Fifty years ago, the viewing of the Miraflores Locks of the Panama Canal launched our tour of the capitals of South America, including Brasilia under construction.

In February, I joined a Lindblad Expeditions cruise on the 62-passenger National Geographic Sea Lion to transit the canal and follow the Pacific coasts of Panama and Costa Rica.

At Colon, we board the Sea Lion and it enters Gatun Locks at night, surrounded by dazzling lights under a full moon. The locks raise the ship 85 feet to the immense, artificial Gatun Lake.

Dawn reveals Barro Colorado Island, a forested hilltop that became an island when the Chagres River was dammed. Poking along the shoreline in Zodiac rafts, we are ecstatic about our first sighting of howler and spider monkeys and blue morpho butterflies. The northwest to southeast transit continues through the 23-mile passageway of Gatun Lake, the source of the 53 million gallons of fresh water that will spill into salt waters with each crossing.

The ship sails into the 8-mile-long Gaillard Cut, sliced through the Continental Divide. The Pedro Miguel Lock and Miraflores Locks drop the ship to the Pacific Ocean, concluding an undeniably impressive 50-mile transit.

In the Gulf of Panama, our first exploration is along the coast of a small, uninhabited island. From Zodiacs, large colonies of birds are observed. Graceful frigate birds circle above; courting males display their red, fully inflated gular pouches. Brown pelicans and blue-footed boobies claim territories.

Walking on Isla Iguana, we see young birds, termite nests and spiders. Underfoot, zillions of hermit crabs busily skitter about.

The Sea Lion drops anchor in Coiba National Park, consisting of 10 islands and 30 islets and the surrounding waters. In front of the ship, a picturesque desert isle beckons, Granito de Oro.

We soon liven up the peaceful setting. My travel companions quickly take to snorkeling, kayaking and swimming, options available at many of our stops.

Our ship moves to the largest island, Isla Coiba, a former penal colony. The Visitor Center houses informative displays about local ecology, as well as the history of the prison. After a picnic lunch on the beach, we stroll nearby to coax out a few of the 147 species of birds of the island.

Costa Rica is entered at Golfo Dulce, a bay of deep, placid water surrounded by forested hills. For two hours, we drift quietly in Zodiacs along the shoreline, probing for birds and focusing on the leafy kingdom. The naturalist explains the characteristics of the mangrove estuary.

For me, a highlight is Casa Orquideas, the private, tropical garden of Trudy and Ron MacAllister, an American couple who settled on this shore more than three decades ago. The self-taught botanists gathered rain forest plants and today lovingly care for more than 100 species of orchids and 50 varieties of heliconias, to mention some of their innumerable plants and trees.

Remote and rugged Corcovado National Park is primarily a lowland tropical rain forest with stretches of uninhabited beaches. The numbers of species of flora and fauna are overwhelming: 6,000 insects (hundreds of butterflies), 500 trees, 370 birds, 140 mammals.

Beaching at Calestas Playa, passengers are offered, as always, hikes of varying difficulty. In the evening, we watch a humpback whale cavorting in front of a vibrant red sunset.

Manuel Antonio National Park is small but popular with the people of Costa Rica and tourists. On the trail, we "shoot" languorous sloths in cecropia trees, troops of monkeys, a basilisk lizard trying to hide on a trunk, and some birds to add to the ship's list of 90 species for the week.

The Sea Lion docks, and we say goodbye to the 26-member crew, the 10 knowledgeable specialists of the expedition team and the 50 passengers.

A coach awaits us; it stops briefly at the bridge over a reserve so we can look up at pairs of scarlet macaws and look down at dozing crocodiles. A two-hour scenic drive over mountainous terrain ends at the San Jose airport.

On returning to the snow, in my hands I have the toucans I could bring home in the form of mola pillow and a painted gourd and an autographed copy of a National Geographic guidebook by Christopher Baker, who was on the cruise.

In my head, I have an enhanced understanding of biodiversity and warm thoughts of the pleasures of shipboard life with fond recollections of the young people of the attentive dining staff and the delicious native fruits and local fish of our meals.

In my mind's camera, I have wondrous images aplenty of faraway places, tranquil waters, lush vegetation and captivating wildlife.

Selma K. Richardson is a professor emeritus at the University of Illinois' Graduate School of Library and Information Science. She has been to all seven continents and traveled in more than 100 countries.