Wednesday, December 06, 2006
Nuthatches and Tools
Among birds, corvids (ravens, crows and jays) seem to get all the good press when it comes to social structure, intelligent behavior and tool use. Sure, they're pretty darn smart and probably deserve the limelight they get, but I'm going to stand behind nuthatches as birds that also behave in remarkable but little known ways.
For example, in response to squirrels climbing up nest trees toward a nest, incubating female Red-breasted Nuthatches will exit the cavity, perch near the entrance and begin a curious anti-predator display. They'll face downward at the squirrel, spread their wings, hold their body in a fixed position and begin swaying slowly in a rhythmic movement from side to side. In response to this hypnotic display, squirrels become motionless, fixate on the bird for several seconds and eventually retreat.
Occasionally following such encounters, both parent nuthatches will collect and smear conifer resin at the cavity entrance - up to one hour in one observation – to deter further confrontations with squirrels. Similarly, the White-breasted Nuthatch has been observed using a crushed beetle held in its bill, sweeping it around the outside of its nest cavity entrance. The beetles they use exude pungent oils that effectively deter squirrels from entering the cavity.
Other instances of veritable nuthatch tool use have been observed in the wild. In Arizona's Chiricahua Mountains, a Pygmy Nuthatch held a small twig in its bill and used it to pry up loose bark while working along a thick branch. Eventually it dropped the twig-probe and pecked at what it found. Also, Brown-headed Nuthatches are reported to use flakes of pine bark to pry up bark while searching for arthropods. Even a White-breasted Nuthatch was seen catching small invertebrates after using a bark flake to pry away loose bark. Once it had thoroughly worked the area, it dropped its bark tool and began exploring the dislodged fragments.
What about cooperative behavior? In defending a nesting site, a group of four nuthatches chased a Red-bellied Woodpecker and knocked it to the ground from a nearby snag. I recall a birder's humorous impression that Red-breasted Nuthatches reminded him of little fighter jets. Imagine a whole squadron of them coming after you with yenk-yenk-yenk-yenk!
All images © 2006 Mike McDowell