An interesting thread. Dividing the sightings per year by the number of observers submitting records for a given year will produce a fraction that is perhaps more representative of the overall pattern. The identification of some species like Dark sided Flycatcher was poorly known prior to the 80's and some species are probably a better marker of what is going on.Additionally , the discovery of 'new' birding hotspots ,like Po Toi, will undoubtedly skew results.Lord knows I would give large chunks of my anatomy to have birded there in the 70's and 80's.To generate meaningful data you probably are best off looking at a fixed number of sites that have been watched over the whole period.
Anecdotally, over decades in some countries, looking at large falls of birds have given an idea of how much populations have dwindled.If you talk to people in Europe and the USA we never seem to see the falls that were historically described.
Sure, some birds do well if they can adapt or prefer areas which has been altered by man. It is naive to think that over all we are not heading for a steady decline in birds across the board as human population expands and habitat is lost.
Make the most of it. I'm not putting any bets on the situation improving over our lifetime.
Eric
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Last edited by EricB at 20/12/2012 06:50 ]
