Yesterday down by the river Koda found a large cow elk carcass. I usually follow the dog when he’s intent on something as he invariably leads me to interesting stuff. And he kept his promise, for this was no ordinary carcass. This elk had a collar, a VHF tracking collar. I assumed, rightly so, that this was a collar left over from Arthur Middleton’s 3 year elk field study in my valley. Just last month I caught an elk on my trail camera by my house wearing a collar. I contacted Arthur because I was surprised there were still some elk with them. Apparently some of the collars employed for the study were designed to fall off; but others were going to stay with the elk for life.
I decided the best thing was not to touch the collar, but to contact the game warden. I knew they’d want the collar back, even if it no longer carried data or was active. The collars can be refurbished and save the WG&F around $600. But I wasn’t sure if they wanted to check the elk’s health out, with the collar on, before I removed it for them. Since the carcass was in a fairly easy access location, I did worry that someone would come bye and snatch the collar for themselves as a souvenir. When I spoke with the warden, he requested that I go back, obtain the collar, and save it for him.
I noticed that she only had one ivory. When she was collared back in around 2008, they took one of her ivories (her eye tooth) to determine her age. Judging by her teeth, she was an older cow, but once the warden retrieves the collar, they can match it up and determine her exact age at death. At long last, she’ll get that collar off. I did feel badly that she had to move around with that collar around her neck all these years.
Arthur Middleton’s study in my valley was commissioned to find out why this migratory elk herd has such a low cow/calf ratio. He spent three years of fieldwork, and several more writing his thesis. Since that time, Arthur was awarded a prize/grant to study the other 5 migratory elk herds in the Greater Yellowstone Ecosystem. You can read the controversial results of that study here on my blog, and here on the web.
One of the many interesting findings was the rate of vigilance displayed by elk relative to wolves. Before the study, everyone was postulating that wolves were responsible for the low calf ratios. The theory out there was that wolves were pushing the elk hard and therefore stressing them out. This additional stress led to less foraging, more vigilance, and just less calving success.
The results debunked this theory. First off, there was no more vigilance with the migratory herd than the non-migratory herd that was used for comparison in the study(where wolves are present although not as many; and they had normal cow/calf ratios). But more interesting was that elk did not show any signs of stress or movement until wolves were within 1 km, and these wolf/elk encounters occurred, on average, once every 9 days. These factors are important to what Arthur is now stirring up a storm of controversy with.
Just recently, Middleton had an op-ed in the New York Times. In it, he contends that his results, as well as other studies, challenge the straight forward idea of wolves and trophic cascades. In other words, that wolves herd the elk sufficiently to allow less browsing on aspens and willows, allowing them to regenerate. The idea of trophic cascades is no doubt true (apex predators affect whole ecosystems), but Arthur is saying ecosystems have a lot more complexity to them then the simple fix of restoring top predators.
One of the ideas rattling around these days in biology is the Landscape of Fear. I’m not a biologist, but the whole notion never sat right with me. Simply put, the theory maintains predators will change the behavior of their prey, through fear, in ways that affects the their movement throughout the landscape, changing their feeding patterns and thus the plant material. True, but maybe not the whole of it I think. Ecosystems are varied and complex. Arthur posted a photo of a wolf den with a herd of elk grazing nearby. We humans have certain notions of fear-consciousness, yet this might not at all be what’s driving all the movements of wildlife. As I said in that previous post, I still think nature has more to do with adaptation and awareness, than with so-called ‘fear’.
Recently I took a class with James Halfpenny in the Park. He was asked about the wolf-coyote relationship. It has been documented that wolves killed about 50% with the wolf reintroduction, but now their population seems to have recovered. Coyotes are using the ‘inbetweens’ of the wolf territories to move around. It didn’t take them long to work out, and remember instinctively, their age-old relationship with their big brothers and how to live with them (and take advantage of their kills).
And if wolves are herding elk from intensive aspen/willow foraging, I have to ask why the pack of six wolves in my valley was slacking on the job. When the snows got really deep, the elk settled in my front yard and forest, topping every single aspen and willow they could reach.
Filed under: Elk | Tagged: Arthur Middleton study, Collared elk, Elk, Greater yellowstone ecosystem, Lamar elk herd study, Rocky Mountain elk foundation, VHF collars, Wolf, wolf elk realtionship, Wolves |