Kid parties can be tough when you're not the guest of honor.

Late spring is a challenge for my grandchildren. All three of their birthdays fall within five weeks, a coincidence that is at once beautiful and terrible for small children to navigate.

Children struggle with sibling birthdays. And with cousin birthdays, too, when the cousins are as close as these three are. They understand everyone gets a birthday. They're extremely interested in the gifts. They love the flurry of cake, ice cream and singing, and it nearly kills them that it isn't their own big day.

They try, they really do, and for the most part they're successful. They sink into someone's arms—plenty of arms are always available—while the birthday child opens gifts. They wait patiently while the celebrant gets the first turn at a new toy, and they ask ever so politely if they can see it next. Their patience is enough to bring tears to the eyes of adult observers. “You're being so good,” the adults tell them, but they scarcely hear. They're barely holding themselves together.

They don't suffer like this at friends' birthday parties, which, as far as I can tell, are purely fun, with sweet treats and goodie bags and games and running around screaming. These events are free of the tension inherent in a family birthday.

I remember that feeling. Even as a child, I knew it was unreasonable, but knowing that didn't dissolve the hard lump in my stomach as I watched my sister collect gifts. My sister, who was older and therefore claimed every new age before I could get my hands on it, already had every advantage—including a birthday 12 days after mine and two days after Christmas, when it seemed I had nothing to look forward to ever again.

Our first grandchild to celebrate his natal day in a given year is also the youngest. At his second birthday celebration, his older brother masterfully checked his emotions. “Can I have the second turn?” he said when his brother opened a plastic lawn mower that churns out soap bubbles. In answer, his brother, already opening the next gift, hooked one small possessive leg around the bubble mower, effectively corralling it. The adults exchanged looks of mingled sympathy for the boy whose birthday it wasn't and delight in the boy whose birthday it was. Certainly the older one was behaving in spectacular fashion, but the younger one had learned to stake his own claims, not always easy for a younger sibling.

Last year, my granddaughter watched her cousin—three weeks her elder—open his birthday presents. She handled it with grace, backing up until she reached her father and then settling into his lap like a bird in a nest. Both of these older children will show the younger one a fine example when his time comes.

With three birthdays in quick succession, it won't be easy for any of them for years, but they'll settle into the annual cycle until they finally achieve emotional equilibrium. This might not be until birthdays themselves have lost their allure (“I renewed your New Yorker,” my sister says offhandedly to me, and I say, “Thanks. I've got your usual Marshall's gift card here.”), but that's OK. Birthdays are about presents, cake and love. And the greatest of these is love.

Margo Bartlett and her husband have two daughters, two sons-in-law, three grandchildren and two car seats. She also writes the Just Thinking column for ThisWeek Community News. You can reach her at margo.bartlett@gmail.com.