Woodpeckers focus on ultra-violet cues

By Dr. Larry Clark, NWRC Director, USDA APHIS Wildlife Services

Pileated woodpecker. ©Clint Turnage

Most birds are sensitive to near ultraviolet wavelengths and the level of UV reflectance has been shown to influence mate selection and foraging preferences in birds. Could that sensitivity be used to discourage woodpeckers from damaging telephone poles and other structures when excavating for nest sites or foraging?

To answer that quetion, researchers at the National Wildlife Research Center and the University of Missouri compared the foraging behavior of 21 wild-caught pileated woodpeckers (Hylatomus pileatus) for food hidden under UV-reflective and UV-absorptive surfaces.

They determined that pileated woodpeckers are visually sensitive to UV wavelengths with UV-absorptive substrates serving as useful foraging cues for the birds. Reducing the UV reflectance of decayed and sound wood didn’t alter the birds’ response, suggesting that a product that only alters substrate UV reflectance would be unlikely to deter or repel woodpeckers from manmade structures. However, products that pair a negative consequence with a UV cue could be useful in conditioning woodpecker avoidance of treated substrates.

This represents the first time UV sensitivity has been documented in the order Piciformes, which includes woodpeckers, barbets and toucans, said University of Missouri graduate student Sean O’Daniels.

The information will help take advantage of UV cues in the development and design of repellents to prevent woodpecker damage.

Wildlife Services is a Strategic Partner of The Wildlife Society.