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Great Blue Heron
an indicator of wildlife sustainability in
the Georgia Basin |
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Table 1. Breeding Bird Survey (BBS) results for
the Great Blue Herons of the Pacific Maritime ecozone of B.C. from 1969.
The annual index is the estimated number of birds that would be seen per
BBS route per year if all routes in the area of analysis were conducted.
Standard BBS analysis require a minimum sample size of 15 routes. In this
case only 13 routes were available therefore results should be viewed
with caution. Data is from C.W. Downes, 2002, Environment Canada, Canadian
Wildlife Service, Ottawa, Ontario.
|
Year
|
Annual Index
|
|
1969
|
18.229
|
|
1970
|
13.701
|
|
1971
|
14.321
|
|
1972
|
11.050
|
|
1973
|
12.186
|
|
1974
|
9.823
|
|
1975
|
8.534
|
|
1976
|
8.059
|
|
1977
|
9.432
|
|
1978
|
6.229
|
|
1979
|
5.952
|
|
1980
|
5.369
|
|
1981
|
5.732
|
|
1982
|
4.843
|
|
1983
|
5.392
|
|
1984
|
2.813
|
|
1985
|
4.417
|
|
1986
|
3.580
|
|
1987
|
2.761
|
|
1988
|
2.430
|
|
1989
|
3.134
|
|
1990
|
1.429
|
|
1991
|
0.985
|
|
1992
|
1.373
|
|
1993
|
1.630
|
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1994
|
2.589
|
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1995
|
1.212
|
|
1996
|
2.835
|
|
1997
|
-0.987
|
|
1998
|
1.397
|
|
1999
|
0.126
|
|
2000
|
0.957
|
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