2011 American Kestrel Season One of the Best

 

Success by the Numbers

Nineteen American Kestrel nests monitored by Dick Phillips and Dick Tuttle produced 75 fledglings from 17 of 18 nestboxes making up the Delaware County American Kestrel Nestbox Project in 2011. This year’s production ranks second only to 2010’s total of 76 falcons raised. Even though all of 2011’s kestrel hatchlings grew to fledge, the average number of fledglings per nest in 2011 was 3.95 fledglings for 19 nests, which is smaller than 2010’s average of 4.47 fledglings for 17 nests. Frequent, cold rains are blamed for smaller egg clutches in 2011 with 4.42 eggs being the average among 19 nests compared to an average of 4.82 eggs for 19 nests in 2010.

All of 2011’s 19 nest attempts were successful. Out of 84 eggs, 75 (89.3%) hatched, and all hatchlings grew to fledge. North America’s smallest falcon, Falco sparverius, has become a very common nester in Delaware County. Since the first successful nest in 1995, 712 fledglings have taken to the air. Today, 16 of the project’s 18 boxes are located in farmland north of the city of Delaware, while two boxes are found across the county’s border in Marion and Morrow Counties.

During four of the project’s seasons, five nestboxes had started a second brood during the same season, but only three second broods became successful. In 2011, two succeeding broods in box K-2 produced three and two fledglings, and K-18 raised five and three offspring. The historic windows for first-egg-dates (FED) for double broods have been March 20 – April 2 for first broods, and June 2 – June 25 for second broods. One second brood in 2011 established a new project record for the latest FED, June 25. The project’s earliest FED is 14 March 1998. For 2011, the kestrel nestbox season lasted 161 days from its first egg on March 19 until the last youngster fledged on August 26.

Project History

Twenty years ago, the Delaware County General Health Department won a grant from the Ohio Department of Resources, Division of Recycling and Litter Control, to introduce recycling to school students by motivating them to recycle aluminum cans and other materials to raise money for nestboxes for sparrow hawks. During the 1992-1993 school year, members of the Delaware County Bird Club and the health department traveled to schools throughout the city and county to promote recycling in order to raise funds for nestboxes for kestrels. After students’ efforts raised more than $135, the bird club met on the Ohio Wesleyan University campus to assemble and paint the project’s first ten nestboxes. The Ohio Department of Highways became the project’s fifth partner when it joined the students, the bird club, Ohio DNR, and the health department to grant permission to the project to attach nestboxes to ten of its traffic signs along two of the county’s main arteries, Routes 23-North and 36/37 East from Delaware, busy highways that pass through all of the county’s school districts. Bird Club founder Jed Burtt wrote press releases to keep the project in the public’s eye and the Delaware Gazette acted as a sixth partner when its reporters chronicled the project’s progress from its first motivational school meetings, through can-recycling, to hanging the first nestbox. The Gazette helped put icing on the cake in a 17-June 1995 article by Jane Hawes, “Club uses Children’s donations to build sparrow hawks’ nests,” that featured a photo of monitor Bob Hanawalt holding one of the falcon nestlings. Yes, sometimes, its takes a community to launch a successful conservation project.

 

After two vehicles collided with signs and wiped out two nestboxes in 1999, decisions were made to move the project’s boxes from vulnerable traffic signs to safer and more rural settings. Consolidated Electric Co-op rescued the conservation effort by granting permission to hang nestboxes from their poles. In 2006, the electric company started adding bands of aluminum flashing around some of their poles to keep climbing raccoons and squirrels from shorting out wires and transformers, so we asked and gained permission to do likewise. By the 2007 season, we made our kestrels safe from all climbers and the electric company had 17 more poles free from expensive mishaps with furry conductors.

Also, after the Delaware project was featured in the Summer 1999 issue of the Ohio Bluebird Society’s Bluebird Monitor, Ann Sander, Fairfield County’s Coordinator for the OBS at the time, donated salvaged white pine lumber that allowed our project to expand to its present size of 18 nestboxes along a fifty-mile route. Even though six bird club members made up the original monitoring team, Dick Phillips and Dick Tuttle have checked and maintained the project’s boxes since the project’s shift from traffic signs to electric poles.

Effective Management Tactics for American Kestrels

1. We place our kestrel boxes no closer than one-half mile apart in rural settings where kestrels can see their nestbox from hundreds of yards away, and from anywhere 360 degrees around it. By the time kestrels fledge, crop fields will hide fledglings from larger hawks. (Stay clear of woodlots to avoid accipiters.)
2. Boxes need not be 20 – 30 feet above the ground as recommended by some publications. Presently, most of our project’s boxes hang at 12 feet, and during the traffic sign stage during the project’s early history, kestrels routinely nested in boxes eight feet above the grassy berm.
3. Hang boxes to face east to southeast to take advantage of a warming, rising sun, while avoiding afternoon temperature extremes.
4. A band of aluminum flashing below the box defeats climbing raccoons. (Raccoons are everywhere, so unprotected nestboxes, whether for bluebirds or kestrels, will ultimately become raccoon-feeders.)
5. Throw out starling eggs, but never throw out a starling nest. Once kestrels eat or evict starlings, they will reshape the starling’s round nest cup into an oval kestrel cup. If you replace a recently usurped starling nest with white pine bedding, a kestrel might freak-out when it returns to its box to find new furnishings. (Usually, starlings will not lay eggs beyond the first week of June.)
6. Beginning in mid-March, check boxes at least every two weeks so you can accurately extrapolate data; and you’ll never have to deal with starling nestlings.
7. While most of a kestrel’s diet is made up of small rodents, large insects, frogs and snakes, small birds are also on their menu, so keep your project and its sparrow hawks out of trouble by not installing nestboxes within sight of homes with bluebird nestboxes, Purple Martin hotels, or bird feeders.
8. Try to think like kestrels when selecting nestbox sites. Kestrels hunt from utility wires, and when compared to wires strung along a straight stretch of road, a T-intersection has 50% more wires, and a crossroads intersection has twice as many grassy berms as a lone road.
9. You will want to park in farm field access lanes during monitoring trips, but do not install nestboxes near “parking zones.” Kestrels are easily spooked by new objects near their nests. Therefore, locate boxes at least one pole beyond the nearest pole so when farmers park their machinery, kestrels won’t become afraid to approach their nestboxes. Cold temperatures can ruin an unattended clutch of eggs.
10. After the nesting season, use a spackling knife to dig out each used nest before adding new white pine bedding. Stomp and pulverize the cemented nest patty to check for remains of prey or kestrel nestlings that might have perished. Also, since many landowners take pride in maintaining neat berms, don’t leave a mess; use your foot to spread the used nest debris into the grass.
11. When a nestbox needs to be removed for repairs, always replace it with another box so a kestrel does not find a bare pole upon its return. Kestrels hold on to their territories before and after the nesting season. Our project has three extra boxes that we momentarily trade for boxes needing attention in the workshop.
12. Since our project’s kestrels are not research subjects, we never grab adults off their nests. We are convinced that most of the veteran nesters “know who we are” when we peer in on them during our King Kong routine. They know we will soon be gone as they tolerate us while experiencing the least amount of fear. Our visits are always as short as possible, just long enough to gather data so leg banding events can be accurately planned. (There are successful kestrel projects that band adult birds, but usually nets or traps are employed outside nests.)
13. Most utility companies will say “No” when you ask to hang nestboxes from their poles. It is a traditional policy, but since bucket trucks, also called cherry- pickers, have replaced the need for linemen to climb poles, policies are gradually changing. On the other hand, many projects across North America make their own free-standing poles. Our project has one such pole that stands in Gallant Woods Preserve, and by next season, it will sport a winch to raise and lower the box for easier monitoring. Two other parks in the county, Deer Haven Preserve and Blues Creek Preserve, sport free-standing kestrel boxes recently installed by an Eagle Scout candidate.
14. If anyone shows interest as they pass by when you’re monitoring your boxes, engage them, and explain your project. Neighbors, young people, families on bicycles, motorcyclists, and fishermen in their hobby vehicles, will become allies of your project if you call them over to the nestbox during leg banding, etc. Kestrel nestlings with their large, dark eyes, and ominous, sharp talons, are powerful ambassadors for all birds of prey. They aren’t Bald Eagles, but explain that more than forty years ago, captive-bred kestrels were used to prove the connection between DDT poisoning and its threat to the reproductive health among birds – and people. We owe Falco sparverius for helping us to expose our chemical threat to ourselves.

Make an effort to see some of Delaware County’ successful kestrel boxes, and plan to replicate the effort. Try to “raptor on” for our smallest falcon.