Friday, January 9, 2015

Annual report: 2014 compared with previous 7 years

A starting point is the number of species reported in each month.

In the chart above the year in which the highest number of species was observed for each month is highlighted in yellow.  Most of these months occur between September 2011 and May 2013 when observer activity was at peak levels and abundant rain fell, leading to an explosion of water birds on the Hoskinstown Plain.

While we have lost some observers since then - the two red months are particularly light on - the column showing 2014 as a % of the average for the period as a whole shows that we are still going rather well.  Thank you to all observers who have contributed observations.

As reported in the overview we added 2 species to the list in 2014:

  • Black Kite is uncommon but regular in the Canberra area; and
  • Red-kneed Dotterel is less common than Black-fronted Dotterel in the area generally but was probably overdue to be observed in the area.

Of the 150 species for which comparison is possible, 19 have been recorded in every month throughout the 7 years (obviously including every month of 2014) These are:

  • Australian Wood Duck; Galah; Sulphur-crested cockatoo; Crimson Rosella; Eastern Rosella; Laughing Kookaburra; White-eared Honeyeater; Noisy Miner; Willie wagtail; Magpie-lark; Welcome swallow; Yellow-rumped thornbill; White-throated treecreeper; Common starling; Grey butcherbird; Australian Magpie; Pied Currawong; Australian Raven; Little Raven.
A simple way of summarising the difference in reporting rate between 2-14 and earlier years is by a tree diagram.
In comparison to the situation in the last Annual report the are more 'decreasers'.  To some extent that is an outcome of effort, where missing an expected month (eg July) would reduce the rate for 2014 by 9%.  The number shown as 'same' is those with exactly the same rate.  Extending this to 'effectively the same" - which I define arbitrarily as with 2% either way - would move 10 decreasers and 16 increasers into the category "Same in 2014".

The next table shows the number of increasers and decreasers by category of bird.  (I should point out that these categories are rather arbitrary, but just provide a few groupings that cover birds of broadly similar behaviours and/or habitats.)
Many of the changes have been hinted at in earlier sections. 

My impression is that the high number of increasers in waterbirds reflects the impact of drought in depressing the results for 2007-09.  While early 2014 was pretty dry there was still water in most dams.  Also, I at least was more aware which dams were likely to be productive (for example Musk Duck and Black Swan are nearly always observable when looking down on Foxlow Lagoon (but nowhere else).

Other smaller birds include a range of migrants and grassland birds which have been reported more recently due to other observers joining in.  My view is that the early years were a serious understatement of the diversity of birds in this area and we are now getting a good reflection of the situation.  

The major area of decrease is obviously the Kingfishers and other non-songbirds.  This is a diverse group of birds and  can't really pick out any common factor aother than most of them being rather unusual birds anyway!  As with last year Rock Dove has taken a particularly large tumble so i repat the possibilities seen then:

  •  someone has had pigeon pie; 
  • the local Peregrine Falcons and Brown Goshawks have been more active. or
  •  someone has recently started shutting the door on their loft!

Links to other sections of this report

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