Thursday, February 15, 2007

Man-eating Pelican terrorizes beach

Through the 40's and 50's, the pesticide DDT was used to control mosquitoes, lice and midges. The diseases they carried (malaria, typhus, etc) were effectively controlled if not eradicated throughout the developed world and DDT is still used in 3rd world countries across the globe. While the chemical did the job it was intended, it also had the unfortunate consequence of bioaccumulating in the food web if not outright killing unintended species. Bats, birds, fish and other predators that fed on sprayed arthropods (insects and arachnids) ingested DDT which was then stored primarily in fatty tissues. Animals that preyed upon them ingested greater concentrations of DDT and as it continued up the food chain, the high level predators were consuming toxic and potentially fatal amounts of the nasty chemical.

For birds such as Bald Eagles, Osprey and Brown Pelicans, one of the resulting effects of this noxious condiment was thin egg shells that under the weight of an incubating adult, were often crushed. This led to higher egg mortality and population crashes across their range during the 60's, 70's and 80's. Al l three of these piscivorous (fish-eating) birds were nearly extinct by the late 70's. The ban of DDT in the US in the 70's began the slow recovery of these and other species that were effected by the chemical.

DDT is still produced and sold to mostly tropical countries where it's used to fight typhus and malaria and sadly still has the same effect on the environment.

Today, Brown Pelicans abound along Florida's coasts. The trouble they have today is that they are so well loved and so often fed by locals and tourists, that in many places, it's not uncommon to find 25-30 foot tall Brown Pelicans stomping around piers and sinking fishing vessels. Brown Pelican (Pelecanus occidentalis)
Fortunately they only eat tourists which leads to high levels of sunblock bioaccumulating in these man-eaters. The two individuals in the left hand corner were gobbled up just after this photo was taken. The brown headed ones - pictured below - are the juveniles. The white-headed ones - pictured above - are the adults.

3 comments:

  1. Today I was ANGERED that after a hard day of work there was no blog!!!

    ReplyDelete
  2. You need to relax and enjoy the tranquil sound of traffic

    ReplyDelete