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Nature's Way

turtlePond Turtles See Their Shadow

By Lakin Khan

Not all days in February were rainy and cold. In the way that fall will have an Indian Summer, this year, we had a false spring. For a week, the days were unseasonably, spookily warm. The balmy weather hustled the cherries and plums into blossom, pulled the daffodils and narcissus up out of the damp earth, exploded the acacia trees into vibrant bloom, big yellow pollen bombs detonating across Sonoma County.

One could have a worse lunch break than lingering by the pond, watching turtles haul themselves patiently and methodically up the slant of the concrete bank to bask in the unexpectedly warm mid-day sun. The first day out, I spotted 10 larger turtles and two young turtles. One of the elders carried drapes of dark, slimy algae over most of carapace, like a tattered nightgown. I can only guess that it had only recently pried itself from the bottom of the pond after a long nap.

These creatures are slow on the ascent, scrabbling for purchase with their pointed claws in the tiny nicks of the concrete. But when disturbed, they can turn, tuck up their legs and slide back into the pond like tobogganers on a short slope where they float just under the surface of the water. Only their pointed little noses poke out, tiny triangles and vague dark blobs cruising about, waiting for the coast to clear.

With binoculars, a guidebook and some patience over the next few days, I identified a few Western Pond turtles and many Red-eared Sliders. The Western Pond turtles (Clemmys marmarota) are the native creatures; in fact the species is the only freshwater turtle along our Pacific west coast. They are drab creatures, with a dull, murky brown carapace (top shell), though the plastron (bottom shell) is an attractive yellow.

The chin, neck, legs and tail can sport varying amounts of yellow stripes and specks, but in general this is a creature that is quite invisible in the muddy California streams it favors, blending into the leaf litter of the creek banks where the mother lays her clutch of eggs, sometimes quite a distance away from the home pond. This turtle is noted for its land wandering, sometimes traveling miles away from home base for reasons not quite known to turtle experts (Homo herpetologi).

The Western Pond turtle ranges in a band from British Columbia to Baja California, generally west of the Sierras. It is a creature threatened not only from loss of nesting and basking habitat as creeks are diverted, covered over, banked in concrete, with ponds and wetlands drained. it is also losing ground to the invasive Red-eared Slider, the ubiquitous dime-store pet of yore, so often released to nearby streams and ponds when it outgrew its plastic turtle house and usually its young owner's fancy.

The Red-eared Slider (Trachemys scripta elegans) is the gaudier, more flamboyant of the two, easily distinguished by the red smear that runs from behind the eye sockets down the neck, like excessively applied scarlet eye makeup the morning after. With whorls of a pale yellow in the squares of the carapace, it stands in stark contrast to the more plebian, muted mien of the Western Pond turtle. The Red-eared Slider has now earned the distinction of having one of the widest distributions of all turtles. Thanks to humans who release them when they are tired of them as "pets," it is found in every state of the U.S. and on several continents: Europe, Africa and Australia. These are aggressive niche monopolizers and prolific breeders. They tilt the balance of the ecosystem where ever they land; the shyer Western Pond turtles are retreating before the Slider’s onslaught.

Above, Western Pond turtle at Fairfield Osborn Preserve can also be found in the lakes area of the campus. (Photo by Linnea Mullins)

E-mail our amateur campus naturalist with any observations, stories or column ideas about our shared environment with the natural world on campus. Khan is an administrative coordinator in the biology department and can be reached at lakin.khan@sonoma.edu.

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