Boulder's Birds of Prey

A juvenile Bald Eagle soars above a pasture outside of Broomfield. Bald eagles are brown for the first few years of their life and develop their white heads and black bodies around 3 years.

Derived from the Latin raptare, “to seize and carry,” birds of prey are defined as a species of bird that hunts other animals for food.

Those that hunt during the day are classified as either Accipitriformes and Falconiformes, while those that hunt at night are classified as Strigiformes.

Boulder County is home to 24 raptor species.

Accipitriformes

Defined by their sharp hooked beaks, long broad wings, and soaring flight behavior. Eagles, hawks, and ospreys, and kites all fall under this order.

Eagles

Among some of the largest raptor species, eagles are known for their sharp, hooked beaks that allow them to tear into their prey with ease. There are 60 species of eagles worldwide, two are found in Boulder County.

Bald Eagle

Haliaeetus leucocephalus

Range:

Canada to Mexico

Habitat:

Forests near water

Diet:

Fish, reptiles, small mammals
Scavengers

Boulder Population:

First observed in 2002
Nesting pairs found near reservoirs and riparian areas
Increased since DDT ban in 1972

General Population:

Increased since DDT ban in 1972

Golden Eagle

Aquila chrysaetos

Range:

Canda to Mexico

Habitat:

Grasslands
Nest of cliffs

Diet:

Small mammals like rabbits, prairie dogs, and rodents

Boulder Population:

An estimated 15 to 20 nesting pairs
Declining due to encounters with humans

General Population:

Declining due to encounters with humans

Photo By: Howzy

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Photo By: Deborah Mancino

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Sound: NPS

Osprey

Large birds of prey that are known for their fishing, Osprey are found all over the world.

Photo by: Seokhee Kim

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Sound: NPS Sound Gallery

Osprey

Pandion haliaetus

Range:

Found on all continents except Antarctica

Habitat:

Lakes and ponds
Nest in tall trees or structures

Diet:

Fish

Boulder Population:

Nesting pairs in Boulder Reservoir, Longmont Fairground ponds, and Sawhill ponds
Increased since DDT ban in 1972

General Population:

Increased since DDT ban in 1972.

Hawks

Among the most common bird of species, hawks can fall into 2 major categories: Buteos or Accipiters.

Buteo

They have broad, rounded wings to help them soar over long distances.

Photo by: Tony's Take

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Ferruginous Hawk

Buteo regalis

Range:

Western plains of North America

Habitat:

Grasslands
Nest in tall trees

Diet:

Small mammals like rabbits and rodents

Boulder Population:

Declined due to habitat loss and fragmentation

General Population:

Stable in recent years

Photo by: Greg

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Sound Creative Commons License

Red-Tailed Hawk

Buteo jamaicensis

Range:

North America

Habitat:

Almost any type of habitat
Urban cities

Diet:

Small mammals and reptiles

Boulder Population:

Doubled since 1990

General Population:

Estimated at 2.3 million

Photo by: Jon David Nelson

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Rough-Legged Hawk

Buteo lagopus

Range:

Canada and the United States

Habitat:

Grasslands and wetland

Diet:

Small rodents

Boulder Population:

Declined more than 90 percent due to habitat loss

General Population:

Somewhat stable with an estimated 500,000 individuals

Photo by: Dick Daniels

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Swainson's Hawk

Buteo swainsoni

Range:

North and South America

Habitat:

Grasslands

Diet:

Small mammals and insects

Boulder Population:

Declined due to habitat loss, tree invasion, and red-tailed hawk competition

General Population:

Somewhat stable with an estimated 580,000 individuals

Accipiters

Smaller than buteos, accipiters are agile birds of prey with short, round wings and long tails to help them maneuver with ease.

Photo by: D A Murphy

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Sharp-Shinned Hawk

Accipiter striatus

Range:

North America

Habitat:

Dense forests

Diet:

Small songbirds

Boulder Population:

Not enough available data to determine current conservation status in Boulder
Douglas-fir forests of Boulder County most likely benefit nesting populations

General Population:

Stable with an estimated 700,000 individuals

Photo by: Ellen and Tony

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Coopers Hawk

Accipiter cooperii

Range:

United States and Mexico

Habitat:

Forets and heavily wooded areas
Urban cities

Diet:

Small birds

Boulder Population:

More now reside in urban settings than the native habitat of conifer forests

General Population:

Stable with an estimated 700,000 individuals

Photo by: Mark Robinson

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Northern Goshawk

Accipiter gentiles

Range:

United States and Canada

Habitat:

Dense old-growth forests

Diet:

Small birds, mammals, reptiles, and insects

Boulder Population:

Uncommon in Boulder County
Extremely reclusive and very sensitive to urban and recreational disturbance

General Population:

Stable with an estimated 400,000 individuals

Harriers

Harriers are very distinctive hawks with long-wings and long-tails and their looks are often compared to those of an owl.

Photo by: Haricharan

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Northern Harrier

Circus hudsonius

Range:

North America

Habitat:

Grasslands
Ground nesters

Diet:

Small mammals

Boulder Population

Extremely endangered
Only successful nests have been west of Boulder Reservoir and Coot Lake

General Population:

On a steady decline

Falconiformes

Defined by their smaller stature, keen eyesight, and fast flight behavior. Falcons and kestrels fall under this order.

Falcons

Known for their speed, Falcons have thin, tapered wings, which enable them to fly at high speeds and change direction rapidly.

Photo by: Evilfoo

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American Kestral

Falco sparverius

Range:

North America
Most common and widespread falcon

Habitat:

Grasslands
Urban cities

Diet:

Small songbirds, rodents, and insects

Boulder Population:

Doubled since 1990

General Population:

Stable

Photo by: Paul Balfe

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Peregrine Falcon

Falco peregrinus

Range:

Found on all continents except Antarctica
One of the most widespread birds

Habitat:

Shorelines
Nest on cliffs and skyscrapers

Diet:

Small birds

Boulder Population:

Recovered since DDT ban in 1972
Compete with Prairie Falcons for food and nesting habitat

General Population:

Slowly recovering

Photo by: K Schneider

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Prairie Falcon

Falco mexicanus

Range:

Western United States

Habitat:

Grasslands
Nest of cliffs

Diet:

Small birds

Boulder Population:

Stable
Compete with Peregrine Falcons for food and nesting habitat

General Population:

Stable with an estimated 80,000 individuals

Strigiformes

Defined by their nocturnal habits, sharp talons, and feathers adapted for silent flight. All owls fall under this order.

Owls

A nocturnal bird of prey, Owls are known to be stealthy hunters and live a somewhat solitary lifestyle.

Photo by: Laura Ngo

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Barn Owl

Tyto alba

Range:

The United States and Mexico

Habitat:

Grasslands
Nest in tree cavities, cliffs, and barns, and buildings

Diet:

Small rodents

Boulder Population:

Steady increase

General Population:

Steady increase especially as more people are putting up nesting boxes

Photo by: David Ellis

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Eastern Screech Owl

Megascops asio

Range:

Central and Eastern region of United States

Habitat:

Forest

Diet:

Small mammals, insects, and lizards

Boulder Population:

Little is known but believed to be increasing

General Population:

Stable

Photo by: Alexandre Rouxe

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Northern Pygmy Owl

Megascops asio

Range:

Small patches along the western portion of North America

Habitat:

Forests

Diet:

Small birds and rodents

Boulder Population

Little is known
Fluxtuates depending on availability of prey of small birds and rodents

General Population:

Stable

Photo by: Mario Madrona

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Long-Eared Owl

Asio otus

Range:

North America

Habitat:

Forests and dense thickets

Diet:

Small mammals and reptiles

Boulder Population:

Close to extinct due to habitat loss and predation by Great Horned Owls

General Population:

Declining

Photo by: Andy Reago and Chrissy McClarren

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Northern Saw-Whet

Aegolius acadicus

Range:

Primarily Canada and the United States with small patches in Central Mexico

Habitat:

Forests

Diet:

Small mammals

Boulder Population:

Little is known due to lack of data

General Population:

Stable

Photo by: Coconino National Forest

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Flammulated Owl

Psiloscops flammeolus

Range:

Small patches in Western United States and Central Mexico

Habitat:

Dense forests
Ponderosa pines and aspens

Diet:

Insects

Boulder Population:

Little is known but believed to be extremely rare

General Population:

Little is known but believed to be on a steady decline

Photo by: Marcelo Albuquerque

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Sound by: Daveincamas

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Great Horned Owl

Bubo virginianus

Range:

North and South America

Habitat:

Forets, grasslands, city limits
Generalist species that thrives in almost any environment

Diet:

Small mammals, birds, frogs

Boulder Population:

Continue to increase every year
Out compete and prey upon a number of native owl species

General Population:

Stable

Photo by: Chris

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Burrowing Owl

Athene cunicularia

Range:

Most of the United States and Mexico

Habitat:

Grasslands
Nest in abandoned burrows formed by other animals

Diet:

Insects and small rodents and reptiles

Boulder Population:

Close to extinct due to loss of habitat and predation by Great Horned Owls

General Population:

Stable in some areas but on a steady decline in others

Photo by: Ian Sexton

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Short-Eared Owl

Asio flammeus

Range:

North America

Habitat:

Grasslands
Nest on the ground

Diet:

Small mammals

Boulder Population:

Rare sighting

General Population:

Dramatic decline due to habitat loss

Photo by: Aki Mykkanen

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Boreal Owl

Aegolius funereus

Range:

Primarily Canada with small patches in the United States
Norther Europe and Asia

Habitat:

Forests
High elevation

Diet:

Small mammals, birds, and insects

Boulder Population:

Little is known due to species preference to live in high mountains

General Population:

Stable