Hi Coglisters
I have about 43 breeding records for Gungaderra Grasslands Nature
Reserve in 2007. My observations have clustered around the North-western
end of Gungaderra where there are some very old trees, some older
re-growth and some younger re-growth. (Some of the standing dead timber
and some of the fallen logs in the older re-growth show signs of having
been ring-barked). Some of the older trees and the younger re-growth are
set in extensive grassy areas. A burnt area within the larger wooded
area also contains a fair bit of grass. The wooded area is surrounded by
grasslands to the North, East and South and by a four lane highway and a
suburb on the West. The area is rich in hollows. To me, the interesting
thing is that that about 24 of the breeding records are of Common
Starlings and Common Mynas. (As an overall proportion of breeding, I
believe I tend to observe more Common Starling breeding attempts because
they simply cannot help themselves. When they have a beak full of food
they just go right ahead and pop into the hollow in full view of the
observer. So the picture is very probably distorted).
One vignette at Gungaderra may say it all - several smashed eggs -
apparently Crimson Rosella eggs - lying on the ground under a Common
Myna nest. I know, circumstantial evidence only...
The adult birds can be seen flying considerable distances (I estimate
out to about 500 metres) carrying food gathered from adjacent grasslands
to the nest hollows in the woodlands. By way of contrast, I have very
few records of either species breeding on Black Mountain NR or Bruce
Ridge NR where the breeding percentage of the two species would be less
than 5% of the total of all my breeding records. Essentially, these
reserves are not surrounded by grasslands. The few breeding records in
these areas for Common Starlings and Common Mynas are at the edges of
the reserves. Gungaderra is apparently managed as a Grassland Nature
Reserve. Cattle are used to keep the grass from becoming too rank. (And
it was nice today to see Pipits, Rufous and Brown Songlarks). But this
management target may be at the cost of woodland birds. I recognise that
we can't maximise all variables. However, it seems to me that a good way
to reserve the scarce hollows in Gungaderra for native species is to
allow regeneration of woodland so that the core area is simply too far
from the grassland feeding areas to make breeding in the hollows a
competitive proposition for starlings and mynas. In fact, it has already
started to some extent.
Not sure about this - it is just an idea.
As an addendum, this afternoon's highlight at Gungaderra was being
swooped twice by a very intent female Brown Goshawk. A bit unnerving.
Both birds of the pair were calling loudly. Haven't found their nest yet
but I have hopes.
Con
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