Current Avian Research

Raptor Research Project

1998 Hack Site Report

Raptor Resource Project Background Information

The Raptor Resource Project (RRP) is a 501(c)3 foundation located in Bluffton, Iowa. We work to restore the Midwest's population of Peregrine falcons and other raptors by breeding and releasing Peregrine falcons, establishing nest sites for various raptor species, and increasing public awareness through lectures and raptor displays.

RRP became a 501c3 in 1993. Since that time, we have:
1. Expanded our very successful utility peregrine nesting program. 41% of the Peregrine chicks banded in Minnesota in 1998 hatched on stacks - an amazing figure when one considers that Peregrines didn't nest on stacks until 1990. Utility stacks have the highest production rate of any nest type.
2. Designed a successful Osprey nest pole. At least four of these are currently used by nesting pairs in the Twin Cities metro area.
3. Produced between fourteen and twenty-five Peregrines for release each year.
4. Given talks free of charge to colleges, public schools, and organizations. School children have helped design and build nest boxes and band birds.
5. Begun our plan to return Peregrines to the Mississippi River.

The Raptor Resource Project is governed by a Board of Directors that includes falconers, enthusiasts, biologists, and ornithologists. The Project's Director, Robert Anderson, has been breeding Peregrine falcons since 1985 and is considered one of the country's top breeders. In 1987, Minnesota recognized his contribution to Peregrine recovery by naming him the Minnesota Conservationist of the Year.

Mississippi River Project Overview

The overall mission of the Mississippi Recovery Project is to develop a self-sustaining population of Peregrines nesting, with no human interference, along the banks of the Mississippi River and its tributaries. Our long-range objectives are:
1. To restore the Peregrine falcon to its traditional range on the Mississippi River and its tributaries.
2. To develop a methodology with which to overcome imprinting in animals raised for release - a methodology whose basic principles can be applied over a wide range of species.
3. To apply that methodology to recover other raptor species, or to assist other organizations in their recovery work.

There is debate over whether or not the Peregrine falcon can be considered truly recovered. While the number of Peregrine falcons has increased since the species' near-extinction by DDT, we have yet to see a self-sustaining population. First-year mortality rates are very high - around 75% - and the number of birds producing young in any given year fluctuates from year to year. According to the Peregrine Fund, 35 pairs of Peregrines produced 51 young last year in Iowa, Minnesota, Michigan, Wisconsin, Indiana, Kentucky, Ohio, Illinois, Missouri, Kansas, and Nebraska. This figure means that roughly 12 new birds were added to the population last year, given the first-year mortality rate of 75%.

The majority of Peregrine falcons nest in urban/industrial locations, which require a great deal of maintenance and the continued cooperation of building owners and businesses. Peregrines have attacked building tenants and delayed construction at several urban sites, leading building owners in Minnesota, Iowa, Ohio, and Wisconsin to ask that Peregrine nest boxes be removed. In short, the species currently depends on the continued good will of building and business owners, which shows some signs of eroding. The species does not carry itself from year to year, but is assisted by organizations and individuals that volunteer a great deal of time and effort to support Peregrine recovery at its current level. Finally, the species has not returned to its native habitat in the Midwest - the cliffs of the Mississippi River and its tributaries - despite seventeen years of recovery work and Peregrine releases. The Raptor Resource Project plans to release 60 Peregrine falcons from Effigy Mounds National Park along the Mississippi River in Allamakee County, Iowa, as outlined below.


Two factors may be interfering with the Peregrine's return to the cliffs. One is nest-site imprinting and the other is tradition - the propensity of the species to nest in spots where the species nests.

1. Imprinting
Research done with raptors indicates that nest-site imprinting plays a very important role in determining where Peregrines nest. Simply put, Peregrines tend to nest in places similar to their natal nests, and disregard potential nest-sites which do not physically resemble their natal nest site. Urban birds will fight other birds over potential territory rather than nest on a rock face.

Our experience raising and releasing Peregrine falcons tabs with the research mentioned above. We are convinced that young Peregrines must be raised in a location as similar as possible to a natural rock face if they are to nest on rocks as adults. We have built a "natural eyrie" - a cliff-like nest built of real and simulated rock - to raise young Peregrines in. Exposure to humans will be as limited as possible. After the first few days, Peregrines are cared for without human contact. The eyrie opening faces a natural view, with no man-made structures/stimuli in sight.

2. Tradition
Research indicates that establishing even a small population of cliff-nesting Peregrines in an area with more urban-nesting birds than urban nests may cause the "overflow" population to migrate to the cliffs instead of battling over territory, as is happening now. By releasing birds that have been imprinted to nest on rocky ledges, we ultimately change the behavior of the existing "wild" population, which nests almost entirely in urban/industrial locations. In short, this project is designed to address the dual barriers of imprinting and tradition to nesting on cliff sites.

As mentioned above, the Peregrine chicks to be released as part of this project are being raised in a rock, wood, foam, and fiberglass "cliff" that closely simulates ledges on the bluffs of the Mississippi River. This cliff has already been built - nine young were raised inside the cliff this year. Peregrine falcons are released through a special technique called "hacking," commonly done from the tops of tall urban buildings. The Raptor Resource Project will hack, or release, these Peregrines from the bluffs of Effigy Mounds National Park, located in Allamakee County, Iowa, along the banks of the Mississippi River. We are building special hack boxes to resemble rocks - human interference and involvement will be minimal. Hacking will be done in two to four batches, three to five birds at a time. Project volunteers, friends, and members will monitor the release site, cliff faces where Peregrines historically nested, and urban sites where Peregrines currently nest. Project methodology is based on the work of ornithologists in Germany, who succeeded in re-establishing a historic tree nesting population by directing their releases at the canopy. Peregrines tend to nest in spots that very closely resemble their natal nesting and fledging spots - by raising and fledging birds in cliffs we imprint them to nest on cliffs as adults.


There are several benefits to the proposed project. Among them:
1. The return of Peregrines to the Mississippi River and its tributaries.
2. The establishment of a Peregrine population that nests without human intervention.
3. The development of a raise/release methodology that could be used to recover other species (the swallowtail kite comes to mind.)

The Peregrine's swiftness and aerial acrobatics are unmatched. Prior to DDTs introduction, Peregrine falcons pursued their prey along the Mississippi River Valley: eyries have been identified near Prairie Du Chien, Maiden Rock, and Effigy Mounds. We will begin our reintroduction effort at Effigy Mounds. Utility dispersal rates along the river give us reason to believe that cliff nesting Peregrines will travel along the river valley from this point, affecting urban nesting populations as they go.

Our work will restore a once-extirpated species to the Mississippi River Valley, establish a core self-sustaining population of Peregrine falcons, provide valuable data on the role that nest-site imprinting and tradition play in site selection, and provide other groups with an easily-replicated method of raising and releasing endangered raptors.

Amy Ries
Raptor Resource Project

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