DNR monitors record number of osprey nests

A record 70 Osprey nests were monitored during the 2025 nesting season, an increase of 20 nests compared to 2024. This increase is likely a result of both an increasing Osprey population and an increase in nest reporting.

Of these 70 nests, 54 were active and 16 were inactive. Of the 54 active nests, 30 were reported as successful (at least one young survived to fledging), 12 were reported as failed, and 12 had no outcome reported. Twenty-two new nests were reported this year with eight of those new nests near the Des Moines metro area and six in Blackhawk County.

Osprey are a migratory raptor species that breed in Iowa. Osprey experienced population declines in the mid-20th Century. The Iowa Department of Natural Resources began the Osprey restoration program in 1997 which involved translocating young birds from Minnesota and Wisconsin to strategic locations across Iowa.

The last year that birds were released was 2016, and the current objective is to monitor nesting activity.

There are three main areas in the state where Osprey have become well established, the Iowa City to Waterloo corridor, Des Moines metro area, and Spirit Lake and vicinity, though there are other scattered nesting locations across the state.

Monitoring of nest sites is accomplished primarily by volunteers. Volunteers are assigned to a particular nest or nests and new nests are reported opportunistically. Volunteers visit the nest multiple times during the breeding season and gather information on nest activity at the start of the nesting season and whether the pair is successful in fledging young toward the end of the nesting season. Some opportunistic reports of nesting activity are also accepted if no formal data are available.

In 2025, 22.2% of monitored active nests had an unknown outcome. This rate is slightly lower than last year (23.1% unknown outcome nests in 2024).

Based on available data, 55.6% of monitored active nests were successful (30 nests) and a minimum total of 58 young were fledged. This is a slight decrease in the percentage of successful nests from last year where 64.1% of monitored active nests were successful (25 nests) but with an increase in the number of known active nests, the number of young fledged increased.

An average of 1.38 young were produced per known-outcome active nest, down slightly from last year but higher than the three years prior. The majority of new nests monitored in 2025 were in the Des Moines Metro and in Blackhawk county near Cedar Falls and Waterloo. These areas have plenty of water resources for foraging, and no shortage of tall structures, like communication towers, for nesting.

Osprey breed for the first time at three or four years of age and, in areas with abundant resources, prefer to nest in loose colonies with other Osprey pairs, often returning to the general area where they were hatched and raised. The increase in active nest sites in these areas is likely due to the return of adult birds that successfully fledged from nearby nests in recent years.

As the number of nest sites increase the expansion of the breeding area quickens, and we would expect to see these areas continue to support new nesting pairs in the near future.

Continued monitoring and reports of new nests in these areas will help us track this anticipated trend

The DNR will continue to monitor Osprey nest sites with the partnership of volunteers. An ongoing challenge is that Osprey like nesting on cellular towers. Osprey don’t generally cause damage to the towers but conflicts can arise when work must be done on a tower during the nesting season, especially since over 81% of the 2025 active Iowa nest sites were on cellular towers. We will continue to work with partners on managing this potential conflict.

Contact the Volunteer Wildlife Monitoring Program Coordinator at vwmp@dnr.iowa.org if there is an Osprey nest in your area and you are interested in helping with monitoring in the future.