In 2015, North America’s smallest falcon had 18 nestboxes in the northern third of Delaware County to choose from. They chose 14 boxes and 55 young fledged from 12 successful nests for an 85.7% nest success rate. From 67 eggs laid, 55 (82.1%) hatched and all hatchlings fledged for an average of 4.58 fledglings per successful nest, a very good effort, indeed.
Of the two nests that failed, one nest appeared to be abandoned since no adult birds were seen once the eggs failed to hatch. The second failed nest always had adults in or near their box, indicating that the eggs were infertile, possibly due to parents being spooked off the nest during incubation by activity overflowing from a bridge construction site.
The season was late compared to the average. The first kestrel egg in 2015 did not appear until April 9. In past years, March 14 has become the record first-egg-date, and since 1995, more than one third of 257 nest attempts had eggs before April 9. Since the 2015 season was late, no boxes were used for second families. The last fledgling of 2015 flew into the outside world around July 9 to end a 92-day nesting season. During past seasons, the latest fledging date has been August 26, completing a possible 166-day season when March 14 is the first-egg-date. The 2015 season was truncated to 55.4% of the possible duration for kestrels that nest in Central Ohio.
Dick Phillips and I monitor the project’s boxes. Dick’s truck hauls our ladder and we start checking the boxes in mid-March to add bedding and check for needed repairs. We diligently check the boxes every two weeks until eggs appear, then once first-egg-dates are ascertained, or nestlings are aged by comparing their traits to sequential growth images in the book, A Photographic Timeline of Hawk Mountain Sanctuary’s American Kestrel Nestlings, then we visit only boxes that hold nestlings that are between 14 and 24 days old in order to attach leg bands. While banding nestlings, we can determine their sex since males have blue-gray wings and females show brown and black wings. Once we band nestlings, we no longer check their box until my data book shows me that the family must have fledged. Also, since the latest first-egg-date in the history of our project has been June 25, any empty boxes prior to that date must be checked during the earliest days of July to make sure we don’t miss late nests. Otherwise, there is no need to check boxes until late summer or early fall when we clean out used bedding and add new.
We made ten monitoring trips between March 18 and October 20. Of course, there were no eggs or nestlings during our first and last visits. During four of the eight remaining monitoring trips, we banded nestlings. On June 24, we traveled to only one box to band its resident family, the last banding of the season.
Twice, we hosted visiting kestrel conservationists that wanted to see the hows, whys, and habitats where we had located our project’s nestboxes. On June 13, fellow bird banders Bob Thobaben and Sylvia Hadley traveled from Clinton County to join Dick Phillips and me as we monitored our boxes.
Sylvia and her husband, Larry Lankford, had installed five kestrel boxes by the 2015 season and kestrels nested in two boxes. Presently, the Clinton County effort has expanded into Warren County with a total of 14 boxes, including two mounted on free-standing poles. It was a good day with much information exchanged as six kestrel boxes held nestlings, including families of 5, 5, 4 and 3 nestlings, respectively, that were old enough to receive leg bands. Cameras recorded much of the action for future programs promoting conservation.
On July 11, Dick and I hosted Taylor Joray and Andrea Pacheco from Illinois. Taylor is a master’s student studying conservation biology at Illinois State University in Normal, Illinois. In 2012, Taylor started a kestrel nestbox project of 24 boxes in his home county of Kane County west of Chicago. Later, Taylor read about the Delaware County project and our kestrel box in The Audubon Birdhouse Book, published 2013. Recently, as part of his study of adult kestrels, Taylor has been using a bal-chatri trap to catch and band kestrels throughout Illinois. One of a dozen falcons that Taylor has caught was already wearing a leg band and the Bird Banding Lab will soon announce where and when the bird acquired its permanent identification.
Unfortunately, all our kestrels had fledged prior to our July 11 tour and we only had to check nests for nestlings that might have died. Fortunately, we found no nestling remains and numerous airborne fledglings and adults put on a good show along our trip’s route. Both tours ended in Gallant Woods Park, the home of K-16, our only box that hangs from a custom built pole. The free-standing pole system gives monitors the freedom to mount their kestrel box at any location, and we showed our guests how the box’s winch works to easily lower a nestbox for a trouble-free monitoring visit.
Bad-luck Fledglings
Two kestrel fledglings fell victim to a common threat, the urge to drop from an overhanging utility wire to land on a road’s surface. On June 12, we traveled west beyond Marysville to Donna Daniel’s home near North Lewisburg to band a family of five kestrels. Donna had invited her surrounding neighbors to the banding and a good time was had by all. One family representing three generations thoroughly enjoyed the feisty nestlings that were destined to consume mice, grasshoppers and other pests from their farms’ fields.
Unfortunately, on July 6, Donna discovered the remains of one of the male fledglings flat on the road near her home. Alert neighbors had reported the rest of the family had been roosting in trees in the area and no more road-kills took place.
Five days earlier, on July 1, I had received a phone call from Mike Jordan. Mike had been driving on Harris Road east of Delaware where five kestrels had just fledged from Box K-1. Mike, who with his wife Becky, feeds ground corn meal to thousands of Snow Buntings, Horned Larks and Lapland Longspurs that migrate to Delaware County every winter, was disturbed when he watched a car smack one of our kestrels without its driver making any effort to miss the hapless falcon. Mike stopped to help the bird, but it had died instantly. The beautiful young bird now lies in a freezer at the Ohio Wesleyan Zoology Museum where it awaits a student curator to preserve it for posterity. Hopefully, it did not die in vain and will be used for education and science in the future.
While 17 of our project’s boxes hang along rural roads from utility poles managed by the project’s main partner, Consolidated Electric Co-Op, Inc., it makes no difference where a kestrel box is located in relation to a road since kestrels prefer to hunt from wires that stretch above grassy berms alive with small rodents, insects, and sometimes, if wet enough, skinks. A road’s speeding cars can also offer insects and small birds to kestrels that cannot pass up the opportunity to salvage dead morsels from the road’s surface.
Whenever I spot kestrels standing in my car’s path, I apply my brakes and try to traumatize the distant “sparrow hawks” with my blaring horn. Our smallest falcon does not like loud noises from our world and will become leery of oncoming traffic in order to live a long, peaceful life.
I worry about the absence of grasshoppers during recent years and El Nino’s impact on rodent populations, but I will address those topics at a later date. For the present, I want to recommend another book: American Kestrel: Pint-Sized Predator by Kate Davis. Photos are by the author and Rob Palmer. More than 100 pages in this beautiful book will make its reader an expert on the natural history of our smallest falcon, including conservation solutions to its modern threats.
I could criticize the book for not having photos of life inside nest cavities, but the photographers most likely did not have access to top-opening nestboxes, but to fill that void, I again recommend reading about kestrel nestlings in Hawk Mountain Sanctuary’s book described earlier in this article.
Raptor on in 2016!