A recent survey of the butterfly population in the Aralam Wildlife Sanctuary here has found a declining trend in butterfly migration.
According to the participants of the survey, which included a migration survey, the trend of declining butterfly migration in the sanctuary has been noticed in the past two years. The decline is attributed to various factors including climatic changes.
The survey, conducted from January 13 to 15 by over 80 butterfly enthusiasts from Kerala and Karnataka, has found that the migration of butterflies in the sanctuary during the period of survey was hardly significant. Though the information gathered during the survey is yet to be analysed, the survey team could find no major butterfly migration. According to the survey team, the butterfly-rich areas in the sanctuary have witnessed no major migration over the past two years.
The survey was conducted jointly by the State Forest and Wildlife Department and the Malabar Natural History Society (MNHS). This was the 11th butterfly survey being conducted by the MNHS and the forest and wildlife officials in the area. The programme is organised every year in January/February in the sanctuary, which is one of the base camps for butterfly migration study in the State.
Jafer Palot of the MNHS, who was involved in the survey, said that normally the density of migrating butterflies was high during noontime of the survey period and the survey team could count thousands of butterflies per five minutes. The number of migrant butterflies during the survey period was minimal this time, he said.
He said a shrinkage of mud-puddling sites could also be linked to the decline. Butterflies are often found resting on damp patches along the migratory path. This is the mud-puddling behaviour of the butterflies.
Another factor that possibly affected the migration was the extended monsoon season till November. Migration normally takes place after monsoon, Dr. Palot added.
Mud-puddling is seen on the sandbanks of the two rivers flowing through the wildlife sanctuary – the Urutty river and the Cheenkanny river. According to the participants in the survey, uncontrolled sand-mining in the upstream of the rivers could be another factor for the shrinkage of mud-puddling sites in the sanctuary.
The survey team identified eight more new species of butterflies in the sanctuary this year. The new species found for the first time in the sanctuary are the Yellow Jack Sailer, Aberrant Oak Blue, Tamil Oak Blue, Peacock Royal, Plain Banded Awl, Green Awlet, Banded Royal, and Striped Albatross. During the three-day survey, as many as 148 species of butterflies have been spotted including six which are endemic to the Western Ghats and nine species which come under various protected categories.
