There really are coincidences that have nothing to do with the overreach of internet companies who see what you are reading in one place and put something in front of you instantly, and for a long time following, based on that first subject. In this case, I was reading about the endless quest for a better mousetrap, and then came upon this fascinating article about the ecosystem services that mice convey. This was as smile-inducing a juxtaposition as my reading has provided me lately. I hope I am correct that this pure chance and not some creepy algorithm, which would wilt my grin:

A deer mouse, temporarily captured for a behavioral test before being rereleased to the grounds of a study site at the University of Maine in late October.

Meet the Mice Who Make the Forest

Scientists are unearthing a quiet truth about the woods: Where trees grow, or don’t, depends in part on the quirky decisions of small mammals.

It’s easy to look at a forest and think it’s inevitable: that the trees came into being through a stately procession of seasons and seeds and soil, and will replenish themselves so long as environmental conditions allow.

Hidden from sight are the creatures whose labor makes the forest possible — the multitudes of microorganisms and invertebrates involved in maintaining that soil, and the animals responsible for delivering seeds too heavy to be wind-borne to the places where they will sprout.

If one is interested in the future of a forest — which tree species will thrive and which will diminish, or whether those threatened by a fast-changing climate will successfully migrate to newly hospitable lands — one should look to these seed-dispersing animals.

“All the oaks that are trying to move up north are trying to track the habitable range,” said Ivy Yen, a biologist at the University of Maine who could be found late one recent afternoon at the Penobscot Experimental Forest in nearby Milford, arranging acorns on a tray for mice and voles to find

“The only way they’re going to move with the shifting temperatures is with the animals,” Ms. Yen said of the trees. “Will personality affect that? Will there be individuals who are more likely to help?”

Ms. Yen is a doctoral student in the lab of Alessio Mortelliti, a wildlife ecologist who arrived in Maine nearly a decade ago with a peculiar interest: how seed dispersal intersected with the emerging study of animal personality.

Although researchers already studied the ways that animals move seeds across landscapes, the possible role of their personalities had gone largely unexamined. The Penobscot Experimental Forest, with its 1,800 acres of closely monitored woodlands managed according to various forestry techniques, offered a landscape-scale setting to explore this question.

Each summer for the past seven years, Dr. Mortelliti’s students have trapped deer mice and southern red-backed voles in their study plots — about 2,000 animals in all — and run them through tests that measure where they fall on a spectrum between bold and shy. Before being released, each is tagged with a microchip, not unlike those used to identify lost pets…