Broadcast by KQED, photo by Gina Castro/KQED

HOST INTRO: Brown pelicans are in trouble again — and now, it’s the babies. This spring marks the third starvation event in four years for the iconic California seabirds. Scientists are still looking for answers, as KQED’s Anna Guth reports…

[Bring in ambi] Many emaciated young pelicans have arrived at International Bird Rescue in Fairfield since March. CEO JD Bergeron [BERJ-ER-ON] walks into what looks like a baseball batting cage.

BERGERON: [gate closing] This is the pelican aviary. For folks who know brown pelicans well, you can see that these are all young.

The pelicans swooping between high perches can return to the wild soon – but one tiny bird by the swimming pool needs more time.

BERGERON: See the really pale one against the wall?

That starving fledgling migrated at least 500 miles from its nest in Southern California or Mexico.

BERGERON: That bird was among the farthest north of all these birds — so strong enough to keep searching, but puttered out in Mendocino area. That is a very young looking bird.

Seabird experts have theories about what’s making the birds starve. Last year, pelicans maybe couldn’t find prey — either because late-season storms chopped up the water or the anchovies swam too deep under the warm surface of the Pacific Ocean.

But Rebecca Duerr [DO-ER], who directs veterinary science at International Bird Rescue, said THIS SPRING, a toxic algal bloom first poisoned some adult birds...

DUERR: At the same time we were starting to get these young birds that didn't know how to eat.

That second wave of almost 200 rescued starving babies is still a mystery. Maybe the algal blooms also affected them. Maybe their successful breeding season just meant higher numbers didn’t learn to forage. Or maybe their sick parents abandoned them…

DUERR: It's circumstantial evidence, but it looked like, if mom doesn't come back, they have to leave the nest or they're gonna die. It sure seemed like the chicks were fledging extra early.

It is clear that warming ocean temperatures can make life harder for pelicans. Bergeron [BERJ-ER-ON] says climate change is playing out before his eyes…

BERGERON: Seeing all these birds struggling when they were previously doing just fine is a really scary thing.

So far, there are less starving pelicans than last year. And, luckily, the numbers show the starvation event slowing down.

For the California Report, I’m Anna Guth, in Fairfield