Renfro explains, “and not every tree species or plant species does it, but a lot of them, such as the sourwood, sassafras, Florida dogwood and black gum will start changing their color when their fruit is ripe, and it’s an indicator for migrating birds to come. As if to say, hey, I’m ready for you to disperse my seed different places.” The mechanism is plainer than it sounds. A plant’s fruit ripens. The seed needs to move away from the parent plant and birds can do that simply by eating the fruit and continuing on. The trouble is visibility. Virginia creeper berries are nearly black. So are sassafras. Against a summer forest they can disappear. The dark berry needs a billboard. The audience is not local. Many of the birds responding to these signals in the fall are on their way to Central America, and they need concentrated fuel along the way. “Those berries are super high in things like lipids and fats, and they help fuel that migration” “There’s an ecological process referred to as flagging”
In an analysis of fall fruits, the Center for Conservation Biology found sassafras the most energy-dense of the lot, averaging more than sixty percent fat. “ A sassafras standing on a ridge above Highlands is helping pay for a flight to Central America. It will not see the bird again, nor does it need to. Flagging can turn one tree early. But not every early color is a signal.
FALL 2026
32
Made with FlippingBook - professional solution for displaying marketing and sales documents online