Kestrel Chicks in Nest Box Box 16 at Gallant Woods Preserve


Alum Creek Lake along Hogback Road near Kilbourne, Ohio

Ospreys on Platform One, the most northern, and Platform Four have been incubating eggs since April 17 and 15, respectively. The lone female on Platform Two appeared to be incubating for five days before she returned to standing on her nest or the platform’s perch. All of the fish hawks (a common local name for Ospreys) at Alum Creek seem to get along relatively well with each other.

Hoover Reservoir at Galena

The Osprey on Platform One started incubation sometime between April 3 – 11. Their eggs have hatched and I observed them feeding nestlings on May 15. Platform Two remains unused.

Delaware Lake south of State Route 229

The Osprey pair is very active and supportive of each other, but since no one has seen the birds incubating, apparently no eggs have been laid. This pair seems to have a fertility problem.  Of 19 successful nests since 2001, all Ospreys have started incubation sometime between April 2 and April 26, so it looks like the Delaware Lake nest will not produce fledglings in 2010, but I hope to be proven wrong.


Predicted Hatch Dates: There are several ways to predict when Osprey eggs will hatch. One source says that the incubation period is 37 days long from the first egg laid until an egg hatches. I chose 33 days after incubation starts to predict hatch dates. After hatching, it usually takes ten days to two weeks before heads of nestlings can be seen during feeding. Here are my predictions:

  • Alum Creek No. One: May 20 hatch date.
  • Alum Creek No. Four: May 18 hatch date.
  • Hoover Reservoir No. One: May 10, plus or minus four days.  (The Hoover osprey eggs hatched sometime before May 15.)

Memorial Day weekend looks like a good time to start watching Osprey family life, including hunting dives, fish deliveries, and feedings.

American Kestrels

Kestrel Chicks in Nest Box Box 16 at Gallant Woods PreserveSince the April 7 update, Dick Phillips and I have had three separate monitoring sessions across all or part of 18 roadside nest boxes installed for our smallest falcon.  Most of the boxes hang from electric poles along a fifty-mile-long route in Delaware County. Here are the results:

April 21, 2010

We found 16 active nests. In six nests, female kestrels sat silently and occasionally looked up with opened beaks. Their desire to be left alone is always respected. Nine nests showed clutches of eggs, usually after parent birds flushed when the fiberglass ladder was adjusted against electric poles. One nest held hatchlings with one egg and we knew that we could band this family in two weeks since kestrels can be sexed with certainty after 14 days of age when brown primary wing feathers sprout from feather sheaths on females and blue-gray wing feathers appear on males.

I removed blue European Starling eggs from two nests, proof that no kestrels were interested in these nest boxes.

May 6, 2010

Three Week Old Kestrel Chick in HandThis monitoring trip started with a nest failure. The nest box had held five eggs on April 21, but was found empty with grass in one corner. One whole kestrel egg was found near the foot of the utility pole in a field of sprouting corn. All evidence pointed to a raid by a starling that used its beak to carry kestrel eggs from the nest chamber. Both kestrels are still seen at the site and we concluded that the birds made the mistake of venturing too far from their nest, giving a starling an opportunity to raid it. Things do not go well for a raider caught in the act. In the past, we have found headless starlings, or some with gaping holes in their backs. In the meantime, we expect the failed kestrels to renest with greater vigilance after learning their costly lesson.

The good news is that after finding the failed nest, we found 15 active nests, five with stubborn females, three with eggs, and seven with nestlings or hatchlings. We attached U. S. Fish and Wildlife Service aluminum leg bands to a family of four males and one female. We planned to band two or three families the following week when the nestlings are still young enough to handle without gloves. The maximum age to band is 24 days old, but the birds are nasty at that age and we don’t want to get our blood on their feathers. After we band a family, we do not visit their nestbox until they have had time to fledge. Kestrels fledge around 30 to 32 days after they hatch.

May 13, 2010

We returned to two nest boxes and found two families with wing feathers mature enough to identify the sex of their owners. We fitted those families with leg bands.

All boxes without banded families will be checked the following week, and my data book will be used to predict when remaining families will be ready for banding. So goes the 2010 kestrel season until all banded nestlings fledge to decorate the countryside with more small falcons.

Book Note

The following book helped me to accurately age this family: A Photographic Timeline of Hawk Mountain Sanctuary’s American Kestrel Nestlings by James R. Klucsarits, Jashua J. Rusbuldt, and four other contributors, published in 2007. This 36-page booklet is printed and distributed by Zip Publishing, Columbus, Ohio. [Editor’s note: it appears that this book is no longer available directly from the publisher. You may be able to find a used copy in a local bookstore or online.]  I highly recommend this book for those who study or work to conserve American Kestrels. And since kestrel nestlings have big black eyes that make them extremely cute and appealing, a child of any age would also enjoy this book.