In all its
majesty, it soars over the marsh. Suddenly its bright yellow eyes notice lunch
swimming below, an unlucky fish. Within a split second it folds its wings back and
prepares for a dive. A few seconds more and splash. The Osprey briefly
disappears into the water only to emerge with a 12 inch fish locked into its specialized
talons. That’s right; the Osprey (Pandion
haliaetus) is the best fisherman
you will ever meet, averaging a mere 12 minutes per hunt (all about birds). Although
this fascinating bird of prey seems to be “king of the air”, it has undergone
many adversities in the past 60 years.
"Osprey at sandy beach" taken by Scott Kruitbosch |
You see, there
used to be this pesticide, DDT, which was commonly used. However, DDT (and
other contaminants) was proven to lower productivity of the Osprey and it weakened
their shells, as you would expect this greatly decreased the Osprey’s
population. In fact, a study by K.E. Clark et al estimated that the pre-DDT
population in New Jersey was between 350-400 pairs and in 1975 it plummeted to
only 66 pairs (Clark)! I’m getting ahead of myself though. Before I tell you
about the hardships encountered by the Osprey, you must first have a respect
for them. I don’t know to what extents you would go to for a chance at
breeding, but the Osprey seems to have no limits. Over the winter months
(non-breeding), the Osprey is found typically in Central and South America and
as far north as the southeastern U.S. However, come spring time these birds
migrate north, inhabiting most of Canada and the east coast of the U.S. for the
summer. They travel thousands of miles twice a year for a chance at breeding
and to raise their young in hospitable habitats. For an adult Osprey nearing
old age, (15-20 years) it will have traveled up to 160,000 miles in its lifetime
just to breed (all about birds)! You can see how egg shell thinning by DDT is such
a big deal! Now you understand the level of investment the Osprey puts into their
offspring.
In Pamela C. Toschik’s article, “Effects of
Contaminant Exposure on Reproductive Success of Osprey (Pandion haliaetus) Nesting in Delaware River and Bay, USA” eggs
were collected from 39 nests to look for various contaminants. All of the study’s
together had at least one young Osprey fledge in 66-75% of the nests. They concluded
that “contaminant concentrations were predictive of hatching success” and thus
it is still a major stress for the productivity of Osprey (Toschik).
Since contaminations are still such a major concern, researchers like Robert A.
Grover are using the Osprey as an “sentinel species”, a species to get a broad
idea of what the contaminants can do to other species. In an article by Grover he
states that the Osprey is a perfect organism to study because contaminates
effect the birds immune system, reproduction, behavior, and anatomically
through bird defects. Thus, it is a good model species to get a better
understanding of broad effects of chemical contaminants on Avian (bird)
species. The study did show that populations have recovered nearly everywhere
(even in some of the most polluted era) from the initial DDT destruction (Grove).
Now that you have an understanding for
the level of perseverance displayed by the Osprey you cannot help but have
respect for these birds. Although they have undergone many hardships, they have
rebounded. Although contamination is still a major concern for the Osprey and many
animals, we now know how important it is to limit the contaminants and keep our
waters clean.
To see great footage of the greatest fishers of North America click on the video below.
All
About Birds. The Cornell Lab of Ornithology, N.D. Web. 16
March 2014.
BBC. “Ospreys Catching
Fish-The Animal’s Guide to Britain, Episode 1 Preview-BBC Two”. Video. YouTube.
YouTube, 13 April 2011. Web. 16 March 2014.
Clark, K.E., et al.
“Changes in Contaminant Levels in New Jersey Osprey Eggs and Prey, 1989 to
1998” Environmental
Contamination and Toxicology 40
(2001): 277-284. Web.
Grove, Robert A., et al.
“Osprey: Worldwide Sentinel Species for Assessing and Monitoring Environmental
Contamination in Rivers, Lakes, Reservoirs, and Estuaries.” Journal of Toxicology and
Environmental Health 12b
(2009): 25-44. Web.
Kruitbosch, Scott. “Osprey at
sandy beach.” Photograph. Long Island Sound Study. Osprey Makes Comeback,
n.d. Web. 16 March 2014.
Toschik, Pamela C., et
al. “Effects
of Contaminant Exposure on Reproductive Success of Osprey (Pandion haliaetus)
Nesting in Delaware River and Bay, USA.” Environmental
Toxicology and Chemsitry 24.3
(2005): 29. Web.
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