DACCA, EAST PAKISTAN.-"Our vultures are the happiest creatures in Pakistan," a weary villager said last week, speaking of the series of disasters that have struck the country's eastern region.

Watered by the Ganges and hundreds of tributaries, East Pakistan normally is verdant with rice and jute paddles and grows delicious tropical fruit. But within the past year it has suffered a disastrous flood, followed in turn by a calamitous cyclone ,that took half a million lives and by a civil war (or, rather, a pogrom on a vast scale). The estimate of some foreign observers that another half-million East Bengalis were killed in the butchery may not be greatly exaggerated.

Exact figures are hard to come by because of the practice of dumping bodies in the rivers before the deaths are counted.

Now it appears, in the view of foreign experts, that famine and epidemic cholera are at hand.

And, despite this staggering loss of life, the demon of population growth continues to press against the diminishing supply of land. At the current growth rate, the loss of lives during November's cyclone was replaced in an estimated 83 days.

Of all the catastrophes, it is the civil war that has been the hardest to chronicle.

About 40 foreign newsmen and camera crews happened to be in Dacca, East Pakistan's capital, at the time the national army made up mostly of the Punjabis of West Pakistan, struck with a ferocity that has left the Bengali population cowed. The newsmen, who were seeing more than the Islamabad Government in the West had intended, were expelled from East Pakistan, which is separated from West Pakistan by 900 miles of Indian territory. Their notes and film were confiscated.

Since then, several newsmen have sneaked into East Pakistan from India and reported their impressions of a region under the heel of what amounts to a foreign occupation army. And last week the Government permitted six foreign newsmen (including this correspondent and one from Communist China) into the eastern region.

By now it is probably impossible to determine who was the first to butcher women and children as the violence- stemming from the East Pakistani demand for autonomy and the Islamabad Government's refusal to grant it-spread through the eastern region last March.

There can be little doubt that some atrocities were committed by groups of separatists. Generally such killings were done by Bengali workers nurturing grudges against shop foremen and administrators in the jute mills. Many of the foremen are Biharis, Moslem immigrants from India, who have done well in East Pakistan and whose success is resented by the less successful Bengalis.

The Pakistani Army, for its part, denies that it fired indiscriminately when it attacked in East Pakistan. But the physical evidence and direct testimony of hundreds of witnesses indicates that the army burned and blasted entire neighborhoods in towns and cities, picking off anyone showing himself in a window.

Soldiers smashed their way into apartments in Dacca's Old City district, hunting down university professors and killing them and their families in cold blood. In Jessore, an Italian priest was killed at point-blank range as he stepped from a hospital building, his hands in the air and a Red Cross banner pinned to his chest. West Pakistani troops smashed most Hindu temples and shrines they passed, and leveled all houses anywhere near them. The Hindus are a minority group in Moslem Pakistan and are always suspected of being agents of the "arch enemy"-India.

Mopping up has been continuing ever since, Rubble has been cleared away. Roadblocks erected by rebels have been removed. Gas, telephone and power lines have begun to operate. A few carpenters and sign painters have trickled into the shattered bazaars. And some of the fat vultures have been shot.

LIFE DISRUPTED

But life in the region is still badly disrupted. At least eight vital bridges lie felled by explosives. One of them provided the only link between the port of Chittagong in the south and the northern part of the region. The damage could be repaired in a year, according to Lieut. Gen. Tikka Khan, commander of the occupation forces and military governor of the eastern region.

Industries, services, port facilities and town business in general operate at about 20 percent of normal throughout East Pakistan. Some people have taken to the fields More than a million others-2 million according to an Indian official at the United Nations last week-are reported to have fled the country entirely across the rivers into India.

"East Pakistan is doomed whatever happens," a Pakistani scholar said. "It has no hope as an independent entity and is equally doomed if it remains the colony of West Pakistan. For West Pakistan the East wing is going to be an unbearable economic, military and social burden, and yet we cannot give up East Pakistan, for reasons of religious and national doctrine.

"There is our tragedy and our problem."