Fourth baby orca born this season

(CNN)Spring is in the air and underwater -- especially off the coast of British Columbia.

Four orca babies have been born in the last three months, a higher number than usual, according to the Center for Whale Research.
Orcas in the area are called the Southern Residents and this baby boom brings their total to 81 whales.
"We hope this is a sustained upswing in the population, but they are endangered and will remain endangered until we can get their population up over 100," said Ken Balcomb with the Center for Whale Research.
    The first calf of the season was spotted in December, followed by two in February and this last one in March.
    Balcomb said CWR has been studying the Southern Residents for nearly 40 years. "Early on we used to have seven, eight orca babies, but recently we've had substantially less."
    Michael Harris, executive director of the Pacific Whale Watch Association, said efforts to improve the numbers of orcas include beefing up salmon in the area. "We're going to keep a careful watch on these babies and our fingers crossed -- and of course continue to do everything we can to rebuild these salmon runs and feed these whales."