Once Near Extinction, California Condors Face New Threat: Sea Lions
Have been hearing mostly good news in recent years. The condors have come back from the brink of extinction in more than 250 are now flying free in the skies of the Southwest. The effort to keep the birds thriving has hit a snag. It Seems like the mammals that the condors like to scavenge are increasingly contaminated feeding on animals filled on toxins a threat to the future of the condors. Joining me is Carolyn Kurle. She is assistant professor of conservation ecology at UC San Diego. Carolyn, Welcome to the program. Thank you. When the condor population started to build again in the wild the first threat researchers noticed was from lead poisoning from some of the animals that the birds fed on. And That lead is from bullets, well primarily Whenever professors demonstrated in her paper that the lead East poisoning that's hurting the condors is entirely from lead-based ammunition that's use by hunters in the wild tissue animals and the carcasses are left there. The state of California try to do something about that, right quick Correct. They have a lot in place that will take effect in 2019. How big of a threat is lead poisoning to condors? It's a huge threat, it is the number-one threat to condors. It is because if you are a scavenger NUC carcass the landscape you go for it. So you are going to get that lead poisoning immmediately. It takes the tiniest amount of lead to poison and animal. So it is the number-one threat. Is there any way to treat a Condor who has consumed potentially fatal dose of lead? Four yes. Condors are extremely well-managed by a couple of different groups. They do an excellent job in all of the groups and they capture them at least twice a year and they test their blood for lead and if they have high levels, they send them to one of the sending resumes or they are treated. Even if you get an animal and remove it from the system, led is toxic and can kill the animal before it is treated that has long lasting effects. There was hope that condors along the northern California coast could avoid that contamination from lead because they were eating sea Lions. They were not eating mammals. So no lead poisoning. What have you found now quick Folks that work on the condors noticed that condors on the coast of the Big Sur were -- looked appeared to be on -- they know that they contain contaminants. So we thought we should investigate whether there will be contaminants that were being transferred to the condors. Sure enough if you are a Condor Big Sur, there's a big chance that you are -- that animals on the coast. We found that California sea lions and condors have elevated levels of DDT and Mercury. So if you are Condor eating those Sea Lions you are also given those things in the system from the contaminated marine animals. And you are getting more than each individual Sea Lion is getting because you are any of whole bunch of Sea Lions. How are marine animals becoming so contaminated? There are many different ways but I rarely if you just focus on the Sea Lions the breed on the channel islands so almost all California sea lions spend months on the channel islands in Southern California and there are many contaminants that were dumped by chemical companies and DDT was split into the sewer system and all of that stuff just float out into the ocean especially at one place near Santa Monica. So all of that accumulated and they are just sitting there at the bottom of the ocean. They are pollutants meaning they don't biodegrade so they just persist in the system. If you are a Sea Lion coming down to the channel then you have high chance of picking up that contamination from the fish but then you take that contamination in California sea lions spread out all along the coast and there is a hollow site near the Condor site in Big Sur. There is lots of different sources of legacy pollutants up-and-down the California coast. What do they do to the Condor? Kent they kill them immmediately like the lead poisoning? Not necessarily. We know for sure in this paper the study that came out we are able to make the link between ingestion of DDT and eggshell and condors. So it is well-known that DDT causes eggshell thinning and other birds and in pelicans. So we show that if your Condor on the coast, some of them eat as much as half of their diet for marine animals. Condors up in the coast they show that they have eggshell thinning of the Big Sur compared to the condors down in Southern California that never are on the coast. We can link that eggshell thinning to the DDT exposure. The rest of the contaminants we don't know what they're doing. We know they are carcinogens in their disruptors. They are neurotoxins. Flame retardants also have elevated levels of those . Those are known as neurotoxins. So we know these things have bad effects but we don't know what they are doing to the Condor. Is this threat the kind of thing that could make it impossible for California condors to live in the wild and to exist quick I hope not. I think that the lead poisoning is a bigger deal because if you are lead poisoning that can kill you right away. She like it led to a knife wound and their Mark Drees to like a long-term disease that you need to manage. So I am hopeful that with continued management the folks that monitor these that we will continue to see the population stable and increase. This past year with the first year that they had more successful hatching's. That is a great sign. I just think that these data is that we have figured out are more information from the managers and the conservationist who are working with the birds. I have in speaking with Carolyn Kurle. Thank you. Thank you so much for having me.
California condors became nearly extinct in the 1980s, when the their population dwindled down to just 22. The culprit: lead poisoning from animal carcasses shot with lead bullets.
Recovery efforts and hunter education campaigns have bolstered the California condor population to more than 400 this year, but according to a new study in the journal "Environmental Science & Technology," condors face a new threat. This time, from eating dead sea lions.
Scientists had initially hoped condors living on the Northern California coast would be safer than condors inland in Southern California because sea lions were unlikely to be shot by hunters. But UC San Diego biology professor Carolyn Kurle, one of the lead authors of the study, found the Northern California birds had high levels of mercury and pesticides.
Most California sea lions breed at the Channel Islands in Southern California, which were contaminated with the insecticide DDT from the 1940s through 1970s by Montrose Chemical Corp. and others, according to Kurle. Condors that eat the contaminated sea lions lay thin-shelled eggs with a low chance of hatching successfully.
Kurle said research shows condors may suffer from eating both marine and land mammals.
"They’re both terrible," Kurle told KPBS Midday Edition on Monday. "There’s no safe wild food for these birds."
So is this the kind of threat that make it impossible for California condors to live in the wild?
"Oh gosh, I hope not. ... I just think that these data that we've figured out are just more information for the managers and conservationists who are working with these birds," Kurle said.