A fluorescent green egg has Adelaide Zoo’s bird team celebrating, with 10-year-old Southern Cassowary Martina laying the first cassowary egg at the zoo in 34 years.
The milestone follows the carefully managed pairing of Martina and 13-year-old male cassowary Jeffrey for the first time this breeding season. While the team does not yet know whether the egg is fertile – and there is no guarantee it will produce a chick – its arrival is an exciting step for the species at Adelaide Zoo.
Adelaide Zoo’s first cassowary chick hatched in 1968, with another six cassowaries born in 1992. No cassowary eggs have been recorded at the zoo since that breeding success 34 years ago.
Team Supervisor Birds and Free Flight, Erin, said the team was thrilled to discover Martina’s first egg.
“This is really exciting news for us because it has been 34 years since we’ve had successful cassowary chicks here at Adelaide Zoo, so the team and myself included are very excited,” Erin said.
“Martina and Jeffrey have only been paired since August this year, and this is the first time they’ve ever been put together.”
Southern Cassowaries are generally solitary birds and can be aggressive towards one another outside breeding season, meaning the team needed to carefully monitor the pair before deciding the time was right for an introduction.
The breeding recommendation came through the managed program for the species, after which keepers closely watched Martina and Jeffrey for behavioural signs that they were becoming more receptive to one another.
“We were really watching their behaviours to make sure that we paired them at the right time,” Erin said.
“We were looking for things like vocalisations – a low rumble or boom call – and whether they were more tolerant of eating near each other.
“We removed parts of the shade cloth between them and put their food alongside each other at the fence line so we could watch how comfortable they were around one another.”
Those signs gave the team confidence to introduce the pair in mid-August – and the response was immediate.
“Jeffrey approached Martina cautiously at first, then started preening himself before going over and preening Martina,” Erin said.
“They actually mated on the first day that we paired them together, which was very exciting, and they have since been seen mating on multiple occasions.”
Now, the team is watching closely to see what happens next.
Cassowaries can lay a clutch of eggs between 3 and 5 normally, with the male taking on incubation duties once laying is complete. Jeffrey may eventually be separated from Martina so he can incubate the eggs, depending on the birds’ behaviour.
Incubation takes around 50 days and, if fertile eggs do hatch, it is the male cassowary that cares for and raises the chicks.
But for now, the team is cautious about getting too far ahead.
“It’s not guaranteed that the egg is fertile, but it is still really exciting news that we have an egg for the first time in 34 years,” Erin said.
The egg itself is hard to miss – cassowary eggs are a vivid green colour, helping them blend into their rainforest surroundings.
“The egg is actually fluorescent green – it’s a really bright green colour,” Erin said.
“That colour comes from pigment in the shell and helps camouflage the egg. In the wild, cassowaries live in dense rainforest and will find a safe area amongst the leaves to lay, so that green helps keep the eggs hidden from predators.”
Martina and Jeffrey have chosen a nesting area close to the front of their habitat, prompting keepers to add shade cloth around the area to give the pair extra privacy.
“We’re giving them the space they need and will continue watching closely. Hopefully we may see more eggs and, if they are fertile, hopefully chicks – but at this stage, we simply don’t know.
“For us, having that first egg after 34 years is exciting in itself.”
