ISLAMABAD, Feb. 11 (Xinhua) -- The number of migratory birds from Siberia to Pakistan has declined 70 percent this winter, mainly due to climatic change and human activities, local reports said on Monday.

The harsh winter in Russia forces birds to leave their home in search of warmer places, and Pakistan is one of such destinations where these birds including some rare species stop by.

The migratory birds arrive in Pakistan at the end of August every year via Afghanistan, and leave in February. They all move back to their native lands by March.

Pakistan has 19 sites where birds land, 10 of which are located in south Sindh province. The migratory birds temporarily stop in Thatta, Rann of Kutch and Thar coastal areas of Sindh, from where they gradually spread to other lakes, Express Tribune reported.

Quoting World Wildlife Fund Technical advisor Moazzam Khan, the paper said that less rainfall, dried up water passages and the changing of locations are the major reasons for the decline on the guest birds.

Apart from them, water in some of the lakes near the coastal area has turned saline due to intrusion of sea water, drastically affecting the quality of life of marine animals and plants, and causing the number of migratory birds visiting the lakes to decline.

Human activities, including land reclamation and deforestation, and indirect human influences, such as climate change and fragmentation and degradation of habitats, are also the causes of decline in the number of migratory birds.

Besides, unchecked hunting and netting have caused irreparable losses to bird populations, the report added.