Late this spring, my dad pointed out a line of small holes evenly spaced circumferentially on a large grapefruit branch in his backyard.  The tree is very large, looks healthy and is a prolific producer of sweet white grapefruit.  The branch also appears healthy with glossy green leaves.  My first guess was a bird, maybe some kind of woodpecker, but the only birds that seem to frequent the area are blue jays, mourning doves, hummingbirds, the occasional hawk and a rare black phoebe.  There are no bird nests anywhere to be seen.  I have never seen or even heard a woodpecker in or near their home.  Who or what is the culprit?

My dad did his own research and thought it might be the work of a yellow-bellied sapsucker.  The problem with that conclusion is that yellow-bellied sapsuckers live, work and breed in the Eastern and Southern US.  With a little more digging, I think the perpetrator is a red-breasted sapsucker. 

According to the Cornell University's All About Birds website, red-breasted sapsuckers spend their winters in much of California.  For the rest of the year they prefer the coastal areas of Oregon, Washington and Western Canada typically residing in pine or hemlock forests.  They will live in orchards as well.  Years ago, they were shot by farmers who were losing some fruit and trees to the birds.  Today to kill a woodpecker, a permit from the US Fish and Wildlife Service is required.  Red-breasted sapsuckers eat sap. Sap has a fair amount of sugar that the birds use for energy.  They also will eat bugs and fruit and seeds. To get to the tree sap, the birds drill a shallow hole in the tree bark and then use their brush-tipped tongues to lap it up.  The small holes created by the birds can attract tree insects - more food for the birds.  Over time enough sap could be potentially lost to create a weakened tree limb or tree. 

UC Davis IPM recommends wrapping wire mesh like chicken wire around the tree branches and trunk where the holes are leaving about a 3-inch gap between the wire and the tree so the bird can't reach its intended targets, but know that the birds will likely migrate to another branch and start anew.  Twirling hangers, aluminum foil balls or old CDs can be hung on the tree to scare off the bird, but if that bird really wants that tree's sap, it probably won't work.  Commercial bird repellents also haven't leant much success either.  They can harm the tree and they can harm the bird by coating its feathers.  It's recommended that excluding the birds sooner rather than later is the best management.  Vigilance is key!  It would help if someone actually saw or heard the bird.  Maybe it's a good thing that that hawk has been hanging around.