Apparent decrease of Common Blackbirds

["Philip Veerman" <>]

Hi John,

 

Some comments. Changes in bird abundance within a year is a separate thing from long term changes in bird abundance. Also local changes can be different from the overall trend. One cat or sparrowhawk with a particular preference for blackbirds could cause a change like John notices. It is a very reasonable suggestion that "the present prolonged lack of precipitation does not augur well for worm-auguring blackbirds" and indeed the GBS Report suggests this (and the reduction in irrigation of parks and sports grounds) as a possible cause of the decline of the Starling. Although that was pointed out to me by Ian Baird, who was the director of Canberra Urban Parks and Places and one time GBS Coordinator (before me). For what it is worth, the Blackbird population was fairly stable from year 10 to 21 of the GBS (only the first 21 years having been consistently compiled). Last point is that past trends are just that and a baseline for comparison. Things have changed and will continue to do so.

 

Philip