SEATTLE (AP) — Two more Puget Sound orcas are ailing and probably will be dead by summer, according to an expert on the population of killer whales that live in the Pacific Northwest.

Drone photography taken this past September showed the ailing population of orcas known as the southern residents went into the winter thinner than they were when the whales arrived in the San Juan Islands last summer.

They also are thinner than Puget Sound’s so-called northern resident population of killer whales, which have been steadily growing in population for the past 40 years in their home waters in northern British Columbia and southeast Alaska, where they have access to more fish and cleaner and quieter water. The northern residents gave birth to 10 new calves last year.

Several southern resident whales were documented to be pregnant in September, but so far there has been no sign of babies. The southern residents have not had a successful pregnancy in three years.

The southern resident population is at a 35-year low after three deaths in 2018. There are only 74 left.