Are brown pelicans forecasting an El Niño?
Biologist Kathy Molina was making one of her regular surveys of the Salton Sea National Wildlife Refuge on a recent Friday. Molina keeps tabs on several species of rare sea birds that use the Salton Sea as a nesting spot.
Some birds, such as the gull-billed terns, have been struggling recently to keep their numbers up in the face of increased competition for nesting spots from larger birds.
“It’s looking a lot worse for the smaller species. Because they’re smaller, the bigger guys just kind of push them aside, and so they’re moving. They’re constantly being challenged for a lot of competition for nest space,” Molina said.
This year, that nest space has been further poached by thousands of adult California brown pelicans that are showing up months earlier than normal to roost in spots inland from their normal nesting areas.
Dan Cooper, a biologist who monitors birds at Malibu Lagoon, said he first noticed the birds’ strange schedule in mid-April.
“I was just sort of flabbergasted at seeing 3,500 brown pelicans resting in Malibu Lagoon,” Cooper said. “I checked my notes, and I have numbers in the hundreds, but I’ve never seen anything like that.”
Failed nesting season
While the pelicans regularly use the Salton Sea each year, Molina said it’s usually not until after the other birds’ nesting seasons.
On Friday, the pelicans ringed small islands, both natural and man-made, in freshwater ponds along the sea’s edge. They stretched and preened, almost as though they were on vacation. Molina said she’s seen thousands of the large birds each time she’s come recently.
“The absolute numbers are not shocking. It’s just the timing. They’re early, and when they’re early like this, that’s when they impact our nesting birds,” Molina said.
The pelicans themselves aren’t nesting or rearing young. They’re roosting — essentially hanging out in spots near food sources.
Scientists say that a shift in the locations of their fish food sources has made it difficult for the birds to get enough nutrition to raise young. As a result, the majority of brown pelicans have given up the attempt for the year.
For the past 46 years, Dan Anderson, a professor emeritus at the University of California at Davis, has visited the Baja Peninsula, where 80-90 percent of California brown pelicans are born. This year, he said that he estimates pelicans have reared less than one percent of the young they normally would.
“It’s been almost a nearly complete failure to breed, which is quite unusual actually,” Anderson said. “At one island that we study, Isla Salvatierra, which would normally have 8,000-10,000 young, only had like 20 young.”