Subject: Passenger Pigeon extinction
Date: Dec 15 15:56:03 1995
From: Kathleen Hunt - jespah at u.washington.edu



> the species population nonetheless collapsed. Hence the query: can
> anyone direct me to sources on why the Passenger Pigeon became extinct?
> dale goble

Check out "The Causes of Extinction of the Passenger Pigeon", by
Enrique H. Bucher. It's chapter 1 (pp. 1-36) in Current Ornithology, Volume
9, 1992, ed. Dennis M. Power, Plenum Press, New York.

The conclusions say:
"1. It seems likely that the Passenger Pigeon became extinct primarily as a
result of forest destruction & fragmentation, particularly in its main
northern breeding grounds where snow cover remained long enough to
prevent mast from being exploited by resident species during the winter.
Predation and disturbance from man had an important role in accelerating
the initial decline, but cannot explain the incapacity of the Passenger
Pigeon to survive at low densities. Social facilitation in food finding
may have become increasing ineffective with decreasing population size.
The combination of loss of critical breeding habitat and lack of social
facilitation at low densities would have been enough to lead the
Passenger Pigeon to extinction even without killing a single bird and
despite the existence of considerable remaining forest.

"2. Conservation of large-scale nomadic and migrant species poses unique
difficulties that have to be considered at the precise scale at which
these birds exploit their resources. Beyond the dilemma between the
advantages of having several small or single large reserves, the key
problem is to keep a network of suitable breeding and feeding habitat
areas of the size and distribution necessary to maintain viable
population levels. Interaction between reserve design and regional
planning becomes essential."

ciao,
Kathleen