American Kestrels on Utah Farmlands
By Casey Burns, State Biologist, USDA Natural Resources Conservation Service, ut.nrcs.usda.gov, (801) 524-4566, firstname.lastname@example.org
Attracting Kestrels and Barn Owls for Pest Control
Native predators will rarely completely eliminate a pest problem, but can be part of a multifaceted solution to pest control. Using wildlife to help control pests can improve crop production, cut down on pesticide use, improve water quality, save time, supply important habitat, and provide viewing enjoyment. The concepts outlined in this document are ideal for farmland, but can also be used in parks, golf courses, large gardens and yards, and other open areas.
The barn owl and the American kestrel are easy to attract to farmland by installing nest boxes because natural nesting cavities may be difficult to find. Although many raptor species will hunt on agricultural land, nesting pairs will focus hunting near the nests and will capture increased amounts of rodent and invertebrate prey for their growing chicks.
Barn owls primarily prey on nocturnal rodents, especially voles and gophers. Barn owls are known to kill and stockpile more prey than needed. Kestrels, formerly known as sparrow hawks, will hunt large insects, such as grasshoppers, crickets, beetles, and moths, as well as small mammals and birds. Attracting raptors may also help with avian pests, such as magpies and starlings, by changing their behavior. The presence of predators nearby may make the pest species more cautious and less likely to come into the area to feed or will feed for shorter periods of time.
There are many small details that will make a nest box more suitable to attract and fledge birds. Important factors include the number and location of boxes, timing of box set up, predation and competition, management of the area around the box, and box design. See the fact sheet, “Attracting Wildlife for Pest Control on Farmland” for more detailed information. Ideally, boxes are mounted on wooden or metal poles, but can be installed on other existing structures if safe from predation (see above) and road kill.
Beware, there are many inappropriate designs for these nest boxes on the internet. Be sure to contact NRCS or HawkWatch to get the best designs. The Peregrine Fund kestrel box design is recommended for most situations. There are boxes for purchase on the internet and at some home stores, or you can build your own.
Snags, which are standing dead trees, are important for many types of wildlife, especially species that provide pest control on farmland. Snags provide cavities for nesting birds and other wildlife, important foraging sites for woodpeckers, and perching sites for many species of birds. It is important to maintain natural snags whenever possible. Artificial snags and perches can also be installed to benefit wildlife. Materials can be dead trees or branches, or wooden or metal posts. Artificial perches should be 10 to 30 ft high, and benefit from a small crossbar (1 to 3 ft). Different heights and structures will attract different species, so a variety is ideal. Kestrels prefer perching on fence lines and wires. Installing wire perches, where perching wires are not already present, may attract hunting kestrels. Installing wire perches in conjunction with nest boxes can be especially beneficial.
There are numerous other structures you can build to attract beneficial wildlife to your property. Consider bat boxes to attract insect-eating bats, bluebird boxes to house these attractive insect-eating birds, tree swallow boxes to attract these colonial nesting mosquito-eating birds, and bee blocks to provide nesting sites for these valuable pollinators. Also consider brush piles, downed wood, and rock piles as habitat for terrestrial pest predators.
American Kestrel Nest Box Study
America kestrels populations have declined approximately 65% across North America in the last decade, and experts are not sure exactly why. Theories on what has precipitated the recent decline are climate change and pesticides. The species can be considered an indicator species for ecosystem health, due to its position higher on the food chain. The NRCS has recently joined with the American Kestrel Partnership, coordinated by The Peregrine Fund, to help better understand kestrels and search for a solution to the decline. The Partnership is a network of nearly 600 organizations, individuals, and agencies establishing and monitoring kestrel nest boxes for occupancy and nesting success. With data from across the continent, the cause and solution to the decline is more likely to be discovered. HawkWatch International, based in Salt Lake City, is a member of the Partnership, and will also be contributing data into the national data set. However, HWI is gathering more in-depth information using its volunteer citizen scientists. HWI is looking to better define the variables associated with quality kestrel habitat in Northern Utah.
In order to understand the decline of the kestrel and figure out a solution, landowners with suitable, open field, habitat are encouraged to get involved in the effort by establishing kestrel boxes and joining the monitoring effort. In addition to contributing toward this valuable goal, landowners will receive the pest control benefits of hosting kestrels.
NRCS staff are able to assist landowners in planning kestrel boxes as part of integrated pest management plans, and/or as part of wildlife habitat enhancements plans. Funding may be available for landowners, particularly on agricultural land, to install and monitor the boxes. Monitoring would be optional to the landowners, and would contribute to the Partnership database. More intensive monitoring could be done to support the HWI effort and the Partnership. HWI volunteers may be available to monitor kestrel boxes.
-Casey Burns, USDA NRCS
For More Information:
HawkWatch International: hawkwatch.org, Shawn Hawks, (801) 484-6808
American Kestrel Partnership, kestrel.peregrinefund.org