Field Notes: Rain
~by Jim Eagleman
“Water that is condensed from the aqueous vapor in the atmosphere and falls to earth in droplets” is the definition of rain. Measured at 1/50 of an inch by scientists, you may have wondered what else raindrops (in massive quantities) can do beside water plants, wash out driveways, and raise humidity.
Recent deluges have made life more challenging in Brown County. Highway workers remove fallen trees. Culverts are cleaned and repaired, and loose gravel regraded. More rains have caused power outages. Creeks and lakes are at flood levels. Residents remark it is the wettest spring in several years. Annual rainfall in Brown County is 40.6”, accumulating from all kinds of precipitation: snow fall, mist, fog, drizzling rains, and severe storms. We have already passed that mark and we’ve only just reached the summer solstice.
My morning walk through our woods after an all night rain is refreshing and my senses are peaked. The air is clean and rich with aromas reminiscent of greenhouses and tilled garden soil. Swaying branches overhead cause water to fall like soft, pelting hail on leaves.
Still dripping from run-off with drops falling on my shoulders, leaf shapes help rid surface areas of excess water. “Drip tips” on the ends of most leaves, whether compound or simple, shed rain with air movements. Leaf stems act as pivot points, slightly allowing the broad leaf to turn. Some trees like our native Black Gum (Tupelo) and the domestic Rhododendron have thin, waxy coatings on their surfaces to prevent too much moisture on leaves. Falling through the leafy canopy, understory, and eventually to the ground, raindrops are absorbed below the surface by a thick mesh of criss-crossing root hairs from multiple trees. Last year’s leaf litter retains moisture and helps keep soils from drying out.
A spikey, wet grey squirrel, resembling a punk rocker, jumps from a branch overhead, sending more droplets down on me. It emerged from its overnight shelter, a pileated woodpecker hole near a broken limb. Other rodents, like chipmunks, deer mice, and white-footed mice use underground runways and dens to wait out the storm. Brush piles act as meeting places for other critters: songbirds, insects, and an occasional rabbit. A small garter snake remains still but flicks the air with its tongue, waiting for a sunny spot.
Another day of rain? I check a few weather apps on my phone that don’t always agree. An animal’s instinct is far better to learn tomorrow’s forecast. More advanced at sensing barometric changes than humans, birds anticipate a wet night ahead and feed longer than usual. A preen gland, located at the base of their tail, called a uropygial gland, helps to waterproof feathers. Watch most birds after a rain, poking at their tails. They smooth out and straighten wet feathers. But why is our bird bath an active place during rains? They fly in, dip their entire body in the water, splash about, then perch on the lip of the bath to shake off water. You may have seen this behavior in street puddles. It may be either a shower, or a bath, and I suspect it feels good. They are already wet— why not indulge?
Water levels in streams, ponds, and lakes are replenished after rains. Those water sources are traditional places for wildlife to drink. We mostly think birds and animals rely exclusively on these waterways, but water also collects in tree crevices, knotholes, and even in dished-out, dry leaves on the ground, giving birds particularly, also spiders, insects, and small mammals, a place to get water. These are breeding places for mosquitoes, so birds can get water and food by visiting there. Rock outcroppings, logs, and ditches also provide places for water to collect.
Some plants, because of where they live in dry, sunny places, have adapted their stems and leaves to collect rain. Cup-plant, an aster with a daisy-like flower head, also called Silphium, and native to the Mid-West, is perhaps more adapted to prairies than woodlands. It collects rain at the stem-leaf junction. We can find it here in Brown County. And a more exotic plant, the pineapple, a Bromeliad, has a unique surface on its leaves to allow it to collect water.
“Nature will provide” is a mantra expressed by poets, writers, and scientists. “Nothing is wasted” is another saying we apply to the natural world. Resourceful and adaptable, overcoming difficulties, and versatile, birds and animals respond to our changing weather patterns. Frequent Brown County rains, high water, and even extensive flooding are not exceptions.
Enjoy this lush, green and vibrant Brown County landscape. Oh, yeah—pack the umbrella!