PBS shows trace animal migration and display a snapshot of the US

The Mystery of the Animal Pathfinders PBS, Tuesday, 8-9 p.m. Produced by Peace River Films for ``Nova.'' Presented by WGBH, Boston. A Day in the Life of America PBS, Wednesday, 8-9 p.m. Narrator: Richard Kiley. Producer: Miriam Birch. Presented by WQED, Pittsburgh. Public Broadcasting Service manages to have it both ways. On Tuesday, TV's most consistently excellent science program, ``Nova,'' takes a poetic - yet scientific - look at the exotic in ``The Mystery of the Animal Pathfinders.''

Then, on Wednesday, ``A Day in the Life of America'' creates its own visual portrait of the ordinary.

Both of these specials probe their topics sensitively yet incisively in totally individual styles. And in the end, both come close to touching the essence of their subjects.

The seemingly mystical secrets of migration are examined with a kind of scientific wonderment by ``Nova.'' How do redknots, beavers, wildebeests, honey bees, bats, and monarch butterflies know where to go?

Why is it that, even when winter food is provided for, trumpeter swans move on to warmer climes?

Why do eels swim thousands of miles upstream in New England rivers and then always return south to the Sargasso Sea to breed?

``Nova'' doesn't have the answers; and science hasn't solved the riddles yet. But the program does pose the questions with remarkably beautiful film footage.

Migration, according to narrator Richard Kiley, is a powerful, irresistible, and instinctive urge. But more than a genetic trait, it appears to be a strategy for survival that works.

``The Mystery of Animal Pathfinders'' works, too - as entertainment for everybody, as information for students of nature, and as pure joy for wildlife film enthusiasts.

In ``A Day in the Life of America,'' the task was to create - in one 24-hour period - a ``photo album'' that would capture the diversity which makes America so unique.

The day chosen was May 2, 1986. Altogether, 220 still photographers and 23 documentary camera crews across the country set out, determined to discover America.

A fascinating book seems to have resulted.

But for television viewers, what emerges is a charming potpourri of photographic impressions, a m'elange of snippets of various conceptions of what was worth recording, blended into one overall portrait.

Unfortunately, no single artist-photographer-cinematographer was given enough time to thoroughly explore his own vision.

Therefore, what we end up with is an imaginatively gargantuan project with a tendency to stumble over its own ambition.

``A Day in the Life of America'' is an innovative try at in-depth portraiture. In some segments it works beautifully. But it might have been more exciting to allow one or two of the best camera artists to use the hour, instead of depending so much upon the safe harbor provided by the universality of ``God Bless America'' attitudes.