Tree Swallows Need Toeholds

Tree Swallow Pair on Post - Photo Earl Harrison

In 1975, I enrolled in a summer course, Environmental Interpretation 610, taught by Dr. Gabe Cherem at the Ohio State University. For one of my assignments, I authored the bluebird pamphlet Hit the Trail for Bluebirds, and after the completion of the course, I took my creation to the Ohio Division of Wildlife’s office in Columbus. There, I was introduced to Denis Case, state administrator in charge of nongame management, and Denis introduced me to Jim Glover, the wildlife artist that would ultimately do the final layout of the pamphlet.

Denis encouraged me to be patient since it would take him time to run the pamphlet through a system of required committees before it could be printed. I received my first printed copies in the mail in late December 1976, and I was very happy with the results.

Among the Hints section on the pamphlet’s backside, the following important points are listed: “Roughen the inside surface of the front piece so young birds can cling to it for feeding and to exercise their wings before their first flight. A surface can be roughened by sawing slots 1/8″ deep, punching shallow holes with a screwdriver, tacking on a strip of 1/4-inch hardware cloth or gutter screen, or gluing small scraps of wood.” After all, the original nest sites for bluebirds were whittled by woodpeckers that left a cavity with multitudes of toeholds for any cavity nester.

My pamphlet’s hints had been collected from what I had read in The Purple Martin Capital News from Griggsville, Illinois. Not only were there numerous letters and hints from Purple Martin conservationists, but also bluebirding pioneers such as Larry Zeleny, Ohioan Joe Huber, and many others offered their ideas and methods to help bluebirds.

I will admit that my first 22 nestboxes that I made in December 1967 had no toeholds for bluebirds and other birds at the time. By the time I had spent my first season monitoring trail boxes in 1968, I became aware of the Dick Irwin nestbox, a front-opening box that was raising bluebirds in Kentucky. As my projects expanded to other farms in Marion County, I used my stepfather’s table saw to make new front-opening boxes, and after the 1969 season, I started replacing my original boxes with new ones.

The original boxes did not go to waste. They were used to keep the workshop warm during cold winter days, thanks to a classic wood-burning stove. My original boxes had too many unique features such as a removable floor that was the only way to access the nest cavity along with metal brackets used to attach the box to its pole, etc. It is valuable to learn what doesn’t work in order to discover what does work.

Even though I was trying to attract Tree Swallows at several locations with farm ponds, swallows didn’t nest until 1977 when one pair raised five. Their numbers increased each year, and for 1987, the first year of the Ohio Bluebird Society, swallows were able to fledge 615 young. During the last 43 nesting seasons, from the first swallow nest in 1977 through 2019, my swallows have raised 29,762 bug-snatchers, many from nestbox grids where boxes are spaced 22-25 yards apart to mimic the spacing found in historic beaver ponds.

Ohio’s state parks started adding bluebird boxes after Hit the Trail for Bluebirds became available. The first boxes donated to Delaware State Park did have toeholds along with ten boxes that were provided by the Ohio Division of Parks. Two donations followed and were mounted by the contributors. The boxes looked great and I had begun to monitor all boxes for the 1977 season.

Swallows first nested in Delaware State Park in 1979, and dead Tree Swallows were found in a few boxes that I finally discovered lacked toe holds. The unlucky birds had defecated and had empty crops, signs of starvation caused by an inability to exit the box. Yes, cold weather was a factor since the birds were found in early spring when cold snaps will ground flying insects, causing swallows to weaken. When sunny weather returns, the swallows would be too weak to jump six inches up to the entrance hole with wings that are restricted by smooth walls of a small cavity that becomes too much of a challenge for short legs and small feet.
So, once I was aware of the problem, I used a staple gun to add strips of plastic gutter screen beneath the entrance hole on the inside surface of the front panel. In modern times, I have read the term “swallow ladder” when referring to toe holds, a good term to describe the essence of what swallows need for a safe nestbox.

Nestbox Toeholds and Tools

Several types of toeholds for the inside of Eastern Bluebird and Tree Swallow nestboxes, and some tools that can be your helpers.

The photo to the right shows the inside surface of three front panels. (You can click on the photo to see a larger version). The pairs of screw heads are for Van Ert Universal Sparrow Traps. On the left is a panel with a plastic gutter screen, while the right panel has an aluminum screen. Both screens are attached with staples “shot” by the staple gun shown below the panels. The red tin snips are used to cut and trim gutter screens. I always fold less than an inch of the plastic gutter screen under the main patch so the birds’ feet don’t make contact with sharp edges.

If you find boxes without toeholds, it is easy to retrofit nestboxes with toeholds in the field. Side-opening boxes might offer a nightmare but that’s another story.

I should add that I have used a variety of adhesives to glue patches of plastic gutter screen inside four-inch drainpipes when I make nestjars for Prothonotary Warblers and swallows. I even use staples to add plastic screens below the three-inch entrance holes in kestrel boxes. It is better to be safe, than sorry.

Many times in late winter when I enter a department store, a bird theme store, a nature center, or any other facility with nestboxes for sale, I always check for toeholds. If I find no toe holds, I take the box to the nearest person in charge and explain to them that they are selling swallow death traps, and the conversation goes from there.

I find too many smooth front panels and I will not mention the guilty stores, or the nestbox manufacturers. I will encourage you, dear readers, to do your own criminal investigations, and GOOD LUCK!!

Conserve on by doing the right thing for our avian friends.