Benj and all: See this Extract from my book: "Canberra Birds: A Report on
the first 21 years of the Garden Bird Survey" as follows as usual most
issues have been addressed:
Grey Butcherbird Cracticus torquatus
This is a common species in major east coast cities, yet it is rare in
Canberra. This would suggest that it is not the urban environment itself
that causes the scarcity. In our area it occurs in woodland and along the
Murrumbidgee river corridor. Maybe it is the competition from the abundant
Pied Currawong that impacts adversely on this bird (see also the Laughing
Kookaburra text). Records are mostly of isolated individuals and not many
have repeat observations. So the bird passes through, rather than stays in
the urban area. Numbers are much higher from February to June, than July to
January. This may reflect dispersal during the non-breeding period. Its
distribution suddenly increased from an average of 4.47% for the first 18
years to 10%, 18% then 22% for the last three years, which created the huge
recent abundance increase.
Graphs on page: 103, Rank: 102, A = 0.00310, F = 6.21%, W = 5.1, R = 0.303%,
G = 1.02.
|
