Zoo captures unique egg-cracking trick of Australian buzzard on film

Ever wondered what it looks like from inside an egg when it’s being cracked open?

Keepers from Healesville Sanctuary have captured this wild moment while filming the unique behaviour of one of Australia’s clever-minded birds of prey.

Black-breasted buzzards have become known for their innate* ability to use rocks as tools. The large Australian raptor has been documented holding a rock in its beak and smashing it against an egg in order to get a meal.

Keepers at Healesville Sanctuary have found an inventive way for the zoo’s black-breasted buzzards, Bernice and Beatrice, to maintain this instinctive behaviour using unfertilised* emu eggs.

With Healesville’s young female Emu, Frankie, laying 14 eggs so far this season, the sanctuary had an excess – one might even say “egg-cess” – of unfertilised eggs to work with.

Frankie hadn’t yet been paired with breeding male Patches, so her eggs didn’t contain emu embryos*. To allow Frankie to go through the natural process of laying while making sure the eggs didn’t go to waste, the team started hollowing them out and giving them to the buzzards, who have been happily cracking them open, just as they would do in the wild.

Zookeeper Shaun Scott said very few bird species around the world showed this innate behaviour where they grabbed a rock and used it as a tool to get to their food. Keepers have been able to demonstrate the unique behaviour to visitors during the zoo’s Spirits of the Sky presentation.

“There are only two raptor species that have this unique behaviour. The Egyptian vulture does a similar thing with ostrich eggs. We are lucky to have a bird like the black-breasted buzzard here in Australia that smashes eggs. It’s a pretty unique behaviour,” Mr Scott said. “Breaking open the egg is not a behaviour that we’ve taught them. It’s not a trick. It’s not something that they’ve learnt from their parents. It’s an instinct and adapted skill set. It’s something that all black-breasted buzzards just know how to do.

“In the wild, this is an important behaviour because inside an emu egg is roughly four or five days’ worth of food for a black-breasted buzzard. For the ones that live at the Sanctuary, it is an effective way to use their natural environment and skills as enrichment* to look after their mental health as well as their physical health.”

Wondering why Frankie the emu has been laying eggs even though she hasn’t been breeding?

Like many birds living in captivity (especially chickens), female emus can still lay eggs during breeding season even if they haven’t bred with a male – but the eggs do not contain embryos. Since the eggs have not been fertilised, they will never hatch into baby emus, which is why the staff at Healesville Sanctuary have been able to repurpose Frankie’s eggs in the way that they have.

Emus have one breeding season each year during winter, when a female can lay anywhere between five and 20 eggs in a clutch*.

Emu eggs are emerald in colour, about the size of a mango, and weigh around 500 grams. Approximately 10-12 chicken eggs make up the size of an emu egg.

As for chickens, those kept away from roosters for the purpose of laying eggs can produce unfertilised eggs almost daily and all year ‘round – making chicken eggs a popular food choice for billions of people across the globe.

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GLOSSARY

• innate: a natural ability that is there from birth
• unfertilised: an egg that hasn’t been turned into an embryo through the reproductive process
• embryos: an early developmental stage of an animal after fertilisation
• enrichment: programs that keep the lives of animals in captivity interesting, by enabling them to explore, forage and play in different ways and keep their wild instincts active
• clutch: the total group of eggs laid by a bird in one nesting attempt

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QUICK QUIZ
1. What type of bird is a black-breasted buzzard?
2. Why do black-breasted buzzards crack emu eggs open with rocks?
3. Which other species of bird uses a rock as a tool for cracking open eggs?
4. How many breeding seasons do emus have in a year?
5. Why are Healesville keepers giving empty emu eggs to the black-breasted buzzards to crack open?

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CLASSROOM ACTIVITIES
1. Chicken or emu?
Why do you think people use chicken eggs rather than emu eggs for cooking and eating?

Write a list of as many reasons that you can think of!

Time: Spend at least 15 minutes on this activity
Curriculum Links: English, Health and Physical Education, Design and Technologies

2. Extension
Do you think that it would be possible to train another species of animal to use a tool to find or open food, like the buzzards? Choose an animal, a tool and an action that you think could work. Write a paragraph explaining your choices and a description of how you might go about training them

Time: Spend at least 30 minutes on this activity
Curriculum Links: English, Science

VCOP ACTIVITY
Read with Kung Fu punctuation
Pair up with the article between you and stand up to make it easy to demonstrate your Kung Fu punctuation.

Practise reading one sentence at a time. Now read it again, while acting out the punctuation as you read.

Read and act three sentences before swapping with your partner.

Take two turns each.

Now ask your partner to read a sentence out loud while you try and act out the punctuation. Can you keep up? Swap over?

Try acting out two sentences – are you laughing yet?