A 12-year-old dolphin at a Hawaii resort has given birth to a female calf that seems to instantly recognise her mother in a video of the birth posted online.

Footage of last week's birth on the Big Island shows the baby dolphin's tail moments before she emerges from her mother. Once she is born, she shoots up to the water's surface to take her first breath, then quickly swims alongside her mother.

The birth occurred in a man-made lagoon at Dolphin Quest Hawaii at the Hilton Waikoloa Village, where visitors can touch and swim with the marine mammals.

Resort chiefs will monitor the baby around the clock for now, as its first 30 days of life are its most critical in terms of survival, says Julie Rocho-Levine, manager of marine animals for Dolphin Quest.

Trainers will closely note when the baby nurses, among other things.

Officials say it's the first calf for the mother, Keo.

"I'm a mom myself, so I feel like I was able to appreciate her just calm, relaxed nature throughout the whole entire situation," said Ms Rocho-Levine, who was there for the birth.

"It seemed as though she (Keo) was seeking out that human companionship and finding comfort in the people she knows and spends her days with."

Keo was calm enough to allow vets to perform an ultrasound during labour.

Dolphin Quest plans to wait to name the baby until after its first month of life.

The rate of survival for babies of first-time mother dolphins in the wild is about 50%, Ms Rocho-Levine says. But that rate is much higher for dolphins born with access to top-notch care from humans.

Marilee Menard, executive director of the Alliance of Marine Mammal Parks and Aquariums, said 70% of the dolphins in accredited facilities in North America were born in a zoo or aquarium.