Mast of all kinds is a critical wildlife food


Last week a caller to my radio show asked that I explain the word “mast.” “I’ve often heard you use the term, but I’m not sure exactly what it means,” she said. It’s a great question, especially at this time of year.


Fruits and nuts of trees and shrubs are collectively referred to as “mast.” Fleshy fruits and berries are “soft mast;” nuts are “hard mast.”

Crabapples, grapes, cherries, and even poison ivy berries are sought by a variety of birds including turkeys, grouse, and woodpeckers. Sweet, fleshy persimmons began ripening several weeks ago. Birds take those that ripen on the tree while coyotes, foxes, raccoons, skunks, and opossums gobble up those that fall to the ground. The flat football-shaped seeds that pass through these mammals’ guts are recognizable in their scats.

Soft mast usually disappears quickly in the fall. One day a tree hangs heavy with berries, and the next fruits are gone. Or at least it seems that way. Sometimes it just means a flock of cedar waxwings or some other fruit loving birds stopped by for a few days.


When fruits go undetected for weeks or months, sugars can convert into alcohol, and hungry birds can get drunk. Often it’s been late winter when I’ve seen cedar waxwings stumbling around or even passed out on the ground. At that point opportunistic predators are certain to find and eat the impaired individuals. If I find them first, I collect them and place them in a paper bag for a few hours, let them sleep it off, and then release them.


Hard mast — acorns, walnuts, hickory nuts, and beechnuts – triggers a competitive fall feeding frenzy among squirrels, chipmunks, deer, bears, turkeys, mice, jays, woodpeckers, and nuthatches. During bumper crop years my wife and I sometimes join the competition. Timing is critical. We’ve got to get to the nuts before the critters do.

Important mast

Acorns, the fruits of oak trees, are the most important form of mast in the eastern deciduous forest. Where oaks are common, wildlife usually thrives.


It’s difficult to visit a woodlot in October and not notice a squirrel enjoying an acorn. When not eating, squirrels busy themselves gathering nuts for the winter. They bury them just an inch or two below the leaf litter. Months later, guided by smell and memory, they relocate many, but not all, of their hidden treasures. Birds such as jays and nuthatches that store nuts for winter use usually rely on memory and visual cues to relocate hidden food. Forgotten nuts give rise to a new generation of trees.

Tough shells

The shells of walnuts and hickory nuts are extremely hard and more difficult to crack than acorns. Squirrels and other rodents gnaw through the tough shells. Bears simply crush them with their powerful jaws. Even nuthatches and woodpeckers can find the weakest seam on a nut and hammer it open. Other birds swallow nuts whole and rely on their muscular stomach — the gizzard — to grind up the shells. A turkey, for example, can grind several walnuts in just four hours.

Attractive bird feeders

To make my bird feeders more attractive, I collect and crack the harder nuts before putting them on a tray. This allows smaller birds such as chickadees and titmice to eat these high energy foods and saves larger birds the work required to open intact nuts.

Nut meats

After watching birds flock to a tray of nut meats, it’s easy to understand why some bird food manufacturers add nuts to their better, more expensive mixes.

Black walnuts

This year we’ve had an impressive crop of black walnuts here on the ridge. For weeks my wife and I have been collecting walnuts from the perimeter of the yard. We place them in the driveway and drive over them with the car to remove the husks. If you try this, wear gloves to collect crushed walnuts. Pigments in the husks can stain your skin for days.

Not surprisingly, our driveway has become a favorite destination for gray and fox squirrels. Of course we keep plenty for ourselves, and on cold winter nights we’ll crack the nuts on the butcher block and save the meats for snacking and baking.


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Scott Shalaway, who holds a Ph.D. in wildlife ecology from Michigan State University, writes from his home in rural West Virginia. A former faculty member at Oklahoma State University and the University of Oklahoma Biological Station, he has been writing a weekly nature column for newspapers and freelancing for magazines since 1986. He can be heard on Birds & Nature from 3-4 p.m. Sunday afternoons on 620 KHB Radio, Pittsburgh, or live online anywhere at, or on the Tune-In radio app. Visit his website at or contact him directly at or 2222 Fish Ridge Road, Cameron, WV 26033.



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