What’s the best way to get rid of them? This the second winter they’ve nested in the headliner–after eating an entrance hole hidden by the visor!
Tricky little buggers.
You now have an odor trail in your headliner. In addition to trapping the mice (try have-a-heart traps) you’ll need to tear down and remove the headliner. Or, if this F150 is an old worker truck, just tear it down.
Due to circumstances, I have an unusual amount of experience dealing with rodent and other infestations. I live in a rural setting, in a small Third World village, in the state of Puebla, Mexico. Most houses experience rats; mice; scorpions, and lizards which are alleged to be toxic.
I found ultrasonic repellers at a Mexican subsidiary of Wal-mart. To my surprise, they are also available in the US. These devices simply do not work as well as advertised, due to power issues. The little ones you can get at Home Depot are probably good for a few inches or very short distance.
These claim we would need two for our 2,850 square feet house. We finally solved our problems with 8 of them.
We have proved they work on mice;rats; lizards; and scorpions. The do not work on spiders, though.
Before we used these, I had mice babies in my underwear. No more.
We did for a while have a rare invader at the back of the house, and my wife finally noticed we had two open drain pipes going out of that end of the house. We covered them with hardware cloth, and have had nothing since then.
The problem is you need safe, legal way to plug them in, and will have to plug and unplug each time you drive.
And, based on our experiences before we plugged the drains, you may have a problem with dead, smelly mice if they are there when you put these things in the car.
http://www.sterenshopusa.com/catalog/search3.asp?sku=REPELTRONIC
Cat?
You also might want to consider poison. I don’t like that solution because while it may kill the mice, a rotting mouse is not a pleasant smell and they can find some really inaccessible places to die.
I have had good luck with glue traps and live traps. If you use these and you decide to release them, make sure you release them miles away from where you found them. They have homing abilities.
If properly located the glue traps are quite effective.
The simple solution is to install a cat or constrictor snake in the head liner.