Saturday February 17, 2024 started cold, with a couple of inches of snow on the ground. But the day promised sunshine and so nine intrepid Evergreen Audubon birders converged on the stretch of the South Platte River, north of downtown Denver, to see what winter waterfowl and other birds might be present. The South Platte at this location is particularly hospitable to wintering waterfowl, due to the (permitted) discharge of treated wastewater into the river, keeping the water warmer and mostly ice free. The warmth and nutrients that the wastewater adds to the river drives phytoplankon growth, providing dabbling ducks with a direct source of food, and providing food for fish that are then a food source for diving ducks.
We started at Steele Street Park, which abuts the South Platte at 78th Street and is the site furthest downstream from any wastewater inputs to the river. Northern Shovelers and Gadwall were abundant in this stretch, as were Green-winged Teal, Lesser Scaup, Bufflehead, and Common Goldeneye. Of particular interest were the presence of Northern Pintails, an exceptionally striking duck that, while usually abundant on this stretch of the South Platte, were not observed when the area was scouted a week earlier.
We then went upstream to a site at the junction of 74th street and the South Platte. At this site, surface foams in turbulent sections indicating more direct influence of upstream wastewater. Regardless, waterfowl were well represented. In particular, Buffleheads and Common Goldeneyes were in abundance. Our real excitement was reserved for the possible presence of a Long-Tailed Duck, a sea duck rarely found inland. One had been previously observed at this site, but there’s no guarantee of seeing a single rare species like the Long-Tailed Duck on any given day. However, we were fortunate to find this bird, although it moved rapidly downstream shortly after being observed, making detailed looks challenging. However, the striking winter plumage of this male bird made confirming its ID easy.
We finished our walk at 64th street and the South Platte, just upstream from where Denver’s wastewater enters the river. The distinction between river water upstream and downstream of the discharge is striking, but historically this section has been the roosting area for Black-Crowned Night Herons . We did not find any herons, but our disappointment was tempered by finding a Prairie Falcon perched on a power pole for an extended period.
Winter is a great time to be birding, with cold clear skies and minimal vegetation to impede observation. Dress warmly and get out there!
Good Birding,
Ed Furlong
South Platte River North of Denver between 64 and 84th Streets
February 17, 2024
9 Participants
31 Species
Cackling Goose 36
Canada Goose 14
Northern Shoveler 290
Gadwall 144
American Wigeon 9
Mallard 35
Northern Pintail 15
Green-winged Teal 47
Ring-necked Duck 10
Lesser Scaup 19
Long-tailed Duck 1
Bufflehead 48
Common Goldeneye 32
Hooded Merganser 1
Common Merganser 1
Rock Pigeon (Feral Pigeon) 6
Pied-billed Grebe 1
American Coot 77
Killdeer 2
Ring-billed Gull 5
Double-crested Cormorant 1
Belted Kingfisher 3
Killdeer 2
Red-tailed Hawk 1
Prairie Falcon 1
Black-billed Magpie 1
American Crow 2
White-crowned Sparrow 1
Red-winged Blackbird 1
Black-capped Chickadee 1
European Starling 6