When the formation and rolling of the food ball were started by a male, he violently rejects other males but accepts a female and paired rolling begins.
The food ball is pushed by the male toward the crater and the male then continues digging below the ball while the female is up on top holding on to the ball, without participating in the digging.
Before swallowing a food ball
, bass would often dislodge and eject small pieces of the ball from beneath the operculum.
When bass in the laboratory were given food balls
, those impregnated with shrimp extract were swallowed, but those without flavor were ejected from the mouth after the bass decided that they weren't tasty enough.
Visitors will be able to create bird boxes and food balls
for the birds and organisers say it is suitable for children aged eight and over.