Bird numbers (and diversity) at ANBG

["Philip Veerman" <>]

It is too easy to say that bird numbers are decreasing. Is there any evidence of this? Impressions are potentially flawed. We will easily recall those times of years ago when there were many birds there and yet easily forget those times of years ago when there were few birds there. This is going to invalidate any impression based comparison. Without data to demonstrate either way, it is a somewhat vacuous comment.

 

Of course there will be changes. I went to the ANBG for the first time, on 10 Feb 1975. That day (it was probably only an hour or two), I photographed Double-barred Finches with dependant young there and noted the species as common there. That might have been an unusual event but I don't know. I don't recall having seen them there in the 24 years since then, that I have resided in Canberra. I also recorded among others, the White-throated Gerygone and Speckled Warbler there. These don't seem to be there (at least regularly). So, sure there are changes in composition but we need a lot more evidence to say there has been a reduction. The GBS has highlighted for us the fact that there is ongoing variability that makes it hard to combine data for different species and there is no overall trend of increase or decrease.  

 

Philip