NORTH BEND — Most people hoping to glimpse whales in action head to SeaWorld, catch an excursion boat or wait all year for the majestic mammals to migrate south for the winter.

On Tuesday morning, no planning was necessary. People flocked to the boardwalk behind The Mill Casino-Hotel to watch a gray whale swim along the Coos Bay.

“I actually grabbed my camera and ran across the street,” said whale watcher Chris Tanner, who works at the Coquille Tribe’s main office. “I saw it pop up its head two times and (it) spouted through its blow hole.”

Tanner said he and about 20 other people shared the dock behind The Mill as they waited for the whale or whales — there’s some debate among the  watchers as to how many — to pop up every few minutes for air.

“It was a very beautiful moment for Coos Bay. The sun shining off their skin — that’s a natural attraction,” Tanner said.

Jan Hodder, an associate professor at the Oregon Institute of Marine Biology, identified the creature as a California gray whale from a photograph.

She said it is rare for a larger whale like this one to swim into the bay, but it has happened. A pod of orcas came into the lower bay in Charleston in May and another swam the 15 or so miles up to the upper bay about two years ago. The lower bay also has seen humpback whales.

The gray, she said, likely was migrating from Alaska to Baja California to breed.

“They are on their way south and this one just decided to explore on the way down, I presume,” Hodder said.

Gray whales are baleen whales that spend the summer feeding in Alaska on invertebrates living in sediment on the seafloor. In the winter they swim to Baja and return to Alaska in early spring. Hodder noted that they tend to have a very blotchy look to them because of the parasites — barnacles and whale lice — that live on their skin.

Out at the dock, a large camera swung from Jeremy Young’s neck as he walked with his daughter, Desiree, in the sunlight.

The North Bend resident said his wife, who works at The Mill, called him when she first saw the whale. Young said he lived in Portland before moving here and never got to see whales up close. The one or two he saw Tuesday came within 100 yards.

“It was sweet. You don’t see something like that every day. Stuff like that you usually have to pay for,” he said.

He said 3-year-old Desiree was excited, too.

“When she saw the spout she said, ‘What is that, Dad?’”

Ray Doering, a spokesman for The Mill, said patrons and employees spent much of the morning peeking out at the water in search of a tell-tale spout or a flip of a tail.

“Actually, it’s the beauty of working here, being this close to this really great environment,” he said.

Doering said some people were blown away by the whales, including one woman staying at the RV park. He said she walked out her door, looked at the water, saw a whale, and walked right back inside.

“She said ‘It must be my imagination’ and she kind of walked away,” Doering recalled. “It’s a real surprise the first time you see it. It’s much bigger than you expect.”