About Me

My photo
Native Californian, biologist, wildlife conservation consultant, retired Smithsonian scientist, father of two daughters, grandfather of 4 small primates. INTJ. Believes nature is infinitely more interesting than shopping malls. Born 100 years too late.

Wednesday, January 24, 2007

California’s gourmet squirrel

Some years ago my good friend the late and great ornithologist Luis Baptista made a discovery while bird watching during his lunch hour in San Francisco’s Golden Gate Park. There on the park path was a migratory species rarely seen in the bay area. It was flitting about a dead bird, possibly its mate. Luis surmised that the victim had just died of some mishap. As he marveled at his discovery an eastern gray squirrel scampered into the view of his binoculars. To his horror, it seized the dead bird in its furry squirrel-paws and nipped off its beak, which it started to eat like a nut. Luis charged while cursing the squirrel, and retrieved the now beakless bird for science. The value of the specimen was greatly diminished, but the squirrel enjoyed a protein supplement to its normally high carbohydrate diet.

Getting enough protein is a challenge to any mammal whose dietary mainstay is plants, and the easiest way to get a large dose of protein is to eat an animal. This is the dark side of many seemingly harmless vegetarians—they sometimes submit to carnivory. Even the most resolute vegans have been known to lust for a slice of cheese, an omelet, or even a Big Mac, and some actually submit to the urge, usually surreptitiously. On the other hand, bright-eyed and bushy-tailed squirrels have no qualms about eating birds’ eggs and nestlings. And in Canada, the diminutive and boisterous red squirrel is known to occasionally eat snowshoe hare bunnies, which is a rather horrifying thought.

That brings me to the gourmet habits of our princely western gray squirrels. It was October two years ago that I noticed some gnarly swollen twigs with chew marks in the driveway. They were oak galls. California has about 19 species of oak trees, and there are over 150 species of gall wasps that lay their eggs in the leaves and twigs. "Arthritic twigs" and "wood apples" are the oaks’ responses to the irritations of these tiny wasps. But the precision with which the rodent had chiseled out the larvae made one thing clear. The squirrels weren’t eating the galls. They knew exactly where the protein-rich wasp larvae were ensconced in the gall, and they extracted them with the delicacy of a Frenchman forking escargot. It takes a lot of work to make a meal of gall wasp larvae, but in the fall when squirrels are gorging themselves on acorns, maybe the added protein is needed.

This blog was prompted by a 2-year old observation rather than a recent photo, and you, dear reader, are probably wondering what does this have to do with camera trapping? Well, it was an excuse for the codger to use the "tree-hugger", a contraption built by my good neighbor Richard. The "tree hugger" allows me to set the camera trap in trees (which I intend to use for screech owls and cavity nesting birds--so stay tuned).

As for gourmet squirrels, the one seen here wasn’t particularly thrilled with the peanut butter I smeared on the stub. Like a lot of Californians, it probably prefers more exotic sources of protein.

No comments: