Detection of sap accumulation in the paper birch (Betula papyrifera) by the Yellow-Bellied Sapsucker (Sphyrapicus varius)

Project Overview
Project Abstract: 
The Yellow-Bellied Sapsucker, Sphyrapicus varius, is a double keystone species, which plays an important role in the mixed hardwood forest and boreal forest of North America by providing cavities, as well as feeding sites, for many other organisms in the forest. S. varius feed on tree sap as a primary source of food, and has a strong preference for the sap of the paper birch, Betula papyrifera. It has been suggested that S. varius farm their own sap by girdling the phloem of the trees in which it feeds on, and later on it can detect sap accumulation due to the previous girdling. In this study we determined that S. varius was able to detect sap accumulation due to changes in its foraging behavior. The yellow-bellied sapsuckers made their feeding sites, or sapwells, above artificial girds on B. papyrifera trees, at significant lower heights than previously reported.
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