By Mark Sasser, Nongame Wildlife Coordinator, Division of Wildlife and Freshwater Fisheries

Ideally, bird nest boxes should have been cleaned and repaired by the end of February, well before nesting season begins. But it’s not too late! Many birds still have not begun new nests, but you don’t have any time to waste. So gather up your screwdriver, hammer, screws and nails, pruning shears, a stiff wire brush, petroleum jelly, and gloves and get started right away.
As soon as possible begin cleaning and repairing all the bird boxes in your yard. Start by opening your box and removing old nesting materials from last year. If you did this at the end of the nesting season last year, check it again. Your box may be full of cobwebs, a flying squirrel nest, old wasp nests, or dirt dauber nests. In fact, it may have bird droppings inside because some birds use the boxes during the fall and winter for nighttime roosts, especially during inclement weather.
Once old material has been removed, scrape out any old droppings or other stuck-on residue with a stiff-bristled brush. Make certain holes in the bottom are unclogged for proper drainage. A great way to prevent wasps from building nests in the top of your bird box is to apply a thin coating of petroleum jelly to the inside top of the box where they like to hang their nests. This will prevent adhesion of new nests and will discourage attempts by wasps to colonize the box.
Repairs are the next order of business. If much of the wood is rotted, then outright replacement of the entire box may be necessary. Otherwise replace sides, tops, or bottoms as needed. Check the post and attachment site as well and repair or replace as necessary.
It is highly recommended to place a predator guard to prevent snakes, cats, raccoons and other varmints from making a meal of baby birds. Boxes are most predator-proof when placed on a metal pole. If your bird house is on a wood pole or tree, place several feet of metal flashing around the base. Overhead limbs can be a problem. Prune away any limbs, vines or other vegetation from around the box that might help a climbing predator gain access to the box.
Gray squirrels and flying squirrels will enlarge entrance holes. If this has happened, metal flashing can be added around the entrance to keep them from gnawing. Did you raise English sparrows or starlings last year? Hole dimensions can be modified to discourage starlings by making the holes smaller than one and one-half inches in diameter. Slot entrances can be used to deter English sparrows. An important thing to remember is that perches are not necessary on the outside of boxes. Perches encourage such undesirable birds as English sparrows and starlings, which can stand on the perches and kill and remove any bluebird adults, babies, or eggs inside.
To thwart blowflies, put one-half inch hardware cloth in the bottom of the box to raise the nest off of the floor so the larvae will fall through. Were ants a problem last year? If so, coat poles with petroleum jelly, or if you have hung a wren house, coat the string or wire with petroleum jelly.
Last but not least, don"t raise birds to feed your cat. Put bells on your cat's collar (two work better than one) or better yet, keep your cat inside!
For more information, contact Mark Sasser, Wildlife and Freshwater Fisheries Division, 64 North Union Street, Montgomery, AL 36130, 334-242-3469 or email