If for some suspect wild baby mice have been located in your care, I have included a few tips on caring and feeding to help you give them a chance at life. Please be aware that even in the wild, mice have a 50% chance of surviving beyond 5 months of age, given a general upbringing. The mice that do make it can live up to around 5 years if healthy. A pair will have a better chance of survival than a lone mouse.
As soon as you have your baby mice, it is foremost to keep them safe and warm. You can use a small pet carrier, large plastic tub or any other suitable box in which you can put them. Layer the lowest with a towel and place the mice on top. Then, use other soft material to lightly cover the mice like fleece. Place the box in a warm place, ensuring that it isn't hot; otherwise the mice will come to be dehydrated. A heater on the lowest setting may be all that is needed. Test the towel the mice are laying on so that it feels cosy and warm to your hand.
If the baby mice are less than 14 days old they will need dropper fed with a milk substitute until they are weaned. They commonly open their eyes when they are just about weaned and able to eat by themselves. You will need to feed them every 2 hours so be ready to get up while the night. Set your alarm. When I was finding after wild mice, I was getting up every 2 hours to check them. I have since read that while the night mom mouse would be away finding for food and may only return to the nest once to feed her babies. Use coarse sense, if you can conduct a few night feeds, all the best for the babies chance of survival, especially in the early days.
Kitten milk is available to buy at pet shops. I used raw coconut blended up and strained. It should be 1 cup coconut to about 2 and ½ cups water. You could also use soaked almonds to make an almond milk using the same ratios. Make sure the nuts are natural and plain. Once you've made up the milk, store in a sterilised glass jar and keep in the fridge until required. When you go to feed the mice, take a quarter a cup of the milk and warm it up by pouring it in a small jug and standing in hot water. Use a dropper or baby syringe (you can get these at the chemist) to feed 1 or 2 drops of the milk at a time into the baby mouse mouth. When the mice are verily young, they might not open their mouth. Be meticulous not to get the milk up their noses, they will splutter/cough if you do. It can be hazardous for their health if you do. The way I fed the mice was to put a facecloth down on a table and to put one mouse at a time onto it. Then you can gradually hold the baby's head whilst you administer the milk with the dropper. You'll get the hang of it with a bit of practise. The baby might not seem to be taking much milk, don't worry. Very young babies may only need to get a drop or 2 on their mouth/tongues until they can take more. The main purpose here is to keep them hydrated with a microscopic drop at a time every join of hours.
Once the baby is fed, you need to stimulate a bowel movement. To do this, put some warm water in a small bowl and dip a cotton bud into it. Then, put the cotton bud in the middle of the baby's back legs and gradually turn the bud around. You should see a microscopic brown staining, that is their poo. Dip the other end of the bud into the water and gradually stroke the baby's body, this emulates the mom licking them. After all that, tuck baby up in it's soft bedding and place in a warm spot. This is the basic habit that needs to be repeated every join of hours while the day and at least 2-3 times while the night, especially around 1am and 5am.
As you can see, it's quite a commitment, finding after baby wild mice. But, there is also a great reward in the caring of them and the bonding you will feel as a carer.
When the babies start to open their eyes or at least take a peak, they may be taking a lot more milk and beginning to walk around a little. This is when you need to be extra careful; one fall is enough to be fatal. You can make a microscopic safe roaming area in the lowest part of a pet cage or shoebox/basin. Line it with newspaper and leaves to simulate a natural environment. The youngsters will enjoy stretching their legs and taking their first steps. This is important, as it will build up their muscles and strength.
Once the babies start to bite your fingers quite firmly when you feed them, they may be ready for a microscopic solid food. They will also be beginning to open their eyes (12-14 days old) Start very gradually with this. Try some baby fruit puree to start or natural rice pudding. The food should not be chilled. Let them lick it off your finger. Avoid putting the purees onto a dish for the mice to feed from, as they might get messy and end up with matted fur, which needs to be avoided. Some other foods to graduate to are porridge, banana, tomato, dried oat flakes, strawberry. Just go real easy with the food and keep it simple and verily digested to start with. Congratulations! You've verily made it to the weaning stage, which is quite something with wild baby mice.
Continue to provide a safe space for the mice to sleep and once weaned, they will be able to come out at night to feed. Give them a microscopic dish near their bed so they can feed while the night. At least you can get some sleep now! Continue to offer the milk while the day and provide some water for them. Usually, wild mice will still have some mothers milk up to about 4 weeks of age.
Now you have to decide whether to keep them or issue into the wild. I don't know how many mice have been successfully hand-reared and released into the wild. I would think it unlikely that they can survive. However, you've done your bit and if they seem strong and salutary and quite active, it might be possible to issue them. Or, you can keep them as pets.
Finally, if you did your best and the mice died, don't feel bad. Survival chances in the best of conditions i.e. With their natural mom are still low. Just enjoy the feel you've had with them and the chance to get a view into their microscopic lives. They are microscopic bundles of love and it is remarkable to have at least given them some love when otherwise they might have perished.
