Halo Space Station Evolved

"We must go, the brutes will have our sent"

  What if brutes had the ability to actually "smell" a race in a vicinity around them, kind of like a tracker, but also in the same vain a addition to brutes.

 A way this could be done could just be a a chat notification, or it could also be toggled in abilities

if they added brute stealth packs that would be kinda neat,cloaked brutes tracking marines