Carrion feeders - gruesome!! (1 Viewer)

[matt green]

Hi all

Just wondering if anyone has an insight into why birds (mostly corvids) take the eyes from roadkill rabbits and hares etc, are the birds making specific use of the eyeballs nutritional value (if any) or just taking easy pickings.

I'm assuming that even for a large corvid breaking the skin and entering into the body for soft manageable entrails (sorry, didn't know how else to put it!)
is quite a difficult and time consuming task? so the eyes would make an easy meal!

Matt

 

[Sancho]

Hi all

Just wondering if anyone has an insight into why birds (mostly corvids) take the eyes from roadkill rabbits and hares etc, are the birds making specific use of the eyeballs nutritional value (if any) or just taking easy pickings.

I'm assuming that even for a large corvid breaking the skin and entering into the body for soft manageable entrails (sorry, didn't know how else to put it!)
is quite a difficult and time consuming task? so the eyes would make an easy meal!

Matt

No idea, but in China when a fish is served for guests, steamed with head and all, the eyeballs are considered a delicacy and offered to the guest of honour. At least in my in-laws house. (Only now do I begin to wonder about that..... )

 

[rosbifs]

Crows also take the eyes from newly born lambs!
Lots of nutrition and a quick snack I guess.........
As for road kill unless something is splattered the easiest area for access is the rear - it's how vultures do it - and partly why they have long necks I guess

 

[deborah4]

I think the eyes also provide moisture for corvids.

As far as 'new kills' every predator (avian or mammalian) has a 'signature' so it can be useful for wildlife investigators in indentifying the cause of kill (if indeed it was predation) and responding to it if necessary - eg. Golden Eagles enter carcass through ribs and remove the heart and other entrails, leaving a 'hole' in the side of the carcass - presumably because, as you say Matt, the organs provide the most nutrition - before attacking the rest of the carcass (invariably the animal has died from a fall or natural causes first).

 

[matt green]

Thanks for the replies, Rosbifs and Deborah

Most interesting, I was interested because I hardly ever see dead rabbits etc(and I've seen a few!) where their eyes have not been taken.

Corvids naturally being opportunists want an easy and quick meal, I quess it's a mixture of learned / inherent behaviour with each species, as deborah says.

Matt

 

[pe'rigin]

This is the great thing about these forums, as it debates topics, which you never really consider.

As Deborah states the Birds of Prey tend to go through the chest cavity to get at the heart and liver.

I have photos of Peregrine kills remains with and without the head, on the ones with the removed head, the eyes are still there. Now, you would think that the skull would contain a tasty morsel, brains and eyes but they’re left alone.

 

[joannec]

I have photos of Peregrine kills remains with and without the head, on the ones with the removed head, the eyes are still there. Now, you would think that the skull would contain a tasty morsel, brains and eyes but they’re left alone.

I found just the head of a blackbird the other, eyes were still in place and it looked fresh. I assumed it was the work of a sparrowhawk.

 

[pe'rigin]

Joanne,

More than likely, cats will do the same.

Just to broaden the debate, I’ve yet to find the head of a Sparrowhawk kill.

I get a female regularly chomping through my birds in the garden; I can’t find the heads remains at all. No doubt they have been removed at some stage somewhere.

I can’t think that she eats it?

The other thing that always fascinates me, Peregrines usually leave the feet and legs, my female Sparrowhawk eats the lot.

 

[joannec]

Joanne,

More than likely, cats will do the same.

Just to broaden the debate, I’ve yet to find the head of a Sparrowhawk kill.

I get a female regularly chomping through my birds in the garden; I can’t find the heads remains at all. No doubt they have been removed at some stage somewhere.

I can’t think that she eats it?

The other thing that always fascinates me, Peregrines usually leave the feet and legs, my female Sparrowhawk eats the lot.

I should have said it was in a rural area, just on the edge of a field and wood, well away from any buildings or cats. Don't think it was a cat kill but I'm now wondering what it was.

 

[saluki]

Joanne,

More than likely, cats will do the same.

Just to broaden the debate, I’ve yet to find the head of a Sparrowhawk kill.

I get a female regularly chomping through my birds in the garden; I can’t find the heads remains at all. No doubt they have been removed at some stage somewhere.

I can’t think that she eats it?

Hi pe'rigin,

In my experience spars will often eat heads, breaking through skulls, pulling at bones, etc helps keep the beak short. How a raptor eats prey probably depends on how hungry it is and whether the bird is in a vunerable position. They'll often carry prey to a secluded spot but it can be difficult with larger prey once the bird's grounded. A hungry or vunerable bird might break into the body cavity first and remove organs simply because it's fast and easy, whereas a less hungry bird, or one in a safe place, may leave some organs completely, flicking them away with it's beak and spend more time plucking it's prey.

Jonathan

 

[deborah4]

More than likely, cats will do the same.

agree - just because 'kill' is in a rural/countryside area, cat kill can't be ruled out - seen them on nature reserves, and in the middle of 'nowhere', on alotments, stalking and killing birds - these are just as likely domestic as feral ones - they don't confine their hunting to our back gardens contrary to what some people might think! I would have thought too, cats are more likely to leave the kill remains, than a BoP unless it's been disturbed (which perhaps is less likely the more rural the location?)

 

[Pluvius]

I watched a hooded crow attack a lapwing which was very much alive but unable to fly. It persistently went for the eyes and when the lapwing died it continued to peck out the brains. It is an easy route into the head and brains so my reasoning is that they are after whats behind the eyes as much as the eyes themselves. My mother is a sheepfarmer and would concur with me in that lambs that are predated by hoodies are again attacked through the eyes and on into the brain.

 

[ayasuda]

I know this is gruesome but, I believe the brains and eyeballs of animals do contain more calories than flesh. Bears will eat the heads of salmons and discard the rest if fishing is plentiful.
I've noticed that birds of prey will blind its victim when attacking, and often consume or distroy the eyes first. To eat the head is to gain more concentrated amount of calories than eating other body parts. If there is a chance that your food source is going to robbed from you, eating the areas that contain the most calories is to the birds advantage.

 

[pete woodall]

Just to add a contrary note here. I don't think that the eyeballs do contain many calories, and certainly not digestible calories. The main part of the eyeball is fluid (the aqueous and viscous humor) with some limited protein. The remaining parts of the eyeball would have protein (e.g. the small eye muscles) but not particularly high in calories.
The brain, in contrast would be very high in fats and protein and be readily digestible. So, I think that it is most likely that going for the eyes is to gain access to the brain.

 

[pe'rigin]

Morning Jonathan, Deborah and Craig,

Thanks for the replies, interesting stuff.

I'll catch my female one-day in the dastardly moment.

I know it’s a gruesome topic, but its questions like this, which don’t really get answered in books. You learn more from other people’s observations.

I wonder if any one has information on the larger birds of prey, such as Golden Eagles, do they remove the head or consume it? With a rabbits skull, I would still think that there would be still a fair amount of meat still inside.

 

[saluki]

Morning Jonathan, Deborah and Craig,

Thanks for the replies, interesting stuff.

I'll catch my female one-day in the dastardly moment.

I know it’s a gruesome topic, but its questions like this, which don’t really get answered in books. You learn more from other people’s observations.

I wonder if any one has information on the larger birds of prey, such as Golden Eagles, do they remove the head or consume it? With a rabbits skull, I would still think that there would be still a fair amount of meat still inside.

Hi pe'rigin,

Falconers regularly feed rabbit heads to raptors. It helps to naturally 'cope' their beak and keeps them occupied for much longer than, say, a lump of pheasant breast would - I doubt it's much different with wild birds. It's surprising what large bones a peregrine, for instance, can break up or swallow whole.

Jonathan

 

[pe'rigin]

Jonathan,

Thank you,

What do you mean by 'cope', sharpening?

I will now have to dig out tonight all the photos of Peregrine kills, but I think your right, from memory there is hardly any front bone, ribs left at all, just the spinal chord.

P

 

[saluki]

Jonathan,

Thank you,

What do you mean by 'cope', sharpening?

Hi pe'rigin,

Not so much sharpening, more wearing down. A hawk's beak is slowly but continually growing, in the wild the bill is kept short because the hawk eats full carcasses and pulling at bones helps to keep the bill in shape. The other way it does this is known as 'feeking' in falconry parlance, you'll have probably seen this yourself - it's when a hawk wipes its beak between it's feet on whatever it's perched on (a branch or a rock for instance).

Jonathan

 

[RobF]

I never knew that about raptor beaks. You learn summat everyday.

Corbies are public enemy number one up here amongst the shepherds (foxes are tolerated because of the hunt), they really do make a mess. I told a shepherd about a riggwelted ewe I'd righted and he went straight to her only to find both eyes had been taken out by crows in a matter of 5 minutes.

Badgers too, ain't popular as they have the habit of chewing off the udders of ewes that are rigged or have hung lambs. They don't only eat worms and beetles.

Rob