Yeah many wattles like a bit of soil disturbance to help kick of their germination from the seedbank. Because Australia has lost so many small digging mammals (extinct or range greatly reduced), which would traditionally disturb the soil, you often find places where there's lots of wattles along tracks and roads, but not out in the rest of the forest
Birds might contribute to dispersing the seeds, but they'll often just sit in the seedbank until they get a bit of soil disturbance to trigger germination. Or there's some birds that probably just destroy the seed when they eat them, and thus wouldn't spread many seeds. I've seen a lot of cocky's munchin on wattle seeds - don't reckon many seeds would survive that encounter XD