I had hoped that there still might be open water and loons at Chatfield SP, but the polar vortex that moved in on January 17 and the subsequent cold weather was enough to close all open water.  It appears that the loons that had been at Chatfield over the last several weeks may have moved south to Pueblo Reservoir on the Arkansas River where on January 22 a report from down south included 2 Yellow-billed Loons, 2 Red-throated Loons, 1 Pacific Loon, and 11 Common Loons.

So, on Saturday, having been thwarted in finding any loons, we chose to seek open water elsewhere.  Nearby South Platte Reservoir has aerators which keep the water open and Eaglewatch and Blackrock Lakes in South Platte Park, though they may mostly freeze overnight, can open up slightly during the day due to currents of incoming water.  And, of course, the South Platte is right there as well.

We began with South Platte Reservoir where we found a slew of American Coots and Ring-billed Gulls, as well as three species of mergansers, two Bald Eagles, a Pied-billed Grebe, a few more ducks, and then we had some less commonly occurring species.  We had two gulls that are here each winter, though not all that often, an American Herring Gull and a Lesser Black-backed Gull.  Additionally, the big find was a solitary female White-winged Scoter.  White-winged Scoters nest on freshwater lakes and wetlands of northwestern North America and overwinter primarily along both coasts.  They show up rarely in Colorado as seasonal migrants, and even more rarely stick around as winter residents.

Moving on over to the South Platte we saw a couple of Wilson’s Snipe and a good variety of ducks, including another great rarity, a female Long-tailed Duck.  These guys a true arctic species, breeding globally in tundra and taiga regions.  They then generally spend the winter in such places as the northern coasts of North America, the Great Lakes, western Greenland, the Baltic Sea, and the Aleutian Islands.  As with White-winged Scoters, they are a rare seasonal migrant here in Colorado and a very rare winter resident.  One interesting fact about Long-tailed Ducks is that they tend to dive much deeper than other sea ducks, down to 150-200 feet, and we happened to find our bird feeding on the Platte in only a couple of feet of water.  The only small passerines we saw for the day were some Black-capped Chickadees and Song Sparrows.  Apparently, many birds were content just to hunker down for the morning given how chilly it was.

South Platte Reservoir and Park
Jan 25, 2025
30 species

9 participants

Canada Goose  44
Cackling Goose 8
Cackling/Canada Goose 70
Northern Shoveler  4
Gadwall  19
American Wigeon  22
Mallard  60
Green-winged Teal  23
Ring-necked Duck  10
Long-tailed Duck  1
White-winged Scoter 1
Bufflehead  34
Common Goldeneye  29
Hooded Merganser  12
Common Merganser  25
American Coot  99
Killdeer  4
Wilson’s Snipe  2
Ring-billed Gull  61
American Herring Gull 1
Lesser Black-backed Gull 1
Pied-billed Grebe 1
Great Blue Heron  1
Bald Eagle  3
Red-tailed Hawk  1
Belted Kingfisher  2
American Kestrel  2
Black-billed Magpie 1
American Crow  2
Black-capped Chickadee  5
Song Sparrow  10