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From Nature magazine
After more than three decades on the brink of extinction, the California condor (Gymnogyps californianus) — the largest and most threatened wild bird species in the United States — is making a modest recovery, thanks to intensive captive breeding and medical intervention. But troubling data reported this week suggest that unless hunters change their practices, the condor will require extensive support in perpetuity if it is to survive in the wild.
The cause of the problem is that the condors ingest lead when they feed on the carcasses of animals that hunters have shot. A multidisciplinary study published on 26 June (M. Finkelstein et al. Proc. Natl Acad. Sci. USA http://dx.doi.org/10.1073/pnas.1203141109; 2012) shows that chronic lead poisoning persists among condors, despite a 2008 California ban on the use of lead shot in regions where the birds are being reintroduced.
Building on earlier studies, the researchers collected feathers and blood samples from trapped birds and found no discernible difference in lead levels before and after the ban. Condors feed by scavenging; the results show that many of those sampled have dangerous levels of lead in their bodies. Lead poisoning can severely damage the birds’ nervous systems and impair liver and kidney function, among other problems, and it can be fatal. The study also found that approximately 20% of condors in the wild have lead levels that are high enough to require costly treatment with chemical agents to remove the toxic metal from their bodies.
“By any measure, the lead poisoning rates in condors are of epidemic proportions,” says Myra Finkelstein, a toxicologist at the University of California at Santa Cruz, who led the research.
The California condor population fell to an all-time low of 22 individuals in 1982, but captive-breeding and monitoring programmes have brought it back up to nearly 400 birds. Of those, half reside in captive-breeding centres, which provide a steady supply of new releases. In California, only 24 chicks have fledged in the wild. At that rate, the study shows, it would take 1,800 years for the population in California to reach 150 — the number called for in the recovery plan — without the ongoing release of birds bred in captivity.
Finkelstein’s team did an isotopic analysis of the lead in the birds and identified lead shot or bullets as the main source of contamination. Even though hunters must use copper bullets or other alternatives in condor habitat, some are apparently ignoring the ban. Condors must consume 75–150 carcasses every year to maintain a healthy weight. The study found that even if fewer than 2% of the carcasses contain lead, there is a 50% chance that a condor will eat contaminated meat (see ‘Loaded odds’).
“Kudos to the hunters who are using copper [bullets], but it isn’t going to be effective until you get all the lead out,” says Jeff Miller, conservation advocate for the Center for Biological Diversity (CBD), based in Tucson, Arizona. Lead ammunition is cheaper and popular with hunters. The American Bird Conservancy in The Plains, Virginia, which advocates for lead-free hunting, argues that publicizing the risk of lead shot to human health might persuade hunters to use alternatives.
Pedro Nava, a former member of the California State Assembly who spearheaded the lead ban, says that a lack of resources for enforcing the ban means that the condor’s future depends on the good will of hunters. He says that the California Department of Fish and Game needs more enforcement personnel. “They have 300 game wardens in the state. If they were to be consistent with other states in terms of population, they should have a thousand,” he says.
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20 Comments
Add CommentI'm glad for this study. As conservationists, hunters are going to have to step up and solve this problem. Banning lead bullets for hunting is not much of a hardship--copper makes superior bullets anyway. Note that I'm not saying lead bullets should be banned! Only their use for hunting. I'm an NRA life member, by the way, and I'm going to urge the NRA to discourage the use of lead bullets and shot for hunting.
Reply | Report Abuse | Link to thisI wonder if the problem of lead shot from shotguns has been compared to that of lead bullets. It would seem to me that the smaller size (hence larger surface area) of shot would be a much larger problem in toxicity.
Last time I checked the lead shot was not allowed to hunt waterfowl so how in the world condors are gobbling it down? Not to mention that California Condor diet does not include waterfowl. The argument can be made that lead comes from small game such as quail, but simple wikipedia query indicates that Condor do not eat small game such as quail- they prefer to feast on large terrestrial mammals deer, goats sheep, cows etc... those are not hunted using the lead shot but brass jacketed lead bullets. In order to get lead poisoning from a mammal that hunter supposedly "left" there the carcass must have been riddled with bullets, highly unlikely.
Reply | Report Abuse | Link to thisTypical BS and waste of research money - simple wikipedia "research" points their diet that is exactly the diet not hunted with lead shot.
So where does the lead come from? Millions of tons of lead paint, construction, car batteries dumped in the environment.
But the brilliant so-called researchers - see the only the "lead shot" because they have a culture that is opposed to hunting, and this is their subversive way of tricking the public into going along with their war on the sport.
Why are we funding this pointless "research" studies that have nothing to do with the science and everything to do with the political agenda - blaming hunters. Either the so-called scientists are completely incompetent or most definitely twist the fact to advance their agenda, in either case time to cut the funds to wasting time and money and focus on the real issues.
Yeah.. I love the "science".
Reply | Report Abuse | Link to thisWhat are the condors eating, and where does the lead come from?
My initial query was.. why are hunters shooting stuff, they dont gather up and take with them. My horror thought was that the hunters were shooting at the condors, and hence the lead poisoning.
Great post "spiderpaz". Science is about peer review.
My thoughts go back to when the bald eagles were so threatened. but that was about DDT I think.
@spiderpaz, you may be right about the motivation, but it is still worthwhile to do the research and establish that the condors actually are suffering from lead poisoning. Since Condors were on the brink of extinction, they are being very actively monitored and managed. And, yes, lead shot and/or bullet fragments have been recently found in Condors, with concurrent high blood lead levels. After chelation treatment and removal (or passing) of the lead particles, blood lead levels dropped to normal, and the Condors were released back into the wild.
Reply | Report Abuse | Link to thisI am just as passionate as anyone at defending our gun rights. I know that the tactic most often used now by gun-banners is dishonest appeals to "reasonable" restrictions. But lead poisoning of Condors is a real problem, and we as hunters MUST take it seriously!
I do take it seriously. I've spent hundreds of dollars extra over the last few years buying the more expensive, worse performing, all copper ammunition. And I don't know anyone else that is hunting with lead. And my family's ranch is south of Pinnacles National Monument and I actually see condor on it from time to time. I can't imagine where these birds would be getting lead from since most of what is shot are pigs in this area. Pigs are shot with large caliber, which pretty much never fails to exit the body. There simply are not dead carcasses filled with lead out in the country where condors are living.
Reply | Report Abuse | Link to thisBlaming the lead poisoning on hunters is just a convenient scapegoat because it allows anti-hunter groups to blame their enemy for a problem instead of looking at behaviors in urban populations that may be causing the lead poisoning.
"Laden"? Really? How much lead does it take for an animal carcass to become "ladened"? Is four too few, is six too many? Ladened, as in "this article was ladened with objectivity."
Reply | Report Abuse | Link to thisRead the study. The lead in the condor's body has been positively identified as a specific isotope of lead found only in ammunition, not the kind found in car batteries, old paint, industrial compounds, or lead that is found in trace amounts, everywhere, in soil. The identity of the lead is now known.
Reply | Report Abuse | Link to thisBlaming hunters whether they are breaking the law by hunting with lead shot within the zone or not is exactly the conclusion of the study, which you may not be able to comprehend. The lead isotope is found only in ammunition.
Reply | Report Abuse | Link to this"lead isotope is found only in ammunition"
Reply | Report Abuse | Link to thisThey don't use a special isotope for ammunition. That's how I know you're full of crap. And if it's a choice between having hunting, or condors, I vote for hunting. We already have a ton of buzzards flying around that are faster, smarter, and tougher than the condors, and they don't seem to be dropping like flies from "lead laden" squirrels, so I'm pretty sure mother nature had them slated for extinction anyway. DDT just hastened their departure.
No real surprise that the lead shot ban is not showing effect yet is it?
Reply | Report Abuse | Link to thisThe ban is four years old.
The lead intake is from lead sequestered in the birds crops.
Lead is persistant and cumulative in the body.
It will take a generation of birds before we can reasonably expect to see a change in levels in the population.
@NM156 and @spiderpaz,
Reply | Report Abuse | Link to thisThere is a significant variation in the ratio of Pb-206 to Pb-207 depending on where the lead comes from. @spiderpaz, you're right they use no special lead in ammunition, but they tested the isotope ratios of actual ammunition lead recovered from California Condors. And they claim to be comparing that with background, environmental lead ratios for this location, which they determine from the ratios measured in non-lead-poisoned California Condors.
But here's the problem. If you read the study, you'll see two charts comparing Pb-206/Pb-207 ratios, using two different curve fitting models. But if you look at the charts, they are clearly trying to mislead!
Ratio of Pb-206/Pb-207 is the horizontal axis. Is the vertical axis the number of "hits" at that ratio? It is not! Instead, it is a nonsensical "Probability of Source," which is either "ammunition" or "pre-release" (Pre-release means blood isotope ratios in healthy Condors, as a proxy for the local background lead isotope ratio). Notice that MOST of the data points for pre-release are plotted on the zero probability line! In other words, if the blood isotope ratio of the Condors MATCHES the isotope ratio in ammunition, it still has a zero chance of coming from ammunition. Also, the probability assignment to ratios actually found in ammunition are meaningless! They knew it was ammunition; the probability that any lead isotope ratio measured in ammunition came from ammunition is 1.0!
So what does this mean? It means that the study suppresses the fact that half of the birds have background lead isotope ratios that exactly match the measured isotope ratios for ammunition. Which means that the CLAIM the study makes, to have proved by isotope ratios that the lead poisoning comes from ammunition lead, is patently false.
http://www.pnas.org/content/suppl/2012/06/19/1203141109.DCSupplemental/pnas.201203141SI.pdf
So, @spiderpaz, it looks like your assertion that they did the study just to try to ban ammunition, is exactly correct!!
And, @Pragmatist, according to the study, lead is not cumulative nor (particularly) persistent. Just a couple pellets are enough to kill a Condor fairly quickly. So the ban should have shown more of a signal. Their study in fact shows that lead poisoning has increased since the ban!
@Danthrax, Thanks for covering the science for us. There is truly nothing special about the lead used in ammunition. It can be cast from any source. Many hand-loading enthusiasts cast ingots, and then mold bullets from random sources like the old balancing weights which are put on wheels when they are aligned. And yes, there is a dishonest agenda involved. It is nothing more than a serpentine effort to add another financial and bureaucratic burden to anyone trying to hunt, and the thought process is that if they add enough layers of burden, that eventually hunters will just give up.
Reply | Report Abuse | Link to thisThe lead ban WILL NOT save the condor ... hunters did not cause the bird's demise - natural selection did, and DDT (used by farmers trying to feed yuppy scientists in big cities) hastened it. You are not treating the true causes of their troubles if you blame it on your [convenient] scapegoat.
"And if it's a choice between having hunting, or condors, I vote for hunting."
Reply | Report Abuse | Link to thisRead the article. It is not about banning hunting. It is about banning lead.
If all hunters were as dumbfounded about ecology as you, then I too would advocate banning hunting. All birds of prey are effected by lead poisoning caused by hunters using lead bullets. Buzzards are no exception. The biggest problem with hunting I see is the lack of education many hunters exhibit with their 'shoot anything that moves' mentality.
"It is not about banning hunting. It is about banning lead."
Reply | Report Abuse | Link to thisIt's not about banning led. It's a dishonest way of eliminating hunting one piece at a time by adding layer upon layer of obstacles to do so. The lead ban will accomplish nothing for the condor, and I don't really even believe that's the real purpose of the law. It's the typical modus operandi for self-righteous little bunny huggers who can't get what they want by going after hunting and gun rights directly.
Also as for your "shoot anything that moves" comment ... nobody is shooting buzzards or condor dimwit. That's not what 9999 out of 10000 are doing anyway. Your ignorance about hunters is what's astounding. Your knowledge of ecology seems to be more based in emotion as well.
"The lead ban WILL NOT save the condor ... hunters did not cause the bird's demise - natural selection did, and DDT (used by farmers trying to feed yuppy scientists in big cities) hastened it."
Reply | Report Abuse | Link to thisYou can't blame natural selection for the loss of habitat and the toxins mankind introduced that has decimated their population. That is a cheap excuse and a phoney argument if ever I heard one. Condors were soaring in the sky for millions of years. Good stewardship of our one and only biosphere in this solar system requires that at the very least we acknowledge the problem in order to create a solution. The cold fact is that too many hunters shoot too many lead bullets and lead shot, and that practice can be stopped with a bit of common sense. Please use your head for something besides a place to hang your camouflaged baseball cap.
It has been pointed out many times that it is actually not a fact that "too many hunters shoot too many lead bullets" ... that's just a scapegoat. The real problem may be something you pointed out - loss of habitat. The root of that problem is too many people. So maybe your advocating for reducing the population. That probably has a better chance of helping condors than a lead ban. Good luck with that. I suggest starting with your own gene pool.
Reply | Report Abuse | Link to thisI don't know why you insist on ending every comment with an insult, but it does nothing to demonstrate you debate skills. Try again, but this time use a little logic.
Reply | Report Abuse | Link to thisYour first comment: "If all hunters were as dumbfounded about ecology as you ... "
Reply | Report Abuse | Link to thisIf you are such a stickler for formal debate maybe you should be more cognizant of your own ad homonyms. And furthermore, maybe you should acknowledge the false dichotomy being used to dupe the public into believing we must ban lead ammunition to save the condor, given the fact that saving the condor isn't why many of lead ban advocates want to do so, and banning lead isn't and won't help save the condor.
And while you're at it, you might want to ponder your own cognitive dissonance, which lead you here to post an objection about a personal attack even though your only contribution so far was to regurgitate some stereotypes about hunters in camouflaged baseball caps shooting everything they see with no clue about ecology, as you put it.
Then again - you might want to just continue sticking your fingers in your ears and believing you know best about everything.
There you go again. I suspect it is a psychological disorder. Do you also stutter uncontrollably?
Reply | Report Abuse | Link to thisNobody needs to hear some moron telling them they need to eliminate their gene pool because they can't come up with a decent rebuttal.
The term dumbfounded is not nearly as much an ad homonym attack as calling your opponent a dimwit, especially when it is a statement of fact.
Banning lead is one way of reducing harm to all wildlife that will eventually find those bullets in their food chain. The condor is just one of the examples the average person can relate to. If they said it was for protecting rattlesnakes hunters would never give it a second thought.
I should not interfere into this conversation because I am not an expert in the field in any way. I hope nobody gets disturbed or takes very seriously what I say.
Reply | Report Abuse | Link to thisLooking at the picture that poor birds are very ugly. But they are very big (9.8 feet wingspan and weigh around 25 pounds) and can fly so high (15,000 feet). Of course we do not want to see them disappear.
Any one species that disappears is a tremendous loss.
If the experts say they are getting poisoned by lead, very probably they are right.
It is not a bad idea not to use lead bullets by hunters. I hope hunters pay attention to that. It would be better to use silver bullets, but who can afford that?
But hunters definitely should care about species conservation. That is very important.
Probably the biggest problem for these birds is simple that they do no have enough space all for themselves. Neither the big game they had, as they say, thousands of years ago.
It is very good if we convince hunters not to use lead and be careful. Probably what should be done is to leave large carcasses of healthy cows in areas where they feed. But it seems difficult indeed. And where do they take the water that they need?
It is a tremendously fantastic job that is done by the people that breed them in captivity. These efforts should be increased so too many of these birds are release into the wild. I have no idea what dangers they could pose to air traffic, though.
Here where I live sometimes I look into the sky and I see vultures flying in circles above. I can spend several minutes looking how they fly until they disappear into the horizon. They are of medium size.
We want to see the California condor flying over USA and Mexican territories in sizable quantities.I hope some day we may be able to invest whatever it takes for their full recovery.
But we should be realistic and we should be brave and ready to see them part if there is nothing we can do about it.