From egg to chick: how we hatch eggs for our conservation breeding programmes

The arrival of spring, with its lengthening days and its brighter colours, provides the perfect trigger for renewal and refreshment.

Nothing represents the fresh, young days of spring and new hope like ducklings can and do: from Easter cards to chocolate figures, ducklings are represented wherever we look during the weeks of spring. Any day now WWT nature reserves will be awash with new families of ducklings.

In happier times when we're not undergoing a global pandemic, the techniques developed by aviculturists at WWT centres are used to improve the odds of chick survival for species on the brink of extinction, species such as the Madagascar pochard. But what is involved to hatch an egg and to raise a chick?

From egg to chick in 6 steps

1. Holding a candle to it

How can you tell if an embryo is doing well while it’s still in the egg? The answer is through ‘candling’. As the name suggests, ‘candling’ was invented long before electricity came along, and involved shining a candle flame on one side of the egg to illuminate its contents from the other side.

The process does not affect the precious embryo and, these days, WWT conservationists use a modified torch. And if the torch batteries run-out, as they do for example during field-work, sunlight can achieve the same effect.

2. Just pipping out

While inside the egg, the embryo is able to gain the oxygen it needs from the outside thanks to the porous nature of its eggshell. As the chick grows inside the egg the amount of oxygen it’s able to obtain in this way is no longer enough. By the time the chick is ready to hatch, a special muscle, known as a ‘pipping muscle’, on the back of its neck has developed, and a protuberance near the end of its beak, known as an ‘egg-tooth’, has grown. This ‘pipping muscle’ and the ‘egg tooth’ come into their own during the pipping and hatching processes. Using its ‘pipping muscle’, the chick drives its ‘egg-tooth’ into the air sac at the blunt end of the egg to create a hole. This provides the chick with enough oxygen to give it the strength, after several hours or even days, to break through the shell of the egg itself, ultimately, to hatch!

Here the duckling has “pipped” and is in the first stages of breaking through the shell of the egg

3. You can lead a duck to water

Born with soft downy feathers, tiny chicks would become waterlogged if they were immersed in water at too young an age. In our conservation breeding projects, WWT aviculturists carefully introduce ducklings to water as soon as they’ve dried out after hatching, and their bodies have used up the last of their absorbed egg yolk. Our aviculturists ‘drip-feed’ water into shallow bowls containing marbles, which act rather like pebbles at the edge of a waterbody making it safe for the ducklings to first drink, then wash themselves. The marbles give the ducklings something to stand on while they drink. It’s important to warm the ducklings each time they have a bath or a swim so that they don’t get cold. Aviculturists do this by using heat lamps suspended over their ducklings’ rearing tanks.

Fluffy mallard ducklings finding their feet

Egg-straordinary egg fact

Duck eggs are sometimes blue because of a chemical called oocyanin, which gets added in the duck’s gut early on in the egg-production process.

4. Food for thought

In the wild, ducklings will follow their mother around the edge of a waterbody, picking at tiny insects or pulling on water plants for nourishment. When raising ducklings in our conservation projects, we don’t have bags of insects to hand, so to ensure they receive the right level of protein and nutrients at a young age, we offer the babies what is known as ‘starter crumb’ – specially formulated high-quality protein rations in a crumb form. This is given to the ducklings for around three weeks when they are then weaned onto a protein pellet and grains.

Fluffy mallard ducklings finding their feet

5. Weather the feather

Depending upon the species, chicks tend to develop their first feathers at around three weeks of age. By the time they’re around six weeks old, all the young down has been replaced by a new coat of feathers and they’re now able to keep warm without being brooded by mum and to take their first flights. Around two months later, the full-grown chicks begin moulting into their first adult-like plumages.

A new family of mallard ducklings preening and dozing

6. Calling time

By the time a chick enters its second month, its voice is beginning to break. The high-pitched little peeps start to give way to a more adult-sounding quack, particularly in females, which in many species tend to be a bit louder than their male siblings.

A proud tufted duck mother and her two ducklings take to the water

Egg-straordinary egg fact

Did you know the time it takes for a baby bird to break out of its shell varies greatly? The Madagascar pochard, the rarest duck in the world, takes less than a day, but common cranes take just over a day. Black-tailed godwits take a day and a half, and spoon billed sandpipers take up to three days!

Our work continues: how we're caring for our breeding birds during lockdown

The COVID-19 pandemic has effectively put a halt to any non-essential work or breeding; yet behind the scenes at Slimbridge, the Conservation Breeding Unit (CBU) team continue to care for the critically endangered species we still hope to save.

The species we have on site at WWT Slimbridge are Baer’s pochard and spoon-billed sandpiper; and one UK red-listed species: the black-tailed godwit. And during the COVID-19 lockdown, a skeleton CBU team is working hard to ensure all birds have what they need to be as happy and safe as possible.

Normally during spring, pairs of birds or other ‘social groups’ would be forming, and this is still the case despite the global pandemic. We know that these actions will also strengthen pair bonds for the future, hopefully ensuring a higher likelihood of breeding. What’s more, by letting appropriate-for-time-of-year behaviours be expressed now, it will ensure normal physiological processes are completed later (e.g. feather moult) in all three species. This is important as it minimises disruptions to the birds’ normal lives.

A newly hatched spoon billed sandpiper

During the lockdown, we have established a way to continue our activities that ensure the birds’ wellbeing. Specifically, when on site, we have a rota that ensures people are able to carry out these essential activities in our spoonie, pochard and godwit areas without having any contact with one another:

  • Providing appropriate food and water
  • Keeping living spaces and support areas clean
  • Ensuring the integrity of ‘life support’ infrastructure e.g. predator barriers, aviaries, water-pumps, water-filters, and artificial lighting
  • Managing surrounding habitat around facilities to deter predators e.g. brown rats
  • Maintaining a safe and secure site

So be reassured that we can continue to care for our breeding conservation species despite the current lockdown conditions and that they are doing well! We look forward to updating you further on breeding activities as they progress over the next couple of months.

How you can help wetlands’ most threatened species

At WWT, we take the view that single-species conservation can play an important role as part of a broader conservation strategy, as long as they clearly positively impact the wider ecosystem or environment (and often, humans too). You can help us bring wetlands species like the Madagascar pochard or the spoon-billed sandpiper back from the brink by becoming a member of WWT. As a member, you help protect precious wetland habitats that endangered species rely on. You’ll also get free access all year to explore our wetland sites around the UK, created especially to be havens for wildlife.

Join us