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.
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.
References
1. 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. http://www.pdcbank.state.nj.us/dep/fgw/ensp/pdf/literature/osprey-contaminant-levels_1989-1998.pdf
2. 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. http://www.pdcbank.state.nj.us/dep/fgw/ensp/pdf/literature/osprey-contaminant-levels_1989-1998.pdf
3. 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.
4. All
About Birds. The Cornell Lab of
Ornithology, N.D. Web. 16 March 2014.
5.
Kruitbosch, Scott. “Osprey at sandy beach.” Photograph. Long Island Sound Study. Osprey Makes Comeback, n.d. Web. 16 March
2014.
6. 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.
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