Why do pileated woodpeckers disappear during the summer?
They don't..The trees are in full leaf at that time of year, and the birds are less likely to be observed because of the heavy foliage.
What role does the Gila woodpecker have for the saguaro cactus?
One role that the Gila woodpecker [Melanerpes uropygialis] plays for the saguaro cactus [Carnegiea gigantea] is as pollinator. It's one of the major predators of the saguaro's large, edible, dark plum like fruits. In eating the fruit, it eliminates the seeds by which the saguaro naturally reproduces.
Another role is as predator. In a way, it doesn't matter how many saguaro fruits that that woodpecker eats. What's important is the elimination of the digested seeds. It's a natural way of insuring perpetuation of the saguaro species.
But the woodpecker affects another of the cactus' body parts other than the fruit. The woodpecker is known to drill holes into the stem, for nest building. The drilling and the nesting can be a problem, depending upon the extent of the damage.
I wouldn't necessarily say that they attack humans however, when a woodpecker is in a state in which it is being disturbed and, or it's attention is being drawn from what it's doing (pecking) then it might think of you as a target of which it may start to peck along with the tree.
What do white headed woodpecker eat?
This species diet is comprised mainly of insects. Insects it consumes include (but not limited too) ants, bark beetles, wood boring beetle larva, spruce budworm larva, other caterpillars, moths, crickets, and cicadas. During late summer, fall, and winter, the White-headed Woodpecker augments its diet with seeds of various pines, including sugar pine, Coulter pine, Jeffrey Pine, and ponderosa pine. It also feeds on the sap of ponderosa pine (and possibly other pines) during spring and prior to nesting. It will sometimes come to yards for suet.
How do you get the downy woodpecker to quit pecking on your trees?
Hang suet cakes in locations in the yard. The birds will go for that instead. But, they are doing you a favor by eating insects on your trees.