We have been impressed by the passionate public reaction to the recent capture, radio-collaring, and unfortunate death of the jaguar Macho B.

Arizonans are genuinely interested in the great diversity of wildlife found in our state, and it is understandable that many citizens reacted emotionally to the loss of this magnificent animal.

The professionals at the Arizona Game and Fish Department, Phoenix Zoo and the U.S. Fish and Wildlife Service share a strong passion for all things wild.It is that passion that first brought us into our professions.

Trained wildlife managers realize the necessity of basing conservation decisions on sound scientific data. We need to know what habitats jaguars use, the size of their home ranges, and their cross-border movements.

It is often necessary to take a "hands on" approach to the study of wildlife. Much of what we know about native wildlife was acquired by early naturalists such as John James Audubon, who purposely killed specimens to identify them and learn about their habitats. More recently, the Bird Banding Laboratory at Patuxent, Md., has recorded more than 51 million banding efforts; banding continues at a rate of more than 1 million birds a year and provides knowledge of migration patterns and habitat use.

Biologists worldwide have trapped and collared numerous big-game animals and other wildlife.

These efforts have provided priceless data. They have also resulted in animal deaths.

Biologists are never casual about these outcomes, but recognize them as essential to ensuring a sustainable wildlife future. The Endangered Species Act recognizes this and allows the taking of individuals when such taking contributes to the greater good of the entire species.

The loss of Macho B has touched many of us. We recognize that the natural human response is to second-guess and that others may have an honest difference of opinion.

The Game and Fish Department, Phoenix Zoo and the Fish and Wildlife Service have sought expert assistance and are actively examining and evaluating the decisions made and actions taken regarding the jaguar.

The facts are these:

• According to one of the attending veterinarians, Dean Rice of the Phoenix Zoo, Macho B's likely pre- existing kidney failure would have been fatal within two months.

• The field team had no way to identify the animal as Macho B, or to determine the age of the animal precisely in the field.

• Administration of sedative at capture may have worsened the pre-existing condition, but there were no alternatives to handling a wild jaguar in the field.

• Once sedated, the potential benefits to the whole species of applying the collar far outweighed the negligible additional risk to the individual jaguar.

• A deliberate, scientifically designed capture and handling procedure was faithfully followed. The department was diligent in monitoring the radio signals and acted decisively and swiftly when it suspected the animal was in distress two weeks after the initial capture.

Unfortunately, the short data-gathering opportunity kept us from learning much about Macho B's movements. What we do know is that in the last 15 years, at least four jaguars have made their way to Arizona from a core population in Mexico. We expect that others will come, and we hope to learn more from them when they do.

Contact the writers through the Arizona Game and Fish Department Web site, www.azgfd.gov, and the U.S. Fish & Wildlife Service Web site, www.fws.gov/southwest/es/arizona