Fox Hunting at Night With a Yaggi

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The New York Times, July 28, 1981

FOXES TRACKED THROUGH THE NIGHT REVEAL A SURPRISING GROUP LIFE
By LOIS WINGERSON
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OXFORD, England: IT is nearly midnight and David Macdonald is out in Wytham Woods, as usual, fox hunting. He waits in his little blue van, one hand out the window aiming the antenna mounted on the roof. With the other, he adjusts the knobs of a radio receiver in his lap.

''There she is,'' he says suddenly as a series of intermittent tweets emerges from the hiss of the receiver. ''That's Old Mahogany, right where she should be, on the edge of that wood.'' Because the signal is unsteady and changes pitch, he can tell that the vixen is moving. He marks her position on a map, then drives on.

Mr. Macdonald spends nearly every night alone in this wood, keeping track of eight foxes that he captured here, fitted with radio transmitters set into collars and released. Each transmitter has a different frequency, so he can always tell Old Mahogany from Pintooth, and Bramble from Grizzle.

For the first time, thanks to electronic gadgetry, animal researchers are gaining the advantage over elusive, nocturnal animals such as foxes. Mr. Macdonald, a research fellow with Oxford University's Animal Behavior Research Group, is one of the first to use electronic technology to study the lives of individual foxes and their interaction with each other.

Many other studies, particularly in predator control, have concentrated on the movements of large populations of foxes. But Mr. Macdonald's more intimate findings are helping to rewrite the social history of the red fox, the most widely prevalent carnivore on the earth.

''There is a British and American folklore that says foxes are sly, solitary creatures that hunt alone and do not live in groups,'' Mr. Macdonald says. But years of tracking foxes and watching them with night-vision devices have helped him prove what he suspected all along: Given the opportunity, red foxes are gregarious animals that prefer to live in groups.

But they live in a surprising variety of social arrangements. In some places, such as the United States, foxes seem to live in monogamous pairs, according to most studies. There are also loners that fit the popular concept, traveling scores of miles in a night and trespassing on the territories of other foxes.



Stability of Fox Communities

But from the Arctic Circle to the deserts of Arabia, and from British farmland to dense city neighborhoods, Mr. Macdonald has also found foxes living in stable groups that have a hierarchy of their own. Some even cooperate in raising young and catching prey.

The diversity of fox societies, Mr. Macdonald believes, is directly related to the fact that foxes occupy a wide variety of habitats around the world. A better understanding of this diversity, he thinks, could lead to much better control of rabies because in many areas, particularly Europe and some parts of North America, the red fox is one of the most prevalent carriers of the disease. Mr. Macdonald is chairman of a World Health Organization committee on foxes and rabies.

''His research is very important to understanding the epidemiology of rabies and our ability to control it,'' says Dr. William G. Winkler, an epidemiologist with the national Centers for Disease Control in Atlanta. ''It is particularly important to our efforts to develop an oral vaccine against rabies, an effort which is very active in the United States.''

(Experts say that a successful effort to vaccinate foxes against rabies would be much more effective than killing the infected ones because the strategy should make entire fox communities immune.)


Rabies Eradicated in Britain

Mr. Macdonald has one great advantage over fox researchers in other areas: rabies has been eradicated in the British Isles. Thus he can laugh when recalling the time he tumbled down a hillside, embracing a wild fox he wanted to tag. Mr. Macdonald might well need to worry about being bitten but never about catching the disease he hopes to help eradicate in other countries.

At the age of 5, he wrote a school report detailing how to track red foxes across sand traps on golf courses. And for all the electronics, much of his work still involves the skills of the natural scientist.

''If anything has revolutionized the field of biology, it has been radio tracking,'' Mr. Macdonald says. ''But all the gadgetry in the world will not help if you don't pay attention to the wind direction and whether the ground is moist enough to bring out the worms the foxes eat.''

To some extent, the hours spent fox-watching only provide the questions that need to be asked. Many of the answers have come from the small group of foxes Mr. Macdonald has raised in a large enclosure. They have helped him establish that when a fox hides or caches his prey, it is able to remember and retrieve the food, and that one fox is unlikely to find another's cache by accident. The captive foxes have also helped him define the hierarchies in fox families.



Captured Foxes Provide Answers

By studying two groups of captive foxes, Mr. Macdonald was able to verify that a dominant male generally ignores all but one vixen in his group. But the nonbreeding females provide food, grooming and protection for any cubs that are born.

This year Mr. Macdonald has been concentrating on several groups of foxes living in the rural environs of Wytham Wood, a few miles outside of Oxford. He and his team have spent most of the year observing at night the eight foxes he tagged and named in the area. Each member of the team, working alone, tracks several groups of foxes at once. By their nature, the experiments take years to complete.

Often what Mr. Macdonald does is a matter of just sitting: sitting in his van or driving about the rutted lanes of the wood, his ear cocked to pick out the ghostly bleeps that represent foxes from static and car noise. The signals often bounce off trees and fences to give a completely false impression, and he may need to take readings from several different locations to make sense of the signals.

On other nights, Mr. Macdonald may sit for hours downwind of a spot that he knows is frequented by foxes, peering through either infrared binoculars or an image intensifier, a device that amplifies dim light, and simply waiting for foxes to come around. The yield is low: He only sees foxes about one of every three times, and then for only about 5 percent of the time he spends waiting. But he says the result is worth months of radio tracking since he may have the chance to see foxes courting or fighting.



'A Whole Different World'

The object of this year's effort is to compare the foxes living in Wytham Woods with the urban foxes living a few miles away near Botley Road, a wide suburban street of two-family houses and small stores. ''When you move from this area to that,'' Mr. Macdonald says, ''it's a whole different world from the fox point of view -different-sized territories, different food, different group sizes.''

Great Britain is covered with such different fox worlds, territories clearly defined and jealously guarded. Though several fox groups may occupy the same home range - the same farmland area or the same suburb -and invade each other's territory every night, Mr. Macdonald has found that the home ranges themselves never overlap. A city fox is not a country fox; and almost every aspect of their society is different.

Territory size has been found to range from about 20 acres to several thousand. The smallest territories occur in the suburbs, and the largest ones on places like the moors of Cumbria. The number of animals per territory also varies widely, from two to three in the suburbs to five or six on agricultural land.

But under normal circumstances, what makes the difference? Mr. Macdonald thinks the answer is in the abundance and distribution of food.



Food a Factor in Behavior

In the suburbs, for instance, where different people put out bird seed and the rubbish on different nights, a pair of foxes may need an entire block to be sure of ample food, and may have to live in pairs because the food supply is not abundant. In agricultural areas, on the other hand, the supply of food and prey may be so reliable that a dominant male can afford to support several ''servant'' vixens as well as his mate.

By watching enough foxes in different home ranges for enough time, Mr. Macdonald hopes, scientists may eventually learn enough to predict what kinds of groups foxes are living in by simply using a description of their habitat.

It seems a peculiar, solitary sort of science, this matter of sitting about in meadows, listening to bleeps that represent unseen foxes. Despite the electronic sophistication of radio tracking, he says, study methods are still inadequate. ''The biggest problem with his kind of experiment,'' he says, ''is that it is labor-intensive. It could take one biologist all his time to track one fox, and we simply don't have enough biologists for that.''