Easy-print Carolina Wren Nest Box

The bird

This is a simple bird house meant specifically for Carolina wrens, who tend to like open container-like spaces and are usually the ones trying to nest in absurd places like flower pots, mailboxes, toolboxes, or even old boots in your garage.  This design uses a wide, tall entrance to make it especially appealing to Carolina wrens.

 
A Carolina wren, and their range map

Besides nesting in funny places, these little birds are extremely loud for their size, eat lots of bugs, can be surprisingly nosy and comfortable around people, and often pair-bond while defending a territory year-round. They are as much cocky little goblin as they are songbird.

Carolina wrens often build several nests within their territory and may raise multiple broods across different nests during their February–August nesting season, so anytime before summer is a great time to put up a new house.

A few other birds may also find this suitable, especially birds that use ledges, shelves, or semi-open structures, such as Eastern phoebes, robins, house finches, or house wrens. But Carolina wrens are one of the few birds you can target pretty well with a specific birdhouse design.

Design

There are a lot of really cool birdhouse designs online, but many require assembly. That has given me some trouble when printing in ASA because of shrinkage. This design is meant to be extremely simple: it prints in one piece without supports and is ready to use as soon as it is done.

The roof slopes forward over a large open entrance, with just enough angle in the opening to print cleanly. The design also includes a robust integrated mounting backplate with a keyhole hanger, making it easy to hang from a screw. It can also be tied up with string if needed. Depending on how it is mounted, you may want to add a bit of double-sided tape, such as 3M VHB, to the lower back for extra stability.

The mounting backplate is a separate object in the model, so it is easy to remove if you have a custom mounting solution in mind.

The floor has a slight slope with a raised center, which helps direct any water toward the drainage holes. It also gives the bottom a bit of texture, which can help chicks get footing inside the box.

Use and Placement

Ideal mounting spots are somewhat sheltered, so house or shed overhangs are great. Carolina wrens are very comfortable around human structures and often tolerate more activity near the nest than many birds. They also like dense cover, so nearby trees and bushes are a plus. Mounting on trees or among bushes can work too, as long as the box is secure and predators such as cats, squirrels, raccoons, or snakes do not have easy access to the entrance.

The one thing to watch out for is wasps. They may find this type of sheltered open box appealing, so check it occasionally before birds move in and remove any tiny starter wasp nests early.