This post contains a bit of analysis about some species which have been drawn to my attention in the past month. It started off with 4 species, but has grown as the month has progressed! They are rather different species, and the reasons people have noticed them are possibly different also.
Powerful Owl
This bird has been heard from Wanna Wanna Rd, close to area in which it was heard, for three months, in the same season in 2015. Only one other report, in September 2010 from Whiskers Creek Rd. Of course:
- when I visited the area to hear it, silence was evident; and
- the bird hasn't been heard since.
This bird can be rated as generally unusual in the area, although Tallaganda is a hotspot for them, and the gullies of Cuumbeun contain ideal habitat.
A bird of this species has been resident in Turner, near ANU, for the past 16 months and has been wreaking havoc on the Central Canberra possum and glider populations. I am wondering if the occasional appearance of Sugar Glider components on our property could be taken as indicating this species is more common in the area than records suggest.
Southern Whiteface
This has been reported this month from a property above the Hoskinstown Plain where a flock of 6 - 8 birds was seen. When this was reported I was quite excited about this, as the species is rated by COG as uncommon. The chart below shows that this is the case, at times, in this area.
Looking at the detail of reports to me in the past I believe that the years (2010 - 2012) in which there were many reports coincide with those when I was getting reports from a site in Widgewa Rd overlooking the Plain. For the earlier years my own sightings were generally from areas bordering frost hollows, either on the Plain or around the Foxlow Bridge area.
So it seems that, in Carwoola, the species is quite common in a fairly specialised habitat but unusual; elsewhere.
White-plumed Honeyeater
This species is relatively unusual in the area being reported only in 25 months, out of the total 110 months for which the project has data. Most of the reports have come from the Eastern part of the area. The seasonal pattern is interesting with reduced sightings in the period October to March (although it has been reported in December from 2013 to 2015).
This suggests to me that either bird gets to our area during post-breeding dispersion or it is quieter than its typical noisy aggressive behaviour during the warmer months.
Varied Sitella
This species is the only Australian example of a bird that feeds by moving head-first down trunks and branches. It has been reported more frequently than the White-plumed Honeyeater but also shows a gap in the breeding season.
I was surprised at the relatively high proportion of months reported, as the species is quite unusual in visiting our property. It is quite consistent over the duration of the project with a drop in the past couple of years suggesting a change in observer behaviour (eg we have been away more in Winter in those years).
Australian King-Parrot
This species is not particularly uncommon, being reported in 44 months (ie about 40% of months). However, judging by my experience, it is "here today, and gone tomorrow" rather than a constant presence as with the two Rosella species. Because it is such an attractive bird, and easily identified, observers tend to notice it and share their - very reasonable - excitement in the the sighting.
It has become more frequently reported in recent years.
Note that we only have 3 months for 2016 and the species has been reported - most months from several observers - in each of them. Most noticeably the detailed reports show that the species has been reported every month since May 2015. I believe that the low value for 2014 is a result of observer absence.
In terms of months through the year the reports are almost reversed from the last two species with peak reports in late Spring/early Summer.
A pattern like this made me think the birdswere arriving here after breeding (most of those seen have been adults so it is parents fleeing the kids, rather than the kids being kicked out). However the
COG Birdinfo page ...
... suggests this to be the breeding season so that doesn't work. My alternate hypothesis is that peoples fruit trees are beginning to fruit at this time so the birds - perhaps early breeders - are attracted by a good food supply.
Gang-gang Cockatoo
This species is definitely one of the regulars, reported in 99/110 months. After a couple of lighter years early in the project they have been reported in 11 or 12 months every year. However they are:
- very well known birds (eg the emblem of the Canberra Nature Park);
- easy to identify;
- much more common in this area than just about anywhere else in Australia; and
- very vocal with a distinctive creaky-gate call that draws attention to them.
As with the King-parrot people are justifiably excited when they record the birds and are keen to share their observations.
The monthly pattern is almost the inverse of the King-parrots,
The breeding material shown by COG is not that helpful for this species but, to use some weasel words, it does not disprove an hypothesis that the low reports in Spring suggest the birds go somewhere else to breed and return in Autumn. The peak in April coincides with hawthorn fruiting on the Hoskinstown Plain when large (10-30 birds) to huge (a reliable report of 100 birds on Woolcara Lane) flocks have been seen.
