Pesticides, Persecution and Legal Protection Population effects on birds of prey.

This report reviews the effects of pesticides, persecution and legal protection from a population perspective. In the past, legal hunting and organochlorine pesticides severely affected raptor populations. What lessons can be learned for the future? Is a second mass extinction, by other environmental pollutants, entirely out of the question? What use is legal protection, as long as habitat destruction and illegal persecution continue? Organochlorine compounds had a massive impact as a result of a combination of factors: 1) widespread use, 2) persistence and bio-accumulation, 3) effects on reproduction. These same characteristics apply to many compounds with weak hormone-like effects, for instance PCB's and organic tin compounds, which presently form a major environmental problem. Raptors, as top predators and long-lived specisproved most vulnerable to this set of circumstances. They suffered major population decline in many parts of the world. After regulation of organochlorine use, populations started to recover, but still faced an older threat: persecution. It appears that legal protection makes considerable difference, but in many areas illegal persecution remains quite a problem