 Woodpeckers do their 
							damage by pecking into the bark of trees looking for 
							boring insects beneath the bark. They can hear the 
							critters moving around but usually cannot find them 
							with the first hole. So, they make one hole and then 
							move a little horizontally and make another one 
							until they are successful. That is why you will see 
							a serious of horizontal holes in the bark of trees 
							that are being bothered by woodpeckers.
Woodpeckers do their 
							damage by pecking into the bark of trees looking for 
							boring insects beneath the bark. They can hear the 
							critters moving around but usually cannot find them 
							with the first hole. So, they make one hole and then 
							move a little horizontally and make another one 
							until they are successful. That is why you will see 
							a serious of horizontal holes in the bark of trees 
							that are being bothered by woodpeckers.
							This is one of those situations where the woodpecker 
							damage is actually a secondary sign of a more 
							serious problem...namely 
							borers. The bird is only 
							interested in the tree if it has these insects 
							working inside it. So, the real problem is the borer 
							which is cutting tunnels in the wood of the tree.
See 
							Borer 
						Insects...