What is the rarest UK mammal?

[Emma S]

I was having a discussion with a friend today, and we couldn't agree on what is the rarest mammal in the UK

I reckoned it was between:
-wildcat
-pine marten
-black rat
-dormouse

what do you reckon?

anyone know of accurate up to date stats for this?

sorry if this thread has been done before...had a quick look and couldn't see it.

[eeyore]

It depends how you define it

The scottish wildcat is that rarest mammal in britain on the basis of numbers in the uk (less than 400) but wild cats are also found in scandanavia etc .

the st kilda feild mouse (Apodemus sylvaticus hirtensis) is found only on St kilda so geographically speaking its pretty damn rare

and another possibility is bechsteins bat , which is our rarest bat.

(the other species you list are positively thriving by comparison - for example NE estimate that there are 45,000 Hazel dormice in ther UK)

[Emma S]

I suppose I was thinking in terms of numbers within the UK, though what you say about the St Kilda mouse adds an interesting way of looking at it.

[Dorts]

The Lundy Ship Rat? Was down to just 20 a few years ago.
Dorts.

[Emma S]

Are they a separate strain of rat, or are they black rats then? *confused*

[The Woodman]

Black Rats still abound on certain west coast islands, the Shiants included. There are still black rats on Lundy, a friend of mine stayed there recently, took a live trap and caught one.

As for the rarest mammal it might be a difficult call depending on what definition of rarest is chosen. I might be thinking of the Greater Mouse Eared bat - one bat at one hibernation site in 2009 or the recently discovered Alcathoes Bat which is a realistic shout until more are undoubtedly going to be found. These are difficult to ID and some may have been mis-identified in the past and probably still will be.

Forgot to say, Emma S, that the Black, Ship, Lundy rat are one and the same species - once common but now rare and there's the common, brown or Norwegian rat to give it three names, which is widespread and common.

[Dogghound]

Originally Posted by The Woodman

I might be thinking of the Greater Mouse Eared bat - one bat at one hibernation site in 2009 or the recently discovered Alcathoes Bat which is a realistic shout until more are undoubtedly going to be found.

I was just about to mention Alcathoes bat, im sure it will be this or one of the other (migrant) bat species which occurs here in small breeding populations. Not sure you could include island sub-species of rodent or not.

[Dorts]

Originally Posted by Emma S

Are they a separate strain of rat, or are they black rats then? *confused*

It is a unique and historic strain of the Black Rat. Until the mid 18th C the ship rat,(The Old English Rat), was the only rat in Britain, mediaeval Britain was rife with them. There are now only two known colonies, the one on Lundy and the other on the Shiant Islands in the Hebrides, (as the Woodman has said). The Lundy rats are believed to have swum ashore from a shipwreck of the Spanish Armada. So it has been an isolated colony for some time!
Dorts.

[Emma S]

Interesting - thanks!

[The Woodman]

I can't find any reference to a Lundy subspecies (as opposed to strain) mentioned in the 4th ed Mammals handbook.

There is the latest estimate of 1300 animals - Stephen Harris (1995) A Review of British Mammal Populations etc JNCC Peterborough.