Most ducks give themselves up by shape and behaviour before colour — and the drakes are the easy half. Read the guild in a glance, key the drake in seconds, then let head shape and bill crack the brown hens and eclipse birds the plates never quite show.
Get the guild in one glance. Everything after is detail.
Rides high, tips up to feed. Springs straight off the water. Mallard, teal, wigeon, pintail, Shoveler, Gadwall, Wood Duck.
Rides low, big-headed. Vanishes under and patters to take off. Scaup, Redhead, Canvasback, goldeneyes, Ring-necked, Bufflehead, scoters.
Long, low, thin spike bill. Fish-eating sawbills, fast direct flight. Hooded, Common, Red-breasted.
Tiny, dumpy, tail cocked up. A big head on a small body, diving constantly. Ruddy Duck — its own thing.
Behaviour beats plumage. Where a duck sits in the water, how its head and bill are shaped, and how it gets airborne name the guild before you've seen a single colour — and the guild is most of the work.
Tap through to a name.
The full key — follow the arrows to a name.
Head shape cracks the diving-duck hens; bill and speculum crack the dabblers.
Ordered common → rare. Amber box = the clinching mark.
Anas platyrhynchos
The baseline duck, every pond. Learn the hen: white-bordered blue speculum and orange-marked bill separate her from teal and from Mexican/Black Duck.
Bucephala clangula
The default winter diver on open water. Face-spot shape and head gloss split it from Barrow's — see the pairs.
Mareca strepera
No mark shouts — the little white speculum square is the tell. Hen told from Mallard by the crisp orange-edged bill and white belly.
Spatula cyanoptera
A marsh breeder, Apr–Sep. Hen is a genuine trap against Blue-winged Teal (see pairs); the big spatulate bill and plain face help.
Aythya collaris
Ponds and marshes more than big open water. Black back plus the bill ring separate it from the gray-backed scaup.
Spatula clypeata
That shovel bill IDs it at any range in any plumage — nothing else here has it. Shares the powder-blue forewing with the teal.
Lophodytes cucullatus
Sheltered ponds and backwaters. Thin sawbill and crest separate the hen from the round-headed Bufflehead.
Anas crecca
Mud edges and shallows. No blue forewing (unlike the other teal) — green speculum only, and it's the smallest bird on the water.
Mareca americana
Grazes on grass and margins. A rufous-headed, creamy-crowned bird is a rare Eurasian Wigeon — verify (see Don't import).
Mergus merganser
Rivers and large open water. The hen's clean-bordered rusty head splits it from Red-breasted's shaggy, blended one (see pairs).
Aythya affinis
The default scaup on ponds. Head shape, gloss and nail size split it from Greater — a true squint (see pairs).
Aythya americana
Open water, often in rafts. Round head (not sloping) and gray back (not white) are the Canvasback splitters (see pairs).
Aythya valisineria
Big open water. That ski-slope head-and-bill line is diagnostic even in silhouette; the whitest back of the diving ducks.
Oxyura jamaicensis
A stiff-tail, not a typical diver — sits low, dives constantly. The cocked tail, big head and cheek stripe are unmistakable.
Bucephala albeola
Active little diver, small ponds to big water. The hen's single cheek-oval separates her from the crested hen Hooded Merganser.
Anas acuta
Flooded fields and shallows. Even the plain hen gives herself up by the slim long neck, long tail and unmarked gray bill.
Bucephala islandica
The scarcer, mountain-linked goldeneye; scan goldeneye flocks. Face-mark shape (crescent vs round) is the split (see pairs).
Mergus serrator
More on big open water than Common. The hen's blended neck (vs Common's crisp white chin) is the tell (see pairs).
Spatula discors
Migrant and scarce breeder. Drake's face-crescent is easy; the hen is a Cinnamon Teal trap — go by bill size and range (see pairs).
Clangula hyemalis
A rare winter visitor to big open water and reservoirs. Round-headed and boldly patterned — unlike anything else here.
Melanitta deglandi
Scarce on big water. The largest, heaviest scoter; the white speculum flash and eye-comma separate it from Surf.
Aythya marila
Scarcer, and prefers larger open water. Head shape (round + green) and the broad nail split it from Lesser (see pairs).
Melanitta perspicillata
A rare treat on reservoirs and Great Salt Lake bays, mostly fall. The no-wing-patch, skunk-headed drake is the split from White-winged.
Aix sponsa
Wooded ponds and backwaters; nests in tree cavities. Reads rare countywide because it hides in habitat few checklists cover.
Where careful birders still trip.
Lesser vs Greater Scaup
The classic squint. Lesser has a peaked rear crown and a purple head-gloss with a small black bill-nail; Greater is rounder-headed with a green gloss, chunkier, and a broad nail across the bill tip. Lesser is far the commoner on ponds; Greater leans to bigger open water.
Common vs Barrow's Goldeneye
Face mark first: Common's cheek spot is a clean round dot, Barrow's a vertical crescent/comma. Barrow's also shows a purpler, bumpier head and a blacker back (white "windows" instead of a long white stripe). Hens: check bill colour and forehead steepness.
Redhead vs Canvasback
Both rusty-headed divers. Redhead is round-headed with a gray back and a black-tipped blue bill; Canvasback is whiter-backed with a long sloping wedge from bill to crown and no forehead stop. In silhouette the head profile alone settles it.
Ring-necked Duck vs scaup
Ring-necked is black-backed with a peaked head, a vertical white flank-spur, and a bold white bill ring; scaup are pale-gray-backed with more evenly gray flanks. Back colour is the fastest cut.
Common vs Red-breasted Merganser
Hens especially. Common shows a crisp white chin sharply bordered from a clean rusty head; Red-breasted's rusty head blends into a paler neck with a shaggier double crest and a thinner, more washed-out look. Common favours rivers, Red-breasted big open water.
Cinnamon vs Blue-winged Teal (hens)
Honestly the hardest pair here — both are plain brown with a powder-blue forewing, and many can't be safely separated. Lean on the bill (Cinnamon's is longer and more spatulate), a plainer face on Cinnamon, and range/season. When unsure, log it as teal sp. rather than guess.
When Merlin offers one of these, slow down.
On the county list, but the UBRC still requests documentation. A photo or clear notes, not a tick.
Per the 2020 UBRC checklist these hadn't been recorded here, or aren't countable natives. Photograph and report to records@utahbirds.org — don't just log the tick.
Ducks hybridise more than any group here — the county data alone holds ~20 recorded cross combinations.