THEY'RE probably the best known, arguably the most educational, and definitely the most prestigious nature shows on television.
They're the National Geographic specials, and come Wednesday, they will move to NBC - after some 20 years on public television (and before that, on CBS and ABC).
An anniversary program, ``30 Years of National Geographic Specials'' (NBC, 8-10 p.m.), inaugurates a five-times-a-year schedule of hour-long specials on the commercial network - up from the four a year that National Geographic had been producing for PBS.
But will the series remain the good old documentaries - so well-loved for so long by so many - about the way mankind and animals live and relate to their environment? Or will they take on a hyped-up commercial-network feel?
``We made no promises to do anything else,'' Nicolas Noxon, executive producer of the specials, says of concessions to NBC. ``We've been very successful with what we do.''
Mr. Noxon has been involved with the specials since 1965, when he produced the second one to air - ``Voyage of the Brigantine Yankee'' - on CBS. Since then he has produced some dozen others and been connected with dozens more. His 1982 ``Sharks'' was the highest-rated single program to air on PBS.
He's delighted with the move to NBC: ``We put a lot into these shows, and the more people we reach, the more sense it makes.''
And yet, ``I know we'll not be entirely immune to the atmosphere of being on NBC,'' Noxon says. ``I've worked on a lot of commercial television and a lot on public broadcasting, and I know they're very different environments.''
The new commercial milieu also troubles Wendell Leavitt, a biological science professor at Wichita State University in Kansas. ``I have followed the specials for many years, and I think they have been superb,'' he says. ``I went out and polled the faculty in the biological sciences department, and they felt that anything that expands the audience would be desirable. But we can't believe that the sponsors are going to leave it alone'' once it moves to NBC.
Not surprisingly, NBC itself maintains that no such danger exists. ``They've been doing it right for 30 years, and we have no intention of changing it,'' asserts NBC spokeswoman Dorothy Austin about the series.
``The reason we wanted to air the National Geographic specials is that they are quality programs and because they've been so successful since 1965,'' when National Geographic aired its first special, she says.
The anniversary show, narrated by Richard Kiley, makes vividly clear what's at stake. It re-airs many of the compelling sequences that have stuck in the minds of two generations of viewers, an electronic stream of consciousness linking the decades with potent reminders of what research and imagination can do: A young wild chimp hesitantly touches the face of Jane Goodall; a great white shark chomps the bars of what suddenly seems a very fragile underwater cage protecting divers; an 11-year-old Balinese girl meticulously learns the ancient folk dances of her culture.
What's at the heart of this kind of TV?
``Don't say it out loud: information,'' is Noxon's semi-factitious response. ``It's the dirtiest word in television. Storytelling is something we focus on. We spend a lot of time, especially in editing and writing, trying to get the stories exactly right. A lot of us in the documentary field just don't have the time and the resources to focus on it so strongly.''
TIME to get things exactly right - and the production style needed to convey it properly - is what some observers worry may be in danger.
``The National Geographic specials tend to be more contemplative than your typical television,'' says Matt McAllister, a communications professor at Virginia Polytechnic Institute and State College in Blacksburg, Va. ``They are more intellectual, move at a slower pace, and deal with things you don't see much on commercial television.''
Can't that kind of production find a home on a commercial network once in a while?
The change may not happen right away, Professor McAllister says, ``But I wonder if eventually there will be pressure to make National Geographic more network-TV friendly, with more romanticizing of the animal kingdom, a pleasanter spin. When you place a solid educational show in an environment that is sitcom-and-tabloid-TV oriented, what gives?''
Noxon takes the transition in stride. ``It's always changing,'' he says of the programming, ``having been created ... on the networks in the mid-'60s and then going to public television. It's unsettling, but it's also reinvigorating. If we can keep the center of it, if we can hold on to our purpose, it will turn out all right.''