No one questions the rugged beauty of Scotland's alpine region but its moody atmosphere and unforgiving, unpredictable climate naturally invite an inhospitable and savage reputation. To the casual observer who dares visit during the freezing winter months, the high tops of Scotland, Britain's only true alpine region, appear barren and devoid of life. Man's Heritage (Pearl, 8.30pm) attempts to dispel those myths; life is there in various forms - you just have to look for it. Few mammals or birds are truly resident throughout the year, but this BBC film manages to capture stunning photographs of the mountain hare, ptarmigan and golden eagle struggling for existence in their natural habitat. Many of the residents have evolved physiological and behavioural characteristics to become specialists in the conditions. Predatory beetles cruise the snow fields feeding on thermally stunned insects brought from lower altitudes by strong updraughts. Alpine bumble bees generate heat allowing them to forage near freezing point and small insects use the flower heads of stunning alpines that track the sun as solar furnaces. In summer, the high tops can be just as hostile to birds, both young and old. Foxes, ravens, eagles and peregrines patrol the tops in search of prey. And sudden blizzards in summer can catch out newly fledged ptarmigan, dotteral and golden plover, along with the red deer or mountain hare. Still in the animal kingdom, Global Family (World, 6.30pm) journeys to Patagonia, on the eastern coast of Argentina. Each spring, the giant southern right whales migrate from Antarctica to mate and nurture their calves at bay called Valdez. But, now a major oil-producing region, Valdez has created serious problems for the whales in recent years. During the courting, mating and clear nights over the bay, the whales can still be heard 'singing'. There are two good movies on tonight and one that tries but doesn't quite get there. Poltergeist (Pearl, 9.30pm) shows occasional moments of promise but ultimately fails due to overwhelming doses of cuteness when it should have kept on track as a seriously scary movie. Director Tobe Hooper clearly knew what he wanted but it looks like producer Steven Spielberg had more than his fair share of say in the direction. Sunday, Bloody Sunday (Pearl, 2.05am) is almost a classic. The idea is a good one, a menage a trois between homosexual Peter Finch, heterosexual Glenda Jackson and bisexual Murray Head. All know about each other and all put up with it. And therein lies the fault. The characters, excepting Jackson, are far too civilised about the whole thing. What's more, you cannot help wondering what doctor Finch and divorcee Jackson see in the young sculptor, whose character is underdeveloped. But then, why we see what we do in others is impossible to understand. The script is excellent and the stars crackerjack. Look out for Daniel Day Lewis as a young vandal. The made-for-cable Without Warning - James Brady Story (World, 1.05am) is well above average. The drama chronicles James Brady's career from the early 1980s, when he learns he has become the principle spokesman for the Reagan administration, through his battle for life and the way he copes with paralysis.