Published March 9, 2020 | Version v1

Statistics, probability, and a failed conservation policy

Authors/Creators

  • 1. United States Naval Research Laboratory

Description

Many sightings of the Ivory-billed Woodpecker (Campephilus principalis) have been reported during the past several decades, but nobody has managed to obtain the clear photo that is regarded as the standard form of evidence for documenting birds. Despite reports of sightings by teams of ornithologists working independently in Arkansas and Florida, doubts cast on the persistence of this iconic species have impeded the establishment of a meaningful conservation program. An analysis of the expected waiting time for obtaining a photo provides insights into why the policy of insisting upon ideal evidence has failed for this species. Concepts in statistics and probability are used to analyze video footage that was obtained during encounters with birds that were identified in the field as Ivory-billed Woodpeckers. One of the videos shows a series of events that are consistent with that species and are believed to be inconsistent with every other species of the region. Another video shows a large bird in flight with the distinctive wing motion of a large woodpecker. Only two large woodpeckers occur in the region, and the flap rate is about ten standard deviations greater than the mean flap rate of the Pileated Woodpecker (Dryocopus pileatus).

Notes

Raw digital video files (interlaced):

  • 2006i.dv 
  • 2008i.dv 
  • 2007-1i.mov 
  • 2007-2i.mov 
  • 2007-3i.mov 
  • 2007-4i.mov 
  • 2007-5i.mov
  • video-metadata.txt

Deinterlaced versions:

  • 2006p.mp4
  • 2008p.mp4 
  • 2007-1p.mp4 
  • 2007-2p.mp4 
  • 2007-3p.mp4 
  • 2007-4p.mp4 
  • 2007-5p.mp4 

Isolated events:

  • event2007-1.mp4: downward swooping takeoff in 2007-1i.mov (plays at half speed)
  • event2007-2.mp4: upward swooping landing in 2007-2i.mov (plays at full speed)
  • event2007-3.mp4: horizontal takeoff in 2007-2i.mov (plays at half speed)
  • event2007-4.mp4: takeoff with rapid wingbeats in 2007-2i.mov (plays at full speed)
  • event2007-5mp4: upward swooping landing in 2007-3i.mov (plays at full speed)
  • event2007-6.mp4: climbing and double knock in 2007-4i.mov (plays at full speed)
  • event2007-7.mp4: downward swooping takeoff and upward swooping landing in 2007-5i.mov (plays at half speed)
  • event2007-8.mp4: climbing after the landing in 2007-5i.mov (plays at half speed)

Files

event2007-1.mp4

Files (9.7 GB)

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593.5 MB Download
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Additional details