Kestrel Nest Box Program

Kestrel Nest Box Program

In 2006, long-time board member Bob Simons launched our Southeastern American Kestrel nest box program, building, installing and maintaining nest boxes to support these small falcons that require cavities for nesting. This resulted in about 130 boxes being put up in North Florida between 2006 and 2015. Many of the boxes have been used by kestrels or screech owls for nesting but, to begin with, very little monitoring was done. In 2019, it was decided to revive the program, making use of the abilities and energy of interns from the new Alachua Audubon college internship program initiated by UF Professor Katie Sieving. A committee, led by Bob, was formed to carry out the mission.

Southeastern American Kestrels are a non-migratory subspecies of kestrel found in open pine savannahs, sandhills, prairies, and pastures in Florida and the southeastern United States. They are listed as threatened in Florida due to a decline in nesting and foraging habitat.

Former intern Adrian Dougherty installing a new kestrel nest box high above the ground.

A telescoping pole camera for monitoring nest boxes was purchased with a grant from Florida Power & Light. With the help of enthusiastic college interns, we built new kestrel boxes and bluebird boxes. We also started doing maintenance on some of the old, installed boxes, using an extension ladder to access them (most are 12 to 18 feet off the ground). Boxes have been installed on utility poles, pine trees, cabbage palms, and other structures in cattle pastures, agricultural fields, private lands, and other habitats supporting grasshoppers and small lizards, the primary food of kestrels. Hazards to nest boxes include lightning strikes to the host tree, other tree mortality, utility pole replacement, and nest box deterioration from weather exposure. Wasps are a frequent hazard, building nests inside or on the underside of boxes.

Bob Simons installing sheet metal bands to prevent predators from reaching the next box.

Each year in November we begin making trips to check on installed boxes to inspect, repair and clean them and to add nesting material when needed. Interestingly, kestrels do not gather their own nesting material. During the 2019-2020 season, the team began adding aluminum sheet metal bands to the trees and poles that support normally active nest boxes to discourage predators such as raccoons and rat snakes from raiding the nests. We also apply Amdro fire ant bait around ant nests active bird nesting locations. Fire ants are the primary predators of kestrel nestlings. In addition to kestrels, boxes are sometimes occupied by Eastern Screech Owls, flying squirrels, fox squirrels, Eastern bluebirds, Great-crested Flycatchers and other inhabitants.

A rat snake found inside a kestrel box.

In 2022, we saw increased nesting both at and around Ichetucknee Springs State Park (5 nesting pairs). These boxes are monitored by park staff. We also saw increased nesting on the county-owned property at Watermelon Pond (7 nesting pairs). There are other active nests in boxes scattered around the western half of Alachua County.

Some boxes put up in Columbia, Gilchrist and Suwannee Counties have been maintained and monitored regularly by Richard Melvin, a licensed bird bander. Six boxes put up on the Florida Fish and Wildlife Conservation Commission (FWC) property at Watermelon Pond are monitored by FWC staff. Others have put up boxes in Marion and Clay County.

Nest boxes are scattered widely throughout Alachua County and beyond. There is rarely enough time and assistance to check all known boxes so attention is focused on those with documented kestrel nesting activity. Nesting begins in mid-March and is completed by early June. During this most exciting period, the telescoping camera is used to monitor the boxes and photograph eggs and chicks.

Adult kestrel with eggs.
Young chicks waiting for food.
Interns using the pole camera to check the nest box.

To date, Bob Simons and friends, colleagues, his wife, Erika, and interns have built about 150 kestrel boxes and about 220 bluebird boxes. From the limited amount of monitoring (further hampered by Covid), we know that from 2019 – 2022, at least 54 kestrel chicks and 12 screech owl chicks have been seen in the nest or fledged. Almost 200 eggs of kestrels, screen owls and bluebirds have been seen but we were unable to follow up to see if they hatched and fledged.

Going forward, we still have many old boxes to check, and have found potential locations for putting up new boxes. We have continued to make use of interns, rejuvenating old boxes, putting up new boxes, and monitoring the boxes with the pole camera as kestrels and screech owls begin their nesting season. We hope to be able to increase the number of people checking boxes so that we can gather more data, especially during May and June when chicks can be counted. Many of the interns so far have reported that this work has been one of their most rewarding and most hands-on experience as college students. This makes the project a success all around.

Bob the baby owlThis screech owl chick was spotted in one of our boxes in Suwannee County.