UPLAND WILDLIFE HABITAT MANAGEMENT– BIRD BOXES CONSERVATION PRACTICE JOB

Definition:

Bird Boxes are used to supplement nesting sites for cavity nesting birds around wetlands and grasslands that lack cavity trees for nesting.

NRCS-NH is targeting two species in decline which respond particularly well to bird boxes, American Kestrels and Purple Martins. Also, boxes for wood ducks, blue birds and other cavity nesting birds are available.

Program Notes:

Up to 10 bird boxes per landowner allowed.

Considerations:

• houses mounted on metal poles are less vulnerable to predators than houses nailed to tree trunks or hung from tree limbs.

• use no more than four small nest boxes for any one species or one large box per acre.

• don't put bird houses near bird feeders.

• don't put more than one box in a tree, unless the tree is extremely large or the boxes are for different species.

• Place boxes at least 100 yards apart.

• if you have very hot summers, face the entrance holes of your boxes north or east to avoid overheating the box.

With the exception of purple martins, cavity-nesting birds prefer not to share a house.

Accessibility

Bird houses should be placed in easily accessible areas so you can see how your birds are doing and clean out the house each year each spring.

If you clean out your nest boxes after each brood has fledged, several pairs may use the nest throughout the summer. Many cavity nesting birds will not nest again in a box full of old nesting

Ventilation and Drainage

Drill ¼ inch holes in the floor for drainage and just under the roof for ventilation. A roof with sufficient slope and overhang offers some protection. Drilling the entrance hole on an upward slant may also help keep the water out.

American Kestrel

Kestrel boxes have been shown to seriously increase the number of nesting kestrel pairs in an area. Here are some suggestions:

• Nest boxes should be placed in open fields, meadows or along hedgerows next to open areas. A grassy habitat should be near the box so kestrels can use it for hunting.

• Kestrel nest boxes should be firmly attached to a support structure, such as an isolated tree or post, 12 to 30 feet above the ground and spaced at least half a mile apart.

• The support structure should have a sheet of aluminum secured around it to prevent squirrels from climbing and using the box.

• Place 2 to 3 inches of sawdust in the bottom of the nest box.

• Boxes should be installed no later than March 1st, to allow kestrels to find nest sites when first returning north.

• Clean out the kestrel box after each nesting season and replace the wood shavings for next season's nesting pair.

Above a typical bird box design for American Kestrels.

Purple Martins

Purple Martins are endangered in New Hampshire and these boxes are only appropriate in areas with known nesting sites.

You have the best chance of attracting martins if you put a house on the edge of a pond or river, surrounded by a field or lawn. Martins need a radius of about 40 feet of unobstructed flying space around their houses.

Before you decide on a house, take the time to think about what kind of pole you're going to put it on. Martins will occupy a house that's between ten and twenty feet off the ground. Some poles are less cumbersome than others.

Light-weight aluminum houses can be mounted on telescoping poles, providing easy access for maintenance and inspection. Because of their weight (well over 30 pounds), wood houses cannot be mounted on easy-access telescoping poles.

Discourage House Sparrows from nesting in Martin boxes and this is aided by most models which have doors which can be closed until late April for Martins in New Hampshire.

Duck Boxes

from www.woodducksociety.com

Background: Wood duck hens evolved to nest in natural tree cavities. A recent study showed that only about 20% of such nests successfully hatched. Failed nests and dead hens were mostly due to raccoon predation. While it seems natural to mount nest boxes on a tree, it is difficult to protect them from climbing predators. On the other hand, it’s simple to exclude these predators if the box is mounted on a pole and protected with an effective predator guard. Hens readily accept these set-ups, giving them a great chance to be successful. Studies have shown that hens actually prefer low-mounted boxes. Higher is NOT better.

Poles and construction details: Eight-foot treated landscape timbers, flat on two sides, work well and are cheap. Using a post hole digger, carve a hole two feet deep. Place pole, then tamp dirt firmly around its base. You now have a “tree” right where you want it. Bolt the box to the pole so the entrance hole is six feet from the ground. If discarded stop sign poles are available from the local highway department, pole placement is even easier and can be done in wet areas. Bolt two 40 degree angled support brackets (use lock washers) to the pole below the box, then wrap a three foot diameter sheet metal cone guard over them. The lip of the cone should be at least three feet from the ground. A Vise-Grip pliers will hold the overlapped edges of the cone in position. Using a portable drill, affix small carriage bolts or screws through both edges. Then bolt cone (lock washers) to the brackets. Paint the cone an earth-tone color.

Placement: Ideally, choose a site near a wooded area and close to a clean wetland with a strong aquatic insect population. Both the egg-laying hen and her ducklings require a diet rich in aquatic invertebrates. Face the hole toward flight lanes or an adjacent wetland. If you live near good habitat, angle the box  so you can see part of the hole from your breakfast window. Squirrels can leap eight feet horizontally from tree trunks, and drop eleven feet from overhanging limbs, so plan accordingly.

Heat: Pole-mounted boxes are seldom in complete shade. Boxes made of metal, insulated plastic, and even plywood, when exposed to direct sunlight on hot June days, can become way too hot for the hen and her eggs. White paint and vent holes help, but it’s better to choose boxes built with natural wood. Wooden boxes have been shown to be the best at resisting heat build-up.

Job Sheet –Upland Wildlife Management 645

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