Sap tree feeding preference by Yellow-bellied Sapsuckers (Sphyrapicus varius) based on tree size and species in Cheboygan County, northern lower Michigan.

Abstract

To test for preference in choice of sap trees, the area surrounding an active Yellow-bellied Sapsucker (Sphyrapicus varius) nest was surveyed using four randomly selected 20 x 20m plots at the University of Michigan Biological Station in Cheboygan County, Michigan (45 33'30.370""N, 84 40'27.516""W, T37N,R3W,Sec.33). In each plot, all trees >20cm diameter at breast height were measured, identified to the species, and classified as either non-feeding trees or sapsucker trees, indicated by several rows of holes in the tree bark. The range of dbh of feeding trees was 42cm to 161cm. Diameter at breast height data collected were insufficient for conclusions about effects of tree size on sap tree choice by sapsuckers. Eight of the eleven feeding trees were Scotch Pine (Pinus Sylvestris), and the other three were a Jack Pine (P. resinosa), and a Paper Birch (Betula papyrifera). A coefficient of concordance test (Kendall and Smith 1939) suggested that Yellow-bellied Sapsuckers do not select feeding tree species based on relative abundance (W=19.3636, df=9, X2(approx)=3.33, p<0.05). The preference of sapsuckers for certain species of trees may provide information about their related food webs and communities.