Within the past two weeks you may have noticed the arrival of robins.

Last Thursday I had nine at one time in my yard as they hunted for worms. They’re arrival in the beginning of March signals the time to prepare nest boxes for a variety of nesting birds ranging from wrens and bluebirds to screech owls.

As such and if you haven’t already done so in the fall, now’s the time to clean out or repair existing bird houses for the nesting season and perhaps plan for new additions that can be made or purchased from a hardware or birding store or the Pennsylvania Game Commission (PGC).

If you decide to build your own, it’s necessary, says the PGC, to provide the right size of bird house for the bird(s) you wish to attract. The trick, they say, is to provide a bird house that will permit birds from the size of wrens to bluebirds to enter the hole in the bird house. But it should be small enough to exclude large birds like starlings and House Sparrows. The latter two are non-native species that aggressively compete with and exclude native birds from natural cavities. Henceforth, providing a nest or bird house with the smallest possible opening will permit wrens, chickadees and bluebirds inside.

Predation, says the PGC, is an even bigger concern so it’s important that nest boxes are protected from raccoons, squirrels, chipmunks, snakes and other nest robbers.

Installing a birdhouse is equally important as selecting the right size. Installing a nest box in the right backyard habitat or field habitat will dictate what species you’d like to attract. Placing a nest box for bluebirds on the edge of bushes or overgrown trees won’t attract bluebirds - but it will attract wrens.

As for the beautiful bluebirds, they’re early nesters so now is the time to erect one and clean an existing one.

If it’s a new one, the PGC recommends placing a nest box on a pole 3 to 5 feet above ground and facing south if possible, and facing a nearby tree or fence where young birds can safely land on their initial flights from the box. To reduce predation and competition from other species, no perch should be placed on the box; bluebirds don’t need one.

If you don’t have the inclination to build a box, the PGC’s Howard Nursery builds and sells next boxes for bluebirds and other nesting boxes. A single box sells for $14.84 including tax and when purchasing two or more boxes, the cost is $12.72 including tax. Locally, they’re available at the PGC’s Southeast Regional Office at 253 Snyder Road, Reading 19605 (located a short distance off Route 222 outside Blandon), or other regional offices or PGC headquarters in Harrisburg. The boxes are also sold as kits that can be home assembled.

A brochure of the PGC’s bluebird nesting boxes and other nesting boxes is available online by navigating to the Howard Nursery page at www.pgc.pa.gov.