Your Yard Can Be Habitat for Bluebirds and Other Cavity Nesting Birds

There are over 20 resident Florida birds that nest in cavities in trees or branches. These include Eastern Bluebird, Carolina Chickadee, Tufted Titmouse, White-breasted Nuthatch, Great-crested Flycatcher, Carolina Wren, and woodpeckers among others. Woodpeckers are considered primary cavity nesters because they excavate their own cavities, while the others are secondary cavity nesters who rely on naturally occurring holes or ones chiseled by woodpeckers.

Snags, or standing dead trees, are crucial for woodpeckers as they serve as nesting sites, provide a food source through insect-rich wood, offer roosting spots, and contribute to overall ecosystem health by supporting biodiversity. Photo by SunnyS, Adobe Stock.

Most woodpeckers need snags (dead trees) and dead limbs for excavation, and these are often in short supply in neighborhoods. We can make up for this scarcity by installing and maintaining nest boxes for bluebirds and other cavity nesters.

If you must have a tree cut down, ask the arborist to cut the trunk at approximately 12 feet. The snag will slowly decay and, in the meantime, feed and house woodpeckers and other cavity nesters.

Create Habitat

Nest boxes are important but to produce healthy populations of birds, creating habitat in our yards is of utmost importance. What you plant in your yard and how you maintain it does matter! Diversify your yard by planting native trees, shrubs, grasses, and wildflowers which provide sustenance and habitat for native insects that will then be eaten by birds and fed to their young. Connect the trees and shrubs together in beds, allowing the leaves to carpet the ground. Leaf litter is important habitat that supports the food web in your yard. Also, avoid pesticide use.

You do not need to provide bird food for bluebirds as they are excellent hunters of insects, which are highly nutritious. However, if you want to provide them with an occasional treat, they do love mealworms. Because purchased mealworms do not provide complete nutrition (they are lacking in calcium), they should be used as a supplemental food source, offered on a limited basis – a treat for the birds.

Adult bluebirds also eat fruit, so encourage pokeweed, beautyberry, and elderberry to grow in your beds. Plant fruiting species such as black cherry and holly trees. At the feeder, bluebirds will also enjoy sunflower chips and suet cakes as occasional treats. Nestlings, however, are always fed insects.

Bluebirds prefer an open habitat, so the author installed this nest box in her pollinator garden of wildflowers and native grasses. Photo by Donna Legare.

Nest Boxes

When buying or building a nest box, make sure it is designed properly with the correctly sized entrance hole. For instance, bluebird houses should have a hole that is 1 ½ inches in diameter. The same house can serve well for birds that require a slightly smaller hole. I have had titmice, chickadees, and nuthatches use our bluebird house. Interestingly, bluebird nests are almost always constructed of pine needles or grasses or a combination of the two. Chickadees use a lot of green moss in their nest and then line it with soft cottony material. It is just as much fun to watch birds collecting nesting materials as it is to watch the constant visits by parents bearing insects, and I always feel lucky if I am at home when the fledglings leave the box.

A good bird house has ventilation holes or space under the roof overhang, has drainage holes, has the roof extending over the walls for maximum protection from rain and sun, does not have a perch that a predator could use for support and is protected by a snake/raccoon predator guard. These are commercially available, or you can make your own using six-inch PVC piping or stove pipe below the house.

Nest boxes should be cleaned after each use. Remove the old nest. I carry a bucket with soapy water and a rag so that I can wipe the inside thoroughly and then rinse well with clean water. Most nests are clean because parents remove fecal sacs. Watch as they fly in with an insect and leave with a white sac. This keeps the nest clean, so it is less likely to attract predators and decreases the chance for disease. Fledglings often defecate while leaving the nest so there is usually a need for cleaning.

Old Nests May Become Bumblebee Habitat

Place old nests on the ground tucked up under a tree or shrub. It may be used by an overwintering bumblebee. Once I forgot to clean a gourd which held a flycatcher nest. I laid it on the ground at the base of a parsley hawthorn tree. Next spring, I lifted it, heard a buzzing sound, and immediately placed it back on the ground. A bumblebee flew out. She had overwintered in the old nest. Isn’t nature fascinating!

A Great-crested Flycatcher feeding a nestling. Photo by Danita Delimont, Adobe Stock.

Great-crested Flycatchers

These flycatchers migrate to our area in springtime and are quite common; listen for their distinctive “zweep, zweep” call. As their name would indicate, they are insect eaters. They are also cavity nesters and will accept a gourd or wooden house. They usually place a snakeskin in the nest if they can find one. If not, they will include a piece of clear plastic litter. I have seen flycatchers nest in abandoned newspaper boxes and even in a clothespin bag hanging on a clothesline.

Joyful Observations

There is no doubt that watching bluebirds and chickadees nesting in our yards brings us joy. I have been installing nest boxes and teaching about cavity nesting birds for 50 years, beginning as a volunteer with Alachua Audubon Society while in forestry/wildlife school in Gainesville. This summer we observed something we have never seen before, though we have included this behavior in our classes.

Bluebirds nested successfully in our front yard nest box early in the season and then a second time in June. When we returned from a late July vacation, we noticed that bluebirds were once again using the box and this time there were four birds tending the young – a mature male, a mature female, and two juveniles. One time a juvenile carried a pokeweed berry to the nestlings, which the parents would never do. Later a juvenile was clinging to the entrance hole with nothing in its beak. The mature male flew up with an insect in his beak, passed it to the juvenile who then, rather than eating it, fed it to one of the nestlings. These youngsters are learning parenting skills. It was a privilege to watch.

For more information on nest box dimensions and creating habitat in your yard, pick up the free booklet Planting a Refuge for Wildlife by FWC (Florida Wildlife Commission) at their office or at Native Nurseries.

Birds Up Close

A cold Sunday morning, fire in the fireplace, relaxing on the sofa with a cup of hot coffee, a pair of binoculars by my side, I am enjoying the parade of songbirds visiting our feeders. Life is good. It was a productive birding morning. My wife and I totaled 17 species between 10 a.m. and noon.

The author’s squirrel-proof feeder set up for winter feeding with white millet on the lower level for White-throated Sparrows and a variety of other seeds in the tube and on the top tray. Note the simple wire suet cage attached to the pole. Photo by Jody Walthall.

It is fascinating to observe the different food preferences, feeding behaviors, and social interactions between the species. Our primary feeder is an easy-to-clean tube feeder on a pole with a squirrel/raccoon baffle below it. We feed a blend of black oil sunflower, hulled sunflower (sometimes called hearts or chips), and safflower seed in the tube feeder. Cardinals, Chickadees, Titmice, White-breasted Nuthatch, and Downy Woodpeckers visit regularly.

On the tray below the tube feeder, we put out small handfuls of peanut halves and hulled sunflower along with crumbled suet cakes. The peanut halves go quickly. They are eaten by Brown Thrashers, Blue Jays, Red-bellied Woodpeckers, Tufted Titmice, Carolina Wrens, and Summer Tanagers. Usually, these birds grab a peanut half and fly off to eat it elsewhere. Blue Jays may stuff down four or more halves in one sitting; they are known stock pilers.

Chipping Sparrows, a common Tallahassee winter migrant, prefer white proso millet. Normally we scatter this seed on a flat stone platform feeder, six inches off the ground. Other ground feeding birds like the Rufous-sided Towhee and Mourning Dove also prefer white millet. That Sunday morning one Slate-colored Junco joined the Chipping Sparrows feeding on white millet.

A Carolina Wren fills the air with its vibrant chirps. Photo by Stephen Gensits.

The problem with feeding on an open rock is that squirrels can easily access the seed. Because we have had problems with squirrels in the attic, we try not to deliberately feed them. Instead, we have added a platform feeder with an easy-to-clean screen floor below the tube feeder tray, but above the squirrel/raccoon baffle. We scatter white proso millet all winter on this tray to the delight of many Chipping Sparrows. After the sparrows leave, we put that feeder away until the following winter. The squirrels can still enjoy anything that drops to the ground.

The suet cakes were eaten by seven species that morning: Downy Woodpecker, Yellow-rumped Warbler, Orange-crowned Warbler, Gray Catbird, Carolina Wren, Summer Tanager, and Baltimore Oriole. The Orioles, about 10 of them, also went to a special feeder that dispensed an orange slice along with grape jelly. We do not put this feeder out until we see Orioles at the suet feeder. Sometimes we attach a wire mesh suet cake cage to the pole between the baffle and the tube feeder. This is another good way to dispense suet.

Goldfinch have not visited our yard yet this year, but their food preferences are black oil sunflower, sunflower chips, and Nyjer seed. The winter plumage of Goldfinch is rather drab, a “dirty” yellow/green with distinctive black and white wings. In Tallahassee, the males will sport brilliant yellow feathers around the first of April and leave Tallahassee by mid-April going to their northern nesting areas, Atlanta to Canada. When purchasing Nyjer seed towards the end of the Goldfinch season, buy smaller quantities. Any leftover seed will not keep until their arrival the following winter.

Chipping Sparrows eating white proso millet. Photo by Sandy Beck.

To lessen your carbon footprint, rather than feeding Goldfinch Nyjer shipped from Africa or India, use American-grown black oil sunflower or sunflower hearts. This hulled seed is also favored by many birds that cannot crack open a sunflower seed such as Bluebirds, Pine Warblers, and Wrens.

Also, in relation to your carbon footprint, if you like to give your birds a special treat of mealworms, consider their source. Read the label. Most dehydrated mealworms are shipped from China. One Chinese insect farm ships 200,000 tons of dehydrated mealworms worldwide a year. They also ship 50 tons a month of live mealworms. Purchase mealworms raised in the United States for a more carbon-friendly source. They are easily raised at home as well.

I recommend feeding mealworms on a limited basis, as a special treat, not as a constant food source. Mealworms do not provide complete nutrition for insect-eating birds, as most are lacking in calcium.

Offer suet this winter to attract birds like this colorful Baltimore Oriole. Photo by Sandy Beck.

A flock of Robins also came by that Sunday morning, but they are not seed eaters and seldom visit feeders. They gorged on holly berries and took advantage of the bird bath. A bird bath with plentiful cover nearby for hiding and staging is needed by every species. Refresh water every three days to prevent mosquitoes and disease.

Some folks use multiple feeders and spend considerable money on bird food. I like to keep it simple. I may use the four feeders mentioned, but when the winter migrants leave in spring, I reduce it to one feeder for the summer and fall. Only put out as many feeders as you can keep clean. They should be washed with hot soapy water and rinsed with a mild bleach or vinegar solution and then rinsed again with fresh water. Allow them to dry before refilling.

Feeding our feathered friends is an enjoyable hobby. For me, it is uplifting and educational. Keep in mind that the birds do not need the seed. You shouldn’t feel obligated to feed them. They do very well on their own in nature if good habitat is provided. And that is a topic for another day!

Create Urban Forest Diversity

Black cherry hosts tiger swallowtail caterpillars and many other species of butterflies and moths. Photo by Michael Singer.

Tallahassee is fortunate to currently have a considerable urban forest, though it is constantly being whittled away through development, storms, and fear of storm-related damage to homes. The average tree canopy is rated at 55% of land. This average puts Tallahassee close to number one in the nation for urban forest coverage. One problem with our forest is the lack of diversity in the species make-up. According to the City’s Urban Forest Master Plan three native trees (Carolina laurel cherry, water oak, and laurel oak) and one highly invasive non-native tree (Chinese camphor) are short lived, weak wood species that make up a full 38% of the forest. The long-lived sturdy live oak makes up 7% of the forest.

Loblolly pines and live oaks dominate the canopy in Walthall’s backyard. Photo by Donna Legare.

The diversity of tree species has an impact on the overall health of the forest, its wind resistance, and the food value for wildlife, from invertebrates to mammals. In terms of wind resistance, the four species making up this 38% are all considered to have very low wind resistance. If you are concerned about tree damage during a storm, choose smaller trees such as holly, greybeard, flatwoods plum, redbud, and red buckeye. The most wind resistant large trees are Southern magnolia, live oak, sweetgum, cabbage palm, pecan, and red maple.

For wildlife food, always turn first to American native species. Don’t put your entire focus on berries for birds. Berries are important seasonal sustenance for birds, especially during migration, but insects are the key to healthier food chains.

As an example, birds will eat the berries of Chinese camphor and spread seeds all around town, growing the percentage of Chinese camphor in our urban forest. Meanwhile, there are few insects that can find sustenance on this foreign tree. In contrast, native oak trees in our area can host 395 species of butterflies and moths in their larval form as caterpillars. A native red maple may host 171 species. These caterpillars are functionally soft bags of proteins for birds, lizards, frogs, and other wildlife.

White oak and fringe tree add fall color among the evergreen magnolias and pines in this yard. Photo by Vanessa Crisler.

Caterpillars are not the only insects in our native tree canopy. Thousands of species are on the leaves and branches, though we seldom see them. Many insects try to hide or use deception and stillness to survive the winter. Our resident and migrating birds search the treetops like a fine-tooth comb looking for this source of food, yet the insects are usually no threat to the tree or humans. Don’t fear the bugs! Search the National Wildlife Federation’s Native Plant Finder and enter your zip code; the site will show how many species of caterpillars use particular native plants in your area. This tool can help you select a tree for your yard.

A diverse native tree canopy is a major component of a healthy ecosystem that we need for human survival. What happens to us if we do not have trees supplying nectar, pollen, and leaf food to native pollinators? The flowers of trees such as red maple, black gum, black cherry, magnolia, tulip poplar, dogwood, redbud, Chickasaw plum, Southern crabapple, native hawthorns, and sassafras all supply nectar and pollen for bees along with hosting insects for many types of wildlife to eat.

If you have native trees in your yard, be sure to leave the leaves on the ground where they fall. Experts suggest leaving the leaves out to the dripline of the tree’s branches. Hundreds of species of insects live in the leaf litter. Some moth caterpillars eat no green leaves, consuming dead leaves on the ground exclusively. Many moths or butterfly caterpillars drop to the ground and hide in leaf litter to spend the winter in a cocoon or chrysalis. If lawn grass is beneath the tree, they usually die. Other insects merely hide through the winter, often becoming food for birds and other wildlife. Dead leaves are a critical part of a healthy ecosystem. I give you permission to be lazy – leave the leaves! If you prefer to have some open lawn in your yard, as I do, just rake the leaves into existing beds.

Silverbell in its spring glory among the urban forest at Native Nurseries. Photo by Jody Walthall.

As our city population grows, we clear cut and bulldoze hundreds of acres of stately trees for apartments, houses, parking lots, and roads. If you have open space for trees in your yard, you can help make up for this loss. There are too many beautiful and useful species of trees to mention. Some large trees to consider are winged elm, Southern red oak, white oak, Shumard oak, swamp chestnut oak, basswood, mockernut hickory, and bald cypress. Rather than the smaller non-native Drake elm or crape myrtle, choose blue beech, hophornbeam, silverbell, hoptree, Hercules club, American olive, or redbud. Choose a tree based on your soil and sunlight conditions.

Trees, especially live oak and pine, give Tallahassee a sense of place. They are so valuable for multiple reasons: preserving our mental health; cooling our streets, parking lots and homes; creating beauty; sequestering carbon; controlling erosion; naturally feeding wildlife.

Every yard matters and every tree counts. What you plant in your own yard makes a difference to the local food web. If you have room for more trees in your yard, winter is the best time to plant.