I’ve heard plenty of talk about “empty nest” syndrome, but never thought I’d experience it myself.

After watching the pair of merlins I first mentioned in my May 5 column raise a family of four, I was somewhat taken aback one day to find the young grown and fledged.

I approached the nest tree expecting to find the offspring perched on or near the nest, as they had been the last couple of times I had visited. Instead, the young birds were nowhere to be found. Nor could I locate either one of the parents.

The nest was truly empty, and the feeling of letdown and loss surprised me.

It had been a thrill to discover that a successful mating had taken place. I had been able to confirm the location of the nest by finally seeing the female alight on its rim and settle herself into it, thus becoming hidden from view. I had witnessed the male giving prey he had caught to the incubating mother, and marveled at this sign of avian devotion.

When I eventually caught a glimpse of the four little chicks in the nest, I was overjoyed. They looked like puffy little snowballs, because they were completely covered with natal down feathers. This type of feather helps to keep them warm, and precedes the development of contour and flight feathers as they grow.

I was able, at intervals, to view the chicks as they perched on the rim of the nest. One day I saw the mother feeding them prey the father had caught. She’d tear off a little bite-size chunk of meat and hold it delicately in her beak as she offered it to a youngster. A chick that was bigger and stronger than the rest – as is often the case with raptors, since the female starts incubation as soon as the first egg is laid, thus causing the eggs to hatch at intervals – took a more active role. It tugged at the prey item itself, enthusiastically trying to emulate its parent.

Each time I visited, I noticed more down feathers being replaced with mature feathers on the chicks. Then one day, I found only one chick in the nest. The rest were perched on limbs below the nest, testing and exercising their wings.

The next couple of times I visited, I found no merlins at all. I worried: Had something happened to them? Or had they just dispersed from the nest area?

Finally my questions were answered when I returned to find three of the young perched on the lower branches of a white pine, and the fourth in another tree. In all of them, the transformation was complete – only a few wispy, telltale down feathers gave away their youth. Otherwise, they were sleek little falcons and strong fliers.

They are now entering the most crucial stage of their development. It is hoped they all will learn to become adept at capturing prey; and that they will develop the strength and stamina needed to undertake migration in the fall.

Chris Corio, a volunteer at Fields Pond Nature Center, can be reached at fieldspond@juno.com.