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‘CSI: Crime Scene Investigation’ comes to Denmark Farm!

Last weekend, Denmark Farm hosted an owl pellet analysis workshop with the Ceredigion Mammal Group, which turned out to be a fascinating excursion into a world of small bones and detective work.

DSC03438 photo by Becky CROwl pellet analysis workshop at Denmark Farm with Ceredigion Mammal Group

Many bird species produce pellets including owls, raptors, gulls and even sparrows. The prey is swallowed whole, and the pellet containing the indigestible parts of the food such as the fur and bones is then regurgitated. Pellets can be found in roost sites (a licence is needed to enter when the roost is in use), but can also be found on or below fence-posts and walls where a bird has perched to feed, so it’s worth looking for them when you’re out for a walk.

As well as being an interesting way to spend a few hours, owl pellet analysis can also generate useful data on the birds’ diet, and the distribution of small mammals. During the session on Saturday, we were keeping a close look-out for harvest mice remains in our barn owl pellets, as these would give an indication that harvest mice are present in a location. Harvest mice records are scarce in Wales, so this could provide valuable information about their distribution. We didn’t find any on this occasion, but did find a range of other small mammal remains including field and bank voles, house mice, and common and pygmy shrew with their distinctive red-tipped teeth.

DSC03433Assorted field vole jawbones and teeth, with common shrew skull top right

Becky Clews-Roberts from the MaMoNet project led us through the session, and gave a very useful presentation on how to identify the mammals from their jaw bones and teeth. We were then let loose with the mammal detective’s equipment of white tray, tweezers, hand lenses, and occasional tooth-brush – hopefully not returned to their original purpose after the session was complete! There was a range of leaflets and books available for those who were puzzling over the numbers of roots in their jaw bones (could this be the elusive 5 rooted tooth of a harvest mouse?)  or wanted to know more about the weird and wonderful selection of other bones. If anyone wants to give this a go themselves, more information and resources are available on the Mammal Society website.

Denmark Farm provided an excellent location for the workshop, with plenty of space in the training room for our equipment, tea-making facilities, and the loan of laptop, projector and microscopes. Room hire  is available to anyone needing a well-equipped, comfortable meeting space.

The session was supported by the ‘Mammals in a Sustainable Environment’ project. The project provides opportunities for volunteers in Wales and Ireland to get involved with mammal surveys, from red squirrels in mid Wales, to harvest mice in Pembrokeshire and otters in North Wales. Visit their website for more information.

The Ceredigion Mammal group is open to everyone. We are a newly formed group who get together every month or two for a mammal-related activity. There’s no formal membership, but if you’d like to be kept informed of our events, just drop an email to and we’ll put you on our mailing list, or visit the ‘Ceredigion Mammal group’ Facebook page .

There are also two comprehensive courses, coming up at Denmark Farm Conservation Centre, if you’d like to discover more about our furry friends great and small.

Mammals I:  Gnawers, Nibblers and Insect Crunchers, 16th-18th May 2014

Mammals II: Predators and Hunters, 3oth May-1st June 2014

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