Germany, Japan and Brazil.

Those were just three of about 10 countries represented as Rotary youth exchange program students met Saturday in Watertown. Thirteen past and present exchange students helped the New York State Zoo at Thompson Park get ready for the summer.

They cleaned dead leaves and plants out of the Heather A. Freeman Butterfly House, covered the metal, half-cylinder frame with netting and reinstalled the screen doors.

Michelle D. Pfaff, local chairwoman for the exchange program, decided on the service outing for the exchange students. She said their outings regularly include the best things of an area or city.

"The park is one of those things for me," she said.

As they worked, the teenagers chatted and joked.

Marcus G. Lorenz, 17, came to Ottawa from Dresden, Germany. He's enjoyed his year in Canada.

"Life is calmer here," he said. "I don't know if it's because I'm away from my family or if it's just a slower pace."

The adjustment to Canada wasn't bad, he said, but the stereotypes he's encountered are: "beer, Nazi and sausage."

One of his two host families includes Nathan W. Jennings, 17, who spent last year in Osaka, Japan, and came back fluent in Japanese.

"I had a little bit of culture shock, but everyone in Japan is so nice," he said. "It was just fun. Even everyday tasks are really interesting when you start because you have to ask how to do everything."

By the end of two months, though, he felt comfortable in Japan. The misunderstanding with him usually was his age.

"People thought I was 23, because of my height and face," he said. "I'd talk to strangers and they'd ask 'Where do you teach English?'"

Local Rotary members and the district's student exchange committee also helped. Rotary District 7040 includes 65 clubs in Northern New York and parts of Ontario and Quebec.

"Rotary is an international service organization," said Kevin J. Laplante of Saranac Lake, the district's Youth Exchange Committee chairman. "This is one of the international programs — the goal behind it is world peace."

The district includes the dozen incoming exchange students, or inbounds, and last year's outgoing exchange students, or rebounds, in the six or seven gatherings each year. This weekend, nine inbounds and four rebounds are participating. Other weekends together have included the Winterlude festival in Ottawa and skiing in Lake Placid.

Even with language and cultural barriers, "I've never had a problem where I've got them fighting," Mr. Laplante said. "It doesn't make any difference where they're from."

Local clubs volunteer to send and accept exchange students, which usually costs about $3,000. "The biggest obstacle is getting host families," Mr. Laplante said.

Each student stays with at least two families. Families do not need to have children or to have adults of a certain age, he said.

The students go through an application and interview process. They usually become involved in the program as sophomores and are involved for three years.

Community projects aren't usually a part of the exchange program, but, Mrs. Pfaff said, "It is a good idea for them to work at the zoo, helping to put the butterfly house together."

The zoo often has school or church groups or service organizations help on larger projects, said Susan M. Sabik, the zoo's general curator.

"We very much appreciate having them come out," she said. "It took a lot of teamwork to get the netting up."

She said the butterfly house will open about Memorial Day. The zoo will begin receiving chrysalides — butterflies in the pupal stage — this week.

The chrysalides will take about two weeks to emerge into adults and then they'll be brought into the butterfly house. Over the summer, the butterflies may have several life cycles, with eggs, caterpillars, chrysalides and adults. Zookeepers have planted host plants that butterflies like for laying eggs and eating.

Like other species at the zoo, the butterflies will be native to the area, such as swallowtails and painted ladies.

"The only issue is that some natives species are so tiny, it would be impossible to control them," Ms. Sabik said.

The students relished their year abroad, even with the challenges.

"Being able to relate to people across the world seems so intimidating at first, but it's really great," Nathan Jennings said. "In the end, it doesn't matter where you go."