Wildlife managers say nearly a third of the mule deer they tested in Southwest Boulder were infected with chronic wasting disease.
City and state officials said this week they tranquilized and tested 115 deer, and 29 percent were infected with the brain-wasting ailment.
In a memo to city leaders, Boulder’s open space and mountain parks department said the disease is probably the reason the herd’s size is declining quickly.
The department says killing the infected animals probably won’t control the disease because there are so many of them.
The department says some models predict the disease will level off on its own when the herd shrinks to a certain size.