Hi Peter
You're probably referring to a form of "ptiloerection": the raising
of feathers permitting the escape of heat. I've only ever observed
birds using the plumage of their mantles/upper back region for this
but they may well use their crests too.
You'd have to do some pretty stringent testing to state categorically
that this is the same behaviour in your bushlark images but the
chances look good that it may be so, especially if this was always
performed along with the panting and only on hot days.
Happy birding
Ricki Coughlan
Belrose, Sydney
On 12/12/2006, at 12:19 PM, wrote:
Hi All,
On the weekend I photographed a few Singing Bushlarks (Australian
Larks)
with thier crests raised.
4 Images of 3 different birds can be seen here:
http://www.peterfuller.com.au/essays/bushlark/bushlark.html
The field guides I have say that a Singing Bushlark is
distinguished from
a Skylark by the lack of crest.
Can anyone with HANZAB confirm whether a crest is listed as a
feature of
Singing Bushlarks? Is it only a feature for certain subspecies?
Also, does anyone know whether crests are known to act as a "heat
sinks"
for birds to regulate head temperature?
Regards,
Peter
P.s. Photos taken near Geelong in Southern Victoria of two isolated
groups. The temperature was heading towards an expected 40 degree
day, but
it was only about 30 degrees at the time.
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