Here’s another repost from my old tumblr blog norfolknaturalist.tumblr.com. I’ve added some newer photos of the species involved but otherwise unchanged. Much of this article was inspired by my reading of the book Life Everlasting: The Animal Way of Death, by Bernd Heinrich. I thought the subject and title were appropriate for Halloween season.
Just as we were about to turn into my parents’ driveway last weekend (in April 2018), we saw probably the most iconic bird in North America less than 100 metres away from us down the road. A Bald Eagle (Haliaeetus leucocephalus) was dining on a Raccoon roadkill in clear sight.
Perhaps it’s surprising that a bird of such noble renown was seen stooping to consuming carrion, something that we often see as repulsive. The truth is that the line between ‘predator’ and ‘scavenger’ is often a very blurred one. Most animals that eat other animals are willing to eat one that has already died or been killed. To the predator, it contains the same nutrients that it would obtain from its own kill but with much less effort (valuable time and energy) on their part. This isn’t to say that eating pre-killed remains is without risk for a predator or a scavenger. Besides the conflicts with other hunters over the resource, there is an omnipresent and invisible threat to all dead flesh.
Bacteria: organisms that are so tiny they are dwarfed by individual cells of our bodies. Despite being so small, and unseen without a powerful microscope, bacteria operate everywhere in the natural world and one of the most profound activities they perform is nutrient recycling and breakdown. While they disassemble cells and consume dead flesh, bacteria proliferate. Bacteria are the reason that predators can’t eat an animal body that’s been dead for too long. They are the reason dead things go “rotten” and become unpalatable by almost any animals. They are the unseen “competitor” with the visible and charismatic predators.
After at least an hour of feeding, and the frequent interruptions of cars passing, the eagle flew off and left the dead Raccoon. That is when the Turkey Vultures (Cathartes aura) moved in, creatures much more commonly associated with scavenging. And for good reason. Turkey Vultures have the most powerful sense of smell of any bird, and can detect a dead animal from over a mile away. What’s more, they can eat flesh that other creatures would turn down as too far gone. Their digestive system is able to break down the toxins of the ever-present bacteria, making them capable of consuming rotten flesh, where others cannot.
It may be a grisly business, the consumption of the dead, but it is an essential (and amazing) part of ecosystems around the world.