Delaware County Kestrels in 2017

American Kestrel - Photo Alan Schmierer

American Kestrel on Wire - Photo Earl HarrisonOn December 4, 2017, Dick Phillips and I went about trading two repaired kestrel nestboxes for K-5 and K-10, two boxes of 18 boxes in the Delaware County American Kestrel Nestbox Project. During Dick’s drive of nearly 20 miles from his home in eastern Delaware County to my home in Delaware City, Dick counted four of our small falcons perched on utility wires hunting for rodents below. Of course, modern counts are made during a time when the once called sparrow hawks have diminished down to 34% of North America’s count in 1966. To help bring back our continent’s smallest falcon, our boxes in Delaware County have fledged 1,102 young since our project’s first successful nest in 1995. Seventy-three kestrels fledged in 2017 alone.

All but one of Delaware’s 18 boxes hang from utility poles that belong to Consolidated Electric Cooperative. Only one box, K-16, hangs from a cable connected to a winch on its own pole in Gallant Woods Park, making Preservation Parks our second partner in the project’s conservation effort. From the beginning, other partners include Roger Wren of the Delaware County Health Department. Roger was awarded a grant from the Ohio Department of Natural Resources’ Division of Recycling and Litter Control to encourage school students from throughout Delaware County to recycle aluminum cans at Worly’s Recycling to finance the first ten boxes that were attached to traffic signs maintained by  the Ohio Department of Highways from 1993 – 2000. Members of the Delaware County Bird Club constructed the first ten boxes.

Once the morning’s task was completed, we discussed the fact that if ten-year-old students recycled aluminum cans to finance the original ten nestboxes during their 1992-93 school year, it’s quite possible that they could be fathers or mothers of children of the same age today. We hope  parents are now pointing out to their children nestboxes and kestrels as they drive along Delaware County’s roads. Passing knowledge to younger generations is one definition of culture. During 2017, as we traveled our roadside trail 15 times for monitoring and banding, many people waved at us as they traveled by. We wonder if some had helped to launch the project 27 years ago when they were students.

Monitoring trips in 2017 started on March 17 as we added white pine bedding to four boxes that had been excavated by European Starlings. We also encountered a female kestrel on a dead starling in K-11, and most promising was finding the season’s first kestrel egg in K-9. At our last box check at K-16, we used the pole’s winch to provide the only up-and-down ride for a gray Screech Owl since it failed to show up during later checks. I reported all of these events in an earlier article.

The second monitoring trip on April 2 found three grassy starling nests. We do not remove starling nests since kestrels can use them; we only remove starling eggs and check the boxes every two weeks to remove alien eggs before they can hatch. By April 16, four boxes had starling eggs, and starlings always stop laying eggs by the end of the first week of June. For 2017, we removed 78 starling eggs from 17 nests among four boxes.

Only two kestrel nests were active during the April 2 check, but by the next check on April 16, fourteen boxes held eggs or female falcons that remained committed to stay on their nests to conceal their eggs from the monster man in their ceilings. One half of the active nests contained incubating females.

By the end of the season, kestrels would attempt 17 nests with eggs in 14 boxes. Sixteen nests (94.1%) became successful by fledging one or more young. From the first egg laid on March 17 to the last fledgling on August 18, the kestrel nesting period lasted 155 days for a typical season. A total of 84 eggs was laid, 75 (89.3%) hatched, and 73 (86.9%) fledged. Once hatched, 97.3% of hatchlings grew to fledge. Kestrels in 2017 fledged 35.2% more young than the 2016 total.\

Only one nest failed due to unavoidable reasons. Electric lines along Cline Road were being updated with new poles that required weeks of work on site. Kestrels are easily spooked by our species’ activities, and even though the electric company and their contractor did everything possible to minimize their impact on the falcons, the first nest failed. Also, there were no pastures or hay fields in K-2’s territory where kestrels could hover over low vegetation away from human activity to harvest small rodents and large insects. There were only corn and soybean fields that forced the falcons to hunt only the grassy road berms that were occupied by efforts to install new utility poles and electric lines.

Only two kestrels hatched from K-2’s five eggs, and by May 26 the box was empty, probably because the young died and were then consumed by their parents. We told the utility crew that the box could now be moved to the new pole and the old pole was pulled. We could not check the nest on June 3 because it had been attached to the new pole too high for us to reach it with our ladder. Arrangements were made for the box to be lowered during the following Monday. One bucket truck was used to lower the box and to everyone’s surprise, the kestrels had started a second nest with three eggs. After the technician gently lowered and reattached K-2 to be twelve feet above the ground, it took three of us to roll the old post so I could salvage the aluminum sheeting and reinstall it below K-2 on the new pole, all to deter climbing raccoons. Everyone was pleased by the progress.

At the next visit to K-2, we found four eggs and the determined falcons went on to raise four fledglings by August 6. Human beings and birds had worked together for a successful nest.

Two boxes produced two families each in 2017. Historic data from 287 nest attempts reveals that if the first egg of the season appears before April 12, there is time for a second family that will produce a first egg before June 25. The frequency of second successful broods averages one in 36 nest attempts, so second broods are not that common.

Three kestrel fledglings were lost to traffic while one fledgling was rescued and successfully released by a crew from the Delaware County Engineers Office. I have listened to criticism of installing nestboxes along roadways, but even if nestboxes raise young in the middle of fields, the young kestrels will still fly to utility wires in order to hunt large insects from the road’s surface. It takes time for the birds to learn to avoid fast-moving automobiles, and some don’t learn fast enough.

One of the best developments of 2017 was that K-14 became productive again, fledging five from five eggs after two years of failing to hatch eggs. We concluded that the eggs had been infertile because both parents were present for both years and they incubated the eggs well into both seasons. If the eggs were fertile, then nearby bridge and road work could have possibly caused two years of nest failure. Yet, all was peaceful, quiet, and productive in 2017.

K-14 Kestrel Shields Hatchlings

Finally, after two years of failing to hatch eggs in K-14, a female kestrel shields hatchlings on May 19, 2017. The five hawklets grew to fledge around June 16.

All 73 of 2017’s nestlings fledged wearing U.S. Fish and Wildlife Service leg bands. We aim to band nestlings between 14 and 24 days old when they can be sexed and their muscles are too immature for them to draw blood from their captors’ hands.

At each box, I would climb the ladder, disengage the roof’s hook, lift the hinged roof and look in to count the nestlings. I would pick one nestling and descend the ladder and hand the young bird to Dick. I would list band numbers in my banding data book before attaching the band as Dick held the nestling. The sex of the nesting is recorded next to its band number. Dick would climb the ladder to return the nestling to its nest, then he would pick the second bird and descend as I waited with the second band in the jaws of the plyers, etc. The process proceeded repeatedly until the entire family wore their new bracelets. We do not band the adults and it is usually a very peaceful and rewarding process since we enjoy the behaviors and personalities of the spirited young falcons.

Finally, after two years of failing to hatch eggs in K-14, a female kestrel shields hatchlings on May 19, 2017. The five hawklets grew to fledge around June 16.

Practicing conservation is an entertaining and rewarding team endeavor, so Raptor On into 2018!