Editor’s Note: Marjorie S. Rosenthal is an associate professor of pediatrics at the Yale University School of Medicine. She was a 2015-2016 public voices fellow with the Op-Ed Project. The views expressed in this commentary are her own. Read more opinion on CNN.

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This past spring, my daughters and I noticed a bird’s nest in our backyard, less than a foot from the kitchen window. The nest was cradled where the branches of our birch tree and our Rose of Sharon had overgrown into each other. For years, my mother had suggested that I should trim both sets of branches. And—like so many great ideas—it was one of those tasks on the to-do list that I didn’t get done.

Marjorie Rosenthal

I have tons of excuses. I’m a single mother of two teenage girls and I have chemo every other week for my colon cancer. But on my good weeks I manage to work (I’m a pediatrician), travel (Haiti, India, and France this year), and tend to our vegetable garden.

Which makes me wonder if my excuses for not cutting back the trees have more to do with how the thriving trees make me feel. The leafy tangle of branches provide shade in the kitchen on hot summer mornings. And, like flower boxes just outside my kitchen window, the Rose of Sharon presents tightly coiled lavender buds that burst into rings of soft, bright petals. When I feel bad about my motherhood blunders, I look to my backyard for reassurance that there are some living things I nurture seamlessly.

In early summer, when I walked under the trees to water the vegetable garden, or stayed inside to wash dishes, a bird – blue-gray feathers and a tan-colored beak—squawked at me from the nest. I tried to move slowly and quietly. I drank my coffee in the kitchen while she regurgitated into the nest.

One morning, in the middle of the summer, I noticed the mother was gone. That afternoon, I saw a bunch of wet feathers, a tiny beak and a shiny, black eyeball in the middle. The baby bird – with the same blue-gray feathers as her mother – was looking right at me. She was inches from the kitchen window. Almost in our home. She didn’t squawk.

Being a pediatrician, I did what I always do when observing a newborn. I counted her respiratory rate. It was about 80 times per minute.

About twice as fast as newborn Maya’s was when my obstetrician first handed her to me 18 years ago – when Maya’s dad was still alive, and I didn’t have cancer.

Even back then, I cried at moments of separation from her. When Maya was born I cried. When her dad and I moved her bassinet out of our bedroom I cried. I cried on the night before her first day of day care and the first time she looked away while she was breastfeeding.

Each time, my sadness felt normal and expected. Her separation was part of typical development and what I had hoped for.

When I became a widow and then a widow with cancer, each separation from Maya was shrouded by my fears. What part of her experience was altered by our family tragedies? What if she couldn’t take the next developmental step because of our difficulty and grief? And then, of course, what if I wasn’t going to be here for her next step?

When Maya skipped off with her new kindergarten teacher. When she ran up the stairs for a play date at a friend’s house. When she texted me she made it onto the bus on the first day of high school. Each time I worried about how her dad’s death or my cancer shaped these events. And then I felt guilty for worrying at joyful moments and I wondered if the depth of my feelings was unique to me.

When I found myself late to Maya’s high school graduation, outside on the sidewalk while the senior class started processing onto the football field, the man ushering me inside saw my tears.

“It’s OK mama, you made it,” he said. He didn’t know me, so I’m sure this is not what he meant, but what I heard in his words was that I had survived my cancer long enough to make it to graduation.

Sitting on the bleachers that afternoon I felt the ways in which our family of three was not unique. We were like all the other families at graduation, filled with the complicated feelings of pride and separating from our children, of closing a chapter that we can’t reread. I was in a place where widowhood and cancer didn’t define our family. Maya’s graduation did.

On a Saturday this summer, when I was in and out of the kitchen, the baby bird spent the day doing laps around the edge of the nest, looking up at the other birds in the backyard and then settling back down in the nest. She seemed to be wondering if flying was a thing she should do.

I was fascinated. All day Saturday I kept making excuses to myself to go into the kitchen. Sometimes the baby bird would poke under her wings with her beak. Maybe she was getting rid of a bug, I thought. Or maybe, she was pretending to get rid of a bug, so she could stop thinking about whether she should try flying. Or maybe, I thought, I should stop projecting my human anxieties on this hollow-boned being.

On the morning I dropped Maya off at college orientation, she comfortably joined her peers and left me standing at the check-in desk. I wasn’t ready to leave campus, so I went to the bookstore. I meandered around, trying to imagine Maya buying notebooks and pens and textbooks. I chose a shirt from the sale rack and on the way to the cashier, picked up a stuffed animal, the school’s furry mascot. I figured I’d put it on Maya’s pillow as a gift.

As I drove home from the bookstore with the stuffed animal in the passenger seat, it hit me. The stuffed animal was my transitional object, not Maya’s. An object to provide comfort to me. I could not be following a textbook of feelings of separation any more clearly.

Maya moving to college at the end of the summer – even with our complicated family story – is a joyful, mundane event. But like childbirth and first steps, it feels miraculous.

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    I shared what felt like the spectacular story of the baby bird with a birder friend. I told her how lucky I felt to be in such proximity to the nest. I told her that watching the baby bird hatch, walk and fly away felt incredible. She asked me to send her a photo.

    “A robin,” she replied. It was an ordinary, expected, typical backyard bird. But for me, feeling a part of its life, for even a little bit of time, felt miraculous.