"That male rat-a-tat-tat is the equivalent of saying 'hey, baby'"
In the corner of my Santa Fe backyard is a power line pole, a large, old, wooden post towering above the adjoining yards. For the past several mornings, I've been serenaded by little woodpeckers from that and other neighboring towers.
Woodpeckers serenading, you say? Well, yes. Although not known for melodious voices, many woodpeckers signal quite effectively by tattooing a beat on hollow tree trunks, house siding or gutters, or other suitably loud drums. Loud, rhythmic tapping has nothing to do with finding food. That male rat-a-tat-tat is the equivalent of saying "hey, baby" to others in the area: it declares territory to other males and sexual availability to females. Woodpeckers are very selective in choosing their drumming surface and return again and again to good spots; loudness and resonance are important. Woe be to the homeowner with a shed or house having a good drum.
With practice, woodpecker species can be identified by the cadence of the drumming. Like other bird song, there may be slight regional "accents" or variations but the careful listener will know who's out there!
For an example of telling two of our most common woodpeckers apart by their drumming visit here.