September 2017

The most exciting sighting this month is a Grey Goshawk seen between Stony Creek NR and the Molonglo.  This is only the second sighting of this species in the area. 

A number of other less common species have also been recorded including White-bellied Sea-Eagle (flying over Whiskers Creek), Black-winged Stilt (seen from the road at Foxlow Lagoon), Powerful Owl (Wanna Wanna, flying into Cuumbeun) , Red-capped Robin (Whiskers Creek), Yellow Thornbill (Whiskers Creek) and Varied Sittella (Whiskers Creek).  

In total 90 species have been recorded, a little below average for the month.

It is tempting to ascribe the reduced number of species in recent months to the weather.  Very low rainfall will have reduced the food resources and horrible strong winds make birds seek shelter and thus be hard to spot.  That being said one observer reported:

 ... the upside of the wind at our place is that we have watched some kestrels do some amazing aerial acrobatics! Remaining in a stationary hover in 50k/h winds and then diving in a straight line and swooping low to return to 100m... it's truly amazing. ""

In terms of breeding, I have received reports of 14 species at various stages of the breeding cycle (marked in red text below), mainly nest building.  On average this cycle appears to be happening about on schedule, with the number of early records balancing the number of late species.  The records are a little "thin" so I'd welcome any additions. I haven’t yet found a nest of Flame Robins but they are still around in the same places, after being difficult to spot mid-month.  

Linking the breeding cycle and migration, Fairy Martins are a little early returning and are building nests in the usual spot.   An unusual element of migrant return were the large (by Whiskers/Widgiewa standards) flocks of Yellow-faced Honeyeaters heading West.  We recorded 150 on one dog walk, which is more like Autumn departure than the more gradual return.  Of the regular migrants 11 of the expected species have returned on time, two are late and four have been early returners (so on average everything is normal - or perhaps a tad early).  Those seen have orange highlight below.

As always, thanks to the observers who have provided reports to me for the month.  These have covered sites in Whiskers Creek Rd, Widgiewa Rd, Wanna Wanna Rd, Molonglo Valley, Forbes Creek and Hoskinstown Village and Plain. Please pass on interesting sightings to me by email to martinflab@gmail.com.  

Before getting to the list you might enjoy a snap of a Striated Pardalote, taking a break from gathering nesting material.

1  Waterbirds (pt 1):  (pt 2); (Pt 3); (Pt 4):Musk Duck; Black Swan;  Australian Shelduck; Australian Wood Duck; Grey Teal;  Pacific Black Duck; Hardhead; Australasian Grebe; Hoary-headed Grebe; Little Pied Cormorant;  White‑faced Heron; Eurasian  Coot; Black-winged Stilt; Masked Lapwing; 

2 Birds of Prey:  White-bellied Sea-eagle; Collared Sparrowhawk;Grey Goshawk; Wedge-tailed Eagle; Nankeen Kestrel; Peregrine Falcon.

3 Parrots and Relatives:  Yellow-tailed Black-Cockatoo; Gang‑gang Cockatoo; Galah;  Little   Corella; Sulphur‑crested Cockatoo; Australian King-parrot; Crimson Rosella; Eastern Rosella; Red-rumped Parrot

4 Kingfishers and other non-songbirds (Pt 1) (Pt 2) (Pt 3): Common Bronzewing; Crested Pigeon; Tawny Frogmouth;  Horsfield's Bronze‑Cuckoo;  Pallid Cuckoo; Fan‑tailed Cuckoo; Southern Boobook;  Powerful Owl; Laughing Kookaburra

5 Honeyeaters: Eastern Spinebill; Yellow-faced Honeyeater; White-eared Honeyeater; Noisy Miner; Red Wattlebird; Brown‑headed Honeyeater; White-naped Honeyeater; Noisy Friarbird; 

6 Flycatchers and similar species: Rufous Whistler; Grey Shrike-thrush; Grey Fantail; Willie Wagtail; Magpie-lark; Scarlet Robin; Red‑capped Robin, Flame Robin Welcome Swallow; Fairy Martin; Tree Martin

7 Thornbills, Finches and similar species (Pt 1) (Pt 2):  Superb Fairy-wren; White-browed Scrubwren; Weebill; White-throated Gerygone; Striated Thornbill; Yellow Thornbill; Yellow‑rumped Thornbill; Buff‑rumped Thornbill; Brown Thornbill; Spotted Pardalote; Striated Pardalote; Silvereye; Double‑barred Finch; Diamond Firetail; House Sparrow; European Goldfinch

8 Other, smaller birds:  White-throated Treecreeper; Varied Sitella; Black-faced Cuckoo-shrike;  Olive‑backed Oriole; Dusky Woodswallow; Skylark; Common Blackbird; Common Starling; Australasian  Pipit;

9  Other, larger birds: Satin Bowerbird; Grey Butcherbird; Australian Magpie; Pied Currawong; Grey Currawong; Australian Raven; Little Raven; White-winged Chough

Start of Tawny Frogmouth nesting

I have been monitoring the breeding activities of a pair of Tawny Frogmouths since 2008 - a period of 10 years.  I have good measures of when nest building started for 7 of those years.  Of the other three years:

• 2008 was the first year and I didn't realise the nest existed until I spotted the male in incubation mode;
• 2011 the nest site moved to another tree, and again I didn't realise what was going on until the male went missing and I found him incubating.;
• 2014 had - I now think - a false start, in that some twigs were blown into the nest site and gave a misleading picture.

For this year the birds seemed very late in starting their activities but on 6 September 2017, when we returned from Mallacoota, there were a few twigs in the nest fork.  On the morning of 7 September more twigs had arrived, but they hadn't yet been trampled ...

... so I am taking 6 September as the start of nest building.  (If they had started while we were away I think it would be no more than one day earlier.)  This is the latest date I have recorded: counting back from the date of fledging chicks 2008 may have been later but making assumptions like that is a very slippery slope.

This year has been pretty dry and - in terms of average minimum temperature - quite cold.  I wondered how these factors went in explaining the relatively late start on nest building.

I have daily data on rainfall, maximum and minimum temperatures for the period 2009 to the present.  I used this to build some data for analysis:

• total rainfalls and average extreme temperatures for official Winter (June to August) and my version of Winter (July and August); and
• number of days since 1 January to start of building

for each in-scope year.  On looking at the correlation coefficients it seemed that the 2 month weather data correlated more closely with the date of starting than the three month values so the shorter period data form this table (actually an image of a table)

The correlation coefficient for rainfall with date of starting building is quite strongly negative, suggesting that the lower the rainfall, the higher the number of days (ie the later the start of nesting).  The correlation for minimum temperature with date of starting is not so strong but again suggests a cold year gives later nesting.  The coefficient for maximum temperature is too weak to be considered.

The data can be plotted on a graph.

From my inexpert view this reinforces the idea that rainfall in July and August is the most important factor (of those I have assessed) in determining the start of nesting.

As the breeding event proceeds I shall look at other benchmarks (start of incubation and nest being empty).