My eclectus female has begun biting her wing feathers

by Carol
(Creedmoor, NC, USA)

My eclectus female has begun biting the ends of her wing feathers. She is not plucking them out, she is pulling at them. Hard enough that she looks like she is going to flip herself over. This morning, she bit the tip off of one. They are the feathers that would be cut to limit flight so it is no huge loss, but I don't want it to continue or worsen. What might be the cause and what can I try to stop it? Thanks.