April at Chatfield

Constructed primarily for flood control and completed in 1976, Chatfield Reservoir has since become the centerpiece of a large State Park, in southwest Metro Denver. Characterized by extensive grasslands, the open lake, backwater wetlands, ponds and riparian woodlands, the Park is an excellent place to study the flora and fauna of Colorado's Piedmont ecosystem. On this warm, sunny morning, it seemed like the perfect destination.

Spring runoff, exacerbated by the recent heavy snowfall, had produced a high lake level and significant flooding along Plum Creek and the South Platte River. Coot, mallards, green-winged teal and wood ducks gathered on these backwater shallows, joined by several flocks of American white pelicans at the South Platte inlet; pairs of Canada geese were nesting along the marshy shores and the distinctive calls of red-winged blackbirds and chorus frogs echoed across the wetlands. Western and Clark's grebes fed on the deeper waters, which also attracted double-crested cormorants, common mergansers and a few common loons. Yellow-rumped warblers were abundant in the woodlands, joining the usual mix of woodpeckers, chickadees, nuthatches and sparrows; a few house wrens, just back from the south, were also found.

Meadowlarks and magpies dominated the grasslands, joined by Say's phoebes, kestrels and a lone prairie falcon. Checking a large prairie dog colony at the Park's south entrance, I found plenty of rodent activity but, unfortunately, no burrowing owls. By mid morning, a pair of Swainson's hawks, back from their winter in Argentina, soared above the prairie, no doubt enjoying a spectacular view of this vast refuge.