Then of course there is the diet of the bearded
vulture (Gypaetus barbatus), also known as the lammergeier (or lammergeyer)[a][3][4] or ossifrage,
is a bird of
prey and the only member of the genus Gypaetus.
Traditionally considered an Old World vulture, it
actually forms a minor lineage of Accipitridae together
with the Egyptian
vulture (Neophron percnopterus), its closest living
relative………………..
The
bearded vulture is the only known vertebrate whose diet consists almost
exclusively (70 to 90 percent) of bone.[…………….. The bearded vulture can swallow whole or bite through
brittle bones up to the size of a lamb's femur[20] and its powerful digestive system quickly dissolves
even large pieces. The bearded vulture has learned to crack bones too large to
be swallowed by carrying them in flight to a height of 50–150 m
(160–490 ft) above the ground and then dropping them onto rocks below,
which smashes them into smaller pieces and exposes the nutritious marrow.[11] They can fly with bones up to 10 cm (3.9 in)
in diameter and weighing over 4 kg (8.8 lb), or nearly equal to their
own weight.[11]
Extract from : https://en.wikipedia.org/wiki/Bearded_vulture
From: Simon Cherriman
[
Sent: Friday, 12 June, 2020 10:57 PM
To: Plaxy Barratt
Cc: ;
Subject: Re: [Birding-Aus] casting
Hi Plaxy,
Thanks for your thoughts and for sharing this interesting
observation. We are going ok here thanks, madly writing as much as I can during
the final weeks of PhD scholarship time and lovely the recent wet weather :)
Although it isn’t commonly recorded, WTEs do eat echindas
and the descriptions given below certainly point to this species as the owner
of the pellet, and not others (certainly not owls). I have found either skins
or pellets containing echinda spines in at least a dozen WTE nests during research
in WA, although it hasn’t been ‘published’ as such. It is truly incredible that
spines can go both down, and then back up again, but raptor digestive systems
do deal with some very abrasive items! I once watched an adult female swallow a
whole rabbit hindlimb - from the pelvic girdle to the toenail, in a few gulps.
This must have measured 20-30cm but it seemed to just fold up and disappear, no
doubt to be regurgitated again in a much more compressed form.
Many folk assume WTEs must either rob or scavenge ‘hard to
get’ prey species, rather than actively hunt them, but in my experience they
hunt most things (except most dead roos on the roadside) and are incredibly
capable at knowing the habits of their prey and spending long periods waiting
in low perches ready to pounce. During the breeding season, most prey taken is
live - from mudlarks through to large, live kangaroos which are tandem hunted.
One would think echina spines should deter most predators but all it takes is a
quick ‘hand shake’ at the right time and it’s all over. Predators have spent
millenia evolving techniques to outwit their prey!
If anyone is keen to read more about their movements, you
might like to check out this website (due for some updates!)
Have a great weekend and thanks again!
On 11 Jun 2020, at 8:23 pm, Plaxy Barratt <> wrote:
Hi Simon
I hope you and your fam are keeping well. Just thought these
emails might be of interest to you, if you hadn't seen them already...
You must be pleased to be able to get farther afield in the,
ah, ...field, with regional travel restrictions lifting. I know I'm looking
forward to visiting a few bittern swamps on the south coast again, soon.
Cheers, Plaxy
---------- Forwarded message ---------
From: Philip Veerman <>
Date: Tue, 9 Jun 2020 at 16:55
Subject: casting
To: Mike Fitzgerald <>,
<>
I had a
quick look in HANZAB and did not find a mention of Wedge-tailed Eagles having
included Echidna in their diet. I am a little surprised at that, although they
are obviously a difficult prey item. Could of course have been taken as dead -
carrion, such as road kill, as is a lot of their food. You probably do have
other large raptors locally, even if you have not identified them. I agree that
a WtE is the most likely cause. Hard to think of what other predator it could
be. Though likely, that is not proof. And yes a daunting thought to have eaten
this, then bring up spines as a pellet. The same applies whatever predator it
was. So it is not common knowledge and would be worthy of note.
Philip
From:
Birding-Aus [ On Behalf Of Mike
Fitzgerald
Sent: Tuesday, 9 June, 2020 3:11 PM
To:
Subject: [Birding-Aus] casting
We found on our property at Barkers
Vale NSW what appeared to be a raptor casting. On examination of contents it
contained 100% echidna bits, all spines and one toe/claw. Having handled many
of these, it is a somewhat daunting prospect as a prey item for a raptor, but I
understand is recorded in Wedge Tailed Eagles. The only large raptors observed
on our place have been WTE and Sooty Owl. Haven't heard the Sooty lately but
have seen the wedgies overhead. Apologies if this is common knowledge or
unremarkable but it is another data point (!), but the thought of thought of
those sharp spines travelling in both directions through a predator is pretty
clever, if a tad uncomfortable.
Would love to hear if this is a
common thing and whether folks agree WTE most likely?
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