Friday mystery object #68 answer


On Friday I gave you this object to identify:

It’s one of my own specimens, found in 1997 and prepared using the simple method of suspending the body from a tree in a bucket with small holes drilled in the bottom to allow rainwater to drain. The specimen could have been bleached with a mild hydrogen peroxide solution, but the original intention was for it to provide an indication of the bone damage that may suggest insect activity, so I didn’t want to risk causing any additional chemical damage.

Everyone was on the right track with their suggestions – the hooked bill and large orbits making it clear that this was a predatory bird, with most people correctly opting for some kind of owl. However, Jake managed to get the species right in no time by using specimens from his own collection to inform his identification of Tawny Owl Strix aluco sylvatica Shaw, 1809. It’s a small individual, so it may be male (the females are substantially bigger) although the long bones were still fusing, so it may be small because it was still fairly young when it died. I expect a combination of these two factors accounts for the small size of the specimen.

How this bird died is of some interest, since I found the body on a very cold and snowy day in December at the foot of a tree in my local woods.

 I thought it may have died of hypothermia, but the small size and low mass of the specimen makes it seem likely that starvation also played a role in its demise (after all, starvation would make the bird more prone to hypothermia). I certainly didn’t find any small mammal bones in the bucket when I came to sort the skeleton, despite the smallest bones of the owl being preserved, suggesting an empty stomach.

Unfortunately, it’s quite rare to get this much information about a specimen – even if it was known to the original collector. Many people who make their own collections don’t make notes on the circumstances under which they found their specimens, relying on their memory of the event. Of course, memory can be unreliable and when someone dies the information is lost. This is a real problem for museums when they are offered collections by the families of collectors who have passed away – the material may be of interest, but the information that would have conferred real value to the specimens is often missing.

An individual probably of the western subspeci...

Tawny Owl by jimfbleak via Wikipedia

For a curator this lack of information is both frustrating and challenging. We can often look at something and have a good idea of what it is, but making assumptions is dangerous and identifications need to be checked. To do this we rely on descriptions in scientific papers and identification keys, specimens with good data also allow comparison that help with identification of specimens without data.

Even so, there will often be room for doubt, since even if we do have a comparative specimen with good data, we seldom have available the full range of the variation that might be expected within a species (as mentioned by Steven D. Garber, PhD). Ideally, we would at least have examples of males and females, old adults, young adults, late stage juveniles, early stage juveniles and common variants. This is one of the reasons why natural history collections in museums are usually far bigger than other collections – for example, at the Horniman the Natural History section has more than twice as many specimens as the Musical Instrument and Anthropology sections combined.

 

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