Table 3. Probabilities of sighting at least one Ivory-billed Woodpecker for populations of different sizes, given areas surveyed in 2004–2005 and 2005–2006 in an estimated 19 700-ha tract along White River (WR) and a 9500-ha tract at Bayou de View (BDV). Also included are joint probabilities of detection in at least 1 year, assuming independent probabilities between years.

Population Size
Survey Area 1 2 5 10 20
BDV 2004–2005 0.483 0.733 0.963 0.999 1.000
2005–2006 0.544 0.792 0.980 1.000 1.000
combined 0.764 0.944 0.999 1.000 1.000
WR 2004–2005 0.587 0.829 0.988 1.000 1.000
2005–2006 0.443 0.690 0.946 0.997 1.000
combined 0.770 0.947 0.999 1.000 1.000