In the books, there are several families of squirrels that make the journey to White Deer Park including Squirrel, who is the elected leader of the group. It is never specified in the books whether they are red or grey squirrels. The squirrels often struggle to travel and sleep at ground level, as they are much more comfortable spending their time in trees. They also struggle to swim across the river and panic, but Weasel helps them to get across to the other side. The squirrels are also among the animals carried across the motorway by Whistler. Despite their struggles, all the squirrels arrive safely at White Deer Park with the other animals. The squirrels are among the animals that struggle most through their first winter at the park as they are unable to reach the nuts and berries they buried due to heavy snow, so they suffer losses. Many squirrels survive the winter, but one is killed by Scarface in a mass attack on the more helpless Farthing Wood creatures. Unlike most of the other smaller creatures from Farthing Wood, Squirrel is still alive at the beginning of The Siege of White Deer Park. The most reasonable explanation is because red squirrels and eastern grey squirrels have been recorded to live for more than 6 years. It is unknown whether any of the other original Farthing Wood squirrels survive to this point.
The ancestors of the Farthing Wood squirrels appear in Farthing Wood: The Adventure Begins, the prequel set five years before the journey to White Deer Park. The most prominent of these is Nervous Squirrel who shouts warnings to the other animals as humans begin to move into Farthing Wood.
In the TV series, only two squirrels make the journey to White Deer Park; Squirrel and Mrs Squirrel, who are both grey squirrels. Both squirrels make it across the river without any problems, and they even head back to help rescue the rabbits. Unlike in the books, the squirrels are not carried across the motorway by Whistler but manage to run across safely. They don't appear to struggle as much as they do in the books without the use of trees, and they both make it to White Deer Park safely. However, they do go missing after the animals escape from the church, but are quickly found by Kestrel and return to the group. Upon entering the park, they try to befriend a family of red squirrels, but they are greeted with hostility and warned to keep away, before being pelted with nuts later in the episode. During the winter, Weasel steals some nuts that the squirrels have stored away, causing them to go hungry until the birds start collecting food from the town. Both squirrels survive through the winter and to the end of the second series.
Although squirrels do appear in the third series, it is unclear whether any of them are the original Farthing Wood squirrels. There is a squirrel who sounds identical to Squirrel from the first two series, but he refers to his "old dad", suggesting that he is one of Squirrel’s offspring. The "old dad" himself also appears later in the series, but sounds nothing like the original Squirrel, suggesting that the original Farthing Wood squirrels may have died of old age by this point in the TV series or he has gained a more raspy voice due to old age. The "old dad" is believed to perish during the hurricane whilsts its child survives it.