Prothonotary Warbler right - Photo Earl Harrison

The “golden swamp warblers” had a very successful nesting season at Alum Creek Lake this season.


I reinstalled the first six boxes to their pipes on March 23 when I could walk on dry lake bottom due to the fact that the lake was at winter water level. Later, I used my canoe to reinstall the remaining 39 boxes on April 9 and 11 after the lake rose three feet to its summer level, all professionally controlled by the U.S. Army Corps of Engineers. Starting on May 17, more than a dozen canoe trips were required to monitor nesting Tree Swallows and House Wrens and to attach leg bands to Prothonotary Warbler nestlings.

The project of 45 nestjars and nestboxes is located along the northern and western shores of the lake along Hogback Road south of Kilbourne in Delaware County, Ohio. Most nestboxes are paired five yards apart, with one box having a 1-1/8 inch entrance designed for warblers or wrens and the other with a 1-3/8 inch hole for Tree Swallows. By August 14, all boxes and jars had been removed from their pipes and stored in my basement.


During the 2017 nesting season, 34 warblers fledged from nine nests. In 2016, the project produced only 20 fledglings, so 2017 was a more productive year by 70 percent.

Primary wing feathers have erupted from their coverings making the warbler nestlings at least six days old, a perfect age to attach leg bands.

The first Prothonotary egg was laid on May 17 and the last nestling fledged on July 26 for a 70-day nesting season. Historically, data recorded during a 14-year period from 2004 through 2017 reveals a 98-day nesting season from May 4 through August 9. Most impressive is the nesting cycle within the nestbox: eggs are laid one per day for three to six days, followed by 12 – 13 days of incubation, then fledging, the most impressive event, occurs only twelve days after hatching, the fastest growth period of all altricial species that I work with.

The 2017 season presented two additional cases of Tree Swallows weaving Prothonotaries into their nests. The first time I had found a swallow nest with a dead warbler was May 24, 2015. The warbler’s prone body made up one third of the nest rim and the nest cup held six swallow eggs. The nest appeared to be a warbler’s moss nest topped with a swallow’s grass cup.

Lost Prothonotary
The deceased female Prothonotary Warbler was extracted from a Tree Swallow nest on May 1, 2017.

After two more dead Prothonotaries were found encased in swallow nests this year, I feared that I might be witnessing a trend, but I hope not. The second discovery took place on May 1, 2017 in a nest with four swallow eggs, and like the first case, the dead warbler was woven into the rim of the grass nest. The warbler was fresh enough for a photo.

I always excavate used nests to search for unhatched eggs and deceased nestlings in order to record accurate data. Used swallow nests can be quite dirty with a thick layer of guano. The third unlucky warbler was revealed as I extracted a used swallow nest from its nestjar and shook it in the lake water. A swamp warbler’s remains floated, and I was able to record an unpleasant photo of my hand holding the remnant of what was once a beautiful bird. All three warblers had entered nestjars with 1-3/8 inch holes meant for swallows.

Tree Swallows

Tree Swallows are not exempt from having bad luck. On May 17, 2017, I found the remains of a male Tree Swallow that had squeezed through a 1-1/8 inch opening into a nestjar’s nest chamber where it failed to exit. The nestjar is made from a plastic drainpipe and its wall is 1/8 inch thick. Since the round outside surface of the nestjar allowed room for wings to flap and wiggle as the swallow squeezed into the nest chamber, the opposite became true as the unlucky swallow found that the nest chamber’s round walls restricted every movement as it tried to squeeze out into the outside world. The dead swallow appeared to be sitting in a human-like posture with its tail and wings supporting its torso in an upright position as it contemplated the entrance. It was a disturbing image for sure.

Back to more positive results. Tree Swallows raised 90 young from 23 nests, and House Wrens fledged 69 offspring from 13 nests. Wrens will continue to be part of the story since the project’s boxes stand along a brushy shore. If boxes were placed in a flooded woodland saturated with beavers, brush would be hard to find and wrens would lack their preferred habitats.


Golden swamp warblers continue to be part of the wildlife community in the northern reaches of Alum Creek Lake. Their average distance between active nests has been around 280 yards and they like to nest near willow trees and buttonbush.

As I row my canoe to check on their progress, another resident provides much entertainment. Three of four Osprey families occupied three of four platforms installed for them over the past twenty years. A fourth family raised their family in the same dead tree for the third straight year. All four families fledged triplets for a total of twelve young fish hawks. During my canoe trip on July 19 to band three Prothonotaries, many of the young fish hawks were beating their wings, trying to get into shape for their first flights. I had many reasons to smile.

Conserve on!