I have seen park and farm red deer chewing rabbit carcasses on several occasions.
I have seen hinds kill adult grass snakes on two occasions, both times they were killed by a single hind who stamped on them repeatedly then picked them up in her mouth and tossed them around a couple of times. Both times the rest of the mob in that particular paddock became quite agitated at this behaviour.
I have also found dead, stomped hedgehogs a few times in red deer sheds but never personally witnessed one being killed.
I expect most experienced park or farm deer keepers will have seen similar things. I don't think the behaviour is peculiar to captive deer its just that we have a better chance of observing it.
I have heard reports of deer chewing on carcasses of rabbits and have always attributed these to interesting gut smells from the fermented stomach contents, or mineral deficiencies that the deer tries to compensate by chewing bones. But to see it actually eat a live bird is very unusual I would say. and the video does not seem like an obvious fake. anyone else has any experience with this?
Not that unusual. There are a number of ungulates that take to eating meat occasionally. Some species of Duiker do this, particularly in rain forest environments where there is a lack of salt and minerals in their diet.
Never seen it in deer, but I've seen sheep eating roadkill on moorland roads several times Often in "batches" in a certain area, which lends itself to the diet deficiency theory if grazing is poor for whatever reason in thay location...
Deer, like all ruminants need protein. The bugs in the ruminant are feeding off the carbohydrates and cellulose in the plant material and a nitrogen source and this usually comes from proteins. You can keep ruminants reasonably healthy on ammonia treated straw, or even ammonia treated newspaper - so long as there is of 15% nitrogen to carbon (carbohydrate or cellulose) the animals will do reasonably well.
In the spring time there is plenty of protein in young leaves of grass and bushes, but in the depths of winter all you are left with is cellulose type material ( dried dead grass), and low quality green stuff. Add a bit of protein and this can actually a good maintenance diet, hence munching a dead animal, or seeds and nuts, fungi, lichens etc - all of which are high in nitrogen.
Same happens in the tropics where in the midst of the dry season high nitrogen seed pods, such as acacia are incredibly important in allowing animals to survive. Take away the acacia trees, and whole bush becomes unproductive.
Deer are ruminants they "ferment" in the rumen not the gut. Protein can come in a few different forms.
Animal protein ( that from other animals) can "trick" the oesophagus groove to bypass the rumen & go straight to the gut like an omnivore. This is a hang over from being milk fed (mammal), as the last thing a young ruminant needs is for the precious milk to enter the rumen & be consumed by the bacteria instead of going to the true stomach.
This whole idea of protein opens up a really interesting aspect about the role of ruminants & the production of animal proteins & then the invaluable role of non protein nitrogens in ruminant production. However, I believe it will be lost on the majority of hunters & raise further confusion. Lets just say its normal for deer to consume "novel" sources of protein, be it true protein, animal protein or non protein nitrogen. It's all about energy & minerals & how the level of protein is effected by rumen activity if it doesn't by pass.
Happy to discuss this further, as understanding the rumen process & non protein nitrogen is the only war we can survive droughts down here.
Red deer were witnessed eating shearwater chicks as they emerged from burrows on Rum and I have seen them eating frogs/toads in the hill. They also ingest bone and antler, sometimes to their detriment as the bones can get trapped across the jaws, especially shin bones which sharpen to a double point on each end.