SHORT COMMUNICATIONS 
167 
benefit from increased sap flow on the sides of 
trees most exposed to sunlight during daylight 
hours at this latitude. 
Secondary benefits of increased sap flow may 
also exist. This species feeds primarily on sap, but 
they are also known to forage on insects that 
congregate near sap wells (Foster and Tate 1966, 
Tate 1973). Sapsucker foraging opportunities on 
arthropods may increase along with greater sap¬ 
foraging opportunities if insects are drawn to 
sunlight during the cooler days of early spring. 
However, there is little evidence supporting the idea 
that insects have a dominant role in orientation of 
sap wells, as other studies report few insects around 
wells during the winter months (Wilkins 2001); it 
has been suggested that sapsuckers may perceive 
insects in close proximity to sap wells as compet¬ 
itors rather than prey (Walters et al. 2002). 
My research indicated a pattern of southwestern 
sap well orientation, but other studies examining 
the distribution of sapsucker wells on tree boles 
found sap well orientation to be oriented to the 
north (Varner et al. 2006) or random (Wilkins 
2001). In the southern United States where these 
studies were conducted, sap flow may be less 
influenced by ambient temperature and tree 
exposure to wind may be greatly reduced. The 
significant southwest orientation of sap wells in 
this study, and lack thereof in other studies, may 
be a result of variation in solar angle, wind speed, 
and wind direction, in addition to physiological 
differences among tree species used by foraging 
sapsuckers. Future research regarding this topic 
should examine latitudinal variation in sap well 
orientation and the influence of tree physiology on 
sapsucker foraging behavior. 
ACKNOWLEDGMENTS 
I thank B. R. Smith and S. E. Delmott for assistance with 
data collection. I also thank R. B. Thomas and W. E. Jensen 
for the use of equipment and helpful discussions. C. E. Braun, 
h. D. Wilkins, and one anonymous reviewer provided helpful 
comments on an early draft of this manuscript. 
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