Breeding Peregrine Falcons (Falco peregrinus) disappeared from Iowa in the mid-20th Century. Peregrine Falcons historically nested on cliff ledges, but have also adapted to nest on human-made structures like tall buildings and bridges. Iowa DNR began a Peregrine Falcon restoration program in 1989 with 23 birds released in Cedar Rapids followed by another 19 released in Des Moines in 1991. Between 1989 and 2003, a total of 169 birds were released in Iowa feeding into a regional restoration effort that saw 875 birds released across the Midwest. In 1999, the first pair of birds nested on their historic nesting grounds along the Mississippi River bluffs. As of 2024, most of the Peregrine Falcon nesting occurs in the eastern half of the state in three main environments: Urban, Mississippi River bluff faces, and energy plant towers.
Monitoring of nest sites is accomplished by a network of volunteer and professional surveyors. The Raptor Resource Project monitors and bands a number of Peregrine nest sites in the northeastern corner of the state. Several of the nest sites are on power plants which have restricted access so we rely on employees who not only monitor the nest sites but are often wonderful stewards for the birds. Surveyors collect data on the nest’s activity and whether the pair are successful in producing fledglings. Some opportunistic reports of nesting activity are also accepted if no formal data are available.
There were a total of 17 nests monitored in 2024 with no new nests reported. Of these 17 nests, 15 were active and 2 were inactive. Of the 15 active nests, 11 were reported as successful, 2 were reported as failed, and 2 had no outcome reported. The average number of young produced per nest with a known outcome was 2.77, a notable increase from last year (1.92).
Compared to recent years, 2024 was an above average year for Peregrine reproduction, with a higher percentage of successful nests (73.3%) than the previous four years. A minimum total of 36 young fledged from the 11 successful nests, notably higher than 2023 (25 young fledged), and the average of 2.77 young produced per nest is the highest since 2016.
Though Peregrine Falcon nest success increased in 2024, continued monitoring is warranted with ongoing disease threats such as Highly Pathogenic Avian Influenza (H5N12.3.4.4). Highly Pathogenic Avian Influenza (HPAI) predominantly affects wild waterfowl and shorebirds but can also be spread to species that eat waterfowl and shorebird prey, such a Peregrine Falcons and Eagles. In 2022, the Iowa DNR documented the loss of one nesting Peregrine to HPAI and in 2023 documented the loss of one Peregrine that wasn’t a nesting individual. Overall, Iowa’s nesting population of Peregrine Falcons appears to be stable, with birds generally returning to historic nesting sites each year, but this recovering population continues to warrant annual monitoring.
A huge thank you to all of the volunteers who are vital to tracking Peregrine Falcon nesting in Iowa. The DNR will continue to monitor nest sites with the partnership of volunteers and others who care about falcons in Iowa. Falcon nest sites can be very challenging to monitor because of their location and the territoriality of the birds so any data received are much appreciated. Please contact the Volunteer Wildlife Monitoring Program coordinator if you are interested in helping with monitoring in the future; vwmp@dnr.iowa.gov .