This section is intended to be a very basic guide to Denver metro area birding hotspots. It is by no means exhaustive. For more complete coverage, (including important things like directions!), see Birding the Front Range: a Guide to Seasonal Highlights by Robert Folzenlogen, and the new and improved A Birder's Guide to Colorado by Harold Holt.
Bel Mar Park, including Kountze Lake (Lakewood) There is always something good here - It's one of the best spots I've found for ducks in the winter: Bufflehead, Hooded Merganser, Goldeneye, (I've seen both Common and Barrow's), Wood Ducks, Ruddy Ducks, Wigeon, Canada Geese, and Mallards are common, along with the ubiquitious circle of Northern Shovelers. In spring and summer American Coots and Pied-billed Grebes nest in the marshy areas, as Black-crowned Nightherons, Great Blue Herons, and the occasional Green Heron stalk their prey. Several species of swallows spend the warm months here, as well as many warbler species and millions of Red-winged Blackbirds and Common Grackles, (okay not really millions - it just sounds like it!) The Park is located at about Ohio Ave. and South Wadsworth in Lakewood.
Prospect Park (Wheat Ridge) Prospect Park is notable not only for birds but for the resident foxes, (whom some people foolishly feed...!). Warblers are common here throughout the spring and summer, especially during migration. Waterfowl I have seen here include: Greater and Lesser Scaup, Goldeneye, Canvasback, Bufflehead, and Ruddy Ducks.
Barr Lake (Brighton) Notable for the resident Bald Eagles, and Great Blue Heron and Double-crested Cormorant Rookeries. From the Nature Center bridge: to the left is good for shorebirds and waterfowl, (and leads to the eagles and rookeries where a permanent spotting scope is set up); to the right is good for songbirds. This is a good spot any time of year.
Roxborough State Park (Littleton) This park is best on cool mornings. The afternoons are extremely hot, and even in the mornings water is a necessity. Broad-tailed and Rufous Hummingbirds are attracted to the feeders by the nature center, and a pair of Say's Phoebes has nested there for the past few years. Other likely birds are: Evening and Black-headed Grosbeaks, Blue-gray Gnatcatchers, Scrub Jays, Vesper Sparrows, White-throated Swifts, and several warbler species. I always think I'm
going to see raptors, but I never have.
Sombrero Marsh (Boulder) I like Sombrero Marsh because I saw a Garganey there. I've also seen a large variety of waterfowl, White-faced Ibis, and Wilson's Phalarope. This small pond is definitely worth a detour when visiting other spots in Boulder.
Sawhill/Walden Ponds (Boulder) Recently played host to a Tufted Duck. I actually got to see it which is quite unusual for me - usually when I twitch, so does the bird. This area usually produces good waterfowl including Canvasback, Hooded Merganser, Bufflehead, Lesser, (and sometimes Greater) Scaup, and Ring-necked Ducks. Also, Sawhill/Walden can get a breeding attempt by the Least Bittern plus a spring
visit of the Little Blue Heron (immature or adult).
Remember when birding these or any other places to follow the ABA Code of Ethics.