An Odd Relationship

Two's Company Three's A Crowd
For the last 2 years in springtime a Canada Goose attaches itself to Lumpy and his partner, and follows them around ( I call him/her Robin). Robin is especially attached to Lumpy and gets upset if Lumpy is having one of his disputes about territory with his neighbour, Mrs Lumpy just about tolerates Robin but Lumpy is fine with it all. I haven't worked out what is going on but their is an alliance which is comical to watch. I wonder if Robin will make an appearance this year.
Mr & Mrs Lumpy with Robin