Tuesday, February 14, 2012

Summer of ground squirrels

By all accounts, the summer of 2010 was a good one (though I waited until January 2012 to finish writing about it). My favorite count, though, is the number of species of ground squirrels I saw this summer: at least seven. I had the good fortune to travel to a number of places with new and different non-arboreal scurids this summer.

Why bother studying ground squirrels? The best reason is that they're adorable. The second-best reason is that their numbers and habits make them among the most readily observed mammals in North America. I could spend my whole vacation in a blind waiting for a monkey-faced disco hawk or some other rare bird or mammal to come into view for a few seconds, or I could take a short walk along a talus pile on a sunny day and see who pops up. I took all the pictures below with my Canon Powershot SX110 IS, a nice but not terribly expensive point-and-shoot with a 10x optical zoom.

1. California ground squirrel, Otospermophilus beecheyi
Lisa and I saw this little fella, formerly known as Spermophilus b., on a bay-front walking path in Alameda, California.

2. Golden-mantled ground squirrel, Callospermophilus lateralis
This handsome rodent, formerly called Spermophilus l., superficially resembles a chipmunk, but is distinct in that chipmunks' stripes extend onto the face. This guy was scampering among the rocks at a Donner Pass Road overlook in Nevada County, California, near the famous Donner Summit Bridge. The American Society of Mammologists species account describes its running gait as "clumsy" (ASM Report #440, Spermophilus lateralis, 1993), which seems unnecessarily harsh. Perhaps the authors had observed only pubescent ground squirrels going through that awkward phase - want to make fun of their cracking voices and acne, too? Not cool, mammologists.

We also saw a yellow-bellied marmot there; my mother-in-law almost ran it over (unintentionally), but he safely scampered away.

3. Belding's ground squirrel, Urocitellus beldingi
Despite appearances, this guy is not a prairie dog. Formerly known as Spermophilus b. (noticing a pattern here?), this squirrel hangs out in alpine meadows. His habit of standing bolt upright to watch for danger led early settlers to call him the "picket pin". There was a small colony of these guys in the summit resort area at Squaw Peak.

4. Yellow-bellied marmot, Marmota flaviventris
Mr. Chubby-Cheeks here was seen hiding in a landscaped rockpile next to the hot tub at the Squaw Valley summit resort area. Lisa pointed out that some of the teenagers in and around the hot tub probably thought I was being creepy, hanging around with a camera in hand. I don't care - this picture was worth it. Click to enlarge it - you can see the marmot's nose hairs!

5. Chipmunk, Tamias sp.
This handsome rodent was spotted on a talus pile at a Lake Tahoe overlook and could be one of three species:
Tamias amoenus - Yellow-pine Chipmunk
Tamias speciosus - Lodgepole chipmunk
Tamias quadrimaculatus - Long-eared Chipmunk

6. Thirteen-lined ground squirrel, Ictidomys tridecemlineatus
This many-striped ground squirrel was known as Spermophilus t. prior to taxonomic revision. Lisa and I saw this individual feeding on some spilled popcorn on the central mall at Brookfield Zoo, in the Chicago suburbs. Nothing like a good stretch while eating unpopped kernels of salty goodness, eh?

7. Woodchuck, Marmota monax
I saw this chunky 'chuck at a family friend's place in Waukesha County, Wisconsin, on Labor Day. I think he safely sneaks under the radar as the last official ground squirrel of the summer. In some parts of the country, it's socially acceptable to call this animal a "whistle-pig", which is awesome.

View Summer of Ground Squirrels in a larger map

My identifications were assisted by:
  • Squirrels of the West. by Tamara Hartson (Lone Pine Publishing, 1999). I stumbled across this book in a Forest Service visitor center and instantly knew I had struck gold. I also recently acquired Squirrels of North America by Tamara Eder, who apparently is the same person.
  • San Francisco State University - Sierra Nevada Field Campus species list
  • National Audubon Society Pocket Guide - Familiar Mammals of North America
  • American Society of Mammologists species accounts (#221, #440, and others); some of them are freely available

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