Nest Boxes

Guidelines for being a good nest box landlord

It can be difficult for secondary cavity-nesting songbirds, such as Western Bluebirds and Tree Swallows, to find appropriate safe housing to raise their young. Competition from non-native species such as European Starlings and English House Sparrows, and the removal of dead and dying trees in Sonoma County have significantly reduced the number of potential nest sites and placed additional pressure on cavity-nesting species.

Offering artificial cavities in the form of nest boxes can be a useful resource for cavity-nesting songbirds. However, nest boxes can present substantial risks to the birds if the box is a poor design, installed incorrectly, or placed in an unsuitable location. Songbirds expend a tremendous amount of time, energy, and resources to rear their young. It is very important to take seriously the responsibility of offering nest boxes and ensure the highest probability of nesting success for the occupants. Here are some important guidelines to consider when offering a nest box to your songbird neighbors:

Box Design:

Only use nest boxes with a top or side that opens so that nests can be safely monitored, if needed, and cleaned out after nesting season is over.
To regulate temperatures in nest boxes, ensure the nest box has 1/4 to 1/2 inch wide ventilation slots at the top of the side walls (inadequate ventilation can cause the death of nestlings).
For additional relief from hot weather, make sure the roof extends 2.5-3" over the front of the box, and consider painting the roof or the entire box white to help deflect the sun.
Never install a perch on the front of a nest box as this provides predators such as jays easy access to nestlings and eggs in the box. Natural cavities do not have perches and cavity-nesting songbirds have the skills and anatomy to enter and exit their nest without a perch.
To attract desirable occupants, use boxes with appropriately sized entrance holes .
In areas with predator problems, attach Noel Predator Guards to nest box entrance holes to protect box occupants.

Placement:

To reduce competition and predation by House Sparrows, keep all nest boxes at least 100 yards away from cattle feed stations, feed lots, areas where poultry are fed, and bird feeders.
Do not install boxes in areas with free-roaming cats or areas with bird feeders that attract predatory birds, such as crows and jays. Each breeding season, our hospital receives many orphaned nestling bluebirds and other cavity-nesting songbirds whose parents were killed or injured by free-roaming cats, jays, and crows. These predators are keenly aware of the activity at nest boxes and attack parent birds as they're attempting to enter or exit their nest box while caring for their young.
Be aware of competition between species for boxes, as this can reduce nesting success, particularly between Western Bluebird and Tree Swallow and between House Wren and Bewick’s Wren. Boxes placed in pairs can alleviate competition between bluebirds and swallows. Consider removing at-risk boxes entirely if the problem continues.
Do not place boxes in areas where there will be disturbances such as sprinklers hitting the boxes, harsh invasive nighttime lighting shining into the box entrance, construction, brush clearing, or spraying of pesticides or other harmful substances. Vineyards, for example, are an undesirable location for nest boxes intended for songbirds.
Install boxes in locations that receive morning sun and afternoon shade or light shade all day. This is important as our summers in California are becoming hotter with an increased prevalence of extreme heat events. Placing boxes in full sun or afternoon sun locations is dangerous for nestlings and often leads to high mortality rates during extreme summer heat events.
Always secure boxes to predator-proof poles to prevent predators such as raccoons, rats, snakes, and free-roaming cats from climbing up to the nest box. Poles such as 8' metal t-post with a PVC pole “sleeve” placed over the pole (as pictured above) or a metal cone-shaped baffle at the top of the pole are effective in preventing predation of nestlings and eggs.
Never install boxes on fence posts, fences of any type, trees, or any type of substrate or structure that can be climbed by predators.

Need a nest box? Give us a call or send us an email. We often have nest boxes available for sale. Boxes are made by our volunteers and meet our guidelines for songbird-safe nest boxes.