Summer 2004 Resurveys of Kaibab Squirrel Plots on Walhalla Plateau, Grand Canyon National Park

Kearsley, Michael

Plots established by Dr. J.G. Hall in the early 1960s were revisited with two primary goals in mind. First, to document the presence of Kaibab squirrel activity, measured as terminal needle clusters from ponderosa pine trees and associated stripped subterminal twigs. Second to determine if there had been a change in the level of observed activity since surveys were done in 2001 and 2002. The data collected in 2004 showed no systematic change in the number of terminal needle clusters, the number of twigs, or the proportion of plots with these feeding signs in them since the surveys were re-started in 2001. The location of the feeding has shifted slightly; plots which had signs of feeding in 2001 and 2002 did not have sign in 2004 and sign was found in others in which no feeding had been evident in the previous two surveys. However, the overall level of occupancy and feeding activity (measured in this way) had not changed significantly since 2001. This led to the conclusion that there has not been a great deal of change in the abundance of squirrel feeding sign, and that these data support a view in which squirrel activity occurs in cycles which may vary spatially across the whole North Rim.