July 22, 2017
This morning, Madelyn and I laid out a transect at Schwabacher Landing, the fifth of our series on beaver ecology. We set up the line, prepared our sample bags, and started collecting data on a variety of riparian plants and wildflowers.
About half an hour into data collection, I heard a loud animal call beyond the forest line. We gathered our things (left the transect line in place) and prepared to head to the car – we didn’t want to be anywhere near a grizzly bear, which was in the area just a few days ago.
As we were picking up our things, a moose and her calf emerged from the trees and walked straight for us on the river bank. When they saw they had company, they shuffled up the river about 50 meters.
We hung back for a few minutes – the moose and her calf were now positioned on the trail between us and the car – and I took some pictures and video. They mostly navigated along the established park trail, rather than making their way through thick brush. On that note, it’s important to consider how our trails impact animal navigation as well. By creating a clear path, we’ve routed moose along the trail and along the river, possibly disrupting their natural movements.
Another example of this comes to mind. In Montana, a natural salt outcropping attracts mountain goats near Goat Lick Bridge. Before the bridge was installed, the goats had full range to cross at whatever points they so chose. But after the bridge was put in, the goats were funneled under the bridge (they can’t cross the road as easily), so the landscape underneath and near the bridge has accumulated the wear and tear of an entire population that would have otherwise been disbursed over a large area.
The moose seemed to be attracted to a willow bush on the river bank. They stood and fed on it for about ten minutes while I took notes and photos – I mean, might as well, right? They seemed to pull leaves off of the plant in a twisting and ripping motion. I’d assumed they ate similar to cows by slowly grinding their food to a pulp, but it looks like they’re a bit more selective with the particular plant material they ingest.
In contrast to other moose calves we’ve seen, this one was particularly attached to the mother. It kept attempting to eat off the teat, rather than the plant, but the mother would make a gentle noise at it and encourage plant feeding instead.
After she realized we didn’t have any intention of bothering her, the mother moose faced away from us and feasted while her baby stayed close behind.
After a quick snack, the pair cautiously crossed the Snake River and headed for the trees.
After I was relatively certain they’d moved along, I walked over to the plant they were feeding on and noticed that the stems were covered in sap-feeding ants.
The ants seemed to bunch up near leaf nodes as in the photo below.
The after effect of the moose feeding was a plant that was completely cleared of its highest reaching leaves. In this way, feeding moose “trim” the plants down to size, preventing them from outcompeting with their peers and maintaining a full-bodied plant, rather than a tall and scraggly one.
A closer look shows how the sap-feeding ants gravitated to the damaged area, probably to take advantage of the plant’s leakage.