A new calf was born to J pod of the southern resident orcas, Center for Whale Research director Ken Balcomb confirmed Tuesday morning.

But the birth to orca mother J37 is tempered 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.

J19 and J36 appear to have decreased significantly in body width, and neither had calves with them, the scientists reported.

“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 stated.

“Unfortunately, reproductive loss has become normal for this population.”

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.