Sap tree foraging preference of Yellow-bellied Sapsuckers, Sphyrapicus varius.

Abstract

Foraging preferences vary among avian species and multiple factors influence this preference including maximizing energy efficiency and utilizing the resources available over time (both seasonally and throughout successional periods). The Yellow-bellied Sapsucker, Sphyrapicus varius, is a woodpecker that forages by drilling wells into trees to obtain sap. The main objective of this study was to investigate if a relationship exists between foraging preference of Yellow-bellied Sapsuckers and the period of time in which foraging is observed. During Spring 2015, we examined and collected data on the foraging preference of sapsuckers at the University of Michigan Biological Station (UMBS). Our results indicated that foraging preference of sapsuckers differ significantly among tree species (χ28 = 22.19, p = 0.005). Upon comparing previous studies done at UMBS, a change in foraging preference of the Yellow-bellied Sapsucker appeared to correlate with the successional changes of the mixed hardwood forest. Previous studies have found that paper birch (Betula papyrifera), an early successional species was the primary foraged tree of the Yellow-bellied Sapsucker. However, based on our current results that were collected over 17 years later, their primary foraging preference has changed to red maple (Acer rubrum), a late successional species. Future analysis of sapsucker foraging preference could further investigate this trend.