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

Black Phoebe

Sayornis nigricans

4/14/2026Walden Ponds Wildlife Habitat--Boulder Creek/Heatherwood Trail2 observed

Acorn Woodpecker

Melanerpes formicivorus

4/14/2026Mountain View Cemetery (Boulder Co.)1 observed

Semipalmated Plover

Charadrius semipalmatus

4/14/2026Union Reservoir1 observed

Semipalmated Sandpiper

Calidris pusilla

4/14/2026Lagerman Agricultural Preserve--Lagerman Reservoir1 observed

Wilson's Phalarope

Phalaropus tricolor

4/14/2026Firestone Gravel Pits (view from road)6 observed

Broad-tailed Hummingbird

Selasphorus platycercus

4/14/2026Morey Wildlife Reserve1 observed

Forster's Tern

Sterna forsteri

4/14/2026Horseshoe Reservoir1 observed

Willet

Tringa semipalmata

4/14/2026Horseshoe Reservoir1 observed

Recent Observations

Species reported at this location in the last 14 days

Northern Shoveler

4/14/2026

Gadwall

4/14/2026

Green-winged Teal

4/14/2026

Mourning Dove

14/14/2026

Killdeer

84/14/2026

Marbled Godwit

14/14/2026

Franklin's Gull

4/14/2026

Ring-billed Gull

14/14/2026

California Gull

14/14/2026

American White Pelican

104/14/2026

Osprey

14/14/2026

Bald Eagle

24/14/2026

Red-tailed Hawk

14/14/2026

American Kestrel

14/14/2026

American Crow

14/14/2026

Horned Lark

14/14/2026

European Starling

4/14/2026

American Robin

34/14/2026

House Finch

14/14/2026

Song Sparrow

14/14/2026

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.