Naturalist's Notebook

Buffleheads and Flickers

All this rain has flooded the nearby pastures. You know your pond has just about become a lake when the regular dabblers like mallards and wigeons are joined by diving ducks. Today I’ve found a pair of buffleheads swimming along a mostly submerged barbed wire fence.

Always entertaining and energetic, buffleheads are one of our smallest ducks. They are here in winter. The females are slate gray with white ovals on their heads. The males remind me of the Nike basketball shoes I used to wear, gleaming white on black.

Along the edge of the flooded field, two birds spook from the ground with a flash of white butt patches. They land upright on the trunk of a dead fir. Their big bills swing as they look back to admonish me. Black spots cover their breasts.

These are northern flickers, the only local woodpecker you will find pecking the ground. Flickers eat ants. Often this means they are high in snags searching for carpenter ants, but just as often they will walk awkwardly through grass and probe the ground. I wonder if the heavy rain has concentrated ants in this place, perhaps even flooded them from their homes.

Research has shown that flickers can read the weather to anticipate where ants will be most active. For example, below 75 degrees ants in open habitats tend to be more active than ants in the forest. Above 75 degrees it is the opposite. Indeed, on a recent warm-for-January day, a fence line thatch ant nest was crawling with ants while a massive one back in the woods remained in its winter dormancy. Foraging animals go where prey is most abundant and safe. Following flickers would be a good way to learn ant behavior.

Which makes me wonder, why are the buffleheads here? They eat snails and aquatic insects and, in saltwater, loads of crabs. Did they merely come to relax or has this pasture somehow held snails or aquatic insects in reserve, waiting for a flood to offer them life? That’s the kind of question I like: one best answered in waders.

Far to the north, in summertime Canada and Alaska, buffleheads and flickers have a connection. Buffleheads use old flicker nests, which are holes in trees, for their own nests. A flicker’s nest hole is just small enough that larger ducks cannot get in to harass the buffleheads.

Rain, Slugs and the Bird’s Nest Fungus

I’m out in a pasture gathering branches that have been blown out of firs when I see a half-buried stick adorned with white growths that look like molds for casting pearls.

Hello to the bird’s nest fungus. They are tiny, scurfy things. They grow on wood and dung. The smooth interiors of their cups hold “eggs,” each of which contains a mass of spores. The nests I have found are half full of rainwater and empty of eggs — except for one, I notice, which is tucked off to one side. The tiny eggs look like misshapen jelly beans covered in brown goo.

The stick is not big. It will be gone in another year or two, rotted by bacteria and fungi. And there are no bird’s nest fungi up in living trees. So how do they get to these fleeting homes? How did the egg that birthed these nests travel through dense tangles of pasture grass, where it cannot grow, to arrive at this fallen stick?

Enter the slug. The spores of bird’s nest fungi pass unharmed through the digestive tract of slugs (and that of insects as well). I cannot find any studies on the speed of slug digestion, but it is slow enough that, even at the pace of slug travel, the spores make it a good long way by the time they are pooped out again.

So, you might think the slugs raid the nests to eat the spore eggs, but apparently that would be far too simple. In fact, the eggs are usually eaten off surrounding vegetation, up to several feet from the nests. How they get there explains another old name for bird’s nest fungi: splash cups.

When a raindrop hits the lip of a nest, its energy boomerangs around the curved bottom of the cup and flings the eggs into the air. (A raindrop hitting the center of the nest does not disturb the eggs.) The eggs fly off at up to 10 mph. In some species they reach heights proportionate to a human throwing a discus a mile into the air.

And then they must stick to whatever they hit, lest they drop into the dirt below. In species like the one I have found, the eggs are coated in a sticky goo. In other species, the egg is not sticky but attached to a sticky thread coiled in a tiny purse. When the egg hits a blade of grass, the thread gloms on and, like the rope of a tetherball, swings the egg back to rest.

As long as I’m walking backward through the chain of these fungi’s reproductive events, let’s follow the raindrop upward from its splashdown. For a naturalist like me, acting like a tracker who follows a coyote’s prints back to its den can bring to light otherwise hidden connections in the flows of life and energy. A raindrop falls at 20 mph. If it is large, it has the power to dislodge far more than just spore eggs, which need less than 2% of a raindrop’s energy to fly. Conservation districts warn against leaving your soil bare because raindrops can literally splash away soil that has taken a thousand years to accumulate.

And from whence did the raindrop come? The energy it holds is not magically created high above. Like the spore eggs it is carried there by a larger force, in this case global weather patterns of evaporation driven by the sun itself. Energy flows in circles — sometimes at the speed of a splash; sometimes at the speed of a slug.