Paul:
> My office bird list (since early 1990) stands at 55 species, 11 of these
> are birds of prey. This would have to be considered a fairly high ratio.
> Most of these would have been sighted as a response to the N.m's alarm
> calls. It is now an inbuilt unconscious response for me to look up
> whenever I hear the alarm. I am even starting to differentiate the
> various subtle differences in the alarm call which appear to be species
> specific. Mind you, I have not achieved anything near perfection, but
> then neither have the miners; they still set off when a helicopter flies
> over. I have spotted a lot of helicopters.
Interesting observations. Can you be more specific about the different
types of alarm calls. I recently, wrote a short article on alarm calls
and I am not aware of N. Miners having more than one type of call in
response to predators (aerial or terrestrial). I do recall birding in a
local park (Mt. Coot-tha) and suddenly all of the N. Miners in the local
population started calling (a short, descending whistles). To me, what was
exciting is the fact that all of the birds within hear shot started to
call.
>
> By contrast, the miners that inhabit the area near my home seem to be a
> lot less vigilant about BoPs and my four chooks (domestic chickens, for
> North American readers) are a more reliable guide to the presence of
> BoPs than the local miners.
>
Can you identify if local habitat differences between the two populations
of N. Miners? Perhaps, your chickens are better at spotting the hawks and
beat the Miners to the task. I assume that the N. Miners chime in when
they also spotted the intruder. Do they, or are they using your chicken
as sintinels?
> Noisy Miners are not highly regarded by many Australian birdos because
> they tend to exclude a lot of other birds, particularly small
> insectivorous ones and other, smaller honeyeaters, from their territory.
> In suitable habitat, such as occurs near my home, this is not a problem
> as the Miners stay in a fairly small area for a while until food
> supplies start to decline and then move on to a nearby patch of bush.
> When they vacate an area the small birds that were previously excluded
> move in in large numbers. When the Miners left the immediate vicinity of
> our home, we were invaded by Yelow-rumped Thornbills, Speckled Warblers,
> Superb Blue Wrens, Yellow-faced and Brown-headed Honeyeaters, Spinebills
> etc. etc.
>
What time of year?
> The colony at Newcastle University, however, have nowhere to go, their
> patch of bush is an island in a sea of suburbia, wetland and yes, even a
> golf course. So they stay put. They actively 'farm' lerps, which feed on
> the leaves of Eucalyptus and secrete a sugary substance for the birds.
> In return the lerps receive protection from the small insectivorous
> birds that eat them. The net result is that the environment slowly
> degrades over time. The trees appear to be slowly weakening, in dry
> times a few succumb and die. The weather has been relatively kind
> lately, so the trees seem to be doing better but in the long term a new
> balance will be arrived at. Whether or not this will result in a crash
> of Noisy Miner numbers remains to be seen.
>
I am confused. I wasn't aware that N. Miners (as oppose to Bell Miners)
also farm lerps.
Cheers, Jim Davis
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