Build a Winter Bird Roost

Photo courtesy: Shaw Creek Bird Supply

It is never to early to plan ahead; and, once again, I am blogging about our feathered friends.

Most people know that putting out a nest box will attract nesting birds in summer. But did you know that small birds often use these same boxes for shelter at night, particularly in winter? Sometimes more than a dozen birds will pile into a single box to conserve heat. But nest boxes are far from ideal for overnight roosting. They are usually too small for a group. Plus most birds need to perch or cling while roosting, but nest boxes have no perching surfaces inside.

You can help your backyard birds keep warm overnight with a specially designed roost box. Any backyard favorites that typically nest in boxes — bluebirds, chickadees, titmice, nuthatches and small woodpeckers — may seek refuge in it.

Roosting boxes differ from nest boxes in several important ways. A good roost box is designed to prevent the birds' body heat from escaping, so, unlike a nest box, it lacks ventilation holes. Also, its entrance hole is near the bottom of the box so the rising warmth doesn't escape.

Inside a roost box there are several perches made from small wooden dowels, staggered at different levels. In addition, the inside front and rear walls are roughened, scored, or covered with hardware cloth so that woodpeckers can cling to them. A hinged top allows easy access so you can clean the box.

An entrance hole about 5.1 cm (2 in) in diameter will admit most small birds, but to exclude aggressive starlings reduce the opening to about 3.8 cm (1.5 in). Larger woodland birds, such as flickers and screech-owls, need a 7.6 cm (3 in) entrance hole.

If you don't wish to purchase a roost box; and, would prefer to make one - here's the plans.

- Using 2 cm (0.8 in) board, cut one floor panel, one roof panel, two side panels, one back panel and one front panel. Assemble the pieces. The roosting box compartment is usually about 35 - 45 cm (13.8 - 17.7 in) wide, 40 - 50 cm (15.7 - 19.7 in) tall and 30 cm (11.8 in) deep, though the overall size is not important.

- Use screws instead of nails to make it easier to correct mistakes. 4 cm (1.6 in) coated flathead screws are best as they will allow you to open the hinged front panel. The pieces should also be held together with bond-fast glue.

- Make several perches out of dowel 0.7 cm (0.3 in) or 1 cm (0.4 in) in diameter, mounting the perches at varying heights in the box. Don't forget to stagger them in the roost or the birds will be eliminating on each other.

- Locate the entrance hole near the bottom of the front panel to stop heat from escaping as it rises. A box for each species is not necessary; one for smaller birds and another for somewhat larger ones will do. As with nesting boxes, different sized entrance holes will attract different species.

- make the box as airtight as possible with no drainage or ventilation holes.

- put hinges on the front rather than the top, so that the box can be cleaned easily and thoroughly when winter is over.

- a latch can be installed to keep the door shut.

- place the roosting box in a well-sheltered spot on the south side of building or large tree.

When summer arrives, close the box up or put it away to prevent sparrows and mice from moving in.

Via Shaw Creek Bird Supply and Canadian Wildlife Federation