Balancing the cat equation.

Natalie Angiers of the NYTimes wonders about free-range felines.

Willow House typically has a dog and a mix of cats. The cats are hard on the local ecosystem; they poop in our garden beds and they hunt small game. Fledglings are the most vulnerable, and our yard has certainly seen a few nests but not too many fully reared birds.

We've had buntings, woodpeckers and sparrows attempt to raise families here. Mockingbirds are apparently smart enough to try elsewhere. I see very few lizards or snakes around; I suspect two of our cats keep the population low.

The studies that Ms Angiers points to could be reductionist folderol. But there is a mention that coyote predation on cats in habitat fragments does increase bird diversity.

As an individual element, the cat, the most abundant predator in North America, is out of balance. Here at Willow House, we appreciate our cats' mousing skills when they are inside. The goal is to modify cats' impact in the yard, where their poop is unwelcome in the garden beds of potatoes or carrots (pause and think on that for a moment) as is their predation on small beneficial vertibrates.

The problem isn't necessarily an excess of cat; it could be a lack of dog.

We let the dog run about in part of the yard. It has little to no interest in birds. It is very interested in cats; some felines it appears to want to play with, and others it appears it will tear them apart. The dog keeps rats away. The dog also scares off raccoons from nesting in the attic. I've watched our cats stand aside and let a raccoon wander through the yard, sampling produce, staring longingly at the chickens. The dog tolerates none of that.

We're doing a style of gardening that seriously limits the amount of fresh-turned earth that is so attractive to cats. To keep the poop out of the garden beds, we have a sandy litterbox. The cats clearly consider it a last resort.

Overall, biodiversity is high in this yard. Squirrels, jays, ravens, voles, mice, newts, lizards, woodpeckers, buntings, robins, possums, raccoons and humminbirds all make homes or wander through. Considering we're surrounded by asphalt and concrete it's sort of amazing.

Working a balancing act with the cats is part of the discovery.