Microscopic characteristics of the plumulaceous feathers of Australian birds: a preliminary analysis of taxonomic discrimination for forensic purposes

The microscopic characteristics of downy barbules of feathers can assist with species identification in forensic investigations, particularly when only minute fragments remain. Using light microscopy (LM) and scanning electron microscopy (SEM), we characterised the feather morphology of 62 species of birds from 18 Orders including representatives of all Orders found in Australia, except Sphenisciformes (penguins). We demonstrate that with a few notable exceptions, Australian birds display similar feather characteristics to their well-studied Northern hemisphere relatives. We also show that the microscopic characteristics of downy barbules can be used to differentiate these Orders. A more detailed investigation of 39 parrot species revealed substantial similarities among the species, indicating that microscopic characteristics could not differentiate among parrot species. However, there were some features (barbule length and macroscopic features, i.e. colour), that may provide clues as to the species of origin. Importantly, the microscopic feather characteristics provide investigators with a simple, fast and cost effective mechanism with which to test assertions about the potential species of origin. This may preclude the requirement for further more expensive testing (such as DNA analysis) or direct further testing towards a smaller, more targeted number of species, reducing the amount and cost of testing required.