Sunday, July 4, 2010


The first hint of something extraordinary is all the activity along the South Fork road, just below the bridge. A dozen Black-headed Grosbeaks forage on the ground and munch breakfast in the branches overhanging the road. Apache Fox Squirrels nestle in the sprays of leaves. Acorn Woodpeckers are very busy, doing what they do best. A big Silverleaf Oak––one of the biggest I've ever seen––has produced a bumper crop of tiny acorns, and word of the feast has spread.

Acorn of Silverleaf Oak (Photos by Narca)

Normally Silverleaves are shrubs or small trees, associated with Madrean Evergreen Woodland. This giant stands about 40 feet high, with its roots well-watered by the nearby spring. (Google tells me that the national champion is 85 feet high, so our South Fork champ is just a teenager!) Like other oaks of arid climes, the leaves are leathery to resist water loss. The name comes from the leaf's silvery, reflective underside.

Underside of Silverleaf Oak leaves

In a good year, many animals thrive on the acorn crop, and last winter's El NiƱo rains have brought on a true bounty of acorns. I tasted one and it wasn't bitter––the amount of tannin in acorns varies with both species and individuals. Native Americans harvested acorns, prizing the best-tasting (such as Emory Oak), and giving special treatments to those that were bitter from tannin. This particular tree's acorns must be especially good-tasting, to attract so much attention from diners, while the surrounding oaks are ignored, at least for the time being.

Acorn Woodpecker caching food
(Mixed media by Narca)

Acorns alone don't account for the feeding frenzy happening today near the South Fork bridge. There also must be plenty of insects in the vicinity of the spring. Flurries of flycatchers––Brown-crested and Dusky-capped, Sulphur-bellied, Western Wood-Pewees––add to the tumult, while a male Blue-throated Hummingbird squeaks from the top of the Silverleaf and a Painted Redstart tumbles from tree to tree. An Elegant Trogon still maintains his territory near the bridge. Plumbeous Vireos, Bridled Titmice, and Brown Creepers search for food for growing nestlings.

Ahh, South Fork. How good it is to walk here again!

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