What kind of herons are in Colorado?

Colorado is home to several species of herons that can be found across the state. Herons are wading birds in the family Ardeidae that are common sights around wetlands, rivers, lakes, and coastlines. Some of the heron species known to inhabit Colorado include the Great Blue Heron, Green Heron, Black-crowned Night-Heron, and Yellow-crowned Night-Heron.

Quick Facts About Herons in Colorado

Here are some quick facts about the herons found in Colorado:

• There are at least 4 species of herons known to breed in Colorado – Great Blue Heron, Green Heron, Black-crowned Night-Heron, and Yellow-crowned Night-Heron.
• The Great Blue Heron is the largest and most widespread heron in the state.
• Herons can be found near water sources like rivers, lakes, ponds, and wetlands across Colorado.
• They nest high up in trees and tall vegetation near water.
• Herons are carnivorous and feed mostly on small fish, frogs, aquatic insects, small mammals, and other prey.
• Some species like the Green Heron are solitary while others like Great Blue Herons nest in colonies.
• The best places to see herons are wetlands, nature preserves, state parks, and along slow-moving rivers.

Great Blue Heron

The Great Blue Heron (Ardea herodias) is the most common and largest heron found in Colorado. It stands over 4 feet tall with a wingspan of around 6 feet. It has slate-gray plumage with a white crown stripe on top of its head. Its long legs and neck are blue-gray in color. Great Blue Herons can be seen alone or in small groups slowly stalking prey in shallow waters or fields.

Great Blue Herons nest in colonies called heronries that are usually located high up in trees near water. They build large, messy stick nests and lay between 3-7 eggs. Both parents incubate the eggs for about a month before hatching. The young fledge in about 2 months but stay near the nest to be fed by parents for some time before dispersing.

In Colorado, Great Blue Herons can be found near waterbodies across the state during spring and summer breeding season. Some notable breeding colonies are found at Barr Lake State Park, Rocky Mountain Arsenal National Wildlife Refuge, and Colorado National Monument. During winter, they migrate south or to the coast but some may overwinter along the Colorado River and other ice-free waters.

Great Blue Heron Facts

• Scientific Name: Ardea herodias
• Length: 45 inches
• Wingspan: 72 inches
• Weight: 5-7 pounds
• Diet: Fish, amphibians, reptiles, small mammals, insects
• Breeding Season: February to June
• Incubation: 25-30 days
• Nestlings: 45-55 days to fledge
• Nest: Large stick nests high in trees

Green Heron

The Green Heron (Butorides virescens) is a small, shy heron that inhabites wetlands across Colorado during spring and summer. It has greenish-brown upperparts, a rusty neck, and a dark cap atop its head. It has a short neck and stands under 2 feet tall. Green Herons are solitary nesters, unlike other colonial herons.

Green Herons hunt small fish, frogs, and insects while standing still or walking slowly along wetland edges. Their diet consists mainly of small aquatic animals. They sometimes use lures like feathers or insects to attract prey within striking distance. Green Herons nest in small depressions lined with twigs and leaves, often over water.

Some key spots to see Green Herons in Colorado are Tamarack Ranch State Wildlife Area, Monte Vista National Wildlife Refuge, and Colorado Gators Reptile Park. They tend to avoid human disturbance so are found in more secluded wetland areas.

Green Heron Facts

• Scientific Name: Butorides virescens
• Length: 18 inches
• Wingspan: 25 inches
• Weight: 5-8 ounces
• Diet: Small fish, frogs, reptiles, insects
• Breeding Season: April to August
• Incubation: 19-21 days
• Nestlings: about 4 weeks to fledge
• Nest: Small platform of sticks and leaves in vegetation over water

Black-crowned Night-Heron

The Black-crowned Night-Heron (Nycticorax nycticorax) is a medium-sized heron best known for its nocturnal feeding habits. It has gray and black plumage with a black cap and white cheeks. As the name suggests, it has eyes adapted for nighttime hunting. By day, these herons roost communally in trees near water.

Black-crowned Night-herons eat a variety of aquatic animals including fish, crabs, crayfish, snakes, insects and small mammals. They nest in mixed colonies with other heron species, often on islands or overhanging vegetation. Males select nest sites and bring sticks for females to assemble into nests. Females lay 3-5 eggs that hatch in about a month.

Some notable rookeries in Colorado include Barr Lake State Park, Jackson Lake State Park, and Colorado Gators Reptile Park. Look for these herons flying out at dusk or returning at dawn to feed at nearby wetlands and rivers.

Black-crowned Night-Heron Facts

• Scientific Name: Nycticorax nycticorax
• Length: 25 inches
• Wingspan: 43 inches
• Weight: 1.5-2.5 pounds
• Diet: Fish, crustaceans, insects, small vertebrates
• Breeding Season: April to June
• Incubation: 25-26 days
• Nestlings: 50-55 days to fledge
• Nest: Bulky stick nests high up in trees

Yellow-crowned Night-Heron

The Yellow-crowned Night-Heron (Nyctanassa violacea) is a small, stocky heron with relatively short legs and neck. As the name suggests, it has a yellow crown and black face mask. Its back is bluish-gray, and the underside is pale gray to white.

These herons are primarily nocturnal or crepuscular feeders. Their diet consists of crustaceans, fish, frogs, aquatic insects, small mammals and other prey. Yellow-crowned Night-herons nest in nearby trees or dense vegetation in loose groups. The female lays 3-5 eggs that hatch in around 3 weeks. Chicks fledge in 6-7 weeks.

In Colorado, these herons can be seen near waterbodies like lakes, marshes, and rivers across the state. Good locations to observe them are Barr Lake State Park, Jackson Lake State Park, and Colorado Gators Reptile Park.

Yellow-crowned Night-Heron Facts

• Scientific Name: Nyctanassa violacea
• Length: 22 inches
• Wingspan: 41 inches
• Weight: 1.5-2 pounds
• Diet: Fish, frogs, crustaceans, insects, rodents, birds
• Breeding Season: April to July
• Incubation: 21-26 days
• Nestlings: 42 days to fledge
• Nest: Loose stick colonies in trees or dense vegetation

When and Where to See Herons in Colorado

Here is some more information on the best times and places to observe different heron species across Colorado:

The best months to see herons in Colorado are April through August during the breeding season. However, some species like Great Blue Herons can be observed year-round near open waters. Spring and fall are ideal times to witness migrations or dispersed wintering birds gathering at nesting sites.

Notable wildlife refuges, state parks with waterbodies, and wetland areas offer the best vantage points for spotting herons. Look for them standing statue-like at water edges or flying overhead with slow, arched wingbeats. With some patience, you may catch them in the midst of courtship rituals, feeding young, or hunting for fish!

Heron Behavior, Hunting, and Diet

Herons exhibit some interesting behaviors and adaptations suited to their aquatic lifestyle:

• They often stand motionless for long periods to scan for prey or avoid detection.
• Their sharp vision allows them to spot and precisely stab prey even in murky water.
• Herons fly slowly with necks retracted in an S-shape.
• They have special vertebrae in their neck that allow them to strike like a spear.
• Most species have long legs suited to wading through shallow water.
• They hunt mainly in early morning and evening hours.
• Some use lures to attract fish or release feathers that elicit curiosity.

Herons are carnivorous and have a varied fish-based diet. Here are some of the common prey items:

• Fish – sunfish, trout, bass, perch, minnows
• Frogs
• Crabs and crayfish
• Aquatic insects
• Rodents like voles or mice
• Snakes and lizards
• Birds like ducklings

Herons employ different hunting techniques to capture their prey:

• Standing still – Herons often stand motionless allowing prey to come near before spearing it.
• Walking slowly – They sometimes walk slowly through shallow water watching for movement.
• Hovering – Some herons hover above the water before plunging their bill down to catch prey.
• Lures – Using feathers, insects or other items to lure curious fish closer.
• Pursuit – Herons may actively pursue prey like jumping fish in deeper waters.

Heron Conservation Status

Overall heron populations are stable across most of North America. However, habitat loss and disturbance are growing threats. Here are the conservation statuses of Colorado’s herons according to the International Union for Conservation of Nature (IUCN):

• Great Blue Heron – Least Concern
• Green Heron – Least Concern
• Black-crowned Night-Heron – Least Concern
• Yellow-crowned Night-Heron – Least Concern

The major threats facing herons today include:

• Wetland habitat loss and degradation
• Disturbance of nesting colonies
• Pollution and water quality decline
• Climate change impacting prey availability

Protecting wetland habitats through preservation and responsible water use is key to heron conservation. Limits on development near heronries and public education can also help reduce disturbances. Herons serve as important indicators of ecosystem health in wetland and aquatic habitats.

Conclusion

Colorado hosts a nice diversity of heron species that grace wetland areas with their beauty and fishing skills. The most noticeable is the widespread Great Blue Heron that can be spotted across the state year-round. But also keep an eye out for the diminutive Green Heron and crepuscular Yellow-crowned and Black-crowned night herons near waterways. Late spring to summer offers the best chance to see herons congregating and nesting. As wetland ambassadors, the continued presence of herons in Colorado signifies healthy freshwater ecosystems worthy of our protection.