Lake birding habitat

Union Reservoir

Colorado · Rocky Mountains

Habitat
Lake
Best Seasons
Difficulty

Moderate

Best Months

June-October

About This Location

Union Reservoir is a productive birding destination in Colorado, with 281 species recorded on eBird. This lake habitat attracts American White Pelican, Canada Goose, and Mallard among many others. Elevation changes create diverse habitats, from riparian valleys to alpine meadows, supporting a wide range of species.

Location

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Notable Species

Live Bird Data

Powered by eBird / Cornell Lab of Ornithology

Notable Sightings

Rare or unusual species spotted nearby in the last 14 days

Eastern Warbling Vireo

Vireo gilvus

7/13/2026Walden Ponds Wildlife Habitat--Sawhill Ponds only1 observed

Brown Thrasher

Toxostoma rufum

7/12/2026Rabbit Mountain1 observed

Red Crossbill (Ponderosa Pine or type 2)

Loxia curvirostra

7/12/2026Kanemoto Park and Neighborhood, Longmont US-CO1 observed

Northern Cardinal

Cardinalis cardinalis

7/12/2026Golden Ponds Park and Nature Area1 observed

Pine Siskin

Spinus pinus

7/11/2026Broomfield Commons Open Space--Tom Frost Reservoir1 observed

Brewer's Sparrow

Spizella breweri

7/11/2026Broomfield Commons Open Space--Tom Frost Reservoir1 observed

Broad-winged Hawk

Buteo platypterus

7/10/2026Pearl Street Mall1 observed

Solitary Sandpiper

Tringa solitaria

7/10/2026Lagerman Agricultural Preserve--Lagerman Reservoir2 observed

Western Sandpiper

Calidris mauri

7/9/2026Lagerman Agricultural Preserve--Lagerman Reservoir2 observed

Northern Pintail

Anas acuta

7/9/2026Lagerman Agricultural Preserve--Lagerman Reservoir1 observed

Upland Sandpiper

Bartramia longicauda

7/9/2026Piedra Pond1 observed

Recent Observations

Species reported at this location in the last 14 days

Mourning Dove

37/13/2026

Killdeer

147/13/2026

Spotted Sandpiper

17/13/2026

Ring-billed Gull

17/13/2026

Western Grebe

207/13/2026

Great Blue Heron

37/13/2026

American White Pelican

177/13/2026

Red-tailed Hawk

27/13/2026

Cliff Swallow

47/13/2026

House Finch

47/13/2026

Yellow-headed Blackbird

27/13/2026

Red-winged Blackbird

47/13/2026

Brown-headed Cowbird

37/13/2026

Great-tailed Grackle

17/13/2026

Northern Shoveler

67/12/2026

Mallard

187/12/2026

Green-winged Teal

57/12/2026

Rock Pigeon

17/12/2026

Sora

17/12/2026

Lesser Yellowlegs

27/12/2026

Birding Tips

  1. 1

    Scan the water surface methodically for diving ducks, loons, and grebes.

  2. 2

    Check the shoreline and mudflats for shorebirds and wading birds.

  3. 3

    Acclimate to altitude before hiking to high-elevation birding spots.

Frequently Asked Questions

When is the best time to visit Union Reservoir for birding?
The best months to visit Union Reservoir for birding are June-October. The best seasons are Summer and Fall.
What birds can I see at Union Reservoir?
Notable species at Union Reservoir include American White Pelican, Canada Goose, Mallard, Killdeer, Bald Eagle. The area supports lake habitats.
How difficult is birding at Union Reservoir?
Birding at Union Reservoir is rated as Moderate. Some trails may require moderate fitness and basic hiking ability.
What amenities are available at Union Reservoir?
Union Reservoir offers the following amenities: Parking, Trails.