Bird Watching: Cowbirds and Mourning Doves, 1 by Niere

Niere wrote:
Can anyone tell me if there is a way to discourage cowbirds and mourning doves from cleaning out my feeders? I'd rather not get rid of my hopper feeder as the cardinals love it, but the cowbirds and doves sure know how to go through seed! Any suggestions? I don't mind the cowbirds so much because I love their song and they're not there all the time but I feel as though the mourning doves have claimed my feeders as their own personal Trough and Brew and seem to have taken up permanent residency in the surrounding trees.

Here's a picture of my current feeder set-up (minus the hummingbird feeder that is hanging off the right side just out of view: