Home Forums Hunting & Shooting Hunter's Campfire California Condors Just Aren't Cut Out for the 21st Century

Marine mammals are so polluted that they are poisoning endangered condors, according to a new study. California condors (Gymnogyps californianus) that fed on marine mammal carcasses had high blood levels of several toxic chemicals, including broken-down forms of the banned pesticide DDT. The findings could explain why condors living on the coast in Big Sur have thinner eggshells and lower breeding success than their inland cousins.

“It is showing pretty solidly that if you’re a condor from Big Sur, you’re spending time on the coast, you’re eating marine mammals, and it’s going to be detrimental to your reproduction because marine mammals have higher levels of contaminants,” said Carolyn Kurle, an ecologist at the University of California, San Diego and one of the authors of the study published last month in Environmental Science and Technology.

California condors are immense vultures that feed on carrion, including the washed-up carcasses of whales, seals and sea lions. Most of these marine mammals are top predators, and their bodies accumulate mercury and long-lasting organic pollutants such as polychlorinated biphenyls (PCBs), flame retardants (polybrominated diphenyl ethers, or PBDEs), and chlorinated pesticides including DDT. Chemicals in these categories have been shown to disrupt hormones, increase cancer risk and damage the nervous system.

The U.S. banned production of PCBs and DDT in the 70s, but in the mid-20th century, chemical companies pumped thousands of tons of the toxins into the ocean near California’s Channel Islands. The Channel Islands are still heavily contaminated, and they also happen to be the breeding site for more than 95 percent of California sea lions (Zalophus californianus), the marine mammal most often eaten by condors. DDT and its breakdown product DDE are known to cause eggshell thinning in birds, and past research has found that coastal condors have thinner eggshells than condors from inland populations. The coastal birds’ eggs are also 20-40 percent less likely to hatch.

For the new study, the researchers aimed to pin down the connection between condor eggs and sea lions, as well to investigate the birds’ exposure to other pollutants. Using stable isotope analysis, they showed that coastal condors got 8-52 percent of their food from marine mammals. Compared with inland condors, these sea lion-fed birds had 12-100 times more mercury, PCBs, PBDEs and chlorinated pesticides in their blood. The researchers estimate that 40 percent of coastal condors have DDE levels high enough to cause eggshell thinning.

“We don’t know what those [other] pollutants are doing to condors, but we can assume that they’re not doing anything good, because they’re known carcinogens and endocrine disruptors and neurotoxins,” said Kurle.

Pollution from marine mammals isn’t the only threat facing condors. The most immediate threat is lead poisoning, which condors get from eating animals shot with lead bullets. Lead kills condors quickly, while the chemicals in marine mammals are likely to cause long-term harm to populations, says Kurle.

“We were really worried about lead poisoning, which is still a huge problem inland, but now we’re also worried about contaminants from the marine system,” Kurle said. “There doesn’t appear to be any wild food source that’s 100 percent safe for these birds.” (Emphasis mine)

Timely propaganda, given that the use of completely safe DDT would easily save the world from Zika, among other mosquito-borne diseases.

Lead poisoning from lead bullets and shot ? Their evidence was one (1-!) condor found dead. He had a lead fragment in his gullet. Cause of death could not be determined due to the advance state of decay of the Sample of ONE.
So, Kalifornia banned the use of lead bullets/shot for hunting in condoe range and is in the process of banning lead for all hunting.
Yep. Real careful and well documented research that is.
And now we hear about how horrible DDT is again. It "saved" the Peregrene Falcon and tne Brown Pelican. But, according to the UN, of all people, it cost no less than 500,000 human lives.
By all means, let's save the critters. E

A lot of the fish in the California Delta have elevated mercury levels. When I was living there, people were warned not to eat striped bass weighing over 8#, as they were among the worst for mercury levels.

The seals & seal lions do swim well up the Delta to chase fish, with no sharks or orcas to worry about.

They don't taste like they used to. I know that.

The whole egg shell thinning thing with DDT has been thoroughly debunked. Any time you see that old canard put forward, you know you are dealing with junk science or propaganda.

I liked the way DDT tasted

I fondly remember running behind the spraying trucks and having a blast.

This was on the coast of MS.

The good old days,like drinking out of the hose.

Can anyone explain why the condors are so danged endangered? Around here turkey vultures, which have the same life style, are probably the most common large birds.

Maybe some creatures are just meant to be extinct. After all, look at all the animals that have become extinct. Scientists tell us almost no species lasts for more than 5MM years.

So are the enviromentalists going to ban marine mammals now?

Tex, about a hundred years ago i was building boats in Stockton for servicing the off shore oil rigs and we would go out right at the port of Stockton and catch sharks.not very big and suspect they were bull sharks but they were in there clear up to Stockton.
Man what a pit that has turned into.

Yep , something like 99% of all the critters that ever existed are extinct. It's probably just naturally time for the condorbuzzards to be on that list.
Besides that , if the Kalifornia Kooks just have to have buzzards so damn bad North Carolina has plenty we can send 'em.

Mike

Years ago I read that condors were dying off because of people shooting lead bullets.I thought to myself that has to be bullshit.Since I have been alive(52)yrs.How many deer have been killed in Md? Im not sure of the exact amount....lets just say [bleep].There are buzzards everywhere and I have seen more bald eagles in the last 5 yrs then I have seen all the rest of my years.Lead bullets my ass.

You've always been pretty reliable, Denton, so I'm loath to doubt you, but do you have a source on the debunking. I knew some of the guys involved in the peregrine project at C.S.U. and they didn't have any doubt about the egg shell thinning.