Birdhouse basics

Spring is almost here and in this part of the world, February is an important time to think about birdhouses. February is when birds begin courting and looking for nesting places. Having a bird nest and raise its chicks in your yard is very gratifying for wildlife gardeners. Now is the time to install bird houses and to do seasonal maintenance on them (see below).

Although it is fun to see birds nest in your yard, there are many things to consider before hanging a birdhouse. Know what species of bird you want to attract and have reasonable expectations. Birdhouse need to be designed for a specific bird species to be successful and to not foster exotic, invasive species (like European starlings and house sparrows in much of North America, including Missoula). Generic bird houses that are sold all over actually encourage nesting by exotic birds, and this make life harder for our native birds. These houses infuriate me because people buy them thinking they are going to help native birds. Actually, the opposite is true.

Here I describe houses and pertinent information for four common, easy to attract species in the Missoula area: red-breasted nuthatches, black-capped chickadees, house wrens and northern flickers. Where I live these can all be enticed to use nest boxes in your yard. Even in our small lot, we have often have chickadees, nuthatches and flickers nesting simultaneously. Although this information is tailored toward Missoula, I suspect that this information may be appropriate to a lot of wildlife gardeners.

Nest boxes
All four of these species are cavity nesters (that is, they nest in hollow spaces in dead trees), so they require box-like houses that simulate tree cavities. The reason I encourage people to cater toward cavity nesters is that these birds are having a tough time, from habitat loss, loss of snags (nesting sites), to competition from invasive birds (typically secondary cavity nesters). Chickadees, nuthatches, and northern flickers prefer to excavate the cavity themselves, because this assures a clean home free of pests and predators (see video below, I find this adorable). House wrens, on the other hand, will only use empty boxes.

Plans for a chickadee, nuthatch or wren box are identical and northern flicker boxes are much larger. Here is a link for nest boxes for both houses.

Unless you live near a large expanse of open space or prairie or see bluebirds regularly, I do not recommend you build and install bluebird boxes. More often than not these get used by European starlings and house sparrows. Again, it is really important to know what birds you are targeting and have realistic expectations.

Although northern flickers are common, they are declining across much of their range. Northern flickers are incredibly important species since they are the largest, most abundant primary excavator and they occupy a wide variety of habitats. The ability of flickers to create cavities is crucial for the survival of many other secondary cavity nesting birds. Birds that use abandoned flicker nests range from chickadees to American kestrels.

A nest box for chickadee sized box has an opening that is 1 1/8” diameter- an opening bigger than that will encourage starlings and house sparrows. Do not use a perch for any of thee species- they do not need them. In addition, perches encourage exotic birds, and since few native birds need them there is no reason for a perch.

Chickadees, nuthatches and wrens will add nesting material for their nest. Chickadees use animal hair, fur, and moss. Nuthatches will shred up bark into various layers of increasingly soft bedding, and they also smear sap on the outside of the hole to discourage insects and parasites from bothering the nestlings. It is really fun to watch them do this. You can help chickadees by providing fur (see picture below- one of the best uses for a squirrel, more about squirrels in a post to follow), animal hair or sphagnum moss in your yard for them.

Flickers will nearly completely remove all the wood chips for the box and they do not require any nesting material. Another benefit to having he house filled, is that is discourages use by non target birds like house sparrows and starlings, which will not excavate. However, once the flickers excavate their nest box, often European starlings will follow. It is crucial to remove the starlings, their nests (they bring in nesting material), or otherwise dissuade them from taking the flicker’s nest box.

General box information

• I recommend using western red cedar for the box construction, a naturally decay- and insect-resistant wood, which needs no protection from the weather it should last for many years. Fill and pack it with fine wood chips or coarse saw dust each year. I fill my boxes with Douglas fir (typically chips from my thickness planer), but you can use any species except cedar, teak, or mahogany. These species contain oils that prevent rot and insect damage but the dust can irritate nestlings.
• Place the box from 6- 15’ from the ground and face the hole away from prevailing winds and weather (usually east).
• Place the house in an area where you can easily observe it.
• Install the house by February, but the earlier the better- you will be amazed how quickly birds discover it and return to it.
• Clean out the box after the breeding season. A good time to do that is in early fall. I like to leave the box empty in the winter- birds will use them as winter roosts.
  

Nest box selection times
Red-breasted nuthatches are the first to begin excavating their selected box- they begin excavating in early to mid February (between February 5 and 21 at my house) and they are usually complete by the first week of April (April 1-9) when they begin to fill their boxes with nesting material.

Black-capped chickadees start excavating about a month after nuthatches, with peak excavating around first week of April (from March 25- April 4), until middle April when they bring in nesting material (April 11-15).

Northern flickers are on a similar schedule as chickadees and they begin excavating in late March – early April (March 24-April 8), but they search for nesting locations in February and may do some exploratory excavating as early as the beginning of February.