The incident occurred yesterday evening when a Border Security Force team noticed movement of some suspected widlife smugglers coming from the other side along the Kalyani border outpost area in North 24 Parganas district.
"The troops chased the smugglers but they fled leaving behind cages containing 20 parrots of a rare variety called African Grey.
The parrots, which have an estimated market cost of Rs 9. 5 lakh, were handed over to local forest department authorities later, a senior BSF officer said.