Helping Birds combat climate change

In the summer of 2024, I began monitoring Bluebird boxes for the Ralph T. Waterman Bird Club in the Hudson Valley, New York. Bird boxes are a vitally important substitute for many bird species as habitat loss and degradation have resulted in fewer tree cavities (the primary nesting location for many birds). 

In nature, woodpeckers are the primary creators and users of tree cavities. Abandoned holes frequently become future homes of other tree cavity nesters like the Eastern Bluebird and Tree Swallow. Due to tree cavity loss and increased competition, building bird boxes is critically important to the ongoing survival of these, and many other, species. 

My weekly monitoring began with box cleaning and some minor repairs in the spring, but my role, quite literally, heated up quickly. In mid-summer, our area experienced a heatwave with temperatures in excess of 95 degrees and a heat index of over 100 degrees for much of that week which coincided with the hatching of Bluebirds, among many other species.  

Temperatures are rising annually around the globe. Summers are longer and heat waves are coming sooner. In more regions across the United States and abroad, heat waves are increasingly occurring during nesting season. This past season, I witnessed firsthand how these global changes are negatively impacting bird populations and how challenging it is for birds when I came across Bluebird and Tree Swallow nestlings who were struggling to cope with extreme temperatures.  I refused to accept that there was no way to help these poor birds and set out to research what I could do to make a difference.

During my research, I came across the following:

• Day time temperatures in uninsulated next boxes can be 5-10 degrees Fahrenheit higher than insulated boxes
• Hotter temperatures may cause nestlings to fledge prematurely which lead to an increase in predation
• Hotter temperatures affect nestling growth and health
• Hotter temperatures increase the chance of dehydration and mortality

In an effort to help save the nesting birds from the oppressive heat and possible death, I searched for methods to insulate the boxes with minimal trauma to the birds and devised a quick fix that provided immediate relief to the box inhabitants. 

What was the solution I came up with? Heat shields, which can lower temperatures by up to ten degrees. Those ten degrees can be the difference between life and death for some birds!

I was elated that the heatshield I devised and applied to my nestboxes led to the survival of birds who might otherwise have perished. I knew, however, that I needed to do more and that more meant sharing what I had learned. 

Insulation materials needed to create a heat shield can be found at any local hardware/home store. Here are some materials I recommend: 

• Foil Faced polystyrene board insulation (1/2 - 3/4 inch thick)
• Duct Tape
• Utility Knife / sharp edge
• Tape Measure and Pencil

• Step 1 - Measure the dimensions of the nest box roof and add at 2-4 inches to the width and length for foam board dimensions
• Step 2 - Measure and cut foam board according to specifications
• Step 3 - Apply duct tape directly to the foam board and place on top of the roof of the bird box
• Step 4 - Apply additional tape as needed to secure bird box without harassing the occupants inside
• Additional Step if birds are absent - Staples or appropriately sized nails to attach insulation in lieu of tape

The method that I used to place the heat shields on the boxes during nesting season was temporary in nature as I wanted to minimize the disruption to the birds inside. Sometimes you work with what you have! However, I've already taken the steps to construct more permanent insulated bird boxes that will increase nestlings' chances of survival (the photo above shows just one box that I've constructed this past fall/winter).  

If you decide to create insulated boxes, note that there are various types of insulation to consider. One easy to find option is polystyrene board insulation. Reflectix, or double bubble foil insulation, is another option that is more malleable.  

Insulation can be placed on the roof and/or placed around the walls of the box.  Proper venting is needed to ensure air can escape the box. Remember that insulation acts as a thermal layer to minimize interior temperature fluctuation. Better insulated houses require significantly less heating and cooling to regulate temperatures, and this same method applies to bird box building. 

Below is an Australian based manufacturer of insulated boxes I came across:

• Thermal Haven Nest Box Specifications | Bird Habitats 

Eastern Bluebirds are small insect eating birds that live and breed throughout Eastern North America and all the way south to Nicaragua.  As you may have guessed, they get their name from their brilliant blue backs, tails, and heads. Females have some additional blue tinge on their wings that is paler and less vibrant in coloring. Both males and females sport the classic rusty orange belly, breast, throat, and flanks, but as with the blue coloration, the females sport the orange less brilliantly, with theirs being a more muted orange/rusty/brown. Bluebirds can have more than one clutch per season, and the young from the first clutch fledge in the early summer whereas the second clutch tend to stay with their parents over the winter.  

 Tree Swallows are small songbirds with long, pointed wings and a short, squared notched tail. These are the classic birds that you most likely see swooping over a lake and wheeling over fields. Their range spans coast to coast across North America from Alaska to Florida and everywhere in between. Tree Swallows also make use of nesting cavities of the same size as bluebirds. In regions where natural tree cavities are scarce, Tree Swallows compete for artificially made nest boxes with Bluebirds. Their diets, similar to bluebirds encompass more than just insects: they also consume berries (especially bayberries), which can be found during the colder months. 

It is only by sharing our experiences that we can make a difference! My hope is that the information you come across here motivates you to take action for birds!

The Ralph T.  Waterman Bird Club was inspired to make a difference for bluebirds in 1962 when, during that year's census, they came across only six bluebirds.  Sixty-years have passed since RTWBC set out to make a difference. Birds are now facing a new threat - climate change - and still need our help. Throughout the bluebird monitoring season, I shared my efforts with other RTWBC members, and in the early fall, I was fortunate to have the opportunity to present my findings regarding the increasing importance of insulated bird boxes as climate changes impacts our region at the annual trail monitor's picnic. 

Trail monitors are on the frontline of Bluebird and Tree Swallow monitoring, and I was honored to also share my work with the New York State Bluebird Society, which oversees bluebird conservation efforts throughout New York. Founded in 1982, the NYS Bluebird Society has been working to restore bluebird habitats, monitor populations, and oversee nestbox building programs. My story was published in the Winter 2024 newsletter (pages 7-8) and in the Ralph T. Waterman's Wings newsletter as well. 

As I continue to advocate for the use of heat shields while also building permanent insulated structures for the birds and further researching the impacts of climate change, look for updates here. 

It is my hope that as our climate changes and the planet continues to warm, more birders build and insulate boxes with warmer temperatures in mind. Climate friendly updates to bird box construction should become commonplace. Birds desperately need our help, and it is our job as birders and conservationists to spread the word.

Here is a short video I created that documents my experience and provides some heat shield installation tips - Click me.

Below are some are useful resources I came across during my research (links below) that highlight the issues birds are facing and also offer solutions:

• How to Keep Nest Boxes From Turning Lethal in Extreme Heat | Audubon. 
• Study published in the Journal of Urban Ecology in November 2021 - Insulated nest boxes provide thermal refuges for wildlife in urban bushland during summer heatwaves | Journal of Urban Ecology | Oxford Academic 
•  Agriculture and hot temperatures interactively erode the nest success of habitat generalist birds across the United States | Science 
•  Nest box design for a changing climate: The value of improved insulation - Larson - 2018 - Ecological Management & Restoration - Wiley Online Library 
•  Hot Birds - Climate change and desert birds | FitzPatrick Institute of African Ornithology 
•  The Basics of Bird Boxes - Upper Thames River Conservation Authority 
•  NABS factsheet - Nestbox Recs.pdf 
•  Facing the heat: nestlings of a cavity-nesting raptor trade safety for food when exposed to high nest temperatures - ScienceDirect 

• Bluebird photos - Click Here
• Tree Swallow Photos - Click Here
• Finished box photos - Click Here