A rare type of whitetail deer has popped up from time to time in Bucks County, the kind of deer that has more than the usual amount of white in its coat.
They’re known as piebald deer, and their mottled brown-and-white coat comes from a rare genetic trait, said Don Wagner of the deer research center at Pennsylvania State University.
The piebald trait, known scientifically as a form of leucism, is different from albinism. Albino deer may have no melanin at all, while even piebald deer with all-white fur typically have dark noses and eyes.
A typical doe and piebald fawn spotted near Ottsville in Upper Bucks County in October 2025.
Leucism also causes skeletal deformities in some piebalds.
How rare are piebald deer?
The trait is recessive, which means both of a piebald deer’s parents must have carried the gene. Fewer than 1 in 100 white-tailed deer are piebald, although the trait can become more common within a local deer population, Wagner said.
Pennsylvania doesn’t estimate deer populations for the area around Philadelphia, but the state as a whole hosted an estimated 1.5 million deer in 2000.
The pattern of each piebald deer’s coloring is unique, and their distinctive look makes the individual deer more recognizable to their human neighbors. The killing of a piebald deer in a protected public park in Lancaster County in October generated outrage among locals who had grown attached to the unusual animal.
Pennsylvania Game Commission officials are investigating the case since the deer was hunted in a prohibited area.
A piebald deer stands behind foliage near Ottsville in June 2025.
Isolated deer populations can lead to higher piebald rates, Wagner said, but that would occur only in extreme situations, such as deer trapped within a city park.
“If the males have the ability to disperse away from their natal home range it’s likely not a problem,” Wagner said.
Is it legal to shoot a piebald deer?
Although some states ban the killing of certain types of white deer, piebalds are legal to hunt in Pennsylvania, Wagner said.
“Some hunters would see them as unique trophies while others may want to protect them and pass on a harvest opportunity.”
Jess Rohan can be reached at jrohan@gannett.com.
This article originally appeared on Bucks County Courier Times: What are white deer in Bucks County and what causes it?