'I wonder why. They know food is plentiful there, and they must know where the house-clearing is.'
Good question, and for a change, we think we know the answer. Think back to the posts about the distances that emus travel -- either Dads with clutches, or mobs, or individuals, or breeding-pairs.
Suppose AntiqueB Emu crosses for the day to the National Park -- now that's only a half a mile from the house-clearing. But suppose she/he bumps into a mob crusing through. She joins up with them, and at dusk, they all move into the bush to roost.
Now, if she follows this group the following day, she may be four or five miles from the house-clearing by the second dusk. Again, she/he roosts with the mob.
This is good and natural. Emus love to 'shmooze' with other emus. But at this point, coming back here for a bit of wheat is too much of an investment.
Now, Felicity Emu was once absent for four-and-a-half years. So we presume that she got a long long way away.
Here in closing is another perspective on this:
an emu or pair or other achieves 'an orbit.' That is, for some time, that emu does a certain daily 'round' of pastures and water, including perhaps the house-clearing here.* They may stay in that 'orbit' for literally months -- as when Eric brought his clutches here for the plums.
But then, for whatever reason, an emu 'breaks out of their orbit.' They may be away for a week or a year, or we may never see them again.
*There's another house-clearing, you know, across the road, on the old Oudman place. It's not as good as here, but it does have pasture and permanent water and a little fruit to scavenge.
SE