Ungentlemanly objections to the ancient royal sport of falconry enjoyed annually by visiting Arab princes could affect India's oil supplies, manpower exports to the Middle East, foreign exchange earnings and trade with the booming Gulf countries.

Unmindful of these benefits. New Delhi schoolchildren recently took to the streets chanting such slogans as, "Eat custard not bustard," and, "don't oil our palms for birds." They were most vociferous outside the Saudi Arabian and United Arab Emirates missions and at the home of External Affairs Minister Atal Behari.

The purpose of the demonstration was to assert the rights of the rare Great Indian Bustard. A king of miniostrich, the bird was found all over the subcontinent only 60 years ago, but a flock of fewer than 1,000 has survived indiscriminate poaching.

The bustard has been a protected species since 1972 with, in theory at least, a total ban on hunting. Indians who dare touch it run the risk of being jailed for six months with a minimum fine of $350.

The furor was provoked by suspicions that Prime Minster Morarji Desai had wainved these to oblige Prince Bandar bin Mohammad bin Abdul Rahman, one of the many relatives of King Khalid of Saudi Arabia.

The prince had pitched his tent in the Rajasthan Desert, the last refuge of the bustard, with 87 retainers, 27 vehicles, modern weapons and high-powered radio transmitters and a flock of trained falcons. He was also armed with an official hunting permit from New Delhi.

Indian hospitality was extended only last month to another keen falconer, Crown Prince Khalid of Abu Dhabi, son of the United Arab Emirates president. The list of other recent guests includes his father, Sheik Zayid bin Sultan Nahyan; the Emirates vice president, Sheik Rashid bin Said Maktoum of Dubai; and Crown Prince Fahd of Saudi Arabia.

These royal hunters have been regular winter visitors for five years and are believed to have killed about 2,400 rare game birds.

The sport passed unnoticed at first because of the remoteness and inaccessibility of the Rajasthan Desert. But finally, acting on a petition submitted by the Indian Wildlife Preservation Society, the Rajasthan High Court ordered Prince Bandar to call off his hunt.

The campaign forced Desal to send the prince packing after only five days of sport. Indian officials are still nervously explaining that there were no protected species among the 35 birds bagged by the prince and his party and that their permit explicitly excluded the Great Indian Bustard.

Villagers, however, claim that more than 200 birds were killed.

With the hunters gone, New Delhi is speculating on the likely fallout of this contreatemps. The consequences could be serious, albeit so far in the realm of the theoretical.

Out of the 30.5 million metric tons of oil India expects to consume in 1979, India wants members of the Organization of Petroleum Exporting Countries to provide at least 17 million. Iranian supplies are now uncertain and Kuwait's rejection of an Indian request has only increased dependence on Saudi Arabia and Abu Dhabi, which last year together provided 5 million metric tons.

The Middle East also offers lucrative jobs for emigrants. About 214,000 Indians have gone there since 1973, last year's migration figure standing at 72,000. The $2 billion they sent back in 1977 was India's main source of foreign revenue.