The following was published in the Biddeford-Saco Journal Tribune Sunday edition, 5/10/2015.

Because I love science, and because I have kids, I watch a lot of nature films. My favorite bit of animal cinema involves day-old ducklings emerging from a hole in a tree trunk and plummeting 50 feet down to the leaf-strewn ground below. Their stubby wings flap in vain, but the baby wood ducks all survive. Ducklings bounce, it turns out. Their mother, who had been waiting (anxiously? nonchalantly? impatiently?) for them to emerge, guides them to a nearby lake. Their real lives begin.

A couple weeks ago, on the first warm morning of the year, my wife removed the training wheels from our seven-year-olds bicycle. I left for work, knowing that by the afternoon, our boy would either be serenely pedaling down the street, or he would never touch his bike again. His first taste of freedom was on his lips.

It made me think of the ducklings. The mother wood duck leaves the nest first, to show them how its done. She doesnt push them out; she waits far below, merely making encouraging peeps. Inevitably, her ducklings all jump. Their first flight is a leap of faith, as much for the mother as the babies. Has she made sure the landing zone is free of sharp rocks? That there are no salivating coyotes waiting below, jaws agape? How does she know theyre ready?

What makes a mother? Biology, but more. I asked my wife: whats the best part of being a mother? The continual ability to love our boys more and more over time, she replied. The delight she takes in watching and helping our children grow and learn and meet the world  that is the icing of motherhood on the cake of selflessness and anxiety beneath. Aged seven and four, our boys dont yet appreciate all that their mothers done for them. For Mothers Day, theyll make her a card and offer some terribly wrapped presents. To them its like a birthday party, sans candles.

Someday theyll understand. For the non-bacteria, non-fungi, non-plant kingdoms of the world, mothers are essential. If youre an animal with a backbone, or at least an exterior skeleton, you had a mother to whom you owe quite a bit. Economically, mothers provide incredibly valuable services to us, starting with bringing us into the world.

Arctic terns migrate from nearly pole to pole just to bear children. Two-hundred pound baby elephants walk within minutes of being born, but their mothers carry them for a record 22-month pregnancy. Whales are born swimming, though they need a lift to the surface to get their first gulps of air. One doesnt come between a lioness or a mama grizzly and her cubs. Some spiders watch over their eggs and then let their children devour them as a first meal in a final generous act. Thank you, mothers.

At the Wells Reserve at Laudholm last week, we hosted a conference on ecosystem services in the continuing quest to put monetary values on the things  like the air, water, food, shelter, etc.  that the earth provides to us for free. Ungrateful and analytical humans that we are, we are only beginning to truly determine just how valuable nature is to our survival.

I wonder how far we could get in our understanding of these ecosystem services if we started at the first relationship we all benefit from, the one with our mothers. It seems to me wed quickly come to the obvious conclusion: mother nature, mother earth, and mommy dearest  theyre simply priceless.

Nik Charov is president of Laudholm Trust, the nonprofit partner of the Wells National Estuarine Research Reserve in Wells, Maine. His Sunday column, Between Two Worlds, ventures forth from the intersection of art and science, past and future, mom and dad. More at wellsreserve.org/twoworlds.