To be unambiguous the tail needs
to be slightly spread so you can see all the feathers, preferably fresh and full-grown
ones.
How about it is paired with a
mate that is either very large or very small? This could involve a bit of a
wait, though. g
From: Julian Robinson
[
Sent: Thursday, 30 December 2010 1:11 PM
To:
Subject: RE: [canberrabirds] Chestnut ID opinions please - Sparrowhawk
Thanks Geoffrey for the reminder
of previous discussion. I am still hoping for some discussion/resolution
of this particular bird (especially the tail shape of which I really don’t
understand what people and books say). The reason I was hoping for a definitive
call from someone who can latch onto some unambiguous diagnostic was because I
want to submit it to an interesting flickr group to which I contribute.
This group has gone a long way towards being a useful photographic field guide
of birds of the world. It uses the collective power of zillions of
photographers (actually ~12,000) to build up a number of hopefully
representative shots of each bird. At this stage they have just on
100,000 photos of over 7,000 species, which teamed with a working index and the
fact that photos have location info attached makes a pretty useful database
that COGers might like to add to their reference resources.
http://www.flickr.com/groups/birdguide/discuss/72157594382295215/#comment72157594382316800
Julian
From: Geoffrey Dabb [
Sent: 30 December 2010 11:30
To:
Subject: FW: [canberrabirds] Chestnut ID opinions please - Sparrowhawk
For those who came in later, I
reproduce below from the archive Julian’s summary of a previous ‘Which hawk is
this?’. This will save some repetition.
I would add a further thought
that has occurred to me. Not only is the male goshawk similar in size to
the female sparrowhawk, but other characters are similar as well, eg thinnish
toes and a less strong bill. It is the FEMALE goshawk that has the
heavily scowling brow, less pronounced in the male goshawk. Below I have
taken the liberty of placing Julian’s photo between 2 snaps of a certified male
goshawk. Similarities are evident. So far as I’m concerned Julian’s
bird could be either, but I’d lean slightly to a female sparrowhawk for reasons
given by Julian.
|
Thanks to those who answered this post. Here's a summary
of responses which were very educational, not so much about the actual
identity of the bird, but the take-home messages for me as a bird
photographer. Which have been said many times before but still ...
- identifying difficult birds from a single view or a photo can be hard or
impossible. Without call, giss/jiz (how do you spell it?), or alternate
viewpoints half the information is missing, and lighting in a single view can
add great confusion by changing colours and giving false impressions of
dark/light patches, or losing or overly emphasising some
characteristic. (On the other hand a photo does have the advantage that
it exists in front of the puzzled observer for ever to allow detailed
comparison with guides and books, unlike an ephemeral field sighting which
can be contaminated by later thoughts and inputs).
- birders have to make calls on identifying between similar birds but there
is often plenty of room for doubt despite how certain we can be as
individuals (something which must make the work of the rarities panel quite
difficult).
- even obvious things like "long toes" can mean very different
things to different people and have to be used with caution.
Below's extracts of responses, some of which were in another conversation of
which I was unaware until later. With the exception of Philip's
informative post to the chatline, I've anonymised them to remove possible
embarrassment although no embarrassment would be called for. I doubt we
will ever know for sure since later sightings might not be the same bird. As
far as I know all responders are knowledgeable birders, some extremely so.
For what it's worth I'm going back to my original call, which was Goshawk
knowing this goes against opinions of some vastly better birders than
me. I didn't really see the bird other than in the photographed
location.
------------------------------------------------
Don?t worry about being confused xxx, beyond an obvious female
Goshawk or male Sparrow-hawk, the in between zone is much more difficult than
people would have you believe especially when trying to work from photos as
apposed to seeing the bird in the flesh.
If ever I've seen an obvious photo of a Goshawk that is it. Tail
shape, feet, eye ridge, beak size........
I vote for immature Collared Sparrowhawk going by the stare which strikes me
as "wide eyed" rather than the "heavily hooded"
glare of a Brown Goshawk.
I would put my bet on your bird being a Brown Goshawk.
I?d say pretty certainly a sparrowhawk, given the very clear view of the
diagnostic toes. ... While the sparrowhawk does not have the scowling brow,
it does have a little ridge above the eye that does not overbear it ... The
tail is in moult so not that much help.
For what its worth, and based on things like the G Dabb ID
lessons, I reckon it?s a Goshawk. It has a bit of a cranky look, and
the middle toe really isn?t very long compared to some of the winkle-pickers
I have seen in photos of Sparrowhawks.
I was looking at your hawk shots from Callum Brae, and based on
the long middle toes and skinny shanks I think they are Collared
Sparrowhawks.
I reckon that the ... photo... show a male Brown Goshawk. I'd
argue that the middle toe is too short and thick for Collared Sparrowhawk,
that the brow-ridge is typical for Brown Goshawk and too heavy for a
sparrowhawk, that the tarsus is a bit too stout for a Collared Sparrowhawk,
and that the tail shape (funny though it is) can only fit Brown Gos.
The tail of the... bird could be moulting, and I suspect that t2
and t3 are growing, not full length; t1 seems to be retained juvenile, t6 is
probably first basic. (It was) reported a few years ago that in Brown Gos,
the tail of juvs is slighlty longer than that of adults. I looked for this
effect in Collared Sparrowhawk and couldn't find it. Maybe I should look
again - if it's only Brown Gos in which juv tail is longer than ad tail, then
there might be a new ID feature to work with on moulting birds.
I must admit when I saw ...the photos I thought, sparrowhawk...
|
From: Julian Robinson [
Sent: Thursday, 30 December 2010 8:21 AM
To: canberrabirds chatline
Subject: [canberrabirds] Chestnut ID opinions please - Sparrowhawk
I know this has been discussed many times, but I would value
opinions on this Sparrow / Gos hawk. I have no further info to add
to the photo except the immediately preceding circumstances – in a small
clearing amongst pines near Gundaroo this bird rocketed in carrying prey.
It was intercepted by another just out of view in pine trees, some carry on
then the other bird disappeared and this one reappeared on the branch without
the prey. I assume this parent was feeding its young. The photo is
more informative than the view I could make out with bins in the gloomy
recesses of the pines.
I’m calling it a Sparrowhawk because of the non-heavy brow
ridge and somewhat staring look. Supporting this could be the centre toe
which seems very long given that you can see the front of the centre toe but
not even the nail of the other toes, and also it seems a long way from where
the extended left leg would meet the branch. Counting against
sparrowhawk according to my reading is the shape of the tail feathers, but I’ve
never really worked out what you are looking for in closed position, and some say
that this is an unreliable diagnostic clue.
I would appreciate any educational info and any decisive ID.
Julian
