Monday, February 15, 2010

Spring cleaning for the nest boxes

Spring is nearly here, though the calendar does not say it, and the groundhog evidently begs to differ. Nevertheless, some of the first signs of spring are apparent; black-capped chickadees are singing their lovey-dovey "cheeseburger"song, the smell of road-killed skunk (ahhh, spring), and a mourning dove in our yard today. Soon robins will be back, and spring will be here in earnest. Or not- it is February in Montana after all, but I digress. Anyway, I'll return to thoughts of spring...


February is an important time to think about birdhouses. The following post contains some information about nest boxes I wrote in a post about the same time last year "Bird house basics". 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.

Since I like to keep the nest boxes empty in the winter so many birds will use them as roosts in our yard as a way to escape the cold (see here). Now is the time to clean and refill the nest boxes and it is a fun annual rite of spring (that along with connecting my rain barrels to our downspoutsm,, but that will have to wait, a while). This year the added bonus are tiny cameras I am going to install and hopefully post pictures or streaming video to this blog. This also is the first item on my 2010 to do list I can cross off, and an exciting one.

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 (click here for more information). In our yard, red-breasted nuthatches, black-capped chickadees, and northern flickers are the ones we are most likely to attract. Since they are cavity nesters (that is, they nest in hollow spaces in dead trees), 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). Although chickadees, nuthatches, and northern flickers will nest in an empty box, they prefer to excavate the cavity themselves, because this assures a clean home free of pests and predators.

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. Yesterday (Feb 15), I watched as a pair started excavating.

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). But they investigate and start defending nest sites in February.

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.

As far as cleaning the boxes and refilling, below are some pictures from a chickadee box and flicker box. In the photo below, the lid on the nest box is opened to reveal the excavated cavity. Here you can see how they removed a lot of material, but still left many packed wood chips. This is why it is important to tightly compact the chips.

Here I removed the nest, and the portion of wood chips that covered the top of the nest, you can see they excavated about 1/2 of the box.Here is the nest removed form the box. Chickadees and nuthatches will add material for their nests. Whereas chickadees use animal hair, fur, and moss (this as I have mentioned is the best use for introduced squirrels), 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 ( for more information click here), animal hair or sphagnum moss in your yard for them. The nest is in two parts, a round egg area, and the base.Below are pictures of tree nests from past years, each are unique, based on the availability of nesting material, the age and experience of the builders, etc... They are all soft and adorable, though. You can even see a couple of eggs in one of the nests- this was from a the second clutch one year that evidently had poor germination (a little something for you gardeners).Here is the box cleaned out. This is a good time to inspect for any damage and do repairs. If there is any water penetrating into the box, fix the cause and let the box dry out before repacking. Although I build nest boxes from western red cedar, a naturally decay- and insect-resistant wood, which needs no protection from the weather, I fill my boxes with Douglas fir (typically chips from my thickness planer or jointer- see below), 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. It is important to compact the chips, and I just use a piece of wood to pound it into submission. By compacting the sawdust, the birds can excavate a cavity without the rest of the filling collapsing on them.Normally that is it, but this year, I got a birthday present from my wife...mini cameras! These are the Hawkeye nature cameras (this is not a paid product endorsement, unfortunately). I removed camera shield, to take up less space, I hope this is not a fatal flaw. In adding these cameras, I did not pack the wood chips to fill the box completely as you'll see. The first step is to mount the little bracket, and my only tip here is to mount it, so it is loose enough to be able to swivel the bracket to screw the camera to the bracket. Here is the camera installed in the chickadee nest box, notice the grove cut into the side for the wire to pass.
Below is my northern flicker nest bow, and one thing to notice is that flickers just about completely remove all the wood chips for the box and they do not require any nesting material. although they may use an empty box, one 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. Click here for more information about flickers and starlings.

Below, the camera installed in the flicker box. Plenty of roomHere is the completed, freshly refilled nest box with a camera, waiting to be excavated. If you look closely, you will see one of my own inventions on entrance hole- a Nesting Indicator Bar, also known as a "twig". I place these "twigs" in the entrance hole of all my nest boxes to monitor if birds are investigating the boxes. Kind of low-tech compared to the mini cameras.
Spring is near.

3 comments:

  1. Very cool... can't wait to see what happens.

    ReplyDelete
  2. How about an update, and some pictures of what happened in the nest.

    ReplyDelete