February 2009 - One of two trays of study skins of Short-eared Owls at the Royal Alberta Museum, containing specimens acquired between 1965 and 1979.  Museum specimens are typically sexed using internal organs.  For the most part, the pale birds in the tray above are males, and the dark ones are females - this corresponds to differences in plumage that have been used to separate sexes in the field, but the museum data suggest that some intermediately coloured individuals may be difficult to reliably identify to sex based on this criterion.  (Photo by Marcel Gahbauer)

2002- The Migration Research Foundation Inc.