Many animals store food in preparation for winter or just to be eaten later. Bears and wolves are among those that stash prey remains, with the intent of retrieving them later (if nobody steals them). Crows and ravens often store food items under grass clumps or rocks, to be collected again later. I sometimes stockpile a few things in my food cupboards because our grocery stores always seem to be “out” of at least one thing I want. And some herbivorous mammals and birds also store their harvests and do so in various ways.
Some herbivores spread out their harvested plant parts in small deposits; this is called scatter-hoarding. In the eastern forests, gray and fox squirrels bury nuts, one by one, in little nooks and holes scattered over their territories, and usually remember where they stashed them. Blue jays carry acorns from the parent trees and poke them under the soil and litter, to be retrieved later. Steller’s jay does the same with pine nuts. Scrub jays harvest pine nuts and other big seeds, scatter-hoarding them in little holes in the soil and litter.
These critters are good at remembering when they have stashed their booty, but even so, not all seeds are retrieved. This can achieve seed dispersal: Nuts and acorns that are not retrieved by a scatter-hoarder may germinate in the ground and colonize new places—a benefit to the parent plants. Chickadees and nuthatches often store seeds in bark crevices, to be eaten later; any forgotten seeds are unlikely to germinate and grow, so there is no benefit to the parent plants.
A collared pika at Hatchers Pass. (CC BY-SA 3.0 public domain photo)
Other plant-eaters store food underground in burrows and chambers. They build up notable collections of various plant parts to be used as food in tough seasons. We’ve all seen squirrels harvesting cones to store in underground rooms, which are usually damp, preventing the cones from opening and losing their seeds. When hungry, the squirrels bring up the cones and often eat the seeds right at the entrance of the burrow. They peel back the cone scales one by one, turning the cone rapidly, and munch on the seeds. The lunch area becomes a midden of discarded cone scales.
Other rodents store seeds in underground rooms too, including some ground squirrels, voles and lemmings. Tundra voles store roots and tubers (especially sweet vetch, Hedysarum) and Townsend’s vole does so with wild mint (Mentha canadensis), for example. Beavers are well-known to harvest fresh twigs and branches, especially of deciduous trees and shrubs, and store them in a cache under the ice near the winter lodge (we commonly see some of the twigs sticking up above the ice). Adults chop off nice tender twigs and bring them into the lodge for the young ones.
It’s one thing to store the hard parts of plants but quite another thing to store herbaceous vegetation. However, some herbivores make hay, so to speak, storing greenery to dry for safekeeping. Pikas are small relatives of hares and rabbits. They are the best known haymakers, making hay piles among the rocks in alpine areas, sometimes gathering many kilos of grasses and herbs for this purpose and defending their stores from other pikas.
Some rodents store hay too. The singing vole (Microtus miurus) lives in Alaska and western Yukon. These voles build networks of underground tunnels and chambers with very narrow passages between them. Singing voles generally weigh less than about two ounces, smaller than most predators that might pursue them through the tunnels. Those narrow passages may deter at least the larger weasels. In addition to storing tubers and roots in those chambers, they also store “hay” in above-ground places. They pile up green herbaceous vegetation on rocks, exposed roots, and low-lying branches of shrubs to facilitate drying; sometimes the piles are over a foot tall. Grasses are reported to be favored for this purpose, but horsetails and some herbs may be included.
The wood lemming (Myopus schisticolor) may store some grasses and sedges but, most unusually, it stores lots of moss. It lives in the boreal forests of Eurasia, where its main diet is moss. Its favorite mosses are said to be species of Dicranum and Polytrichum, with some others included at times. In one report, these species were not the most common ones in the nearby area, but they are the ones with the most nitrogen and carbon content.
What about birds? There are lots of birds that gather grasses and such for nests and some (e.g. grouse) that actually nibble on leaves. But I’ve not found any that make hay for the winter. Herbivorous birds don’t usually store food in bulk (they don’t generally live in burrows with underground chambers where bulk storage is easy). However, acorn woodpeckers of Central America and southwestern U. S. make sizeable caches. They store acorns in natural crevices but also create “granaries” in dead trees, where they dig hundreds of small holes into which they fit acorns for storage. Granaries are maintained regularly; as the acorns dry and shrink, they are moved to smaller holes. The woodpeckers live in family groups and defend their granaries from would-be thieves such as jays.
• Mary F. Willson is a retired professor of ecology. “On The Trails” appears every Wednesday in the Juneau Empire.
