Here's my take on the subject of Tas Moreporks on the Aust. mainland.
Without going into too much detail & based on my memory of 3 specimens
collected I found dead in Victoria (1 beachwashed at Phillip Island; 1 dead on
road near Ocean Grove & 1 up in the mountains in Camberville) & now lodged in
the Museum of Victoria & then a comparison between these birds, a good
collection of Tas skins, Tas-like birds collected in Vic & a large collection
of mainland ssp all in the Vic Museum.
Firstly the photograph taken at Hamilton is definitely a Tasmanian Boobook.
This is based on bright yellow iris (dull greenish yellow in mainland
Boobooks); small white spotting on crown (if there is any blotching on mainland
birds it is large & cream or brown, more likely to be streaked in this area;
certainly not white & not tiny as in this bird); the patterning below is finely
with whitish blotches (in mainland birds this is occasionally blotched, but not
white & usually streaked; blotches tend to be larger, or streaked and usually
cream-coloured, although sometimes whitish); overall the upperparts seem very
dark (this is more mid-brownish, not so dark brown in mainland birds). I have
seen a Tas bird in Tas & it was remarkably small-looking & very dark with
spotting on crown & blotching as described above.
Within each subspecies (or species?) is a fair bit of variation & there are a
few birds that may be difficult to separate in the field, but most of the
differences hold true & I cannot find any evidence of a mainland bird which has
the Tas Boobook characters that was collected in the summer months of the year.
This is opposed to around a dozen birds (at last count) collected in Victoria,
all in Autumn, Winter (? Spring). So without any evidence of there being any
Summer records of Tas Boobooks, you would have to say they are much more likely
to be migrants. They are just overlooked because of their similarity to
mainland birds.
As for whether the Tas bird is a full species, to me it's a matter of degree. I
actually thought of this well before it was recently postulated & it is a bit
odd that the bird is small compared to mainland birds, with some good plumage
differences. I tend to think this bird is part of a relict boobook population,
which is also true of NZ birds & perhaps the Red Boobook of NE Qld. Whether
they (or the others) are different enough is a matter of conjecture. Be good if
we had some Aussie taxonomists to decide these things, instead of people
overseas. I think if you split this one, there are a bunch of other candidates
waiting to be looked at from Tas, like the small Tas Magpie, the long
shrike-like billed Tas Grey Shrike-thrush (bills are supposed to be smaller
proportionally in higher latitudes, this has a bill at least 33% larger with no
overlap; additionally has a distinct white throat); & wait there are more......
As for the Pink Robin, the Tas bird sounds like a very weak subspecies anyway,
so the only way to decide this one is to band some Tas birds & see if they turn
up on the mainland.
Kevin Bartram
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