Annual report: 2011 compared to 4 previous years

Links to other sections of this report are at the end of this page.

The following table summarises the number of species reported by month and year.

month	2007	2008	2009	2010	2011
Jan		69	84	87	95
Feb	59	74	69	87	89
Mar	69	72	78	72	87
Apr		65	70	77	76
May	61	65	83	80	80
June	51	69	64	77	65
July	54	59	62	77	78
Aug	57	72	73	80	90
Sep	67	77	86	86	101
Oct	67	84	91	97	99
Nov	73	84	106	96	108
Dec	60	83	94	95	94

Looking at the 141 species which were recorded in the area in 2011 in comparison with  the previous 4 years a first comment is that 5 species were observed for the first time in 2011.  These were

• Yellow-billed Spoonbill, Cattle Egret, Silver Gull, Black Falcon and Horsfield's Bushlark.  

Of the 136 species for which comparison is possible, 19 have been recorded in every month throughout the 5 years (obviously including every month of 2011) 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.

For the species recorded in 2011 which changed the proportion of months in which recorded 87 (61.7%) showed an increase in the number of months in which they were recorded and 30 (21.3%) showed a decrease.  I shall return to an analysis of those numbers below.

There are thus 25 species recorded in the prior 4 years which did not appear in 2001.  They are:

• Chestnut Teal; Darter; Royal Spoonbill; Black-winged Stilt; Latham's snipe; White-bellied Sea-eagle; Grey Goshawk; Scaly-breasted Lorikeet; Spotted Dove; Black-eared Cuckoo; Powerful owl; Superb lyrebird; Yellow-tufted honeyeater; Scarlet Honeyeater;Crescent Honeyeater; Rufous Fantail; Satin Flycatcher; Jacky Winter,Red-capped Robin; Zebra Finch; Brown Treecreeper;White-winged triller; Masked Woodswallow; Brown Songlark .

Most of these birds are not common in the Canberra region.  The possible exceptions are:

• Superb Lyrebird (the omission of which probably reflects my not having explored the gullies of Cuumbeun or Yanununbeeyan when the birds were vocalising) and
• White-winged Triller, for which I cannot offer an explanation.

Increasing species
There are 23 species recorded every month in 2011 which have been omitted at least once in earlier months.   With a 5 year series of observations I regard the 10 species only omitted once or twice as observer error (in most cases the missing period is early in the life of the project).   Most of the other species in this group of 23 are cases where the increased number of observers in recent years has added to the completeness of reports.  This is particularly the case for Eurasian Coot now seen every month at a site on Widgiewa Rd.  A second species with an obvious explanation is Tawny Frogmouth, now reported every month from Whiskers Creek Rd since I am specifically searching for a resident family, while in the past observing these birds was serendipity.

At the other end of the spectrum 11 species were recorded in a single month in 2011 and appear in the list of 'increasers' as a statistical quirk since 1/12 > 1/46!  They are clearly unusual in the area and will not be considered further.

A group seen in  at least 6 months in 2011 for which an increase has been noted amounts to 31 species.  I can't offer a comment about all of these so what follows is 'picking the yes out' of the list.

• Common Myna: the rat with wings appears to have established a presence in Hoskinstown and has been reported half of the months in 2011.  A pity.
• Stubble Quail are not unusual n the area but are difficult to see.  However the paddocks of tall grass in early 2011 provided great breeding habitat for them and their calls were very easy to record.
• Eastern Yellow Robin is usually thought of as a bird of the damp gullies.  The wet conditions of late 2010 and early 2011 led to a pair taking up residence at Whiskers Creek Rd.  They have since disappeared.
  
• Black-shouldered Kites: have re-appeared (in astonishing numbers) after disappearing almost completely for a couple of years.  This phenomenon, plus the increase in Brown Falcons is thought to be due to a mouse plague.  (Towards the end of the year Eastern Barn Owls were reported frequently, and sometimes in large numbers.  This was also related to the mouse plague, but they were not seen in 6 months.)
• Musk Ducks and Black Swans were often recorded when looking from the road down into Foxlow Lagoon but nowhere else in the area.  The increase in 2011 reflects the Lagoon filling again as a result of the rain in 2010 and early 2011.
• A number of species regarded as migrants (Shining Bronze-cuckoo, Leaden Flycatcher, White-throated Gerygone,Noisy Friarbird, Fan-tailed Cuckoo, Rufous Whistler, Black-faced Cuckoo-shrike) were recorded more frequently than usual.  Most of these are generally thought to have some 'opportunists who try to survive in the area through Winter and their presence is thus probably not a result of climate change.
• The preceding comment may be strengthened by the increased presence of two species which I regard as winter in-migrants: Golden Whistler and Scarlet Robin.

Decreasing Species
There is relatively little "big picture" material in this category.  In most cases the decrease is a reflection of the wider rage of fractions possible with a 46 month range rather than a 12 year range.  By way of example,

• in 2011 Brown Goshawk was recorded 7 of 12 months (7/12 = 0.58);
• in the previous 4 years it was recorded 27 of 46 months (27/46 = 0.59;
• had the Brown Goshawk been recorded 8 months in 2011 (8/12 = 0.67) or only recorded in 26 months in the previous periods (26/46 = 0.57) it would have shown as an increase.

Overall the proportion of months reported in 2011 and the 4 previous years gives a correlation coefficient of 0.986 - very similar patterns.

The possible exception is Straw-necked Ibis  where the rate of reporting in 2011 was roughly half that of the longer period.  This reflects the Straw-necked Ibises departing for the inland in the deluge of 2010 and (unlike most other waterbirds) not yet returning to Carwoola.
Links to other sections.
Overview report, Comparison with 2010; Breeding