Every spring and summer, people from all over the United States and even other parts of the world congregate at the base of Champlain Mountain. Passing tourists stare in curiosity and amazement at this binocular- and spotting-scope-wielding group of birders, who are hoping to catch a glimpse of the peregrine falcons nesting on the Precipice Trail cliff face.

Sometimes, it is necessary to wait quite a long time before discovering the location of one of the birds or the nest. In the meantime, you develop a cramped neck and a good case of eyestrain.

But patience and perseverance pay off, as I discovered one day two weeks ago.

The Precipice Trail parking area was empty when I arrived late on a Monday afternoon. The grassy knoll in front of the lot – worn down to dirt at its crown by the crowds of birders who gather there with a park ranger every day – was all mine, so I shook out my blanket and settled down to wait.

A careful scan of the cliff face revealed a recessed, well-protected ledge I thought could be the nest site. Upon closer inspection – this is where the eyestrain comes in – I noticed whitewash (the birds’ excrement) on the lip of and below the ledge. Sure enough, I heard faint calls and saw movement on the ledge. One of the three young peregrines had come out and was exercising its wings in preparation for its first flight.

It was comical to watch the young bird flapping its wings fast and furious while still remaining stationary.

What isn’t comical is the fact that these birds were once completely obliterated in the eastern United States, due in large part to the devastating effects of the pesticide DDT.

Intensive efforts to re-establish the falcons led to nesting success in 1991 – 35 years after the last pair was known to have nested on the island. Since then, peregrines have returned each year to raise their young on the Precipice. Peregrines are also nesting on the cliffs above Jordan Pond and at Valley Cove, although the pair at Valley Cove apparently did not produce young this year, according to park naturalists.

Although peregrine falcon populations have recovered enough to be removed from the federal endangered species list, they are still a rare enough sight. The opportunity to observe their courtship and nesting rituals – with a park naturalist interpreting, no less (from 9 a.m. to noon. every day, weather permitting) – is an even greater privilege not to be missed.

Also: don’t forget, I’ll be leading bluebird walks at the Fields Pond Nature Center at 6 p.m. July 11-12, and the loon slide show and talk is at 7:30 p.m. July 5.

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