Online nature lovers were able to watch one of the world’s rarest seabirds hatch on Nonsuch Island at the weekend.

The chick was first spotted on the CahowCam2 livestream at 8.55pm on Sunday, and was fully revealed a few minutes later.

J.P. Rouja, the founder of Nonsuch Expeditions, said in a post on the expeditions blog that researchers went into “hatch watch” on March 5.

It came after Jeremy Madeiros, principal scientist for terrestrial conservation with the Department of Environment and Natural Resources, spotted “dimpling” on the egg.

“Dimples are indentations seen in an egg shell caused by the chick starting to peck its way out from the inside,” Mr Rouja said.

“This is the first visible stage of the hatching process, which can be confirmed by viewing inside the egg by ‘candling’ it with a bright light, and weighing it to track changes as the chick develops.

“Once the dimples pierce the shell and inner membrane, they are then considered ‘pips’, which indicate that hatching is imminent.

“The presence of pips also starts a countdown for the chick to fully hatch, as once the egg membrane is pierced, it will slowly start dehydrating and if the chick isn’t able to break its way out in time, generally about four days for cahows, it runs the risk of dying in the shell.”

The team monitoring the burrow saw the father relieve the mother on the egg on Friday, and the pips were first spotted at about 5.30am on Sunday when the father left the nest briefly to chase away another cahow.

“This was documented by the ‘SurfaceCam’ that is set up outside the burrows, primarily to document chicks fledging, night-time aerobatics and confrontations such as this,” Mr Rouja said.

“With all eyes on the video feed throughout the following day, and with audible peeps being heard coming out of the egg from under the incubating parent, the egg wasn’t seen again until 14 hours later, when a now dime-sized pip, or hole, had appeared.”

The upper body of the chick, still wet, was first seen on camera at 8.55pm, with the full body emerging two minutes later.

Mr Rouja said: “The doting father took very good care of it, keeping it covered and warm while its down dried, until it next emerged from under him, four hours later, and was soon begging for its first meal.

“The father soon regurgitated the black tar-like predigested meal that it had been storing in its gullet for the past few days, which will be the sole source of food for the first few weeks of life until the chick is able to digest fresh fish and squid starting at about two months old.”

Cahows, also known as Bermuda petrels, were largely wiped out by introduced predators and hunting by early English colonists.

By the 1620s, the species was believed to be extinct.

However, it was rediscovered in 1951, with a handful of the birds found nesting on four rarely visited rocky islets, which sparked efforts to rebuild the population.

As part of the project, man-made burrows were created on Nonsuch Island, with chicks translocated to the sanctuary in the hope that they would return to Nonsuch as adults.

The project has borne fruit, with a growing number of birds fledging on the island and, witnessed for the first time since the 1620s, a cahow couple in 2023 successfully digging their own burrow and raising a chick inside it.

A total of 76 cahows fledged successfully last year, including 25 birds on Nonsuch Island.

Cahow season started early on Nonsuch Island this year, with the first chick hatching on February 15 or 16.

The Nonsuch Expeditions blog posted that as of March 5, there were 14 confirmed chicks on Nonsuch along with two more that were suspected, and eight other eggs that were pipping.

However, the check found that three chicks had died or disappeared after hatching.

The blog noted that as of March 1, Mr Madeiros had found 12 chicks and six pipping eggs on Horn Rock after checking two thirds of the nests in the colony, but weather had prevented researchers from checking on the Green Island colony.