> In Austin, many bike racks also are coated in bird poop, though I'm not sure what can be done about this aside from regularly cleaning the racks. I never ran into this problem anywhere else.

Presumably because the racks are underneath trees or shade (which the grackles also like) to avoid baking your bike in the sun.

Austin gets really hot in the summer and non-reflective surfaces can get hot enough to impart burns.