CAPISTRANO BEACH – A baby gray whale, perhaps just hours old, weaved around and over its mom just 2 miles off the coast.

The duo – a 39-foot-long mom and a 15-foot-long calf – were heading south, part of the gray whales’ annual round-trip migration from the northern feeding grounds in Alaska to calving and breeding grounds in the lagoons of Baja California in Mexico.

The calf and its mom were captured on drone video Friday by Capt. Dave Anderson, who operates a whale-watching company in Dana Point Harbor. One of his boat captains had spotted the duo off of Dana Point.

For whale-watch captains, calf sightings are rare; most baby gray whales are born in Baja. Anderson, who uses whale footage to educate the public, jumped on his boat and within minutes found the pair several miles farther south. He kept a 100-yard distance and deployed the drone.

“I don’t know if I’ve ever seen a calf this early in the season,” Anderson said. “The mom and calf were just really close together. I could see the fetal folds on it. When they’re in the mom, they’re folded in a fetal position. It looks sort of funny when you see it. The way the calf looked, I believe it was just hours or days old.”

Friday’s scene comes as whale sightings are hitting record highs, continuing a trend rising from a low point seen four years ago.

As of noon Tuesday, volunteers with the Gray Whale Census and Behavior Project, armed with binoculars and high-power scopes, had counted 370 gray whales heading south this December, including eight calves. In 2012, the figure was 182 gray whales through Dec. 31, and in 2010 the December number was 38.

Alisa Schulman-Janiger, a marine biologist and director of the Gray Whale Census and Behavior Project at Point Vicente, has been tracking gray whale migration for 31 years – and this has been the December with the biggest number yet.

She and other experts can’t explain why there have been more gray whale sightings than in the past four Decembers; she doesn’t know if there is a population boom. Perhaps the whales are traveling closer to the shore, the southern migration started earlier or visibility has been better.

From the Orange County coast, the gray whales have hundreds of miles to go to reach Baja’s northernmost lagoons and a thousand more to Magdelana Bay, the southernmost lagoon.

Calves born on the southbound trip, like the one Anderson filmed, don’t face a lot of threats from predators because they are skinny and not appealing to killer whales.

Along the way, moms slow their cruising speed: Instead of covering 120 miles a day, they do 60, stopping to nurse at least 10 times a day in kelp beds.

Once they reach the lagoons, it is like a preschool: The babies rest, play, grow and socialize. The water is warmer and saltier, making their skinnier bodies more buoyant, with the coves protecting them from storms and predators.

Each year, nearly 21,000 gray whales travel the West Coast, with some traveling more than 12,000 miles during the round trip.

For Anderson, Friday was magical.

“To have these numbers is just off the charts,” he said. “It’s like we’re in high season (which is typically in mid-January). There’s something going on. I don’t know what it is, if we have more gray whales or they’re coming closer to shore. Nobody knows.”

Contact the writer: 714-796-2254 or eritchie@ocregister.com Twitter: @lagunaini