Bald Eagle Work at Voyageurs - Thirty Years of Longevity and Perseverance

By Steve Mazur, NPS Ranger Pilot Longevity, according to the Merriam-Webster dictionary is: 1) a long duration of individual life, 2) the length of life, and/or 3) the length of time that something or someone lasts or continues.

Longevity can be quite remarkable given the life of any one individual depending on their exercise regime, food intake, and their genetics.

What is remarkable at the National Park Service is Voyageurs National Park’s longevity in conducting one of the longest, consecutive running bald eagle surveys in the lower forty-eight states - more than thirty years. What is also remarkable is the same park biologist, Leland Grim, has conducted the surveys since 1973.

“What are you doing?” came over the park radio. “The annual spring aerial eagle survey with Lee Grim, of course,” I replied as we got ready for another quick pass over an eagles nest on Rainy Lake.

The annual spring bald eagle survey is just one of many aircraft surveys conducted within Voyageurs National Park. The eagle surveys run every year from April through June and involve many hours of intense flight activity. It just may be one of the park's most technically demanding flight missions. The eagle surveys require special weather conditions due to the low-level flying involved and special safety equipment worn by both aircraft crew members. The aerial portion of the survey is followed by a ground-based eagle banding where biologists band newborn eaglets and collect valuable blood for DNA studies.

Perseverance, according to the Merriam-Webster dictionary is: 1) the quality that allows someone to continue trying to do something even though it is difficult, 2) continued effort to do or achieve something despite difficulties, failure, or opposition.

What makes eagle flight surveys technical is the same thing that makes them enjoyable – the challenge. This is due to altitude, wind, terrain, sunshine, temperature, and duration of the flight. The altitude for eagle surveying is low – sometimes tree-top level. This allows biologists to see whether nests are occupied and to count the number of nesting eagles and their young.

Eagle surveys have been conducted within the area know known as Voyageurs National Park since 1967. When the park was established in 1975, the National Park Service continued the surveys to gather a better understanding of bald eagle longevity and perseverance.

See more photos of eagle research in Voyageurs National Park