peteralfrey's picture

Mouse sp?

Observed: 28th December 2011 By: peteralfreypeteralfrey’s reputation in Mammals
281211- mouse 031
Description:
Identifications
Species interactions

No interactions present.

Comments

peteralfrey's picture

thanks, will have to get some

thanks, will have to get some other photos of the underparts

chrisbrooks's picture

Species

Gill, is there any way to tell these 2 species apart without close examination. Books say the size of the ears but they all looked much of a muchness to me. Chris

Gill Sinclair's picture

Apodemus species

Hi Chris - no, these 2 species are usually difficult to tell apart unless you can get a good look at the neck markings, and even these can be variable. We had a good photo of a yellow-necked mouse a while back http://www.ispot.org.uk/node/238018 , but it's rare to get such a clear view.
I don't know about the size of the ears, but in theory an adult yellow-necked should be a centimetre or two larger than a wood mouse. However discerning such a small variation would be difficult enough even if the mouse was an adult for certain, but of course what's to say that a smaller animal isn't a juvenile yellow-necked or a larger one just a larger-than-average wood mouse?
The yellow-necked has a more limited distribution than the wood mouse in the UK, so if an observation is well outside the normal yellow-necked range one could be relatively safe in saying the animal was a wood mouse, but where the ranges overlap it's better to only ID to genus level if you're not sure.
If we're in pursuit of 'good science', the best approach is never to ID an animal past the taxonomic level at which you're certain, even if that means saying 'mouse species' as Peter did, 'small rodent species' or even 'small mammal' rather than speculating. Some people do worry that not being any more specific might make them look less knowledgeable, but for me personally an observer has much more credibility if they only go as far as the facts (photos, location etc. allow). If another iSpot user is able to refine the identification with some additional piece of knowledge that's great, and what iSpot is all about.

Gill Sinclair
OU Certificate in Contemporary Science
www.gillsinclair.net
Twitter @Gill_Sinclair

chrisbrooks's picture

Thanks

Thanks Gill, all noted for next time. Regards Chris.

peteralfrey's picture

Interesting subject, Is South

Interesting subject,
Is South London in the distrbution range of yellow-necked or wood mouse or both? Is one more common than the other?
Cheers
Peter

Gill Sinclair's picture

Range of Apodemus species

Both species are present in/near South London. See http://data.nbn.org.uk/interactive/map.jsp?srchSp=NHMSYS0000080209 for the yellow-necked's recorded range (although the NBN website was down yesterday and is slow today).
The wood mouse is much more common. I'm not sure what the up to date figures are, but I did a Mammal Society course a few years ago and the population estimates then were 38 million wood mice and only 750,000 yellow-necked. Wood mice are by far and away the most common mouse species in the UK - even house mice numbered only 5.2 million.

Gill Sinclair
OU Certificate in Contemporary Science
www.gillsinclair.net
Twitter @Gill_Sinclair

peteralfrey's picture

Thanks a lot for the detailed

Thanks a lot for the detailed reply,
really helpful and interesting
Thanks again

the naturalist man's picture

Mouse

Gill is right in every respect. The only thing I would add is that I suspect the population size and distribution of yellow-necked mice is a vast under-estimate, there are just too few people doing small mammal studies and they are difficult to separate. To make matters worse there is evidence of hybrids, animals with a mixture of both species' features!

Graham Banwell

Visit the iSpot Yorkshire forum for information on events, issues and news relating to 'God's own country'
http://www.ispot.org.uk/forum/8411

Gill Sinclair's picture

Hybrid Apodemus

Oh no - I didn't realise that! Hybids - that's the last thing we need to add to our confusion.

Gill Sinclair
OU Certificate in Contemporary Science
www.gillsinclair.net
Twitter @Gill_Sinclair

the naturalist man's picture

Mice

So says the bible, "Mammals of the British Isles (4th ed)"!

Graham Banwell

Visit the iSpot Yorkshire forum for information on events, issues and news relating to 'God's own country'
http://www.ispot.org.uk/forum/8411