THE IMAGE that may come to mind when people think about burros -- which can't be all that often -- is one of stubborn animals helping to frustrate Humphrey Borgart in his effort to retrieve the treasure of the Sierra Madre. But any way you think of them, the scene now being staged in the Grand Canyon must be the most exciting thing that has happened to this class of animals since Jeanette MacDonald and Nelson Eddy.

As evening sets in, six cowboys, 21 horses and two helicopters set out to catch the 300 to 500 burros in the canyon. It is not an easy job. The burros know the canyon well and don't seem to like the idea of being caught. The first week of work, according to The York Times, yielded 34 burros -- cornered, hobbled, put into a helicopter hammock and flown to a corral on the canyon floor. Somewhere along the line, someone should have explained to the burros that their only alternative to being captured is being shot.

The problem is that wild borros in the canyon and some other Park Service areas of the Southwest are too prolific. The herds, decended from the pack animals of the past, have grown huge and are eating too much of the sparse vegetation and are driving out other animals. After long debate, the Park Service decided the most efficient way to save the land was to shoot the burros. In the Grand Canyon, it estimated, shooting would cost $30,000 -- one twelfth of what it would cost to catch the burros and send them away.

The reaction among the humane societies and environmental groups can best be described as ferocious, even though the Park Service had said it would shoot only those animals that such groups themselves and the rest of the public couldn't catch. A lawsuit (naturally) to bar the shooting was filed. But while it is pending, the Fund for Animals has put up $225,000 for the roundup. The burros it catches will go to a ranch in Texas and, eventually, to people across the country as pets.

This is a lovely solution. The Park Service gets rid of the burros -- assuming the roundup is successful -- without spending money it can better use on the other projects. The Funds for Animals gets the satisfaction of having accomplished a part of its mission. And those sad-eyed, long-eared wild beasts do not have to be murdered.

The fund hopes to demonstrate by this operation the wrongheadedness of the Park Service's original decision. But spending $225,000 of private money to 300 to 500 burros is one thing, and spending that many tax dollars is something else. The difference in cost between shooting and catching in other areas, like Death Valley, may not be so large, but the Park Service was right to weigh that difference. If the Fund for Animals wants the burros elsewhere saved, it had best get on its horse (or in its helicopter) and catch them, too.