My sister has five ducks. They are like having pets which don't want to be petted. She calls out to them and they'll come across the padock to see if she has any food for them, else they tend to wander off and enjoy their social time.
Sounds like your aunty had a good friend. Are cockatiels high maintenance?
Maybe since they're in a flock they have a different mentality, opposed to being just one with their owner? My aunt would have to refill his food and water maybe 2 times a week max, clean his cage and reline the bottom about twice a month, and clip his wings maybe once every 2 months.
The most maintenance is easily having to sweep up all the dropped bird feed and loose feathers that make their way out of the cage which seemed to be too often lol