reduce
their speed. At around 25 mph, the butterflies tend to be swept over the
vehicle unharmed. At faster speeds, the butterflies are struck in large
numbers by the grills and windshield of vehicle.So during this period, which may last through June, please slow down and
enjoy this spectacle. In most years California Tortoise Shells are a
relative uncommon species. But in certain years, they emerge in
overwhelming numbers. This species could be responsible for our county’s
name, Mariposa, which is Spanish for butterfly.The larvae of the species feed mostly on ceanothus shrubs. Several
generations of egg-larvae-pupa-adult metamorphosis may occur in
spring-summer, but the butterflies tend to move progressively higher in
elevation as the year advances. Some scientists believe this is because
plants at these elevations have new, tender growth, and lower levels of
tannins later in the season, making them more nutritious for larvae. (S.
Thompson - 5/20/08)
For over 30 years now I've enjoyed hiking, backpacking, fishing, photographing and exploring Yosemite and the Sierra Nevada. 
May 29th, 2008 16:40
[...] cars, which as far as I know is the leading cause of death to the parks bears. Currently, there ishttp://www.yosemiteblog.com/2008/05/23/brake-for-bears/Questions/Answers Inland Valley Daily BulletinQuestions and answers on Daily Bulletin stories from [...]
May 30th, 2008 13:47
Excellent point Loyd, thanks for posting. Not only will slowing down help the butterflies, it also gives US a chance to slow down and enhance our visit to the park.
May 30th, 2008 13:58
Thanks Debbie… though I’m not Loyd
People don’t realize that the speed limits are often set lower in some places, even though one could easily drive faster, because those places have proven dangerous to wildlife (the 25mph limit near Crane Flat is because of spotted owls).
At the same time, if someone is behind you and you’re toodling along at 30mph in a 35 zone, pull over! Some people do that drive every day (or twice a day in fact) and they really just need to get home in time to pick up the kids from school (or whatever).
June 1st, 2008 13:37
Ah yes, life in a tourist zone. I understand completely!