Colorado’s varied geography provides diverse ecosystems that support several species of falcons. These fast, agile raptors are common residents across the state, with different species occupying distinct ecological niches. This article will focus on identifying the most prominent species that reside here, detailing where they can be found, and providing guidance on how to observe them.
Common Falcon Species in Colorado
Three falcon species are regularly found within Colorado’s boundaries, each differing in size and appearance. The smallest and most widespread species is the American Kestrel, which is roughly the size of a Mourning Dove. The Kestrel is easily distinguished as North America’s tiniest falcon.
The two larger species, the Prairie Falcon and the Peregrine Falcon, are approximately the size of a crow. The Prairie Falcon tends to be a slimmer, lighter bird adapted for hunting over open terrain. The Peregrine Falcon is known globally for its speed, achieving some of the fastest recorded dives of any animal. A fourth species, the Merlin, is also present in the state, but is typically seen as a less common migrant or occasional breeder.
Preferred Habitats Across the State
The American Kestrel is highly adaptable and can be found across nearly all open habitats, including suburban parks, pastures, and along roadsides where utility lines offer convenient hunting perches. Kestrels do not build stick nests. They prefer to utilize natural tree cavities, old woodpecker holes, or human-installed nest boxes.
The Prairie Falcon is emblematic of the arid, open landscapes of the West, especially the Eastern Plains and high desert shrublands. These falcons prefer areas with minimal tree cover. They typically nest on cliffs or rocky outcrops below 3,000 meters, creating a simple scrape on a ledge to lay their eggs.
The Peregrine Falcon historically favors high mountain cliffs and bluffs overlooking rivers for nesting sites. This species has successfully colonized urban areas, utilizing the tall ledges of city skyscrapers as modern substitutes for traditional cliff aeries. Peregrines can be found breeding from the Front Range westward, though some populations migrate south for the winter.
Tips for Identification and Observation
Distinguishing between the falcon species requires attention to size, plumage, and behavior. The American Kestrel is the only one that displays strong sexual dimorphism, meaning males and females have different colorations. Male Kestrels have striking slate-blue wings contrasting with a rusty-red back, while both sexes feature conspicuous black vertical slashes on their pale faces.
The Peregrine Falcon is characterized by a dark slate-blue back and a distinct, helmet-like black malar stripe that covers the side of its face. This bird performs a hunting stoop, a high-speed dive that can reach speeds up to 200 miles per hour.
The Prairie Falcon, while similar in size, is noticeably paler and browner overall than the Peregrine and lacks the dark hood. A specific field mark, especially when seen in flight, is a heavy, dark patch beneath the base of the wing, known as the axillaries. This species often employs a different hunting strategy than the Peregrine, coursing low over the open terrain to surprise ground-dwelling prey.