Investigating factors that set the lower elevational limit of Canada jays (Perisoreus canadensis) on Vancouver Island

The biotic and abiotic factors responsible for determining ranges of most species are poorly understood. Canada jay (Perisoreus canadensis Linnaeus, 1766) relies on perishable cached food over-winter survival late-winter breeding the persistence could be a driver range limits. We confirmed that jay’s lower elevational limit Vancouver Island, British Columbia, matches subalpine zone (900 m) then conducted simulated caching experiments to examine influence antimicrobial properties tree (biotic) temperature (abiotic) preservation food. found two high-elevation species, Yellow cedar (Callitropsis nootkatensis D. Don, D.P. Little) Amabilis fir (Abies amabilis Douglas ex J. Forbes) preserved blueberries chicken flesh better than other trees but they also occurred well below jays. effect was similarly unclear; while at 1150 m retained 17 % more mass 550 m, there no difference in percent remaining placed 70 above, versus 120 below, Jay limit. Thus we were unable provide definitive evidence either proposed or setting resident