Ducklings: Development, Behaviour and First Weeks Explained

A duckling hatches ready to go. Within a day it can walk, swim, and pick up its own food — which puts it in a completely different category from a blackbird chick, which hatches helpless (altricial, in the BTO’s description) and stays in the nest while its parents feed it. Biologists call this precocial, and it shapes everything about how ducklings live.

But “ready to go” has limits. A duckling cannot fly for around two months, and in its first weeks it depends on its mother to keep it warm, above all in cold, wet weather.

Before hatching

A mallard lays roughly eight to thirteen eggs, one a day, and only begins incubating in earnest late in the laying period. Incubation was once thought to wait for the last egg, but when researchers put data loggers and dummy eggs in the nests of mallards and seven other prairie ducks, the eggs were heated enough for embryos to develop as early as the day the second egg was laid, and the females spent more and more time on the nest as laying went on (Loos and Rohwer, 2004). The brood still hatches together, typically within a 12-hour period according to Ducks Unlimited, which matters enormously to a bird that has to lead its young to water on foot.

Incubation runs about 28 days. In the last day or two the ducklings begin calling from inside the shell, and the female answers. Two things come of that. The ducklings learn her individual voice before they have seen her, and the clutch synchronises its hatching to within hours. If you want the detail on that, it is in why ducks quack and what their calls mean.

To get out, a duckling uses its egg tooth — a small hard point on the tip of the bill that chips a ring around the inside of the shell over several hours. It falls off shortly after hatching (Ducks Unlimited). Ducks have no real teeth at any age.

Week by week

Day one

The duckling dries, fluffs up, and imprints. Imprinting is a short, powerful learning window in which the duckling fixes on the first suitable moving, calling object it meets and treats it as mother. In the wild that is normally the female. The old idea that imprinting can never be reversed has been refuted, though what the duckling learned about the first object is not simply forgotten (Bolhuis, 1991); duckling imprinting has the detail.

Within a day or two of hatching the whole brood leaves the nest for good. Nests can be some distance from water — Audubon notes that a mallard’s nest site may be more than a mile away — and sometimes several metres above the ground: mallards will nest in tree cavities, on flat roofs and in planters, so the first journey can involve a genuine drop. Ducklings are light and well padded and survive falls that look alarming, though the RSPCA says that if a nest is higher than four metres they may need help.

Weeks one and two

This is the dangerous period: Ducks Unlimited says duckling mortality is highest in the first two weeks after hatching. The duckling is covered in down, which does not generate heat and, eXtension notes, is not enough insulation to stop a duckling chilling except on exceptionally hot days. It makes its own heat from the first day — a 1999 study found day-old mallards producing more as the air got colder or the wind stronger — but loses it fast: in a laboratory study by Banta and colleagues (2004), most two- and three-day-old mallard ducklings kept their body temperature above 39°C for an hour while swimming on water at 5°C, yet at least 70% of the heat they produced went into the water. So the duckling returns to the mother regularly to brood underneath her, and in cold, wet weather she broods for longer to keep the young from dying of hypothermia (Ducks Unlimited).

Where its water resistance comes from is less settled than it is often made to sound. The idea that the mother supplies it, by anointing the young before they leave the nest or through contact with her feathers, is put forward in the writings of Heinroth in 1911 and of the Heinroths in 1928, whom Elder cites. W. H. Elder tested it at the Delta Waterfowl Research Station in Manitoba, with four downy redheads about three days old, taken from a wild hen, against four of the same size hatched in an incubator, watched in washtubs of water for 15-minute periods. The wild-hatched birds “did not get wet”; the incubator birds began jumping to escape within 8 to 10 minutes and showed more wetting of the outer belly down. Elder’s verdict: “The basic question remains unanswered: Did these ducklings jump to escape because they were getting wet or did they get wet because they were jumping?” When a wetting agent was added to the water the next day, both groups sank until only their heads were above water, the incubator birds in half the time, and again he could not tell why they had started jumping sooner. He also found the ducklings’ own oil gland “functional in the first day of life” in redheads, canvasbacks and mallards hatched in the incubator (Elder, 1954). And in the 2004 study, the two- and three-day-old mallards’ belly down stayed dry or was wetted only on the surface while they swam. More on this in why ducks don’t get wet.

What is not in doubt is that cold, wet weather and separation kill ducklings: the 1999 study notes that most duckling mortality occurs in the week after hatching and is often associated with cold, windy, wet weather and scattering of the brood.

Feeding starts as soon as the hen has led the brood to water, and at first is mostly invertebrate. Chura (1961, as summarised by Street) found the youngest mallard ducklings in Utah eating animal food exclusively; at an English gravel quarry, Street (1977) found that 60.6% of the items eaten by ducklings in roughly their first 12 days were of animal origin, largely aquatic invertebrates, with midges (adults, larvae and pupae) the main insect food and adult beetles the insects found most often. The protein goes straight into growth.

Weeks three to five

Down starts to be replaced by contour feathers, beginning on the sides: in mallards the first feathers show at about 19 to 25 days, and the last down to go is on the rump (USFWS brood-ageing guide). Temperature regulation improves as they grow (Ducks Unlimited).

Growth in this period is fast and visible week to week. The birds start to look like small, scruffy ducks rather than balls of fluff.

Weeks six to nine

The flight feathers, which break from their sheaths at about four to five weeks (USFWS guide), finish growing on the wings. The bird reaches near-adult size, the juvenile plumage comes through, and the family group loosens.

Fledging — the first sustained flight — comes at about 50 to 60 days in a mallard (BTO; Audubon gives 52 to 60). Once they can fly, as the days shorten, broods mix with other ducks and join larger flocks as they prepare for migration (Ducks Unlimited).

What ducklings eat, and why it is different

An adult mallard eats a lot of seeds and plant material. A young duckling eats mostly insects.

The difference is protein. A duckling has to build a complete set of feathers, a full skeleton and adult muscle in under two months, and Ducks Unlimited says young waterfowl feed aggressively on insects and protein-rich plants in their first two weeks because large amounts of protein are needed to grow tissue and feathers, which are at least 85 percent protein. The diet shifts quickly: in Street’s study only 5.1% of the items eaten by ducklings aged 12 to 45 days were invertebrates, and in Chura’s, plant food made up 92% of the diet by the stage when only the last down remains.

This is also why invertebrate life matters to a brood: Street linked the unusually high duckling mortality at his gravel quarry, at least 77%, to the ducklings’ relatively low consumption of insect food. And it is one more reason why bread at a pond is a poor idea: it displaces the food a growing brood actually needs. The full argument is in can ducks eat bread, and the adult picture is in what ducks eat.

Why so many do not make it

Wild duckling survival varies enormously. Ducks Unlimited puts survival over the 50 to 70 days before ducklings can fly at anywhere from less than 10 percent to as high as 70 percent, and lists the most common causes of death as predation, adverse weather, starvation, disease and parasites. In more detail:

• Predation — pike, herons, gulls, crows, foxes, mink, cats. A duckling is edible by almost everything.
• Cold and wet — cold, rainy, windy weather can kill ducklings through exposure, and in the first week after hatching they are extremely vulnerable to hypothermia and predation.
• Starvation — where invertebrate food is scarce.
• Separation — ducklings travelling overland can become exhausted or disoriented and separated from the brood.

This is why a female with twelve ducklings in May and three in July has not necessarily done anything wrong. Losses on that scale fall within the range Ducks Unlimited reports.

If you find a duckling alone

The short version: usually, leave it.

A duckling calling loudly on its own usually has its mother close by — the RSPCA says ducklings do not normally stray far from their parents — and calls between the hen and her young are what keep the family together (Ducks Unlimited). Interfering risks the mother flying off and abandoning the brood. Watch from a distance: the RSPCA’s advice is to contact your local wildlife rehabilitation centre if the parents have not returned within two hours or are found dead.

If it is clearly injured, or the mother is confirmed dead, contact a wildlife rehabilitation centre rather than attempting to raise it. Ducklings imprint fast, and a hand-raised duckling that has imprinted on a person is very difficult to release successfully. In many places keeping wild waterfowl is also regulated.

Raising ducklings deliberately

Everything above is about wild ducklings. If you are raising them yourself, the same biology applies but you are supplying what the mother would: heat, safety, and the right feed.

Three things need particular care: heat (too little, or removed too early), niacin (Metzer Farms says a chick starter made only for laying chickens probably does not have enough for ducklings, and the deficiency causes bowed legs and swollen hocks), and water (the RSPCA says water should be designed so young birds can get out easily, to stop them drowning, and Minnesota Extension notes that ducklings chill easily when they get wet in the down stage).

Our step-by-step guide covers it properly: raising ducklings week by week. If you are also thinking about whether they will need open water later, do ducks need a pond answers that, and how long ducks live gives you a sense of the commitment.