Junior Trailblazers: Supporting Cavity-Nesting Birds

Attention, nature enthusiasts of all ages! Did you know that many of our feathered friends face a housing shortage? That's correct – many birds, referred to as "cavity nesters," rely on holes or cavities in trees for nesting. The best place to find these homes is in dead trees, known as snags, which can be hard to find.

An owl pokes their head out of a palm trunk. Photographed by Hari K Patibanda under the Creative Commons Attribution 2.0 Generic license.

In our Nature Preserves and Conservation parks, you might see many dead trees out in the forest. Do you think your neighborhood has as many? How many snags can you count on your street? Unfortunately, snags are usually completely removed in neighborhoods because it looks better, but birds need them! Woodpeckers hollow out cavities in these old trees, and those holes provide a secure place for birds of many species to nurture their young.

A snag near the street. Leaving some of the tree behind like this can benefit woodpeckers and other cavity nesters. Captured by John Salmon under the Creative Commons Attribution-Share Alike 2.0 Generic license.

So, how can we aid these winged inhabitants? We can create nest boxes that replicate the features of natural cavities in trees. Not all species will adapt to nest boxes, but for those that do, these artificial dwellings can significantly enhance their survival chances. So, let's dive into some practical tips for the perfect nest box.

You can buy premade nest boxes and paint them, or you can build them yourself, but firstly, it's crucial to understand the correct size and positioning of your nest box, which varies across bird species. Let's look at some guidelines for a few Hillsborough County bird species:

• Tufted titmice (Baeolophus bicolor) prefer nest boxes with a hole size of about 1.25 inches and placed 5 to 15 feet high, preferably within a wooded or shrubby area.
• Eastern bluebirds (Sialia sialis) enjoy nest boxes with a hole size of 1.5 inches and placed about 5 to 10 feet high, preferably near a somewhat open area with a tree or fence to perch upon.
• Red-bellied woodpeckers (Melanerpes carolinus) favor boxes with a hole size of approximately 2 inches and placed 12 to 20 feet high.
• Southeastern American kestrels (Flaco sparverius paulus) require a more substantial space, with a hole size of 3 inches and the box positioned at an impressive 10 to 30 feet high.

It's fascinating how different bird species have distinct preferences for their homes. But why do these specifics matter?

A cute little house wren. Captured by Rhododendrites under the Creative Commons Attribution-Share Alike 4.0 International license.

Each bird species has evolved to thrive in specific environments, including the exact type of nesting site that suits them best. The diameter of the hole directly influences which species will use the nest box. For example, a larger hole might allow a bigger, potentially predatory bird to enter the nest box, so smaller birds will avoid such a risk. Similarly, a hole that is too small would be unsuitable for larger species.

Height is another key factor. Some species are more adapted to living in the higher reaches of trees, while others are more comfortable closer to the ground. Therefore, placing nest boxes at different heights can attract a more diverse array of species. 

Lastly, the location of the nest box matters as well. Some birds prefer the safety of dense shrubbery, while others require the open air to spot incoming predators or to have enough room for their flight path. Careful positioning of your nest box can significantly improve the chances of it being adopted by a feathered family.

Mounting nest boxes on smooth poles can help prevent predation. Some birds also like being high up! Captured by J.S. Campbell, Jenmedia under the Creative Commons Attribution-Share Alike 4.0 International license.

By understanding these preferences and considerations, you can make your backyard a welcoming space for a variety of bird species. Your nest box not only provides essential shelter, but also contributes to local biodiversity, making it a winning project for everyone involved.

Maybe you’re looking to buy a nest box, or maybe you already have some. Here are some things you should check for, and maybe fix if your nest boxes have an issue!

• Cleaning: Ensure your nest box has an accessible door or similar feature for easy checking and cleaning. While birds undertake some cleaning, you should clean or replace nest boxes after the nesting season.
• Drainage: The bottom of your nest box should feature three or four small holes to allow any rainwater to drain out.
• Attachment: Securely attach your nest box to a post, tree, or building. Mounting nest boxes on metal poles with predator guards (like a baffle) can help protect the birds from predators such as cats, raccoons, and snakes.
• No perches: Refrain from adding perches to your nest box. Natural cavities don't have perches, and neither should your nest box. Perches can attract undesirable species, such as European starlings.
• Roof: The roof should overhang the front of the nest box, offering protection from wind-driven rain.
• Ventilation: Small holes or slits near the top of the nest box promote air circulation.
• Spacing: Some species of birds like living close together, but most like their space. Space your nest boxes as far apart as possible so that the parents don’t disturb each other, unless you’ve done your own research and are targeting a very social species.

Nest boxes can be works of art too! Captured by Dr. Raju Kasambe under the Creative Commons Attribution-Share Alike 4.0 International license.

Building a nest box can be a gratifying project for individuals and families alike. By providing a safe nesting spot, you're directly contributing to the survival of these bird species. Let your creativity fly and craft your nest box today!

You can find more specific instructions on how to build a bluebird nest box here, on the Audubon website.

So many animals depend on snags to survive. Can you complete the image below and see what sort of animals we might have overlooked?