Connecticut wildlife officials are celebrating Bat Week this week to raise awareness about international conservation efforts. 

The international effort to raise awareness of bats' role in healthy ecosystems and economic benefits to agriculture and forestry is observed from Oct. 25-31.

State officials say bats are on the move and three species of tree bats are moving south for the winter, while the six cave bat species are moving shorter distances, where they will spend the winter hibernating underground.

The population of cave bats in Connecticut and across North America have suffered astonishing losses since 2006.

Environmental officials say the disease known as white-nose syndrome has killed millions of bats across 33 states and seven Canadian provinces.

The disease is caused by a cold-loving fungus native to Europe that thrives in caves and mines, and which grows on the muzzle and wings of bats, fatally disrupting their hibernation.

They say bats are the single greatest predator of night-flying insects. A single colony of big brown bats can eat roughly 1.3 million insects every year -- nearly 9,000 insects per bat.

The DEEP says the value of insect control to agriculture that bats provide in the U.S. averages $22.9 billion each year.