I dissected the Owl Pellet that I found and showed to a few MNA members on our coach trip to Carsington Water. The pellet matched the description of a Barn Owl pellet in the RSPB leaflet “Owl Pellets – How To Study Their Contents” http://www.rspb.org.uk/Images/Owlpellets_tcm9-133500.pdf
“They can be quite large (30-70mm long), smooth and rounded. They are characteristically black in appearance (regardless of the colour of the prey it has eaten) often with a varnish-like gloss when fresh. They are very solid pellets, with the material highly compressed.”
I soaked the pellet in a Petri Dish of warm water and gently teased the pellet apart using forceps. I immediately found three skulls and a multitude of other bones. I rinsed the bones in another petri dish of water before laying them on tissue to dry. After finally prising all the bones free I washed the fur and dried this in a laboratory oven at 50 °C. The bones still looked rather dirty so to clean them further I soaked them in a 13% Sodium Hypochlorite solution (essentially Bleach) for 30min before rinsing again a couple of times in water.
The bones were all from Voles and using information on Vole teeth structure from the RSPB leaflet I was able to distinguish them to be Field Voles (a.k.a. Short-tailed Voles) Microtus agrestis then rearrange the bones to show a typical Vole skeleton.