Hi All, Those of you who are interested in learning about the range of items found in regurgitated gastric pellets of vertebrates may be interested in reading the following scientific paper (the full text can be downloaded):
A call to search for fossilised gastric pellets
https://www.researchgate.net/publication/241711693_A_call_to_search_for_fossilised_gastric_pellets There’s no specific mention of of echidna spines, but there are a range of interesting items. A key message from the author is that there is a lot more to be learnt about the subject, and we are encouraged to go looking for pellets and examine them. They are out there, it’s just a matter of finding them. Stephen Ambrose Ryde NSW From: Birding-Aus <> On Behalf Of Philip Veerman
Sent: 15 June 2020 10:27 PM
To:
Subject: Re: [Birding-Aus] casting 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 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! 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 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 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? <HR>
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