Article

Raptor Monitoring Surveys 2022

Rocky Mountain National Park (RMNP)’s 2022 raptor monitoring season began February 21 and concluded August 12, 2022. During the season, 51 monitoring sessions took place at seven major monitoring areas, capturing raptor breeding and nesting data across 17 individual rock formations. This year, staff and volunteers contributed 407 hours of monitoring to the program. While less than the total monitoring hours completed in 2021 (416 hours), 2022 monitoring hours were well above the 10-year average of annual monitoring hours (~300 hours).

Results

2022 was a successful year for raptor management at Lumpy Ridge. Two chicks successfully fledged during the breeding season – one Red-tailed Hawk and one Golden Eagle. While this number may seem low, most raptor species only produce one chick per season. Past monitoring data show that, at Lumpy Ridge, the greatest number of total raptor fledglings observed in a season was seven (2004). Some years, including a stretch from 2016-2019, resulted in no successful fledgling observations in this area.

The Golden Eagle chick was observed late in the breeding season. To ensure the chick had adequate time to fledge, temporary closures were extended at Sundance Buttress, The Needle summit, and Thunder Buttress. Several other closures were lifted early due to lack of breeding and nesting observations.

See Results by Monitoring Location

Surveys Completed: 9
Raptor Observations: Golden Eagle, Peregrine Falcon, American Kestrel, Prairie Falcon, Bald Eagle, Osprey
Breeding Behavior Observations: Peregrine Falcon, American Kestrel
Nesting Observations: None
Management Action: Closure lifted early (June 3rd) due to lack of observed breeding activity

Surveys Completed: 16
Raptor Observations: Golden Eagle, Peregrine Falcon, Red-tailed Hawk, Bald Eagle, American Kestrel
Breeding Behavior Observations: Golden Eagle, Peregrine Falcon
Nesting Observations: On July 17, monitors confirmed a Golden Eagle chick. The chick fledged on July 29th and was observed undergoing flight training on August 12th.
Management Action: All closures in the Thunder area were extended until August 15th to allow the Golden Eagle chick adequate time to fledge.

Surveys Completed: 14
Raptor Observations: Golden Eagle, Peregrine Falcon, Red-tailed Hawk, Bald Eagle, American Kestrel
Breeding Behavior Observations: Golden Eagle, Peregrine Falcon
Nesting Observations: Red-tailed Hawks successfully fledged one chick observed by monitors July 1.
Management Action: Closure was lifted on July 31st.

Surveys Completed: 4
Raptor Observations: Peregrine Falcon, Golden Eagle
Breeding Behavior Observations: Peregrine Falcon, Golden Eagle
Nesting Observations: None
Management Action: This closure was extended until August 15th due to its proximity to the active Golden Eagle nest on Thunder Buttress.

Surveys Completed: 3
Raptor Observations: Peregrine Falcon
Breeding Behavior Observations: None
Nesting Observations: None
Management Action: Closure lifted early (July 22nd) due to lack of observed breeding activity.

Surveys Completed: 2
Raptor Observations: Peregrine Falcon
Breeding Behavior Observations: None
Nesting Observations: Peregrine Falcons were observed nesting on June 2nd but no fledglings were observed during monitoring sessions.
Management Action: This area is not covered by any closures.

Surveys Completed: 3
Raptor Observations: Peregrine Falcon, Golden Eagle, Bald Eagle, American Kestrel
Breeding Behavior Observations: None
Nesting Observations: None
Management Action: This area is not covered by any closures.

Long-term Trends in Successful Raptor Fledglings at Lumpy Ridge

Park managers and scientists utilize long-term raptor monitoring data to explore trends over time. The number of observed raptor fledglings is an indicator for population longevity. This information also can help park managers understand if temporary raptor closures are successful in mitigating human disturbance in popular recreational areas.

Since monitoring began, five species of raptors have fledged at Lumpy Ridge. The following trends have been observed by species:

Golden Eagle - In the early years of monitoring, from 1989 to 2001, observers usually reported at least one successful fledgling per year. Since 2002, however, successful Golden Eagle fledglings have been intermittent (2004, 2008, 2010). From 2020 – 2022, one successful fledgling was observed each year.
Prairie Falcon – Successful Prairie Falcon fledglings were observed in many years from 1996 to 2008, but not since.
Red-tailed Hawk – Only three successful Red-tailed Hawk fledglings have been observed at Lumpy Ridge since monitoring began. The first observation occurred in 1998, with the second and third occurring in 2020 and 2022.
Peregrine Falcon - In 1998, just one year before Peregrine Falcons were delisted under the Endangered Species Act, successful fledglings were observed for the first time in nine years of monitoring. The only other years with observations of successful fledglings were 2012, 2014, 2015, and 2020.
Cooper’s Hawk - In 2004 to 2008, Cooper’s Hawks successfully bred at Lumpy Ridge, but fledglings have not been seen since.

When looking at overall trends in fledgling success at Lumpy Ridge, of note is that the number of fledglings has decreased since 2008, with no successful fledglings recorded from 2016 – 2019.

During most of the 2020 breeding season, Lumpy Ridge, and the rest of RMNP, were closed due to the COVID-19 pandemic. That year, six successful fledglings were observed at Lumpy Ridge and included the greatest number of Peregrine Falcon fledglings recorded there since monitoring began.

While fledgling success is affected by a variety of natural factors including weather, food availability, disease, and predation, these results raise the question of whether human recreational activity outside of temporary closures could be disturbing raptors.

As part of the park’s adaptive raptor management, staff will continue to collect data to inform future raptor protection efforts.