Question

Am I Mouse or Rat?   QUESTION: Hi, I have found signs of either mice or rats in my attic. I live in the UK. The droppings vary in size from 1mm to 5mm or larger.
I put down a few mouse traps and also poison. I have caught what look like 5 mice(maybe baby rats) and also a quite a large specimen(see attached picture). The larger rodent in picture is 5 or 6 inches body length. Could you help identify what rodent I have and the best way to deal with them.

Thanks in advance, Peter

ANSWER: I would need more images to determine the species. As a rule, when you take photos, you should have a standard size object in the photo to show scale, like a ruler. Multiple shots are useful too particularly of different angles. From your comment about five inch body length it seems you have rats. The tail (not fully shown may suggest roof rat). If you bend the tail over the back and if it touches the nose of the rodent it is a roof rat. If not, then norway rat.

Fortunately, control of mice or rats is remarkably similar. As for the "best" method that really depends a lot on what you consider "the best!"  We know what doesn't work, as in ultrasonics and repellents, but there are several methods that do work and sometimes efficacy is improved to use them in combination, a concept known as integrated pest management.



Here are some links to publications that you should consult
Bait stations for rats and mice http://www.ianrpubs.unl.edu/epublic/pages/publicationD.jsp?publicationId=633

Control of rats http://www.ianrpubs.unl.edu/epublic/pages/publicationD.jsp?publicationId=818
Control of house mice  http://www.ianrpubs.unl.edu/epublic/pages/publicationD.jsp?publicationId=66

rodent proof construction  http://www.ianrpubs.unl.edu/epublic/pages/publicationD.jsp?publicationId=23

Follow local laws.

---------- FOLLOW-UP ----------

QUESTION: Hi,
  Thanks for your swift and informative response. I have a few follow up questions-
Is it safe to say that the smaller rodent(seen in original photo) is a baby rat(same species) as the larger one in the photo, or is it possible that I have both rats and mice in my attic?
I have found remains of bird feathers in burrows made in attic floor insulation- do mice eat birds?
The problem seems to be confined to my attic for now, how likely is it that they could enter my house..that would be frightening!
I may deal with this problem myself and will continue to use traps and poison, would you recommend this, or for health and sanitation reasons should I contact a local pest control agency?

Thanks again, Peter

Answer
My suspicion is an adult and juvenile rat but both species can live in the same structure.
Rats do eat birds. Mice do as well in certain circumstances.
You can deal with the problem yourself. Read up on rodent control.
You will need to find the entrances into the structure to prevent future animal entry after you control this infestation. Read up on the paper test on ICWDM.org  NEVER NEVER close holes unless you are certain animals aren't using them. YOu dont' want to trap animals in the structure.

I suggest trapping first then go to toxicants. Pre-bait traps first and leave them unset to get the rats comfortable in visiting. AFter bait is removed regularly, then set. Don't skimp on traps. Think at least a dozen. Remember, with poison, you never can guarantee where the rodent dies.