Colorado’s diverse landscapes harbor some surprisingly vibrant green birds that often go unnoticed by casual observers. While you might expect brown sparrows and gray jays, the Centennial State is actually home to several species displaying brilliant emerald and olive-green plumage.
From iridescent hummingbirds in Colorado that shimmer in mountain sunlight to secretive herons lurking along waterways, these green-feathered residents offer rewarding sightings for anyone willing to look closely.
You’ll find these birds across elevation zones from plains to alpine meadows, each species occupying its own ecological niche. Whether you’re an experienced birder or just starting to notice the wildlife around you, learning to identify Colorado’s green birds opens up a whole new dimension of nature watching.
This guide covers seven distinctive species, providing the identification details and habitat clues you need to spot them in the wild.
1. Green Heron
The Green Heron (Butorides virescens) stands out as one of Colorado’s most elusive waterbirds, preferring to hunt along quiet streams and pond edges rather than open water. Despite its name, this compact heron appears more blue-gray at first glance, but closer observation reveals rich greenish tones across its back and wings that become especially apparent in good lighting conditions.
You’ll recognize this species by its stocky build and relatively short legs compared to other herons. Adults measure 16-18 inches in length with a wingspan of about 26 inches.
The greenish-black cap contrasts sharply with chestnut-colored neck and sides, while the back displays an iridescent green sheen that shifts between olive and blue-green depending on the angle of sunlight. Juveniles show more brown streaking and lack the rich adult coloration.
Pro Tip: Green Herons often freeze motionless when they detect movement, making them incredibly easy to overlook even when you’re standing just a few feet away. Scan the edges of vegetation slowly rather than looking for active movement.
These herons inhabit wooded streams, marshes, and ponds with substantial vegetation cover throughout Colorado’s eastern plains and lower elevation western valleys.
They’re uncommon visitors rather than abundant residents, typically appearing from May through September. According to the Cornell Lab of Ornithology, Green Herons are among the few tool-using birds, sometimes dropping insects or feathers on the water surface to lure fish within striking range.
Look for them hunting from low perches like branches overhanging water or partially submerged logs. They hunt by standing perfectly still and waiting for prey to come within range, then striking with lightning speed. Early morning and evening hours provide the best viewing opportunities when these birds are most active. Their sharp “skeow” call often reveals their presence before you spot them visually.
2. Broad-tailed Hummingbird
The Broad-tailed Hummingbird (Selasphorus platycercus) brings a distinctive metallic trill to Colorado’s mountain meadows and forests from April through September. This medium-sized hummingbird displays brilliant iridescent green across its entire back and crown, creating a jewel-like appearance that catches sunlight as the bird hovers at flowers.
Males are particularly striking with rose-red throat patches (gorgets) that flash brilliantly when light hits at the right angle. The green back contrasts beautifully with white underparts and rufous-washed flanks.
Females lack the colorful throat but share the same iridescent green back and have buff-colored flanks with small green spots along the sides. Both sexes measure about 4 inches in length with a wingspan of roughly 5.25 inches.
What truly sets this species apart is the male’s wing trill—a loud, cricket-like sound produced by modified wing feathers during flight. You’ll hear this mechanical buzzing sound as males patrol their territories or perform courtship displays. The National Audubon Society notes that this trill serves both to advertise territory and attract females, functioning almost like a sonic signature across mountain habitats.
Key Insight: Broad-tailed Hummingbirds can enter torpor on cold mountain nights, lowering their body temperature and metabolic rate by up to 95% to conserve energy—an essential adaptation for surviving at high elevations.
These hummingbirds thrive in mountain meadows, open woodlands, and willow thickets between 7,000 and 10,500 feet elevation. They’re particularly abundant in areas with columbine, paintbrush, and penstemon flowers. You’ll find them readily visiting backyard feeders in mountain communities throughout their range. They defend feeding territories aggressively, chasing away other hummingbirds and even much larger birds that venture too close to preferred nectar sources.
For the best viewing experience, position yourself near clusters of tubular red or orange flowers during morning hours when feeding activity peaks. Males often perch on exposed branches to survey their territories, providing excellent observation opportunities. Similar species like green birds in Southern California include different hummingbird varieties adapted to lower elevation habitats.
3. Black-chinned Hummingbird
The Black-chinned Hummingbird (Archilochus alexandri) represents Colorado’s most adaptable hummingbird species, thriving equally well in natural canyons and suburban gardens. This bird displays a brilliant metallic green back and crown that appears almost emerald in bright sunlight, while its underparts remain grayish-white without the buff tones seen in some other species.
Males feature the namesake black chin topped by a narrow band of iridescent purple that’s only visible when light strikes at specific angles—otherwise the entire throat appears solid black.
Females show plain throats with occasional dark spotting and the same green back as males. At 3.5 inches in length, Black-chinned Hummingbirds are slightly smaller than Broad-tailed Hummingbirds and lack any mechanical wing sounds during flight.
These hummingbirds inhabit riparian areas, canyons, and residential areas with flowering plants across Colorado’s lower elevations, typically below 7,000 feet. They arrive in late April and remain through August, with peak numbers occurring in June and July.
Research from the Hummingbird Society indicates that Black-chinned Hummingbirds show remarkable flexibility in nesting sites, building tiny cup nests on everything from tree branches to clotheslines and wind chimes.
| Feature | Black-chinned | Broad-tailed |
|---|---|---|
| Size | 3.5 inches | 4 inches |
| Wing Sound | Silent | Loud trill |
| Throat Color (Male) | Black with purple band | Rose-red |
| Elevation Preference | Below 7,000 feet | 7,000-10,500 feet |
| Habitat | Canyons, urban areas | Mountain meadows |
You’ll have the best success finding Black-chinned Hummingbirds near water sources in lower elevation areas. They favor sage, ocotillo, and agave flowers in natural settings but readily visit feeders and garden flowers in residential areas.
Males pump their tails while hovering during courtship displays, creating a distinctive pendulum-like motion. Listen for their soft, high-pitched chips and twitters, which differ noticeably from the sharper calls of other Colorado hummingbirds.
Common Mistake: Many observers confuse female Black-chinned and Broad-tailed Hummingbirds since both have green backs and plain throats. Focus on elevation, habitat, and the presence or absence of wing trills from nearby males to distinguish between the two species.
4. Rufous Hummingbird
The Rufous Hummingbird (Selasphorus rufus) earns recognition as one of North America’s most aggressive hummingbirds and longest-distance migrants, traveling up to 3,000 miles between breeding and wintering grounds. While males are predominantly orange-rufous, both sexes display iridescent green backs that shimmer brilliantly in sunlight—the green coloring is especially prominent on females and immature birds.
Adult males show extensive rufous coloring on the back, flanks, and tail, combined with an orange-red gorget that appears to glow when catching light. However, many males retain significant green on the back and crown, creating a striking two-tone effect.
Females and juveniles feature more extensive green backs with rufous sides and some rufous in the tail feathers. All Rufous Hummingbirds measure approximately 3.25 inches in length, making them among Colorado’s smallest hummingbird species.
These fierce little birds pass through Colorado primarily during migration periods—northbound from March through May and southbound from July through September. They’re most abundant along the Front Range and in mountain valleys during these passage periods.
The Cornell Lab reports that Rufous Hummingbirds defend feeding territories so aggressively they’ll attack birds many times their size, including hawks and crows that venture too close to their claimed food sources.
During migration, you’ll find Rufous Hummingbirds in virtually any habitat with flowering plants, from plains to alpine zones. They show particular fondness for red tubular flowers like penstemon, paintbrush, and scarlet gilia. Backyard feeders in Colorado often host multiple Rufous Hummingbirds during peak migration, though you’ll witness frequent territorial disputes as dominant individuals attempt to monopolize food sources.
Watch for their distinctive hovering pattern with rapid wingbeats creating a buzzing sound higher-pitched than larger hummingbird species. Males perform dramatic courtship dives, climbing 50-100 feet before plummeting toward females with wings producing loud rattling sounds. If you’re interested in tracking different fastest birds species, Rufous Hummingbirds rank among the most impressive for their size-to-speed ratio during these aerial displays.
5. Calliope Hummingbird
The Calliope Hummingbird (Selasphorus calliope) holds the distinction of being the smallest breeding bird in North America, yet it undertakes an impressive migration journey between mountain breeding grounds and Mexican wintering areas. This tiny jewel displays a brilliant green back and crown that appears almost luminous in direct sunlight, with the green coloring extending down to the rump.
Males feature distinctive magenta throat streaks that radiate outward rather than forming a solid gorget like other hummingbird species—these elongated feathers can be raised or lowered depending on the bird’s mood and activity.
Females show plain throats with some dark spotting and peachy-buff flanks complementing their green backs. At just 3.25 inches long and weighing only 2-3 grams, Calliope Hummingbirds are remarkably small even by hummingbird standards.
Pro Tip: Calliope Hummingbirds often forage lower to the ground than other species, frequently visiting flowers at knee to waist height. Scan lower vegetation zones where other birders might overlook these tiny birds.
These hummingbirds breed in mountain meadows and willow thickets primarily in northwestern Colorado, typically between 4,000 and 9,000 feet elevation. They’re less common than Broad-tailed Hummingbirds but can be locally abundant in suitable habitat from May through August. According to U.S. Fish and Wildlife Service data, Calliope Hummingbirds show strong site fidelity, with individuals returning to the same breeding territories year after year.
You’ll find Calliopes frequenting willow thickets, mountain meadows with abundant wildflowers, and edges of coniferous forests. They show particular attraction to red columbine, penstemon, and Indian paintbrush.
Unlike more aggressive species, Calliope Hummingbirds often feed peacefully at the same flowers, though males still defend small territories around preferred nectar sources. Their high-pitched, soft chips sound almost insect-like and can be easily missed in busy mountain environments.
Look for males performing their distinctive U-shaped courtship flights, diving toward females while producing a sharp “zing” sound with their tail feathers at the bottom of each dive.
Females build tiny cup nests on downward-sloping conifer branches, often placing them directly above old nest sites from previous years. For comparison with other regions, check out green birds in Pennsylvania which feature entirely different species adapted to eastern forest habitats.
6. Ruby-throated Hummingbird
The Ruby-throated Hummingbird (Archilochus colubris) appears only rarely in Colorado, representing an unexpected find for birders more accustomed to seeing this species in eastern states.
This eastern hummingbird displays the same brilliant iridescent green back and crown characteristic of its western relatives, with the green coloring appearing especially vibrant in males.
Adult males feature the namesake ruby-red gorget that can appear black in poor lighting but glows intensely when sunlight hits at the right angle. A white collar separates the throat from the green back and breast.
Females show white throats sometimes with faint dusky streaking and the same metallic green back as males. Both sexes measure approximately 3.75 inches in length with relatively short, straight bills compared to some western species.
In Colorado, Ruby-throated Hummingbirds occur primarily as vagrant visitors, most often appearing along the eastern plains during migration periods from April through May and August through September.
They’re far less common than the state’s regular hummingbird species, making any sighting noteworthy. The All About Birds resource notes that Ruby-throated Hummingbirds occasionally wander west of their normal range, particularly young birds during fall migration.
| Species | Status in Colorado | Best Viewing Time | Distinctive Feature |
|---|---|---|---|
| Broad-tailed | Common breeder | April-September | Wing trill sound |
| Black-chinned | Common breeder | Late April-August | Purple throat band |
| Rufous | Common migrant | March-May, July-September | Aggressive behavior |
| Calliope | Uncommon breeder | May-August | Smallest size |
| Ruby-throated | Rare vagrant | April-May, August-September | Eastern origin |
If you encounter a Ruby-throated Hummingbird in Colorado, you’ll most likely find it at feeders or flower gardens in residential areas along the eastern plains. They prefer similar habitats to Black-chinned Hummingbirds—riparian corridors, parks, and gardens with abundant flowering plants. Males lack the wing trill of Broad-tailed Hummingbirds and fly silently, which can help distinguish them in areas where multiple species occur together.
Important Note: Identifying female and immature Ruby-throated Hummingbirds in Colorado requires careful attention to subtle details, as they closely resemble Black-chinned Hummingbirds. Geographic location and date provide important context clues—Ruby-throateds are extremely rare west of the Great Plains.
Watch for their rapid, straight flight pattern between feeding locations and listen for their soft, squeaky chips. Males perform distinctive courtship displays involving U-shaped flight patterns similar to other hummingbird species.
Any confirmed Ruby-throated Hummingbird sighting in Colorado warrants documentation through photographs if possible, as these records help ornithologists track the species’ range and movement patterns. You might also enjoy learning about birds with red heads in Colorado for additional colorful species to identify.
7. Green-tailed Towhee
The Green-tailed Towhee (Pipilo chlorurus) stands apart from Colorado’s other green birds as the only non-hummingbird species on this list, representing an entirely different family and ecological niche.
This distinctive sparrow-sized bird displays olive-green coloring across its back, wings, and tail—the green tones are subtler than the metallic iridescence of hummingbirds but still quite apparent in good lighting.
Adults feature a bright rufous crown contrasting sharply with a gray face and white throat bordered by dark stripes. The olive-green back and wings blend seamlessly with the bright yellowish-green tail that gives the species its name.
White wing bars accent the wings, and the underparts show gray coloring. At 7.25 inches in length, Green-tailed Towhees are substantially larger than any Colorado hummingbird and more closely resemble sparrows in overall body shape and behavior.
These towhees inhabit mountain shrublands, particularly areas with dense sagebrush, serviceberry, and mountain mahogany between 6,000 and 10,000 feet elevation. They’re common summer residents from May through September across Colorado’s mountains and high plateaus.
Research published by the Partners in Flight organization indicates that Green-tailed Towhees depend heavily on shrubland habitats that have become increasingly fragmented due to development and fire suppression altering natural vegetation patterns.
You’ll most often detect Green-tailed Towhees by their distinctive cat-like “mew” call notes echoing from dense shrubs. They spend most of their time on or near the ground, scratching through leaf litter with both feet simultaneously in a distinctive backward-hopping motion while searching for seeds and insects. Unlike the aerial hummingbirds, these birds rarely venture far from protective shrub cover.
Key Insight: Green-tailed Towhees are “double-scratchers”—they use both feet together to kick backward through leaf litter, a foraging technique shared with other towhee species but quite different from the alternating-foot scratching of most ground-feeding birds.
Males sing a complex, musical song from exposed perches atop shrubs during breeding season, typically delivering their whistled phrases during early morning hours. The song begins with several clear notes followed by a rapid trill, carrying well across mountain shrublands. During migration, you might encounter Green-tailed Towhees in lower elevation areas and even along the eastern plains, where they frequent weedy fields and brushy areas.
For optimal viewing, walk slowly along trails through mountain shrublands during morning hours when birds are most active. Movement in dense vegetation often reveals their presence before you see the actual bird.
Unlike hummingbirds that can be attracted to feeders, Green-tailed Towhees rarely visit feeding stations, though they may appear in yards adjacent to suitable shrubland habitat. Consider exploring yellow birds in Colorado or black birds in Colorado to expand your identification skills across different color groups.
Colorado’s green birds offer diverse viewing opportunities across multiple habitats and elevations, from the secretive Green Heron along quiet waterways to energetic hummingbirds defending mountain wildflowers. Each species brings unique behaviors and ecological adaptations that make them worth seeking out, whether you’re exploring alpine meadows or your own backyard.
By learning their key identification features, preferred habitats, and behavioral patterns, you’ll significantly increase your chances of successful sightings and develop a deeper appreciation for Colorado’s remarkable avian diversity. The next time you’re outdoors in Colorado, take a moment to look for these green-feathered residents—you might be surprised by what you discover.
