Birdhouse Basics

A drake woodduck on top of a woodduck nest box in a Boise neighborhood.

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I’ve been hunting around for things to do while I recuperate from an anticipated surgery. My wife suggested that we move the recliner into the TV room and I could veg in front of the boobtube. I can think of a few documentaries and even a movie or two that I might enjoy so I didn’t discount the idea completely, but I hope to use the time a little better than that. With that in mind, I picked up a copy of Woodworking for Wildlife, something that combines two of my favorite hobbies.

As I thumbed through the book, I found a section of does and don’ts and this struck me as increasingly important. The assaults on our natural world are happening far faster than we can comprehend and when we try to do something positive, which we ALL should be doing, it is important to get it right and not create more harm than good. Here is an example of what I mean: using things like milk cartons for substitute bird houses may seem like a good idea and was once widely promoted. They are cheap and easy and we are reusing something that otherwise ends up in the trash. That sounds like a double win. However, these “nest boxes” can be death traps as the walls are not thick enough to provide insulation from the heat of the day and the chicks overheat and die quickly. So, using the milk jug or carton ends up with the exact opposite result, harming wildlife not helping it.

So, here are the things to do or avoid when building nest boxes and what to look for in purchased ones.

1.       Not all birds use or need nest boxes. Those that do use nest boxes have precise requirements for the boxes to be attractive, safe and effective for their nesting efforts.  Sometimes these specifications can be very specific.  Find acceptable plans at a reputable site such as Audubon or Cornell University’s All About Birds, or find a copy of the book I used, by Carrol L. Henderson.

2.       Make sure you get the hole size right. Different birds require different hole sizes. For instance, for mountain bluebirds, a hole size of 1 and 9/16 inches is perfect. Much bigger and competing birds, such as house sparrows and starlings, can get in.

3.       Do not include a perch. The bird doesn’t need it (I routinely watch mountain chickadees rocket through the umbrella hole in the middle of my glass picnic table). However, predators really like perches because it gives them a way to hold on while robbing the nest.

4.       Make sure there are drainage holes in the bottom and that the bottom is recessed up about half an inch. These two things help to keep the nest dry. A tightly built nest box can actually fill with water and drown the chicks.

5.       Do not apply finish to the inside of the box. Some finishes can be toxic to the birds. It is ok to apply a finish to the outside, though, and it will make the house last longer.

6.       Use wood that is at least 3/4 inch thick. Rough cut wood is usually an inch thick but it is hard to find. The last time I bought some, it turned out to be green and was difficult to work with. Also, never use pressure treated wood.

7.       Add striations to the inside of the box under the hole that chicks can climb up like a ladder.

Most populations of birds have decreased, often by 90 percent, in the past 50-70 years. It only makes sense to do whatever we can to help birds recover. We benefit as well, having more birds around to control bugs and to entertain us. However, it is essential to ensure that in our efforts to help, we don’t inadvertently do more harm, so paying attention to details is important.

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Help Idaho Wildlife

When we traveled across the state in October 2017, most of the vehicles we saw using the wildlife management areas did not have wildlife plates. Buying wildlife plates is a great way for non-hunters and hunters alike to support wildlife-based recreation like birding.

C'mon folks, let's help Idaho's wildlife by proudly buying and displaying a wildlife license plate on each of our vehicles! 

See below for information on Idaho plates. Most states have wildlife plates so if you live outside Idaho, check with your state's wildlife department or vehicle licensing division for availability of state wildlife plates where you live. 

And tell them that you heard about it from Nature-track.com!

Wildlife License Plates

Great news! as of 2024, there are three NEW designs for license plates. They still are bluebird, cutthroat trout and elk, but they are beautiful.

Idaho Wildlife license plates provide essential funding that benefits the great diversity of native plants and wildlife that are not hunted, fished or trapped—over 10,000 species or 98% of Idaho’s species diversity. Game species that share the same habitats (such as elk, deer, antelope, sage-grouse, salmon, trout) also benefit from these specialty plates.

No state tax dollars are provided for wildlife diversity, conservation education and recreation programs. Neither are any revenues from the sale of hunting or fishing licenses spent on nongame species. Instead, these species depend on direct donations, federal grants, fundraising initiatives—and the Idaho Wildlife license plates.

Both my vehicles have Bluebird Plates. I prefer the bluebird because the nongame program gets 70 percent of the money from bluebird plates, but only 60 percent of the money from elk and trout plates - 10 percent of the money from elk plates supports wildlife disease monitoring and testing programs (to benefit the livestock industry) and 10 percent from cutthroat plates supports non-motorized boat access.

Incidentally, in 2014, the Idaho Legislature denied the Department of Fish and Game the ability to add new plates or even to change the name of the elk and cutthroat plates (very specific) to wildlife and fish plates, a move that would have allowed for changing images occasionally and generating more revenue. It would seem that they believe that we Idahoans don't want a well funded wildlife program.

I think it is time we let the Legislature know that Idahoan support wildlife funding and that we would like to see these generic plates come to fruition.