I emptied my shotgun in less time than it takes to read this, three rounds strung well behind the flashing, twisting knot of ducks that executed stunning acrobatic maneuvers like well-rehearsed fighter pilots.

They were gone, arcing across the prairie to another reservoir, before I could fumble more shells into the gun. They were green-winged teal, maybe the most athletic ducks of the fall flight.

These tiny, compact ducks have been with us most of the year. They are among the earliest spring migrants, settling on cattail-fringed wetlands, small, isolated prairie reservoirs, even roadside ditches. But if they arrive early, they also leave soon after nights dip below freezing and ice starts to rim the edges of their waters.

You’ll find them this month staging on rivers, park ponds and secluded pools in small streams. In mild winters, numbers of these little ducks will stay around if they find open water where they can feed on submerged vegetation and small crustaceans or have access to small grains in waterside fields.

Green-winged teal are named for their brilliant iridescent green speculums — outer wing feathers — of both sexes. Drakes have rich, chocolate-brown heads and bottle-green narrow bands behind their eyes.

These petite ducks — mature hens weigh less than half a pound — are closely related to blue-winged teal, differentiated by drab brown bodies and the slate-blue heads of drakes. As their name suggests, blue-winged teal have neon-blue speculums.

Instead of quacking like other dabblers such as mallards, teal tend to whistle in a musical, high-pitched staccato. You can tell teal in flight by their tight, swift formations that are dazzlingly well choreographed and so nimble that mallards and geese seem like awkward heavy bombers in comparison.

I’m a fair wing shot, but I missed those teal by a country mile. It’s probably just as well. Those birds have a long way to go this fall, and will probably humble more hunters on their flight south.