Mark Westlund: Critter-proof Your Home

If you're a California quail, you're facing tough times in the City. Your preferred habitat of native grasses and brush piles has been replaced by ice plant and ivy; your food sources are drying up; and your numbers have crashed from 1,500 at the turn of last century to 40 or 50 individuals today.

In fact, if it weren't for the SF Recreation and Park Department, the Audubon Society and a handful of dedicated volunteers who are working to restore quail-friendly habitat, the birds might be gone altogether.

If you're a raccoon, opossum, striped skunk or rat, however, you're probably living large.

These species do very well living in disturbed habitats and take advantage of all of the comforts that city and suburban living have to offer. They live, eat and raise their young right alongside of us.

They usually stay out of our way, but with winter on the way these animals could be looking for a warm place to stay ­ and may end up wanting to move in. An unused chimney, vacant attic or the crawlspace beneath a house can become a refuge of choice, and we're starting to get calls at SF Environment asking what to do.

Early prevention is best. We call it "wildproofing" and fall and early winter are the best times to start. Springtime litters have grown up, so you don't have to worry about evicting vulnerable baby animals or trapping them inside your attic where they would certainly die.

Raccoons favor attics and chimneys. Skunks and opossums prefer basements and beneath a structure's foundation. Rats can live anywhere.

If you heard little trilling sounds and lots of bumps in the night, you've got raccoons. Nibbled baseboards or door frames and elliptical droppings mean rats. Skunks, you'll smell first.

Tackle the obvious things first. Remove food sources and keep pet food inside, especially at night. Secure garbage can lids with bungee cords, or store them inside a garage or shed. Seal all gaps around plumbing pipes and electrical wires and make sure there's no room around heating or cooling vents. Lock all pet doors at night ­ or else you may get unwanted nocturnal visitors!

Limit access to your house by removing branches, trellises or fences that might provide natural ladders to your roof and chimney. Prune trees to six feet from the house ­ but wait until after October to keep from disturbing late-born litters of squirrels or birds.

Check the perimeter of the house for cracks and openings and keep your roof in good repair. It takes only half an inch for a rat to get in and four or five inches for a raccoon.

If you suspect a raccoon in your attic and you discover possible points of entry, sprinkle a light layer of flour around the suspected entrance in the late afternoon. Check it hourly after sunset to see if there are prints. Bring a broom or hose with you in case you happen to run into a raccoon ­ never corner or try to approach one.

Once you confirm the presence of an animal, place a bowl of ammonia or an ammonia-soaked rag by entryways after dark. The smell will drive animals away and give them the cover of night to find a new dwelling.

But be patient. When a mother raccoon moves, she may take all night. She needs to find a new home for the young ones, then bring them along. You can turn on bright lights and loud music to make things more unpleasant.

Do the flour test again to make sure animal is gone, then patch the holes.

If raccoons are in your chimney, place bowls of ammonia in the fireplace and block off the hearth so animals cannot enter your house. The ammonia smell will drive the animal out the top. If you've got baby raccoons, however, your only real choice is to have a professional remove them. This same flour/ammonia technique works to drive out skunks, opossums and rats, too.

Mark Westlund coordinates public outreach for SF Environment