SEATTLE (AP) — A new calf was born to J pod of the southern resident orcas, an endangered population of killer whales.

The Seattle Times reports that Center for Whale Research director Ken Balcomb confirmed the birth Tuesday.

But the birth to orca mother J37 was mixed with news of the loss of two other pregnancies in southern resident families. The endangered whales’ population is now 74.

Scientists John Durban and Holly Fearnbach, of the marine mammal research and rescue nonprofit SR3, reported that routine, noninvasive monitoring of the orcas by drone photography determined two of the three expecting orcas had lost their calves.

“A calving rate of 1/3 of the documented pregnancies will, unfortunately, be consistent with the high rate of reproductive loss that has been documented in recent years by our drone studies and by hormone research conducted by the University of Washington,” the scientists said.

The southern residents face at least three main threats to their survival: Underwater noise, pollutants, and lack of adequate Chinook salmon, their primary food source.

Southern Resident orcas have been listed as an endangered species in the U.S. and Canada.