Pesticides can accumulate in animal bodies, and
pass from prey to predator, concentrating in successive steps of the food chain. As
predatory birds, raptors are near the top of the chain and are especially vulnerable of
accumulating large dosages of certain chemicals.
In the 1950's a hcemical called DDT was used
widespread throughout this country. Shortly afterwards reports were received about the
increasing number of failed nest sites, due to eggs breaking and chicks dead in the egg.
Nearly all species of raptors were affected. Soon there were very few young being reared.
The Peregrine and sparrowhawk population dropped
to its lowest level ever and there were fears that a number of our native raptors may
become extinct if this trend was to continue.
Eventually the chemical DDT was banned and the
various raptor species soon began to recover from what can only be called the brink of
extinction in this country.