Among the most endearing bird species of the United States, chickadees (Poecile ssp.) cheerily chirp while searching trees and shrubs for food. Traditionally, chickadees have not been the most reliable birdhouse inhabitants -- but beginning in the 1990s, researchers began using new, tubular styles of nesting boxes. They're both easier to construct and more appealing to the birds.
Naturally, chickadees either excavate their own nests in rotted tree snags or take over old downy woodpecker (Picoides pubescens) cavities. Both sexes engage in the initial construction, but once the nest chamber is about 10 inches deep, the male stops helping, and the female builds a nest in the bottom of the cavity. The nest is cup-shaped and constructed from moss, grass and sticks -- they then add rabbit fur or some other soft material to line the cup.
Traditional Nest Boxes
Construct traditional chickadee nesting boxes out of unfinished 1-inch-by-6-inch pine or cedar boards. The boards for the front and each side should be about 12 inches long. The board for the back -- the mounting board -- should be about 2 inches longer than the front and sides to will allow for a slanted roof. Cut the bottom of the box so that it is about 7 inches long. The roof should be 8 or more inches long to provide an inch or more of overhang to help keep rain out of the entrance hole. Use small wood screws to attach the boards to each other. The entrance hole should be about 1 1/8 inch in diameter and placed about 1 to 2 inches below the roof.
Newfangled Nesting Tubes
Construct nesting tubes from 12-inch sections of 4-inch PVC pipe. Drill a 1 1/8 inch entrance hole 1 to 2 inches from the top of the tube. Make the interior of the pipe slightly rough, by using a rasp or sandpaper, to help the birds move in and out. Use a cap on each side of the tube to keep the nesting container dry. Use nontoxic spray paint to camouflage the white pipe. Always use earth tones -- if possible, paint the tube to match the color of the local trees.
Because of their excavating instincts, black-capped chickadees do not often use empty nesting boxes. Instead, they prefer to use nesting boxes with wood shavings inside. The shavings allow them to use these excavation instincts, which improve the chances that the chickadees will accept your nest boxes. Carolina chickadees (Poecile carolinensis) do not appear to be as finicky as black-capped chickadees (Poecile atricapillus) are, and will inhabit empty nest boxes.
Though they are adaptable, chickadees select alder (Alnus ssp.) and birch (Betula ssp.) trees more than most others. Chickadees do not care which cardinal direction the nest hole points, but they do prefer an unobstructed path to the nest hole. Though chickadees nest as high as 60 feet, you will have to install and tend to the nest box from time to time, so place the box between 4 and 10 feet high. Straps or bungee cords cause less damage to trees than screws and nails do. Be sure to adjust the straps at least once per year to avoid girdling the tree. While you can strap nesting tubes to a tree just like you would a nesting box, you can also attach them to a free-standing post.
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