Duckling Identification: Which Duckling Is This?

The fastest way to identify a duckling is to identify the adult female with it. Downy young of different species look alike in a way adults never do, but a brood almost always has its mother within sight, and she is far easier to name.

A mottled brown duck with an orange bill marked with black is a Mallard. A grey-headed duck with a white eye-patch and a suggestion of a crest is a Wood Duck. A grey duck with a bright rusty head, a sharply defined white throat and a thin red bill is a Common Merganser. Name her, and the ducklings are named.

If no adult is visible, wait and watch from a distance before doing anything else. Waterfowl broods scatter and regroup constantly, and a duckling that looks abandoned usually is not.

Among the common dabbling ducklings, the position of the dark eye line is the single most repeatable mark. A Mallard duckling has a dark line that starts at the base of the bill, runs through the eye and continues to the back of the head. A Wood Duck duckling has no line between the bill and the front of the eye, and at the same age it is the smaller bird.

After that, use the background. Wood Ducks nest in cavities near water, in wooded swamps, slow rivers and ponds surrounded by deciduous woodland, and Audubon records nest sites in tree cavities up to 65 feet above the ground. Mallards nest on the ground in a much wider range of places, including farmland and city parks. A brood of tiny ducklings on a shaded woodland creek is far more likely to be Wood Ducks than Mallards.

Mergansers. The bill gives them away even in down: narrow, pointed and serrated, built to hold a fish, not to strain water. Common Mergansers are on wooded lakes and rivers, and Audubon notes the female tends the young for several weeks while they feed themselves.

Other cavity nesters. Hooded Merganser, Bufflehead and Common Goldeneye all nest in tree cavities, and Hooded Mergansers readily use nest boxes, with clutches of 9 to 12 eggs.

Goslings, not ducklings. A large yellow-and-grey chick with a black bill beside two big grey-brown adults with black heads and white cheeks is a Canada Goose gosling.

One behavior surprises people every spring: cavity-nesting ducklings leave the nest by jumping. Audubon describes Wood Duck young clinging with sharp claws, bracing with their tails, climbing to the cavity entrance and jumping to the ground, and Common Merganser young do the same.

Bright yellow ducklings with no pattern at all are usually domestic. Domestic ducks descend from the Mallard and the Muscovy Duck, and on park ponds they interbreed with wild Mallards, so a single brood can contain yellow, brown, blotchy and normally marked young at once.

A duckling that walks up to people is domestic or has been fed by people, and neither is a good sign. Maine's Department of Inland Fisheries and Wildlife warns that too much protein during growth can cause angel wing, a permanent deformity that leaves flight feathers pointing outward and the bird unable to fly, and that crowding at feeding sites raises disease transmission, including botulism, fowl cholera and duck plague.

Watch first, from far enough away that the adults will return. Oregon's Department of Fish and Wildlife puts it plainly: leave young animals where you found them, because they are rarely orphaned. Connecticut's wildlife agency makes the same point about waterfowl, adding that parents leave young alone for long stretches while feeding.

If the parent has not collected the duckling by nightfall, or the duckling is visibly injured, call a permitted wildlife rehabilitator or your state wildlife agency. Do not take it home. Holding wildlife without a rehabilitation permit is against the law in many states; Oregon classes it as a Class A misdemeanour carrying up to a year in jail and a fine of $6,250.

If you have handled a wild bird, wash your hands thoroughly afterwards, and see a doctor if you become unwell.

Ducklings bought from a farm store or hatchery are breeds, and the down color at hatch is the first clue. Metzer Farms lists day-old down colors for the breeds it hatches, among them:

• Pekin: yellow.
• White Crested: yellow, with a tuft of down on top of the head.
• Buff: tan.
• Black Runner: black, sometimes with a yellow tint on the chest.
• Rouen: black with yellow stripes by the eyes.

So a plain yellow duckling with no markings is most likely a white-adult breed such as a Pekin, and a yellow one with a topknot is a White Crested. A Rouen duckling can look much like a wild Mallard duckling, because the breed is colored like a Mallard; a farm-store receipt, or the absence of a wild hen nearby, is what settles it.

Adult colors take months. Metzer Farms' growth photos show the male's head starting to darken at around 8-10 weeks in Rouens and Welsh Harlequins, 7-10 weeks in Khaki Campbells and 14-16 weeks in Buffs.

For young ducklings there is only one reliable method, and it is not one to try at home.

• Vent sexing: Raising Ducks calls it the only reliable way to sex young ducklings, best done at a day old; Metzer Farms says it can only be learned by having someone show you. Done wrong, it can injure the bird.
• Bill color in Welsh Harlequins: females have pinkish bills and males dark ones on day one, about 90% accurate at that age according to Raising Ducks, but the two colors converge and the trick stops working by about day 4.
• Voice: the loud quack is the female. Raising Ducks puts the change at about 4-6 weeks for females and 6-12 weeks for males, whose voice becomes a hoarse rasp.
• Drake feather: a curled tail feather marks a male. Raising Ducks gives 8-16 weeks and warns it is not 100% reliable; Metzer Farms' photos show it at 16-19 weeks in several breeds.
• Muscovies: male ducklings often have visibly larger, thicker feet from a few weeks old.

Size, wing growth and behavior do not work, according to Raising Ducks. Wild ducklings are a different matter: the only sexing that matters is leaving them with their mother.

A rough age comes from how much down is left and how much heat the bird still needs. The University of Wisconsin-Madison Extension says ducklings should be feathered enough to be outdoors by 4 weeks, except in very cold, wet weather, and need supplemental heat for 5 to 6 weeks in cold weather but only 2 to 3 weeks in summer. It recommends 85-90°F when ducklings arrive, reduced by 5 to 10 degrees a week.

Put together with the growth timeline above: a bird in full down that still huddles under the lamp is in its first weeks; one with feathers coming through and a head that is changing color is around 7-10 weeks; one with a curled tail feather is a drake of about four months.