Sap Wells
You've likely seen the work of the Yellow-bellied Sapsucker whether you know it or not. Sapsuckers make wells in trees to access sap. These wells form neat lines. Sometimes, many old wells on a tree can look like a natural pattern in the bark. Look at some local trees and see if you notice these wells.
Trees seal the wells like cuts in our skin heal over. Sapsuckers come back often to keep them clear. When they run, the wells create big wet patches on the bark. In warm weather, these patches help black, mildewy fungus grow. You may often see this on maple tree bark.
These pictures are of a maple tree I've been watching for the past several weeks. The Sapsuckers are keeping the wells clear and the sap running.
Sapsuckers do suck sap. But many others enjoy drinking from the wells. Squirrels, other bird species, and insects drink the sap too.
