It is estimated that 16 million families participated in some kind of environmental and wildlife activities last year. If you've stood in the national parks behind many tourists attempting to get one candid shot or ventured on a vacation where there's a line-up for a picnic table, this figure may not surprise you. But long lines, overcrowded campsites and limited parking in the canyons probably won't deter many of us who continue outdoor activities carrying backpacks, insect spray and field guides.

Two national organizations dedicated to bringing nature to the public have teamed with leading publishers to produce field guides for young readers. The National Audubon Society, long known for issuing outstanding guides and art about nature and the World Wildlife Fund, a conservation organization "working to save life on Earth" have made efforts for beginners to understand the world around them.Scholastic and the National Audubon Society have combined their focus to encourage young readers with a series called FIRST FIELD GUIDES (Scholastic Reference; $17.95 hardcover, $10.95 paperback). This is a first in guides specifically planned for children age 8 and older debuting with four titles: "Birds," "Insects," "Wildflowers" and "Rocks and Minerals."

There are many features that make this series outstanding. First are the hundreds of vivid full color photos that show species in natural settings, many from your own backyard. For example, in "Wildflowers" the page on sunflowers tells what to look for on the plant, habitat and three similar species. (Did you know the Jerusalem Artichoke is related to the sunflower?) Another feature is the layout of the guides.

In "Birds" the description of the avian anatomy, migration, feathers, reproduction and qualities of the birds in natural settings is given. The identification of birds display more than four dozen of the most common birds in North America as well as 125 additional species. I particularly enjoyed the pages showing the 50 state birds.

An added feature is a "spotter's guide," a ready-reference card for quick identification of a species with a page number source. Other references are in abundance with contents, glossary and index pages. Included also throughout are hints on ecology and protecting the environment while out in the field.

The sturdy vinyl cover is very enticing (field guides do get mud and berry juice spattered on them) and the size, which is slim and compact, is just right for a backpack.

While Scholastic editorial director Wendy Barish admits they were intended for children, parents are likely to find them helpful and interesting.

World Wildlife Fund books has produced books for the preschooler with two new titles, ANIMAL 1 2 3's and BUGS (Cedco Publishing. $12.95 each).

They are designed to teach basic skills through a child's observation of animals in nature. Familiar as well as unusual animals and insects are included with full-color photographs and simple text. In the counting book, for instance, children are encouraged to count the "fourteen macaws" perched on natural stone and the number 14. The creepy crawlers, buzzers and fliers in the Bugs book will delight even the squeamish.

A royalty from the sale of each book goes directly to World Wildlife Fund's efforts to leave our children a living planet.