Thanks Philip.
That's where simple abundance measures from a location don't really tell
the whole story. The relative abundance of resident blackbirds in Tylden is
the same today as it was yesterday - except that a significant number of
non local birds moved through and out. If I hadn't been out walking the dog
I'd be none the wiser!
There are various locations around here that are 100-300m higher in
altitude (so up towards 1000m). I surmise that any blackbirds that are on
the move have come from altitude.
Regards
Lawrie
On Sat, 22 Apr 2017 at 21:45, Philip Veerman <> wrote:
> Abundance of the Common Blackbird is almost constant in Canberra. Minimal
> change through the year (as from the results of 21 years of our Garden
> Birds
> Survey, as in my book). And that variation is entirely explainable by
> changes in levels of conspicuousness. No suggestion of any regular
> movements
> in or out of our region. Similar results from the ACT Bird Atlas. In marked
> contrast to the many native species that show very strong seasonal or
> monthly changes in abundance due to migrations.
>
> Philip
>
> -----Original Message-----
> From: Birding-Aus On Behalf
> Of
> Lawrie Conole
> Sent: Saturday, 22 April, 2017 1:22 PM
> To:
> Subject: [Birding-Aus] Blackbird migratory behaviour in Australia?
>
> Hi birders
>
> Back in 2004 on Birding-Aus I wrote this:
>
> "... /Some musing on that feral pest the Common Blackbird (Turdus
> merula) in Victoria, Australia ..../
>
> /A couple of observations this Autumn have me wondering whether some
> proportion of the Victorian Blackbird population might be migratory -
> even if its just the kind of altitudinal migration seen in various
> indigenous birds here. Let me elaborate .../
>
> /At two sites I've visited in the last fortnight, I've come across
> groups of Blackbirds (about 10 birds in each case) roosting/resting in
> isolated patches of vegetation in farmland during the day. In one case
> the patch was a cluster of pines in a vast dry grassy paddock, no
> understorey - very un-Blackbird-like habitat (Craigieburn, northern
> Melbourne). The others were laid up in a mess of Spanish Heath (Erica
> lusitanica) underneath remnant Swamp Gums (Eucalyptus ovata) in farmland
> (south of Colac, northern Otway Ranges foothills). Both sites were at
> about 200m above sea level, and perhaps less than 50km from more upland
> forest (>500m ASL). In both cases they flushed in groups, and didn't
> give the characteristic Blackbird cackle that usually accompanies such
> disturbance./
>
> /This seems vaguely like migrant behaviour to me. Thrushes like these
> often migrate at night in their natural range, and lay up in various
> copses of vegetation during the day. In the Craigieburn example, several
> migrant Grey Fantails were noted in an adjacent patch in the paddock./
>
> /I'd be interested in any comments on this matter. Does anyone live in
> an upland kind of place with fluctuating Blackbird numbers which might
> suggest regular short - medium distance movements? Any other similar
> observations? The 'big picture' data presented in the New Atlas
> publication are not finely resolved enough to address this question -
> particularly if only some Blackbirds are migrating/moving/ ...".
>
>
> There wasn't much of a response, and nothing to corroborate my musings.
> So until today I hadn't thought about it much since. This morning
> pre-dawn when I went outside briefly (Tylden, central Victoria, ~600m
> above sea level) there was an unusual amount of Blackbird noise - more
> than I'd expect from our apparently resident pair. Out walking with the
> dog a few hours later, around 10am, I saw what could only be Blackbirds
> migrating. Over a period of about 5 minutes, I estimated about 40
> Blackbirds passed through in a loose stream, going N/NNE (and therefore
> down in altitude) - much as you see with Yellow-faced and White-naped
> Honeyeaters when they're migrating - moving from one copse of trees to
> another, stopping briefly before heading on. In this case both males and
> females.
>
> So why does it matter? Just a feral pest. It has been frequently stated
> in the literature that Australian introduced populations of Blackbirds
> are all sedentary. In their native range some populations are migratory.
> Does that reflect here then that the source populations are from
> different populations in Europe with respect to migration, or are local
> environmental conditions just triggering latent migratory behaviour? I
> can't help but be interested ...
>
> If anyone else sees anything similar this autumn, I'd love to hear from
> you.
>
> regards
>
>
> --
> address.html
>
>
> <#*dr.-lawrie-conole*>/Dr. Lawrie Conole/
>
>
> Tylden 3444, Victoria
> Australia
>
> lconole[at]gmail.com
>
>
> --
Dr. Lawrie Conole
Tylden 3444 Australia
lconole |at| gmail.com
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