Less apparent are the strong head and neck muscles, the stiff tail and sharp claws that allow the woodpecker to shinny up and down saguaros as well as cottonwood and mesquite trees hammering away in search of insects. The bird’s keen hearing picks up the sound of insects chewing inside the plant and he pecks a hole to probe for the prey with his long tongue barbed on the end with bristles.
The omnivorous woodpecker will also eat fruits and flowers of desert plants, the eggs of other birds, hummingbird feeder syrup and dog food left out in suburban neighborhoods. People are often annoyed at the incessant rat-a-tat of woodpeckers hammering on chimney flashings or wooden sidings. This is simply the bird’s manner of declaring his territory.
Gila woodpeckers nest in the cavities they peck in the tissues of the saguaro between the skin and the woody ribs inside. The cactus produces sap that seals the wound and forms a smooth boot shaped cavity. The boot maintains a moderate temperature so the eggs and babies are insulated from the heat and safe from predators. After the woodpeckers move on elf owls, flycatchers, purple martins and starlings are new home candidates.
The gilded flicker also pecks cavity nests in saguaros, but these larger birds are thought to favor the topmost part of the cactus where the new growth is softer. The flicker hammers through the tender new ribs to the interior of the cactus for a roomier abode. This can inhibit the flow of water and nutrients to the top of the saguaro and may damage the plant. These two species of birds are responsible for all of the holes you see in saguaro cacti, as no other species has what it takes to build these desert centers.