Bowerbirds in Hughes

["Philip Veerman" <>]

John,

 

Sure, join the club. This has been part of a well known increase in population and spread through the suburbs of this species that started in 1989. It has been well documented and described in my GBS Report (see extract below) a trend that has continued since then and an article (or two) by Jack Holland in Canberra Bird Notes. It is far more widespread than the establishment of the Federal Golf Course Bower.

 

Satin Bowerbird Ptilonorhynchus violaceus

A species of forest that has, in recent years infiltrated the suburbs adjacent to Stromlo forest. This was documented by Holland & Veerman (2000) and Holland (2000). Even though this is a recent occurrence, the bird shows a strong seasonal pattern to its presence in the suburbs. Therefore it is very likely that it was originally an altitudinal migrant. From a July peak, numbers drop smoothly during spring to a December minimum of about one tenth that number and rise smoothly again in autumn. There were no records in Year 1, one record in Year 2 and few in the next five years. In every measure of population the species dramatically increased its prevalence in suburban Canberra in Year 8 and it has continued this, though somewhat unevenly, since then. Many records involve many repeat counts of similar numbers of individuals. The geographic distribution of these records is interesting. Out of the 150 records at 40 sites, all but four records are from the suburbs on the south-western side of Canberra, particularly Weston Creek suburbs. These sites are closest to Stromlo forest and for Kambah records, close to the Murrumbidgee river corridor. In more detail the first records were from Year 2 but the first records in Kambah are from Year 9 and then regularly since then. One of the sites closest to the Murrumbidgee river corridor (Site 213) on the north-west of the suburb, has had the most sustained presence (with bowers built in this garden). Site 236 would be a bit closer but first noted them in Year 19. This may be because this is a newly developed area and the gardens there are still young. The next western-most Kambah Site 152 got occasional records but it took till Year 17 to get birds for a few weeks in succession. The two sites on the eastern side of Kambah have only each had one observation of one bird. There are several sites where (usually young) males have built bowers in gardens. The males will display at them and some people have noted these as breeding records, whereas other people did not. For this species, display including bower building, does not constitute breeding, so these were ignored as breeding records.

The only GBS breeding records were in Years 19, 20 & 21. They have been an "on" observation at Site 60, and a carrying food at Site 253 and the others are all of dependent young from late December to late February. Mostly in the south-western suburbs. These could have been hatched far away. There have been other breeding events of this species in Canberra, as reviewed by Griffiths & Holland (2001).
Graphs on page: 103, Rank: 77, Breeding Rank: 52, A = 0.10665, F = 12.42%, W = 29.3, R = 3.425%, G = 3.11.

Philip