A1258689806MfyuP - PowerPoint PPT Presentation

Title: A1258689806MfyuP


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Accounts of eXtinct Species
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The Heath Hen
The heath hen, a small wild fowl, was a relative
of the prairie chicken. Prior to the American
revolution the heath hen was found in the Eastern
U.S. from Maine to Virginia.
Tympanuchus cupido
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• Expanding human populations in the colonies, put
  an enormous hunting pressure on heath hens. By
  the 1870s the only heath hens left occupied a
  tiny island called Marthas Vineyard off the
  coast of Cape Cod in Mass.

• In 1907 there were only 50 heath hens left on
  Marthas vineyard

• The following year a 1600-acre sanctuary was
  established for their protection.

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• The original 50 birds reproduced rapidly and by
  1915 there were 2,000 individuals

• However the entire population was still confined
  to the Island

• Then in 1916 disaster strucka fire wiped out
  much of the habitat heath hens used for breeding

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• The following winter was harsh and an influx of
  goshawks hurt the population even more

• Finally many of the remaining heath hens fell
  victim to a poultry disease brought to the island
  by domestic turkeys.

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• The last living heath hen, the final survivor of
  his species was seen on March 11, 1932. He died
  that year.

? -1932May you rest in peace!
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Why did the Heath Hen become extinct?

• Fire
• Starvation
• Predation
• Disease

The heath hens continued existence as a species
would not have been so vulnerable to these events
if their populations had not been so severely
reduced by hunting by humans.
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The story of the heath hens demise shows how
reductions in geographic range and population
size caused by human activities can make a
species vulnerable to natural events over which
humans have little or no control. It also shows
that designating a protective zone, or
prohibiting the direct killing of an endangered
species, does not guarantee the survival of the
species.
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Questions for thought
1. Marthas vineyard is an island. What aspects
of island biogeography may have affected the
heath hen?
2. Can the poultry disease that was brought to
the island by domestic turkeys be considered an
anthropogenic factor?
3. Which of the other seemingly natural factors
might have an anthropogenic component?