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Naturalist’s Notebook: “Claim-Jumping” Red-breasted Sapsuckers

By John Schmitt
john schmitt examines sapsuckers in art and prose
Illustration by John Schmitt.

There seemed to be more sapsuckers than usual in the Tillie Creek Campground this winter, with Red-breasted and Red-naped sapsuckers being about equal in number, and one surprise Yellow-bellied Sapsucker.

Early on I began sketching the extremely variable tertial patterns, in order to identify individual sapsuckers and take a measure of their numbers and where they ranged in the campground woodlands. The tertial patterns proved nearly as reliable as fingerprints, and I was quickly able to identify every individual encountered and map out their movements.

I learned that some individuals are prone to focusing their foraging on a few closely spaced sets of trees, whereas others tend “trap-lines” of sap trees spread over distances up to 200 yards. This is a much greater distance than I had long thought a sapsucker would fly to work sap trees on the wintering grounds, and it occurred to me that I wasn’t observing as many sapsuckers as I had earlier thought, but just a few individuals visiting sap trees in far flung corners of the campground.

It also became apparent that sapsuckers are “claim jumpers”: typically I observed the same individuals tending their particular trees, but occasionally I encountered different individuals pilfering another bird’s sap wells. One blue oak hosted a regular Red-naped Sapsucker but had two different Red-breasted Sapsuckers that slipped in from time to time to sneak a sip. But if the “claim owner” returned and found a “claim jumper” at the wells, a furious, winding pursuit followed until the interloper fled.

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