It appears that fairy women all over Ireland find birth a difficult experience. Many fairy children die before birth and those that do survive are often stunted or deformed creatures.
The adult fairies, who are aesthetic beings, are repelled by these infants and have no wish to keep them. They will try to swap them with healthy children who they steal from the mortal world. The wizened, ill tempered creature left in place of the human child is generally known as a changeling and possesses the power to work evil in a household. Any child who is not baptised or who is overly admired is especially at risk of being exchanged.
It is their temperament, however, which most marks the changeling. Babies are generally joyful and pleasant, but the fairy substitute is never happy, except when some calamity befalls the household. For the most part, it howls and screeches throughout the waking hours and the sound and frequency of its yells often transcend the bounds of mortal endurance.
A changeling can be one of three types: actual fairy children; senile fairies who are disguised as children or, inanimate objects, such as pieces of wood which take on the appearance of a child through fairy magic. This latter type is known as a stock.
Puckered and wizened features coupled with yellow, parchment-like skin are all generic changeling attributes. This fairy will also exhibit very dark eyes, which betray a wisdom far older than its apparent years. Changelings display other characteristics, usually physical deformities, among which a crooked back or lame hand are common. About two weeks after their arrival in the human household, changelings will also exhibit a full set of teeth, legs as thin as chicken bones, and hands which are curved and crooked as birds' talons and covered with a light, downy hair.
No luck will come to a family in which there is a changeling because the creature drains away all the good fortune which would normally attend the household. Thus, those who are cursed with it tend to be very poor and struggle desperately to maintain the ravenous monster in their midst.
One positive feature which this fairy may demonstrate is an aptitude for music. As it begins to grow, the changeling may take up an instrument, often the fiddle or the Irish pipes, and plays with such skill that all who hear it will be entranced. This report is from near Boho in County Fermanagh.
"I saw a changeling one time. He lived with two oul' brothers away beyond the Dog's Well and looked like a wee wizened monkey. He was about ten or eleven but he couldn't really walk, just bobbed about. But he could play the whistle the best that you ever heard. Old tunes that the people has long forgotten, that was all he played. Then one day, he was gone and I don't know what happened to him at all."
Prevention being better than cure, a number of protections may be placed around an infant's cradle to ward off a changeling. A holy crucifix or iron tongs placed across the cradle will usually be effective, because fairies fear these. An article of the father's clothing laid across the child as it sleeps will have the same effect.
Changelings have prodigious appetites and will eat all that is set before them. The changeling has teeth and claws and does not take the breast like a human infant, but eats food from the larder. When the creature is finished each meal, it will demand more. Changelings have been known to eat the cupboard bare and still not be satisfied. Yet no matter how much it devours, the changeling remains as scrawny as ever.
Changelings do not live long in the mortal world. They usually shrivel up and die within the first two or three years of their human existence. The changeling is mourned and buried, but if its grave is ever disturbed all that will be found is a blackened twig or a piece of bog oak where the body of the infant should be. Some live longer but rarely into their teens.
There can also be adult changelings. These fairy doubles will exactly resemble the person taken but will have a sour disposition. The double will be cold and aloof and take no interest in friends or family. It will also be argumentative and scolding. As with an infant, a marked personality change is a strong indication of an adult changeling.
Changelings may be driven from a house. When this is achieved, the human child or adult will invariably be returned unharmed.
The least severe method of expulsion is to trick the fairy into revealing its true age. Another method is to force tea made from lusmore (foxglove) down the throat of a suspected changeling, burning out its human entrails and forcing it to flee back to the fairy realm. Heat and fire are anathema to the changeling and it will fly away.