In the 1990s, griffon vulture populations in India, Pakistan and Nepal crashed, some estimates being of a 95 per cent decline in numbers in just a few years. A study conducted in 2000-2002 (J. L. Oaks et al, Nature, January 2004) concluded that the deaths were caused by an anti-inflammatory drug, diclofenac, that is given to cattle to treat lameness and other injuries. As I understand it, very small quantities of the drug release enough uric acid into the vultures' kidneys to cause death.
There are several sub-stories here that may have application to California condor recovery. First, vultures are highly respected in south Asia. They are depended on for their scavenging abilities, including in some areas even the disposal of human corpses. They are also a significant tourism draw. Despite the importance of vultures, diclofenac is still in use in the area, going on four years after its discovery as the problem. Earlier this year, researchers from the University of Pretoria reported finding what appears to be a safe alternative to diclofenac, another pain killer called meloxicam. Hopefully, this will lead to a widespread ban on the use of diclofenac, but will it come in time for the griffons? Nationwide - actually, subcontinent-wide - bureaucracy will have to get a move on. In the meantime, officials in at least one area (Assam province in India) are setting up vulture feeding stations to provide "safe" food for the birds, but this is certainly no answer to the overall problem.
Thankfully, diclofenac is not used as a livestock treatment in the United States. Still, it makes one wonder which of the thousands of drugs and chemicals newly released for use each year could be just as devastating to condors, vultures, eagles, or other scavengers. We've never done a good job anticipating problems; we always find ourselves reacting after the damage has begun. Reacting to a diclofenac-like catastrophe may be impossible.
During my involvement with the condors, questions arose about the use of chemicals on livestock. For example, when I was first on the job, Carl Koford asked me what effects diethyl stilbestrol (DES), a hormone given to cattle to increase growth rates and weight gain, might have on condors. It was commonly applied to Condor Country livestock through treated tags clipped to their ears. It didn't seem like there was much chance of condors eating an ear tag, but who knew what effect the hormone distributed in their flesh might have on condor behavior or reproduction. I didn't know (still don't), and didn't know at the time how to find out. Ten years later, Chuck Henny and others were raising questions about famfur (Warbex), a topical dressing put on livestock to combat insects and parasites. It looked like famfur was implicated in some golden eagle deaths. I was on my way out of the condor program at the time. I alerted the new biologists to the issue, but don't know if it was ever investigated in relation to condors.
My point is merely this: the dependence
for food of the California condor on domestic livestock suggests
that someone needs to be carefully monitoring what is going on
with the livestock industry. We didn't do a good job during my
tenure. Now, when recovery of the population seems more and more
possible, how sad would it be to have the birds succumb to a diclofenac-like
catastrophe, just because nobody was monitoring and paying attention?