Background
Bluebirding is all that follows your first bluebird; it is the hobby that lets you experience the rewards of attracting native birds to nestboxes. At least that is my definition. I raised my first bluebirds in 1968 and my first Carolina Chickadee family nested the following year. Since then, I have recorded 270 chickadee nest attempts where eggs were laid, and 814 young have fledged from 174 (64.4%) successful nests. During my early years, I only tried to attract Eastern Bluebirds, and then when nesting Tree Swallows showed up in 1977, I tried to raise more of them and bluebirding blossomed beyond bluebirds. For years I did not try to attract chickadees, but when they nested, I always did my best to protect their families. I add a 1-1/8-inch Masonite or plastic patch over the larger entrance to exclude all larger birds whenever I find a chickadee nest in a bluebird box. The first time that I tried to raise chickadees on a larger scale took place three seasons after another project failed in 1998.
Chickadees inherited new nesting opportunities after my attempt to win nesting Prothonotary Warblers (PROW) came up short, thanks to my poor choice of habitats and determined House Wrens. Prior to the 1998 nesting season, I designed and constructed thirty “nest tubes” for Prothonotary Warblers after having been inspired by a project led by Dan Best along the Upper Cuyahoga River in Northeastern Ohio. Dan made his warbler nest structures from Metamucil jars and I made thirty nest tubes out of four-inch PVC drainpipe. Much of my design was unique since the nest chamber and raccoon baffle were one continuous piece of drainpipe forty inches long. For the nest chamber, I copied the easy snap-on roof from the Steve Gilbertson bluebird box. I drilled 1-3/8″ entrances for my prothonotary nest tubes. (Most recently, I have learned that PROW’s only need 1-1/8″ entrances.)
I installed my nest tubes on three different properties. I located four tubes in riparian habitats along the bank of the Olentangy River at the Olentangy Environmental Control Center (OECC), a sewage treatment plant for southern Delaware County where 25 nestboxes for bluebirds and Tree Swallows had stood since 1983. I installed OECC’s nest tubes as close to the river as possible while trying to avoid destructive currents during frequent high water events.
Four and one half miles west of OECC, I waded along the bank of the O’Shaughnessy Reservoir to add four nest tubes to the Izaak Walton-Columbus Zoo Nature Preserve where 19 swallow boxes and four Wood Duck boxes had stood above the lake since 1987. (My first Prothonotary Warblers fledged from one of these nest tubes in 2004, but it was the last season for this trail before I removed all of its boxes for numerous reasons.)
In 1998, I was most excited about a brushy swamp at the far northern edge of Alum Creek Lake near where our osprey team had erected three nest platforms the year before. The swamp had been a wet pasture prior to 1976 when the U.S. Army Corps of Engineers flooded the Alum Creek Valley to create Alum Creek Lake. I added twenty nest tubes to the former pasture and as the 1998 season developed, I became ecstatic after I identified yellow swamp warblers singing above a quarter of my offerings during multiple visits in mid-May. The yellow and green dynamos had added moss to several tubes, then within a week, disappointment and depression set in as aggressive House Wrens wrecked everything by covering prothonotary nests with sticks. Jenny wrens had recognized the emerging brush as their favored habitat. Single pairs of Eastern Bluebirds and Carolina Chickadees managed to fledge families from the swamp’s nest tubes since their eggs had hatched before the egg-piercing wrens arrived. I did learn one additional thing from my one-season experiment at the bushy swamp: bluebirds can negotiate a 1-3/8″ opening.
Since I had Osprey nest platforms and kestrel nestboxes on my mind at the time, it was easy for me to admit defeat and pull the nest tubes from the swamp. I put twenty nest tubes in storage and concentrated my efforts on more productive conservation projects. Meanwhile, the nest tubes that remained standing at the two other sites became increasingly popular with Poecile carolinensis, the Carolina Chickadee.
Trying for Carolina Chickadees at the OECC
The OECC occupies 70 acres between the Olentangy River and State Rt. 315, just north of Mt. Air, Ohio. Highbanks Metro Park, whose shale cliffs overlook the neighbor-friendly sewage treatment facility, occupies the river’s east bank. The OECC was designed to please its neighbors, and to everyone’s surprise, its grounds are so aesthetic that the management sometimes receives a request to host a wedding there. The facility has hosted my nestboxes since 1983, and my first chickadees there fledged seven young in 1997 from a nestbox that I had specifically designed for White-breasted Nuthatches. For each nuthatch box, I had custom-sawed thirty inches of wooden fence post to fit over the front panel that allows a nuthatch to descend headfirst, down to, and through, a 1-1/4″ entrance hole. I had installed several nuthatch boxes along the “dry border side” of the riparian forest but the target species has never used them. Chickadees, on the other hand, love the hybrid log-houses.
Since the Olentangy is a state-designated scenic year, the OECC staff has allowed woodlands to reclaim a wide protective zone along its channel. Mature trees, including tall sycamores that hug the river channel, makes up the riparian zone that stretches for 20-30 yards and blends into younger growth that expands the forested zone to a total of sixty yards from the river in some places.
I have always said that a nestbox raises no birds while in storage, and since chickadees had nested in nest tubes over water at the Columbus Zoo in 1999 and 2000, I decided to take eight prothonotary nest tubes out of storage and put them to work for chickadees at OECC before the 2001 season. To limit competition, I made patches with 1-1/8″ openings from small pieces of PVC drainpipe and riveted them over the original 1-3/8″ entrances.
By the start of the 2001 season, I had added one nest tube to a wooded swamp near OECC’s northern border and turned back south along the river to add seven tubes to stand in line with the riparian zone’s original four tubes installed in 1998. Two nuthatch boxes and four standard boxes stand along part of the “dry” edge of 1100 yards of riparian corridor and continue to host nesting chickadees that hunt and feed inside the forest. By 2001, I had also installed a nine-box, three-by-three nestbox grid for Tree Swallows near the property’s three-acre wetland that I showcased during a field trip for the North American Bluebird Society during their 2001 convention hosted by the Ohio Bluebird Society. Today, twenty-seven bluebird boxes are mostly managed for swallows and join two nuthatch boxes, 12 nest tubes, and two Wood Duck boxes that make up a combined trail of 52 nest structures.
Carolina Chickadees at OECC: 1997 – 2011
During fifteen nesting seasons, Carolina Chickadees at OECC have started 73 nests with eggs and fledged young from 44 for a 61.3% success rate. Of the 29 nests that failed, 19 (26%) chickadee nests became victims of wren competition. Two nest failures each are attributed to raccoons (2.7%), bumblebees (2.7%), and “unknown” (2.7%). Raccoons can climb baffles once their wet fur picks up sand, and bumblebee queens like to claim moss nests for their own families and will “buzz off” chickadees as well as paranoid monitors when they sense unwanted company. Cold weather caused four failures (5.5%) out of 73 nest attempts. Chickadees laid 400 eggs, 252 (63.0%) eggs hatched, and 224 (56.0%) eggs matured to fledge. Using the same numbers, chickadees fledged nearly nine of every ten (88.9%) hatchlings.
Clutch sizes ranged from three to nine eggs with an average of 6.23 eggs for 47 completed clutches. Six eggs were the most common clutch size found in 15 (31.9%) nests. Other clutch sizes recorded were nests with three eggs, 2.1%; four eggs, 4.3%; five eggs, 21.3%; seven eggs, 25.5%; eight eggs, 10.6%; and nine eggs 4.3%.
Successful nests raised between one and nine young with 5.09 being the average number of fledglings per nest for 44 successful families. The most common number of fledglings was six counted from ten (22.7%) nests.
The earliest first-egg-date (FED) recorded for chickadee nests at OECC was 12 April 2005. The latest FED for a successful nest was 20 May 2003 for a small clutch of three eggs that fledged two. Using one egg laid per day with an incubation period of 13 days, and a nestling period of 17 days, the active chickadee nest season recorded from the first egg to the last fledgling at OECC runs for 71 days between April 12 and June 21.
Another of my favorite characters, Carolina Wrens, attempted to nest four times within the riparian zone; once in a nuthatch log-box after a woodpecker had enlarged its entrance, and three times in the original nest tubes with larger, 1-3/8″ entrances. Carolina Wrens fledged 14 gregarious offspring after three of their four attempts became successful.
Monitoring Methods
Presently, I try to check my nestboxes every nine days. Since chickadees nest only once, and no first eggs appear beyond Memorial Day (May 31), after chickadees fledge their young, I cover their entrance holes with duct tape. Then, on my last visit in early September when I return to winterize the trail’s nestboxes, I reopen the nest chambers and use new tape to cover both ventilation ports so small forest birds can have draft-resistant winter roosts. In mid-March, I remove tape from one of two ventilation ports to start the new nesting season.
Chickadees cover their eggs with a blanket of moss and hair before they leave their nest, and in order to count eggs, I sometimes have to gently pinch and pull the upper layer of nest material until I lift the free edge of the “egg blanket.” I pull the blanket back to expose the eggs before counting them with my hand-held mirror. Of course, I return the blanket to its original position before I leave. Also, for nest chambers that are top opening, a hand-held mirror works best when counting mature nestlings.
When monitoring, be aware of the “snake act” that chickadees and titmice practice to scare away predators. They puff up, and hiss like a striking snake while smacking their wings on the nest. The sound is more like an avian sneeze or cough, if there is such a thing. Since all humans are borne with a natural snake reflex that kept our ancient ancestors out of trouble, the striking-snake sound has worked on me several times, causing me to jerk away from the nestbox. Of course, once my conscious mind takes over, I break into a healthy laugh.
Results and Conclusion
In 2011, 34 Carolina Chickadees fledged from seven nests at OECC after eight attempts. Other trail boxes at the plant fledged 27 bluebirds, 115 Tree Swallows, four House Wrens and two families of Wood Ducks. I enjoy helping feisty chickadees as I follow a worn path along the Olentangy and observe Wood Ducks, Canada Geese, Mallards, Great Blue Herons and other river life. Of course, warblers and patches of Virginia Bluebells, trillium species, and other forest life are always pleasing. And thanks to the timing of the chickadees’ life cycle, the riparian nestbox trail becomes dormant just as the mosquito population becomes annoying, so I don’t have to put up with the little bloodsuckers.
In conclusion, if your bluebird trail abuts a woodlot or a wooded stream, weave your nestbox trail through tall trees and try for chickadees. And, while every species has its own charm, once chickadee nestlings sprout their black caps and chins, they win my vote for the cutest nestlings on my trails. Happier Bluebirding with chickadees!