When do mice have their babies? I think I found a mouse nest in a closet in the guest room. It’s a pile of fluff and paper and there’s something that looks like mouse poop. I haven’t seen any mice so I don’t know if the nest is new or if it’s been there a while. H. J., Boscawen, NH

Mice do not have seasonal pregnancies or births, at least when food is available and weather is favorable. Indoors, they can give birth year-round, that’s why they’re so darn successful as pests! A female mouse can mate when she is only 6 weeks old. She can have her first litter averaging 5-6 babies just 19 days after mating. During her 1 to 2 year lifetime, she will have 6-10 litters. You can do the math, if each baby has babies, and so on. If you can’t do the math, see The Offspring of One Female Mouse.

Mice Nest Close to a Food Source

It does sound like you found a mouse nest. A typical mouse nest is a loose pile or ball of any kind of soft materials that the female can find in her environment: string, tissues, paper, plastic, fabric, plant stems, etc. (see Could You Recognize a Mouse Nest?) Mice nest within 30 feet of a food source, usually much closer. That 30-foot travel distance can be in any direction, even up or down, since floors and ceilings are not usually a barrier to mice. Since the nest is in a bedroom, the kitchen is probably directly beneath that room (see Where Do Mice Nest?).

Just because you found a nest, doesn’t mean that there are young mice. If the nest belongs to a female mouse who has already given birth, you would no doubt see some evidence of the young mice, such as droppings, as they are traveling to your kitchen or other food source at night.

Mouse Droppings Can Give You Clues

That nest could be old and unused. It’s possible that the closet nest was abandoned in favor of one even closer to the food source. The texture of the droppings you found can give you some clues as to whether it is an active or an old nest. Fresh droppings are dark and soft with a putty-like texture when squeezed. Older droppings will be dry and crumbly (see All About Mouse Poop!). An easy way to tell whether the nest is still in use is to clean up all of the existing droppings and then check back looking for any new droppings.

To put your mind at ease, you could have an exterminator inspect your home for evidence of mice. It’s very possible that additional mouse nests will be found in or around your kitchen. Give Colonial Pest a call. If our technician finds mice living in your home, we can set up a control program that will work for you and give guaranteed results. Guaranteed!

Photo Credit : “White lab mouse cubs in nest” | CC BY-SA 3.0 via Wikimedia Commons.