Liverpool have been warned that they may have to make special provisions to accommodate resident bats in their new-look stadium.
The Reds will soon submit plans to Liverpool City Council to increase the capacity of their current stadium to 60,000.
It is suspected that bats currently roost at Anfield and, as the mammals are a protected species, by law they must not be "adversely affected" by building work.
If ecologists find that bats inhabit areas where redevelopment is imminent, then the club will have to find a way to re-home them in their new stand structure.
A Bats Conservation Trust spokesman told The Mirror: "If it's believed that bats are or are likely to be present at Anfield, an ecologist will have to establish how bats use the site and find out which species are present before undertaking building works, and any works will have to take any bats present into account to ensure they are not adversely affected."
Bats were spotted at Anfield during and after Liverpool's 4-2 win over Notts County in the Capital One Cup in August.