"In sharp contrast to previous years, so far only very few species of migratory birds have arrived from faraway countries. This might be due to extremely deficient rainfall during October and November this year.If the monsoon rains pick up in the coming weeks, the turn out could go up during December," Deputy Director of Bombay Natural History Society (BNHS) S Balachandran said.

"A few thousands of flamingos, shore birds, particularly wader and seagulls--have arrived," said Balachandran, who is camping at Kodiakarai.

He said the migratory birds started arriving at the sanctuary during the first half of October this year.

Last year, Kodiakarai area received 656 mm rain in October and 660 mm in November. This year, the area has received only 145 mm during October and just 92 mm during the first half of November, he pointed out. During the same time last year, nearly 1.5 lakh birds had arrived. This year, about 40,000 birds alone have arrived, he said.

However, Balachandran said this year a good number of birds have arrived from other parts of India. "Usually, Point Calimere would receive birds from other countries. This year Indian birds are seen in large numbers."

He said BNHS was undertaking an extensive research on bird migration pattern at Kodiakarai and had taken up "ringing exercise" on birds.

The rings, equipped with satellite transmitters, help in tracking the movement of birds.

"The signals emitted through the satellite transmitters reveal information on the routes taken by them, time taken for the journey and the changes in their body condition," he said and added that the exercise had already commenced this year.

Balachandran said certain species like the slender-billed gulls, Ibis, painted storks, spoon-bills and pelicans, which are considered rare worldwide, might arrive during December as this sanctuary usually serves as a temporary halt location for them en route to other countries like Sri Lanka.

Meanwhile, the wildlife department has tightened security measures to prevent poaching of birds.