Birders,
Took a roster yesteday and did an overnight walk with my wife over
monday night. We had big plans of going all the way out to the end of
Mt Hay and camping on the (not very inspiring) summit and surveying
the Grosse Valley below. With the track closed for maintenance this
would have pushed a 4k trip out to 24 and frankly I'm too lazy for
that sort of thing. We ended up hiking out along Rock Lily Ridge
(didn't see any rock-lillies though), an east running ridge, off the
N/S Mt Hay ridge.
The weather was miserable overall, but I quite like walking in the
rain. Lots of White-Ear HE's plating in the Mountain Devils, also
spinebills, scrub wrens and thornbills. I didn't take my bins because
the conditions were appalling, but I think they were mostly Brown and
striated. Need to learn the calls!
The best part was waking up to Lyrebirds calling their hearts out in
the valleys below us. From our campsite I could hear up to 6 going at
any time, all 2-3k apart, the furthers probably 6k away from me! Good
conditions for sound to travel I suppose, but it really was remarkable
how much I could hear. One bird in particular was obviously in the
mouth of a cave as it's call boomed spectacularly up to me on the
ridge, but it was also quite directional.
It got me thinking about what might have prompted this loud voice.
Birds need to do 2 things; eat and breed. Lyrebirds like to scratch
around in particular leaf litter, which seems to only form around
certain locations, like on the downhill side of boulders, so they must
roam a broad territory. But then to find a mate they need a loud
voice. This might have further evolved through females being given a
choice, from a long way away, about who was the best singer, and then
selectively breeding with them. The behaviour of Pilot Birds seems to
support this as their strident calls can be heard from a long way
away, but being smaller birds mean smaller territories and therefore a
requirement for a quieter voice. I heard Pilots again, for the 6th
time now, and still haven't seen one.
Anyway, any opinions on this? I've probably re-invented the wheel here
and this was all covered by an undergrad in 1906, but we'll see.
Mt Hay is in the Blue Mountains, the best place in the world.
--
Evan Beaver
Lapstone, Blue Mountains, NSW
lat=-33.77, lon=150.64
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