We buy or build nestboxes following precise instructions, and expect them to be automatically perfect for birds to use. But with increasing temperatures during the spring and summer months, if we are not careful in their construction and placement, nestboxes can be a death trap. A few thoughtful changes can make nesting safer for chicks and their parents.
When your house is too warm, you may open a window, create better ventilation, plant a tree, or maybe make the roof and exterior white. All these ideas apply to nestboxes as well, as they can become dangerously hot inside when there are little ones in the heat of summer.
Here are a few ways to make them safer and more comfortable in hot weather without harming the birds:
- Choose a Shady Spot: Position the box in a shaded area to reduce direct sun exposure. But take predator access to the nestbox into consideration. Will it make it easier for snakes, squirrels or other predators to get into the box? If so, then keep looking for one that provides shade and protection from predators.
- Improve Ventilation: Make sure there is good ventilation in the box but not enough space for predators to get in. Making an opening all around the top of the box just under the roof can allow for better airflow. But, be sure to build it so the roof extends another couple of inches so rain and predators won’t get in the larger opening.
- Consider Carefully Before Painting the Exterior: This one is a little controversial, but in a very hot climate, painting the exterior a light color to reflect light might be an option. The problem is there are fumes and the possibility of toxicity from any sort of paint. In any climate, never paint the interior of the box. If you do paint the exterior, do it in the fall so the fumes can lessen during the winter. Or use a paint that is completely non-toxic – some milk or chalk paints are a possibility. This might not wear as well as other water-based paints, but even exterior painting can be toxic to birds, so do it only after making sure the products you use are safe for birds. Never use oil-based paint and avoid painting the entrance holes, ventilation holes, and insides of the birdhouse as the birds may inadvertently consume some of the paint or be affected by the proximity. And while white is the preferred color for Purple Martin houses, its an predator attractor. So if you must paint your small sonbird houses, use light tan, light grey, or pale dull green.
- Never Use Pressure-Treated Wood: Treated lumber contains pesticides and fungicides that can be lethal to birds. Always use untreated, bird-safe materials.
For more information, this article from Nestwatch gives solid advice about how to build a safe nestbox. And this one from Audubon has some specific things you can do to adapt your nestboxes to increasing temperatures.