Starving birds add to El Niño worries
Chicks found on beaches in Northern California may signal warming cycle
Scores of starving baby seabirds have been washing up on Northern California beaches this summer, raising fears among scientists that a climatic cycle like the one that wreaked havoc on sea creatures a few years ago may be moving in.
More than 100 undernourished common murre babies have been plucked from beaches from Monterey to Marin County by biologists and volunteers with International Bird Rescue and are being rehabilitated at the organization’s Fairfield center.
J.D. Bergeron, the executive director, said it is unusual at this time of year for the center to have more than a handful of baby murres, a native fish-eating seabird that, with its dark color and white belly, looks like a cute, foot-long penguin.
Normally at this time, he said, the chicks are out at sea being fed by their fathers while the mothers go off to replenish energy reserves after giving birth. But rising ocean temperatures may have made it difficult for the fathers to find the cold-water fish the birds normally eat. Large numbers of beached seabirds have also been found in Alaska this year.
“Obviously there could be some sort of envi-
ronmental contaminant, but, since the babies are coming in healthy but starving, we think this is a food issue,” Bergeron said. “One of our concerns is that, while this has been all chicks, we will see a followup event with the adults.”
Record high ocean temperatures in Southern California in August created widespread alarm among marine biologists. Now they are concerned that conditions could worsen if predictions about an El Niño weather pattern over the next few months come true.
El Niños are characterized by unusually warm, nutrientpoor conditions in the equatorial Pacific Ocean and, in the past, have caused the marine food chain to suffer.
In early August, sea surface temperatures went above 78 degrees off the coast of La Jolla in San Diego County — the warmest water in that location in more than a century of measurements.
The warming trend would probably continue under El Niño and could, if strong enough, spread the toasty currents north past San Francisco. The National Oceanic and Atmospheric Administration’s Climate Prediction Center puts the likelihood of El Niño at 60 percent this fall and 70 percent this winter.
Warm water during the last big El Niño in 2014 and 2015 led to the deaths of thousands of marine species, including virtually all the sea lion pups born on the Channel Islands and hundreds of adult murres along the coast. It happened, scientists said, because the fish they eat had migrated north in search of cold water.
Shawn Johnson, the director of veterinary science for the Marine Mammal Center in the Marin Headlands, said more than 1,800 animals had to be rescued that year, triple the average number, because they couldn’t find food.
There haven’t been nearly that many rescues this year, but that could all change if the warm water moves north.
“What we’re mostly concerned about is warm water in Southern California, near the Channel Islands, where the sea lion pups are,” said Johnson, who has taken care of 500 rescued animals this year, about average. “They live with their moms for about 12 months after they are born. A good amount were born this year, but if those moms can’t find the food for their pups, then those pups are going to start starving.”
Forecasters are predicting a weaker El Niño than in 2015, but the overall warming trend in California and around the nation has climate scientists worried.
“The strongly warming climate means that extremely warm waters will become more and more common, especially in El Niños,” said Christopher Field, director of the Stanford Woods Institute for the Environment.
Field said recent analysis of “super peak” temperatures like what has been seen recently in Southern California “showed that ocean ‘heat waves’ are becoming more frequent, longer, and more intense.”
The signs are not all negative. Sea lion births were fairly robust this year, according to biologists, and the number of common murre hatchlings on the Farallon Islands was slightly above average. There also appears to be abundant sea life, including humpback whales, outside the Golden Gate.
“Preliminary data in our region so far shows fairly typical conditions for a productive year,” said Mary Jane Schramm, the spokeswoman for the Greater Farallones National Marine Sanctuary. “There is a lot of food out there this year. We’ve seen it from several research cruises we’ve run already, and the top predators — the whales that require lots of food — are out in force.”
Schramm said the high number of murre strandings — and the higher than average number of murre carcasses found on the beaches — could just be because there are more young birds out there.
“Anytime there is an extraordinary amount of life, there is also an extraordinary amount of death,” she said. “It’s part of the natural cycle.”
Pete Warzybok, the senior marine ecologist for Point Blue Conservation Science, said the murres have been feeding primarily on anchovies, which are a near-shore fish. Large anchovy shoals close to shore are also why so many humpbacks have been seen by boaters and beachgoers in recent years.
Because that is mostly what the birds are eating, Bergeron and others are concerned about what might happen if the anchovy population declines. He said the birds found on shore probably represent only a fraction of the number that are starving.
“We think that the ones that don’t make it to the beach will perish at sea,” he said. “Really, what we’re seeing is a trend of challenges for wildlife living in the ocean.”