Monday, March 11, 2013

American Kestrels and a Plan to Stem Their Decline

by Robert Evans

We recently posted the results of our 2012 Christmas Bird Count. While the results show some good news, such as high numbers for Bald Eagles, they also show that a troubling trend is continuing in our area, the decline of the American Kestrel. American Kestrels have gone from a high of 54 sightings in our 1990 CBC to a low of only 2 sightings in our 2012 CBC. This trend has been seen throughout the Northeast, where the most common falcon in North America is becoming something of a rarity. This year, Valley Forge Audubon Society is putting a plan together with the help of the Willistown Conservation Trust and the Peregrine Fund to stem the American Kestrel's decline.

The American Kestrel is North America's smallest falcon, and it's most colorful. Males sport slate-blue wings that contrast nicely with a rufous back and tail and tawny breast. They also have a slate-blue cap and two dark vertical lines on either side of their face sometimes referred to as "sideburns and a moustache". Black bars spot the back and breast. The female has rufous wings instead of slate-blue and a lighter colored breast. The American Kestrel mostly eats large insects such as grasshoppers, beetles, butterflies, and moths, as well as rodents such as voles and mice. Kestrels are birds of fields, meadows, and agricultural areas. They're often seen perched on a branch or wire overlooking a grassy field, scanning for prey. They can also be found hovering over fields when tracking prey, a behavior that's unusual for a falcon.

A big reason for the American Kestrels' decline is that those fields, meadows, and agricultural areas are quickly disappearing. Open, grassy areas are rarely preserved, often because they aren't perceived as being as ecologically "valuable" as forests or wetlands, and usually turned over for development. Farms are also disappearing and being replaced by subdivisions, and those that do remain use farming practices that no longer support wildlife. The American Kestrel is a cavity-nester, and the removal of dead trees and hedgerows from their habitat reduces the number of places they can nest.  Another factor that could be contributing to their decline is pesticide use, which reduces their prey and can effect their hatch rates and clutch size.

Our best plan to stem the American Kestrel's decline is to look at a plan that worked so well for another cavity-nester of similar habitat, the Eastern Bluebird. Bluebirds were a rare sighting as recently as the 1980s but are much more frequent now. The key to their recovery was the use of nest boxes and nest box trails, which gave bluebirds an opportunity to nest free from the competition of invasive species such as European Starlings and House Sparrows. Like many cavity-nesters, American Kestrels will readily build a nest in man-made nest box. Now instead of a bluebird trail, we're setting up a kestrel trail.

But unlike bluebirds, kestrels are able to outcompete starlings and sparrows for nesting sites. Many questions remain about why this species is in such a significant decline and what can be done to help them recover. One group working to find answers to their decline is the Peregrine Fund. Founded in 1970 to help another falcon in decline, the now recovering Peregrine Falcon, the Peregrine Fund has set up a project dedicated to the American Kestrel's recovery called the American Kestrel Partnership. This project combines the efforts of citizen scientists and professional ornithologists and biologists to find clues as to why kestrels are declining and what can best be done to save them.

Anyone with access to suitable kestrel habitat can set up a nest box and then register that box at the American Kestrel Partnership's website. By actively monitoring the box and submitting those observations online, the scientists at the Peregrine Fund can look at factors that may contribute to a nest box's success. Does close proximity to woodlots force kestrels to compete with Screech Owls for nest sites or Cooper's Hawks for territory? Are there any predators such as raccoons or snakes that actively feed on nestlings? Are nest boxes mounted on a pole or stake more successful than those mounted in trees? When questions like these are answered, an effective plan for American Kestrel recovery can be put into place.

Valley Forge Audubon is doing its part by setting up a "trail", a series of nest boxes at different locations throughout our chapter area to maximize our contribution to finding an effective solution. All of our nest boxes will be registered with the American Kestrel Partnership and actively monitored by volunteers. The difficulty with this has been finding suitable habitat for the nest boxes. This is where our second partnering organization, the Willistown Conservation Trust comes in.

The Willistown Conservation Trust is a non-profit land trust dedicated to preserving the rural areas surrounding Willistown, PA. The trust manages several preserves, such as Rushton Woods and Ockehocking, and has worked with several landowners to permanently preserve their farms and rural homes. Much of the land here is perfect habitat for American Kestrels and nine nest boxes have been set up here, some on preserves, but more on private land. As an added benefit, much of this area is part of the Ridley/Crum Creek Important Bird Area.

We are also working on setting up nest boxes at five other sites. One of these, Charlestown Farm, which is outside of Phonexville, will be the site of a program on American Kestrels on March 23. We're hoping that our efforts don't stop with these 14 nest boxes. Any of our members with access to suitable habitat, at home, work, or school, can set up a nest box and join us on the American Kestrel Partnership website. A concerned and active community is probably the best chance the American Kestrel has at a successful recovery.

Through the help of volunteers, bird and nature enthusiasts, and dedicated scientists, the American Kestrel can join the likes of the Bald Eagle, Eastern Bluebird, and Peregrine Falcon -- birds that were once in significant decline but now on their way to recovery.

Find out how you can help: Join us for our program “How to Attract American Kestrels” at Charlestown Farm on Saturday, March 23 at 2:00 p.m. Charlestown Farm is located at 2565 Charlestown Road, Phoenixville, PA 19460. For more information, contact Vincent Smith at If you're interested in setting up a nest box, you can also contact us at our website, here.

You can learn more about the Peregrine Fund by visiting their website, Their website dedicated to the American Kestrel Partnership is

Valley Forge Audubon Society would like to thank the people at Willistown Conservation Trust for their help. You can learn more about the Willistown Conservation Trust on their website, We'd also like to thank Adam Pinos, Tony Nastase, and Pat Nastase for building the nest boxes.

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