While SweetPDZ bought me time in the infamous floods of 2003 that led up to the lawsuit to keep our birds, it did zero-zip-zilch for the compost, for the yards, and didn't do much other than slightly mask odor.
Pelletized gypsum is magic in a bag. If you have clay or hardpan soil, spread some on and water it in, come back in the morning with a shovel. Put it on your potatoes, too. It aerates the soil so that water drains more easily. Also good on dog spots to help combat the ammonia.
The birds pick it up and eat it, they don't gorge on it, they take what they need and then leave the rest just as they do with grit. It makes a big difference, and it's not harmful.
Menards, Home Depot, and most feed stores carry it in the lawn and garden section.