Birds are the bearers of spirits. 

This theme recurs in Rob's recent works. 

Museum objects bear witness to the men and women of a distant past, but these men and women no longer exist and are now completely anonymous. However, spirits still roam...they teach and uplift us. Spirits are not necessarily a religious or esoteric concept. One might think here of for example, the spirit of a book, or knowledge, or the notion of history.