other, seeking prime spots on the mud drying around puddles left from
recent thunderstorms. The three kinds of butterflies were oddly
familiar: large white ones with delicate black traceries on the wings
(like the pine whites in our own mountains), small blues and
medium-sized orange skippers.
Were they drinking? Well, not exactly.
In a nearby hamlet, a farmer was watering a vegetable garden by
flooding the furrows between the raised rows of vegetables with canal
water. Where were the butterflies? Not near the water in the furrows,
but on the drying tips of soil clods. Water rising through the soil
dissolves minerals, transports them to the surface, then deposits
them as a thin crust when it evaporates. The crust is a mixture of
minerals: salts of sodium (table salt), calcium, potassium,
bicarbonate of soda, plus whatever else is in the water.
What we saw was the male butterfly behavior known as "puddling,"
but despite the name, the butterflies were after minerals, not water.
It's more photogenic when they're are clustered around fresh water,
but they also do it around puddles of large animal droppings and
urine. Butterflies drink nectar, which is mostly sugar and water, and
it is short of minerals and other nutrients. So they go after these
wherever they can.
Minerals are a necessity, not a luxury, and the butterflies brave
danger to get them. For animals with large, fragile wings, standing
water is a hazard; there were drowned butterflies at the puddles and
in the garden. A newer hazard was the occasional car, coming too fast
for all the butterflies to avoid. Bicyclists did somewhat better, and
hikers passed without being an additional problem.
It's not just butterflies; other animals have the same nutrient
problem. Elephants make long treks to natural salt licks, places
where salt and other minerals have been concentrated naturally.
Farmers put out large blocks of salt for cows and other grazers.
Unscrupulous or lazy hunters use salt licks to concentrate game
animals like deer or moose in a known area. Smaller animals like
squirrels and mice can't make long trips for needed nutrients, so
they forage for minerals wherever they can. A good source is bone; on
the forest floor in the eastern Sierra, skeletons don't last long.
That's why every piece of bone has been gnawed by tiny sharp teeth.
Besides the beauty, my enjoyment comes from an "aha!" moment after
some careful observation. Do you need to know which species you're
watching to understand it? Names help if you want to find out more
about the animal later on, but they're not crucial. Take a quiet walk
this weekend in Laguna's back country and make your own discovery!