PARENT SESSION
Poster Session #43: Avian Ecology.
Thursday, August 9, 2001. Presentation from 3:30 PM to 5:00 PM. Exhibition Hall

A test of pitch production in Pinus species used by Yellow-bellied sapsuckers (Sphyrapicus varius) in Northwest Indiana.

Eberhardt, Laurie¹, Dowling, Matthew¹, ¹

ABSTRACT- Pitch, a secondary exudate, may be produced when Yellow-bellied sapsuckers penetrate the bark of pines to obtain sap. On the campus of Valparaiso University in Northwest Indiana, sapsuckers prefer feeding from black pines (Pinus nigra) over red (Pinus resinosa), white (Pinus strobus), and scotch pines (Pinus sylvestris). To test if pitch production could explain feeding preferences, we collected pitch from artificial feeding holes in each of four pine species. We hypothesized that sapsuckers would prefer trees that produce less pitch at a slower rate. Latency to first pitch flow and rate of pitch production were measured during the fall migration of the sapsuckers. The black pine produced significantly more pitch than the other three species (ANOVA, p=0.0005 ,with average rates of black; 0.082g/h, white; 0.012g/h, red; 0.008g/h, and scotch; 0.02g/h). White pine had significantly longer latencies to first pitch production for the trees that produced pitch during the experiment (ANOVA, p<0.0001, with average rates of black; 4.5h, white; 31.9h, red; 2.2h, scotch; 2.6h). Thus, pitch production does not explain feeding preference, because the preferred black pines produced the most pitch, and the least preferred white pines had the longest latencies. Possible explanations for the variation in pitch production include influences of tree health, seasonal changes in pitch production, and tree microhabitat.

KEY WORDS: Sphyrapicus varius, Pinus, pitch, sap