…Sorry, nothing new here, a case review of sorts -a summary of what we know and don’t know.
Is almost 40 years since the last credible sighting of Spotted Bowerbird in Victoria [Robinvale 1979 -pair nested in a palm tree] Is another report from Ned’s Corner Station in 1989 was unable to verify, either way considered extremely rare [on a state level] or locally extinct.
NW Vic was only ever edge of range for a species more likely encountered [these days] in the arid woodlands and rural areas of central Qld and NSW. Historical records do indicate however were widespread in the Murray valley region.
“Formerly Spotted Bower-birds were very common along the Murray River valley from the South Australian border in the west to Kerang in the east. The Mildura district appears to have been their stronghold” [Norman Favaloro: Emu vol 39, 1940 -issue 44]
Map below from Atlas of Living Australia illustrates former range of Spotted Bowerbird in Victoria.
So what happened? According to Atlas Of Victorian Birds  “This species is almost extinct in Victoria. Its decline is attributed to a combination of predation by foxes and cats, loss of habitat and illegal shooting and poisoning by orchardists and viticulturalists.”
A fondness for stone fruit was likely a significant contributing factor in the demise of this species locally.
19th century ornithologist Robert Hall writes “It is asserted by some observers that this bird is the greatest pest the orchardist has to contend against, should his property border a break of scrub resorted to by the pillager.” [Useful birds of Southern Australia 1907].
Efforts to control species [in the Mildura district] were detailed by N. Favaloro  “as many as thirty birds per week were destroyed in the vicinity of the Chaffey homestead. In those days bowers were common on the river flats and along that portion of the river frontage which now forms part of the Loch Island.”
Still, they persisted in the town of Euston[NSW] until at least early 90’s [and perhaps still do]. This is on the Murray river, opposite Robinvale [site of last confirmed Vic breeding record]
There are also reports of birds in NSW just north of Swan Hill [Balranald and Kyalite]. More recently from Mungo National Park NSW [approx. 50km from Mildura] and from Lake Gol Gol [NSW] in Jan 2011 [4-5km from border]
Problem is much of the likely habitat within Victoria is private property. Could be a homestead or acreage anywhere between Mildura and Swan Hill. How do we survey for this?
A 2012 report of bower located somewhere between Mildura and Hattah along Murray River [observer on a houseboat] sounded plausible but once again could not be verified.
‘The Spotted Bowerbird is listed as a threatened taxon under the Flora and Fauna Guarantee Act’ [DSE 2003] but actual existence within Victoria subject of speculation. The trail has gone cold and status unresolved.
These birds are reasonably mobile and well adapted to semi-urbanized rural environments. Are in the vicinity , must still be a chance and search should continue. At least maintain vigilance and line of enquiry. Suspect is more to run on this story.
‘Playhouse of the Spotted Bowerbird’ AJ Campbell, Echuca District, Victoria, 1894 [collection Museum of Victoria]