Monday, January 7, 2019

2018 Annual Report

This will be a little shorter than my usual annual reports as I am somewhat preoccupied with the final stages of moving from Carwoola.

The "big-ticket" item in a year's observations is how many species were recorded.  The answer for the Gazette catchment area in 2018 is 156.  This is the same as in 2017 and is the third time we have reached this number, the highest since 2007.
The first two years are mainly personal records and the pattern is largely constant since  that as other observers have joined in.

Three taxa were added to the list this year: Spangled Drongo (Wanna Wanna Rd); White-throated Nightjar (Hoskinstown) and Hybrid Crimson x Eastern Rosella (Whiskers Creek Rd).  This gets our total taxa recorded to 198.

Looking at the species recorded each month emphasises the pattern I have remarked on over the last year.  For the first half of 2018 we recorded average or better number of species, but in the second half of the year the number of species per month declined.
I am inclined to blame this on the continuing drought, with the number of waterbird species in particular dropping significantly in December and some migrant species (especially insectivores)either not turning up or being infrequently seen in the Spring/Summer. 

I have classified the species to 9 broad groups (mainly for ease of presenting the monthly lists).  The number of species.  When looking at the pattern of number of species reported each year by category an interesting pattern emerges.
5 of the 9 categories show a similar pattern over the years with occasional ups and downs but essentially constant.  The category "Other larger birds" with 8 members, is constant with all of the species seen every year.  The small brown bird category (thornbills, finches etc) is also close to constant ranging between 18 and 21 species per year.  Waterbirds have shown the greatest level of increase - possibly reflecting discovery of better sites in the area over time.  Birds of prey also show a steady increase, although they have been sparse in most months of 2018.

Since 2007, 101 Species have been observed undertaking some form of activity classified as indicating breeding.  A very low 35 species were recorded breeding in calendar 2018.  

Birds are not unduly fussed about calendar years, organising their breeding around a season with  good food supplies - effectively a year ending in June.  Looking at number of species recorded breeding for year ended June  ...
.. shows the last complete season to be about average.  However the number of breeding records for the start of the 2018-19 season is very low.  Again I attribute this to the ongoing drought.

Looking at individual species in 2018 cf other years 42 species are missing in 2018.  Most of these were relatively rare in the past (35 of the missing species being recorded in ,10% of months).  Those recorded more frequently but missing in 2018 were:

  • Brown Quail (possibly due to mis-identification of Stubble Quail on some occasions in the past);
  • Musk Duck - shallow conditions in Foxlow Lagoon unsuitable for this species;
  • White-throated Needletail - always an occasional species, very related to storm fronts.
  • Spotted Harrier - shortage of prey species on the Plain;
  • Speckled Warbler - lack of insect food?
  • Southern Whiteface - lack of insect food?
  • Golden-headed Cisticola - lack of rank grass habitat on the Plain.
In the past 16 species have been seen every month.  In 2018 one of these. White-eared Honeyeater was not reported in 2 months.  Of the other 22 species previously seen in 11 months or more per year only 1 - Little Pied Cormorant was not reported every month in 2018 (due to the parlous state of most dams).  Basically, the common birds remained common.  

The overall comparison between reporting rates for 2018 and earlier years is shown in this scatterplot:
The relationship is quite strong with an r2 of 0.78 for the linear trend.  I have marked an outlier 932% of months prior to 2018 but every month in that year. Unfortunately this is the foul Common Myna, and I hope people are able persuade this species not to become further established here.

That is the lot!  It has been a hoot compiling these reports for the last 12 years and I hope it has been helpful to the readers.  As well as a report onthe area generally to COG I have also published articles in Canberra Bird Notes on the Whiskered Tern breeding event; the (re)appearance of Banded Lapwings on the Plain; and a number of articles about the Tawny Frogmouths breeding at our house.  So the area has done very well

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