Blue whales are arriving off Southern California, searching for enormous krill patches on which to feed.



It remains to be seen whether this will be a productive whale-watching season, given the unseasonably warm water in some areas, and a strengthening El Niño.

But some of these great leviathans, the largest creatures to have inhabited earth, are already making their presence known off Orange County.





They include a famous seasonal visitor named Delta, because the mammal’s upturned fluke ends reminds some of the tail section of a jet.



Delta was spotted over the weekend off Newport Beach and Dana Point with what might be her calf. The photo atop this post, courtesy of Dana Wharf Whale Watch, shows Delta on a very gloomy Friday.

The first video, uploaded Monday by Captain Dave’s Dolphin & Whale Safari, shows the calf approaching the catamaran Manute’a, to the delight of passengers.

“It was almost as if the smaller whale wanted to play with the boat!” states the video description.



The second video, uploaded by Dana Wharf Whale Watch, shows aerial footage of a different blue whale swimming with a calf. Almost immediately, viewers can watch the calf roll over and swim upside down–a behavior that's rarely observed.

If the sun had been out, footage in both videos would have been even more spectacular.

About 2,000 blue whales that feed in waters off California, from about late May through early fall. Where they'll be seen depends entirely on plankton-like krill, which is practically their sole source of sustenance.

A single adult blue whale can consume 4 tons of krill per day, so they need to go where the blooms are largest.