What scientific hypothesis could be used to support the theory that wood thrush decreases are not due to deforestation? could it possibly be written as an " " statement? and

"the species of bird, called a wood thrush, has declined by more than forty percent in the eastern united states since the 1980s. it was originally thought that the decrease was due to deforestation, but scientific research has provided new evidence that the decrease in this population is most prevalent in areas where acid rainfall is higher."