This Squirrel Is Either Blind Or Has Brass Balls

I came around the corner the other day to find this scene, a squirrel nosing around for stray bird-feeder seeds on my patio as a sharp-shinned hawk watched from the patio fence. The squirrel is bigger prey than could be handled by a sharpy, America's smallest hawk. But ... a chance worth taking? I say no.

A few moments later, the hawk turned around and plunged into the holly bush on the other side of the fence, sending sparrows scattering. It came up empty, but returned a few minutes later to make another dive. The more you pay attention to wildlife, the more it ruins your preconceived notions - I'd assumed hawks were only maneuverable in open air, but turns out they're adept at chasing down birds in dense brush.

This is now the third time I've seen a sharpy in my backyard. Looks like I've got great sharpy habitat:

The population of USA and Canada has rebounded since and might even exceed historical numbers today. This is probably due to the combination of the ban on DDT and the proliferation of backyard birdfeeders in North America which create unnaturally reliable and easy prey for all Accipiters.

Think I can train the hawk to catch only invasive sparrows & starlings while leaving the cardinals, wrens and other natives alone?