How can Shriekers be justly assigned a CR of 1?

[jgsugden]

Anyone else ever use a 'greater' shrieker? One that does a shout spell effect in addition to warning neighbors?

 

[Altalazar]

The shriekers are worth CR1 exp, according to the rules.

It is just as hard to eliminate quietly with monsters nearby as it is without.

For that, they should get full experience. Players should not be penalized for a successful performance due to factors beyond their control.