Duck vs Goose: How to Tell Them Apart at a Glance

Key differences at a glance

Ducks, geese and swans all belong to the same bird family, the Anatidae, often called waterfowl. They share webbed feet, waterproof plumage and a flattened bill edged with comb-like plates. “Duck” and “goose” are everyday names rather than strict scientific groups, but in general:

• Geese (genera such as Anser and Branta) are grouped with the swans in the subfamily Anserinae.
• Ducks, including dabbling ducks like the mallard, diving ducks and sea ducks, belong mostly to the subfamily Anatinae.

The two best-known examples in North America and much of Europe are the mallard and the Canada goose, which often share the same park lake.

Size and shape

A Canada goose is roughly two to four times heavier than a mallard. It weighs 2.4–6.5 kg (5.3–14.3 lb) against the mallard’s 0.7–1.6 kg (1.5–3.5 lb), and its long neck makes it look taller still.

Geese also stand differently. Their legs are set closer to the middle of the body and are relatively long and strong, so they walk easily and spend hours on land. Ducks’ legs sit farther back, which is good for paddling but gives them their typical waddle on land.

Size is not a perfect guide, though. Some small geese, such as the smallest forms of the cackling goose, are barely larger than a mallard, while the Muscovy duck, especially domestic forms, can rival a small goose.

Bills and diet

The bill tells you a lot about how each bird feeds.

• A duck’s bill is broad and flat, lined with fine plates called lamellae. Dabbling ducks such as the mallard sieve seeds, plant bits and small animals like snails and insect larvae from water and mud, or tip up to reach the bottom.
• A goose’s bill is shorter, taller at the base and has hard, tooth-like edges that act like pruning shears. Geese are grazers: they walk across meadows, marshes, fields and lawns, clipping grass and other plants, and also eat grain and berries.

That is why you see flocks of geese feeding on golf courses and farmland, while ducks mostly feed on or at the edge of the water.

Plumage and males vs females

In most common ducks, the sexes look strikingly different. The mallard drake has a glossy green head and gray body, while the hen is mottled brown. Females, which raise the young alone, need camouflage; males are colorful to impress females, as explained in why are male ducks so colorful?

In geese, males and females look the same. A Canada goose pair are both black-necked with a white chinstrap; the gander (male) is usually just a little larger. In a pair standing together, the larger, more alert bird with its head held high is often the gander, but even experts often need to watch behavior to tell them apart.

Family life and pair bonds

Breeding habits differ just as much as looks.

• Mallards form new pairs each fall and winter. The drake leaves once the hen starts incubating, and she raises the ducklings on her own.
• Geese usually pair for life, and both parents guard the nest and the goslings. Canada goose families stay together through the first fall migration and winter, which is why you often see geese moving in family groups within larger flocks.

Geese are also famously protective. A nesting gander will hiss, lower its neck and charge at people or dogs that come too close, whereas a mallard hen is more likely to try to lead an intruder away or hide.

Calls and flight

The classic “quack” is the voice of the female mallard; drakes make softer, raspy sounds. Geese honk, and both sexes call, often in duets between mates. Flocks of migrating geese keep up a constant honking.

In flight, geese often travel in V-shaped or long, wavy lines, especially on long migrations, with slower, steady wingbeats. Mallards fly in looser groups with faster wingbeats, and they can spring almost straight up off the water.

Which lives longer?

Geese generally live longer than ducks. A wild mallard has an average life expectancy of about 3 years, although the record for a banded wild bird is more than 26 years. Adult Canada geese often live 10–24 years, and the oldest known wild bird reached about 33 years.

Where do swans fit in?

Swans are the largest members of the waterfowl family and the closest relatives of geese. They are even bigger, with the longest necks of the group, and like geese they usually pair for life and share parental care. Mute swans can weigh more than 10 kg (22 lb).

A rough rule of thumb: swan = very large and very long-necked; goose = large and grazing; duck = small to medium, shorter-necked, often with a colorful male.

Birds that blur the line

Common names do not always follow biology.

• The Egyptian goose is really a large shelduck, more closely related to ducks than to true geese.
• Whistling ducks have long legs, upright stances and lifelong pair bonds, with males and females that look alike, more like geese than typical ducks.
• The magpie goose of Australia is so different that it is placed in a family of its own.
• The Cape Barren goose of southern Australia is a grazing, goose-like bird whose exact relationships have long been debated.

Domestic birds add another twist. Farm geese descend from the greylag goose and the swan goose, while nearly all farm ducks descend from the mallard; the Muscovy duck is the one main exception. Heavy farm breeds of both can look unusual, but the same clues, especially bill shape, neck length and grazing habits, still work.

Whatever the name, the clues above, size, neck, bill, diet and whether the sexes look different, will sort out the birds on most ponds. Both ducks and geese keep dry thanks to tightly packed, well-preened feathers; see how do ducks stay dry?