The reason people are flocking to the Hartke Theatre at Catholic University Friday and Saturday is that there's always a tremendous rush on opportunities to hear poems about birdies and beasties. But in case it matters to you that one of the readers is Princess Grace of Monaco, nee Kelly, here is the report from Pittsburgh, where she began her six-city tour of "Birds, Beasts and Flowers," her first American stage appearance in 26 years.

The persona Princess Grace developed, first in the movies and then in the public appearances connected with her marriage to the prince of Monaco, is impeccable. Those who followed the Bicentennial appearances here of European queens and princesses with longer lineages will appreciate how much better Princess Grace lives up to the American ideal of royalty. The others tended to look dowdy, act democratic and, as schoolchildren were forever pointing out, they didn't wear crowns; Grace is beautiful, of aristocratic bearing, and, if she doesn't actually wear a crown, she weaves jewels into her hair to make a very creditable coronet to wear on stage.

There are advantages and disadvantages to this fabulous character in relation to the material she presents with British actor Richard Pasco (who does some excellent: Shakespearean passages in this program, but suffers from the lack of a crown). It is an evening of verse and some prose passages, both light and heavy, on the eternal poetic subjects of animals and flowers, done as a benefit, in celebration of International Wildlife Year.

When Grace says, "I want to tell you a story about St. Francis of Assisi," or, "In the wonderful world of nature, trees play a very special part," one feels like an underprivileged child being visited by a -- well, a princess. The tendency is not to listen to her words, but simply to drink in the presence of Pretty Lady.

Her manner is so exceptionally well-bred. She tells us so very kindly about the beauties of nature that one feels that they, like her jewels, must belong to her.

When she does light verse, it is charming. In several poems, she takes the part of a cat or of an upper-class pelican -- sleek, elegant, fastidious animals, rather well-pleased with themselves -- and does it wittily. But when she reads religious works, she seems to address God as if He were a dinner guest whom she graciously wished to put at ease.

The works chosen for the occasion by John Carroll include poems by Shelley, Keats, Blake, Tennyson, Pope, Marvell and D. H. Lawrence. It is a curious sidelight how many of them refer with reverence to the splendor and glamor of emperors, kings and princes, a wonder that is equated with the glories of nature. The Grace-groupies are in good company.