Welsh Journals

RADIO-TRACKING OF BADGERS GEOFFREY SPENCER Many people are familiar with conventional Badger watching and a few people have even developed great skill in following Badgers during the night. Newer and developing techniques such as the use of colour-marked food or of radio-tracking rapidly reveal new facts and enable generalisations which before were only suspected. This article is based on a single weekend during the past Autumn in the company of a small expert team working towards the understanding of some aspects of the Badgers daily and annual rhythms s especially as regards food and territorial behaviour. The area was a seldom disturbed wooded valley running through mixed farmland north and south for about two and a half miles. From direct evidence at least forty Badgers occupy the area; indirect evidence suggests that this number may be greater even double. No serious complaints are known as to the Badgers' local behaviour in fact, as in most areas, apart from a few farmers and naturalists, most local people are unaware of their existence. Several Badgers had previously been captured and vital measurements made; they were then fitted with a small neat radio transmitting a pulse every two seconds. Each Badger has its individual wavelength; the life of the transmitter is about four months so that the animals must be recaptured and their battery replaced three times a year. On level open ground the signal can be detected from several hundred yards. Each animal is also fitted with a one inch metal disc emitting the light of harmless beta-rays. With binoculars the light is visible at 200 yards; with the naked eye it is easily seen at about 60 yards. The observer carries a small receiver packed in a knapsack, and a small two-pole aerial. After tuning in to the selected Badger, the signal is picked up as endless 'pips' like the dot seconds of the BBC's time signals. The direction of the animal is then found by rotating the aerial; at the position of maximum signal the aerial is facing towards the animal. The observer now walks along the correct line, hopefully in the direction of the Badger. If after very few yards the signals are becoming fainter the observer is walking away from the Badger like a hound hunting heel; he then about turns and walks towards the Badger as the signals become louder. The observer can also estimate the distance of the Badger and while pausing for a few seconds he knows, with a little experience, whether the Badger is at rest or moving slowly or fast. The signal may disappear when the Badger moves over a horizon, among rocks or underground into a burrow. In the former cases the signal is soon regained but if the last signals had come from near a set they may be very faint until the observer is almost vertically over the Badger. Its exact direction underground is then easily found by the point of maximum signal. Once the light is detected the radio is not needed. Close observation is not usually attempted; where this is necessary infra red binoculars are available. It is important that the Badgers find that the silent