Whiskered Terns in Carwoola pt 1

Today (13 November) I got a phone call saying that some terns were flying around the swamp in the Plain.  By the time I had got down there they'd been identified as Whiskered Terns and 8 were counted.  One of them came close several times allowing me to get some photos.  (As it was blowing a gale, and the birds fly quite quickly, the photographic process was "Point the camera in the general direction and press the button."  Seems to have worked OK).

 Sometimes there were up to 3 fairly close.  Here's a "poetry in motion" or Monetesque snap of a vol de deux.

Why have all the birds gone?

The title is a little reminiscent of a famous Pete Seeger song, but unfortunately that doesn't supply any answers.  As far as I can tell none of the missing bird species have gone to young girls; husbands, the army or graveyards.

We have had a reduced number of observers in the lower parts of the area this year and this would certainly explain part of the 'problem'.  Here follow my other thoughts on the comparison of the  number of species observed in August 2012 and 2013.

		2013
		Yes	No
2012	Yes	72	25
	No	4	na

To deal with the four species 'added' in 2013 first, 1 is unusual (Nankeen Night-heron); the Pallid Cuckoo was an early return; and the Gang-gang and Silvereye are just chance.

More interest is in the (much larger number of) species seen in 2012 but not 2013.

Late arriving migrants
From comments in the COG bulletin 'Gang-gang' it seems that many migrants are delayed in their return to the Canberra Region, despite the warm winter.  For the purpose of this note I take that to be an explanation for 5 species: Fan-tailed Cuckoo; Grey fantail; Horsfield's Bronze-Cuckoo; Noisy friarbird; Shining Bronze-cuckoo.  Interestingly I first heard a Noisy Friarbird on 2 September, so they are only a little late.

Waterbirds
Apart from good rain in June and adequate rain in July, we have been through a relatively dry Autumn-Winter.  Although the dams and other wet areas aren't as dry as in 2009 there isn't a lot of water around.  (interestingly, an observer who has moved to Corryong comments that there is water everywhere down there).  5 species of waterbirds are MIA this year: Australasian Shoveler; Hoary-headed Grebe; Black Swan; Hardhead; Latham's Snipe.

Raptors
There was a surprising absence of reports of raptors in August 2013.  The Spotted Harriers which were regular over the swamp in the Plain have not been reported for a while; neither the relatively common Nankeen Kestrel nor Black-shouldered Kite have been seen; and the less frequently reported Little Eagle and Australian Hobby have been absent.  Perhaps the dry weather has decreased prey numbers?  Perhaps it is an outcome of reduced observer numbers on the Plain?

Quail
These birds are often hard to spot unless a lot of time is spent in the grassy areas.  This is an area where we have been lower on reports in August.  Neither of the local species (Brown Quail and Stubble Quail) were reported this month.  (This could also cover the Spotted Harrier; Latham's Snipe and Golden-headed Cistcola also found - like the rain in Spain - mainly on the Plain.)

Others
This leaves a group of 8 species.  Of these 2 (Red-rumped Parrot and Double-barred Finch) are usually easy to spot along the roads of the Plain but I haven't done so in August 2013.  The other 6 species are all relatively unusual in the area, and their absence is not remarkable.

Annual report 2012: overall picture

This is an overall report on birds observed in Carwoola in 2012.  I use the term Carwoola to cover the catchment area of the Stoney Creek Gazette,  As well as Carwoola itself it includes a bunch of localities (including Primrose Valley and, importantly, Hoskinstown) to the SE of Queanbeyan.  It is illustrated in this sketch map:

The database I maintain is pretty well restricted to that area to provide some consistency.  However if very interesting birds are reported in a some what wider area:

• where people might like to go and view the birds (eg sightings of Banded Lapwings just outside  Bungendore and Plumed Whistling Ducks on dams close thereto); or
• the sighting suggests we should keep an eye in case they also turn up here

I will also include them on this blog but not the database nor - other than mentions like this - in my reports.

While I largely followed the model used for the Annual Report for 2011, in particular the decision to adopt a multi-post approach, what follows has to some extent evolved during writing.  .  (For those that think the result is still too long, the Canberra Ornithologists Group Annual Bird Report is 80 A5 pages - and 2Mb to download!)

This report will be a bit heavy on numbers but I will attempt to explain them in terms of their meaning rather than simply a barrage of percentages!  For those who wish to skip the statistics I have tried to highlight the main points in bold blue.

By the end of 2012 we had recorded, over a 6 year period, 176 species in the catchment area of the Gazette.  89 (50.6%) of these had been recorded undertaking some form of breeding activity. 11 species were observed for the first time in 2012 and as for last year 19 have been recorded in every month.

It is interesting that over a 30 year period the Garden Bird Survey, run by the Canberra Ornithologists Group has recorded 239 species with 108 of these (46.2%) recorded as breeding.  Given the much shorter time span and far fewer observers I think we have, to quote Young Mister Grace, "...all done very well."

In 2012, 150 species were recorded in the study area.  This is 84% of those ever recorded in the area.  This graph shows the number of species recorded per year.

Some analysis of the growth in species recorded has already been posted on this blog.  For the last three years the reporting effort has been broadly comparable and the drop between 2010 and 2011 is, as yet, unexplained.  The increase between 2011 and 2012 is in part:

• a recovery to "normal" increase in diversity; but mainly
• the astonishing variety of birds seen in and near an ephemeral swamp in the Hoskinstown Plain

In 2012 34.7% of the species recorded were observed undertaking some form of breeding activity.  This value is slightly lower than in other years in this area and it is tempting to ascribe this to some attribute of the year (eg the very high rainfall in January - March).  Another possible cause is the inflation of the denominator of this average by a relatively high number of vagrant species

Links to other sections of this report

2012 cf other 5 years, 2012 cf 2011, Breeding

Annual Report 2012: Breeding Activity

It can be argued that recording breeding events is the most important aspect of bird observation since if the birds do not breed they will soon be extinct!  It is however a more difficult task than simple observation as: 

• many birds go to some lengths to conceal their nests; and
• it is necessary to be very cautious with most species to avoid frightening the birds away from the nest.

To ameliorate these problems a wide definition of breeding is employed with the core events of "nest with eggs" and "nest with young" supported by a range of other, indirect, measures of breeding activity ranging from breeding display to dependent young. (I sometimes feel that a new code is needed for "indolent young" when the Magpie chicks are clearly able to fend for themselves but would rather bludge off their parents.) To be rated as dependent young the fledglings must be

• out of the nest and generally be seen being fed by the parents or, 
• in the case of waterbirds, be incapable of flight.  

I have made an exception for the Tawny Frogmouths where the fledglings are fed at night and it isn't possible to determine how this is achieved.  In that case the young are considered dependent until they move away from the parents some 10 weeks or so after leaving the nest.

(In other countries such as Canada studies are undertaken which assume all birds seen or heard  during the breeding season are in fact breeding.)

The number of records of each type over the 6 years of the project is in the table below.

Type of breeding activity	Number of Records
not coded	110
carry food	6
copulate	3
display	19
dependent young	159
Inspect hollow	2
nest building	29
nest with eggs	5
nest with young	55
bird on nest	47

Since this project commenced 439 breeding records have been noted. The decision to use the COG Breeding codes was made in late 2009 and thus approximately 1/4th of the records are not coded to type of activity.  Such is life!  With respect to the analysis of the months where codes are available, the high proportion of records of dependent young is typical: note that this may not mean that the nest site was in the area.

7 species have been recorded breeding in 10 or more periods (year/month combination) accounting for 95 records (31.3% of all records) in total.  At the other extreme 23 species have a single breeding record and 12 species have been recorded twice as showing breeding activity.

A difficulty with analysis of breeding records is that the peak breeding period in the Southern Hemisphere is split by the change of year.  This is illustrated in the following chart.

To overcome this I commenced, in mid 2009, recording the 'financial year" in which observations were made and it is possible from that point on to re-categorise observations to a "breeding year" (running from July to June).  It might be noted that 78% of the records after December are coded as dependent young.  The incidence of type of event x month is illustrated by this chart.

Following from this, the next section mostly covers 3 breeding seasons ending on 30 June 2012 the 2012-13 season will, inshallah, be reported on next year, but at this stage appears similar to history.

The records for 2009-10 show 58 breeding records, 2010 -11 123 breeding events and for 2011-12 137 breeding events have been recorded.  The increase in the number of events recorded since 2009-10 reflects extra effort by myself in recording information from 2010 onwards rather than an increase in amorousness of the birds. I shall not consider the 2009-10 season further in this analysis.  

In terms of number of events, I don't consider the increase between the last two years significant.

In 2010-11 51 species were recorded as breeding while an almost identical 52 species were recorded in 2011-12.  These have been indicated as such in the monthly reports.  

The number of reports received by species is summarised in the following table.

# reports	# species
1	17
2	13
3-5	17
6-9	11
10+	4

As expected most species have only been reported undertaking breeding activity once or twice.  The four species with 10 or more breeding records are:

• Striated Pardalote (10 reports): a common species which often nests in hollows around buildings and frequently calls when in the nest. 
• Australasian Grebe (11 reports): commonly seen on farm dams with nests in the open.  The young birds are both noisy and distinctive,  
• Willie Wagtail (13 reports): The records for this species cover a wide range of types of "nest-centred" events, possibly reflecting the energetic distraction displays, having the unintended outcome of lading keen observers to the nest (rather than away from it).
• Australian Magpie (19 reports): the swooping of defending adults and the whingeing of the dependent young are hard to ignore, however much one tries.

I would note that the Tawny Frogmouths just fail to make the 10 record category since one nest site has been recorded as active for 4 and 5 months respectively over the 2 seasons covered.  A second site has been reported for the 2012-13 season so these excellent birds should crack the big league next year!

Links to Other sections of this report.

Overview; 2011 cf other 5 years; 2012 cf 2011

Annual report: 2012 compared to 2011

While analysing the results of this project over the full 6 years I found that the analysis was hampered by the differing numbers of observers in the various periods.   Was a difference due to a real change in the birds' behaviour or simply an artefact of observer 'X' not being active at a point in time?  An earlier post discusses the issues of observer effort.  To overcome this problem I have decided to compile this post contrasting 2012 with 2011 where the level of observer effort was broadly similar.

Of the  177 species recorded in this project 162 species were reported in one or both of the years covered by this analysis.  Of these 162 species:

• 12 were reported in 2011 but not in 2012;
• 20 were reported in 2012 but not in 2011 (of which 11 were reported for the first time in 2012); and 
• 130 species were reported in both years.

Looking at the entire 162 species there is a very strong correlation (correlation coefficient 0.878) between the number of months each species was reported in the two years.  Thus it can be concluded that the two data sets are reasonably consistent.

Of the species recorded in 2011 but not 2012, 9 were sighted in a single month and 3 were   seen in 2 months. 

For those seen in 2012 but not reported in 2011:

•  8 species (5 of these being additions to the area list) were seen in a single month
• 3 species (all additions) were seen in 2 months in 2012;
• 4 species (1 addition) were seen in 3 months in 2012;  and 
• 5 species (2 additions - surely reflecting a change in observer behaviour?) were seen in 4 months.

In the final category special mention could be made of the White-winged Triller,  which was reasonably common in this area and the urban area of Canberra prior to 2010-11 but reported very sparsely in that year but now seems to have re-established itself.

 36 species were reported every month in both years.

The following table shows the aggregate number of months in which members of the broad groups of species were seen in the two years.

Category	2011	2012	difference
1  Waterbirds	146	200	54
2 Birds of Prey	72	101	29
3 Parrots and Relatives	89	91	2
4 Kingfishers and other non-songbirds	131	124	-7
5 Honeyeaters	90	101	11
6 Flycatchers and similar species	128	126	-2
7 Thornbills, Finches and smiilar species	198	202	4
8 Other, smaller birds	114	116	2
9 Other, larger birds	94	91	-3
Total	1062	1152

The similarity of results between the two is readily apparent except for Waterbirds, Birds of Prey and to a lesser extent Honeyeaters .

The situation for Waterbirds is summarised in the following chart.  I realise it is cheating to include 2010 in a post titled "2012 compared to 2011" but 

• it is my post; and
• I prefer to explain the situation rather than

• leave it obscure; or
• change the title and do a lot of work to include 3 years in everything!

It appears that the number of species reported per month is quite stable from January 2010 until June 2011 (which covers the very wet period of 2010 with many waterbirds absent, breeding in the revitalised the inland) when the number kicks up - presumably as the Inland begins to dry out.  Another period of stability follows until mid 2012 by which time a dry period has resumed and the waterbirds have discovered the swamp on the Plain.

With respect to Raptors (ie diurnal Birds of Prey) the position is summarised in this table of months reported x year x species:

species	2010	2011	2012
Australian Hobby	2	5	3
Black Falcon		1	5
Black-shouldered kite		6	11
Brown Falcon	9	11	12
Brown Goshawk	9	7	11
Collared Sparrowhawk	4	3	6
Little eagle	6	9	9
Nankeen kestrel	12	12	12
Peregrine falcon	5	4	8
Spotted Harrier	1	1	10
Swamp Harrier			2
Wedge-tailed Eagle	12	12	12
Whistling Kite	1	1
White-bellied Sea-eagle	1

Of the 14 species covered by the table, 2 were not reported in 2012 and 1 (Swamp Harrier - finally) was added.  5 species - highlit in yellow- are regular residents throughout the period.   Peregrine Falcon is a localised resident and Black-shouldered Kite and Spotted Harrier have become regular in the past year: the former returning after having moved out of the area during the drought and the latter possibly reflecting greater effort on the Plain.  The impact of these last two species largely explain the increased reporting for this group.

The other "large mover" is the Honeyeater group becomes easier to understand at the species level.  6 species (Brown-headed honeyeater,Eastern spinebill, Noisy Miner, Red Wattlebird; White-eared Honeyeater and Yellow-faced honeyeater) are reported nearly every month in all years.  Scarlet and Crescent Honeyeaters have not been reported since a single sighting of each in 2010.  A few other species do the migrant 'thing' consistently each year.  This leaves relatively high 2012 rates for Yellow-tufted Honeyeater (in Yanununbeyan SCA) and New Holland Honeyeater (mainly a site in Widgiewa Rd) as explaining the increase since 2011.

Links to other parts of the Annual Report

Overview; 2012 cf other 5 years, Breeding