Peregrine falcon eggs laid at the top of a Melbourne high-rise have started to hatch as an audience of nearly 40,000 watches on social media.
Victorian Peregrine Project founder Victor Hurley said cracks were spotted in one of the four eggs on Thursday morning and the chicks were expected to emerge in 28 to 48 hours' time.
Known as the 367 Collins Falcon, the birds have been nesting on the top of the 34-storey building on Collins Street since 1991.
Webcams were installed about five years ago and streamed online 24/7, but it was Melbourne's lockdowns that saw the birds gain a cult following.
Things had heated up last month when online discussions began buzzing about another male trying to make his presence felt around the nest.
Dr Hurley told ABC Radio Melbourne a second male was on the scene and he appeared to be quite meddlesome.
"I got a message from someone saying that her husband had seen a pair on the ground fighting down there by the Yarra River at Federation Square there," he said.
"So they've had a crack and they haven't decided who's going to occupy the site."
Interloper has 'let the side down'
Dr Hurley said it had been a while since original male was spotted.
"We have a first-time breeding female who laid the eggs that were fathered by the old male," he said.
"He's now gone from the scene, being chased off or killed by the new male, who hasn't produced any of these eggs with her."
He said the new male had really "let the side down" — the previous mate spent about 50 per cent of his daylight hours incubating the eggs, but the newcomer had not spent "as much as second" nest-sitting during the three-week incubation period.
"The male that disappeared, he's about eight years old, possibly nine, so very experienced into the sixth season of breeding," Dr Hurley said.
"He really understood the routine and what his job was, where he fitted in with the scheme of things.
"We're at the stage now where she's going to now stay very tight on the nest and she's not going to let him near it until they've hatched."
He said it was very likely all four eggs would hatch.
"I haven't seen anything about their incubation that would suggest to me that one has had any less treatment than the other," Dr Hurley said.
Flying the coop
Observers will not have to wait long to see whether the newcomer's parenting skills are up to scratch, but it will only be about six weeks before the hatchlings leave the nest.
"The females will fledge about a week later — maybe 10 days because they're 30 per cent bigger and it takes them a week to just grow those slightly larger wings to cope with their weight," Dr Hurley said.
They will hang around until early summer while the adults teach the chicks to hunt.
"Once each of the individuals is successful in their first kill, the animals sort of register, 'Right, OK — you're good to go now, I won't be providing you any more food', so that's a real milestone," Dr Hurley said.
"Then sometime after that, it could be a few weeks or whatever, they will then chase them entirely out of the territory for life."
The birds will move as far as 250 kilometres away from their nest to find their own breeding site and start the reproductive process for themselves at about two to three years of age.
