Birds and Greens

The pine siskins have really become a problem.  They've taken a liking to my beet greens and chard and are destroying them.  First it was the small ones, so I covered them.  But now they have discovered the mature chard plants and have been eating them.  So the big ones are now caged as well.  I hate the covers, but I'm not willing to lose my crop.

So far they have not bothered any of the other greens, such as the spinach, kale, and lettuce.