Pygostyle facts for kids

A Pigeon skeleton showing its pygostyle (number 17)

The ancient bird Confuciusornis sanctus with its rod-shaped pygostyle and two long tail feathers

The pygostyle is like the tailbone of a bird. It's a special bone formed when the last few bones of a bird's tail fuse together. This strong, single bone helps support the bird's tail feathers and the muscles that move them. In modern birds, the main tail feathers, called rectrices, attach directly to the pygostyle.

The pygostyle is a key part of a larger area called the uropygium. You might have heard this part of a bird called the bishop's nose, parson's nose, pope's nose, or sultan's nose. It's the fleshy bump you see at the back of a cooked bird, like a chicken or turkey. This area looks a bit swollen because it also contains the uropygial gland, which makes a special oil birds use to keep their feathers clean and waterproof.

What is a Pygostyle?

A pygostyle is a unique bone structure found in birds. It comes from Ancient Greek words meaning "rump pillar." Imagine a strong, fused bone that acts like a sturdy base for a bird's tail. This bone is essential for how birds use their tails.

How Birds Use Their Pygostyle

Birds use their tails for many important things. When a bird flies, its tail acts like a rudder on a boat. It helps the bird steer, balance, and slow down for landing. The pygostyle provides a strong anchor for these tail feathers. This allows birds to control their flight with amazing skill. Without a strong pygostyle, their tails would be too floppy to be effective in the air.

The Pygostyle Through Time

Pygostyles started to appear very early in bird evolution. Scientists believe they first evolved about 140 to 130 million years ago. This was during the Cretaceous period, a time when dinosaurs still roamed the Earth!

Early Bird Tails

The first known birds to have a pygostyle were members of a group called Confuciusornithidae. Having a pygostyle was a big advantage for these early birds. Older birds, like Archaeopteryx, had long, flexible tails with many separate bones. While interesting, these tails were not as good for controlling flight. A strong, fused pygostyle made tails much more useful for flying. Even today, young birds in their embryonic stage start with longer tail bones. These bones then fuse together to form the pygostyle before they hatch.

Two Main Pygostyle Shapes

Scientists have found two main types of pygostyles in ancient birds:

• Rod-shaped pygostyles: These were long and thin, like a rod or a dagger blade. They are seen in birds like Confuciusornis and some oviraptorosaurs (a type of dinosaur related to birds). The tail feathers on these animals were often soft and downy, sometimes with two to four longer "streamers" in the middle.
• Plowshare-shaped pygostyles: This type looks more like the blade of a plow. It is found in modern birds and their closest relatives. This shape is perfect for holding a fan of strong, well-developed tail feathers. These feathers are crucial for steering and maneuvering during flight. The oldest known bird with this type of pygostyle is Hongshanornis longicresta.

Yixianornis grabaui, an ancient bird with a pygostyle similar to those in birds today

It seems the pygostyle evolved more than once in different bird groups. The rod-shaped pygostyles likely helped save weight in the tail. Later, the specialized plowshare-shaped pygostyles helped birds become even better flyers. Scientists even named a group of birds, Pygostylia, after this important feature.

The Funny Names for a Pygostyle

The word "pygostyle" comes from ancient Greek words meaning "rump pillar." But why do people call it things like "pope's nose" or "parson's nose"? These nicknames started in Britain a long time ago, in the 1700s and 1800s. People thought the fleshy part of a cooked bird's tail looked a bit like a nose. The names "bishop's nose" and "sultan's nose" came along later, in the 1900s. These are just funny, old-fashioned ways to describe this part of a bird!

Pygostyle as a Food Item

In some parts of the world, like Micronesia, Samoa, and Ghana, the pygostyle area of a turkey, often called "turkey tail" or "turkey butt," is eaten. This part of the turkey is known for being quite fatty. After World War II, turkey tails became a popular and affordable food in places like Samoa. Sometimes, this part of the bird is also used in pet food.