Cox's sandpiper facts for kids

The Cox's sandpiper (Calidris × paramelanotos) is a special type of bird. It's a hybrid, which means it's a mix of two different bird species. This bird is born when a male pectoral sandpiper and a female curlew sandpiper have chicks together.

Scientists first found the Cox's sandpiper in Australia in the 1950s. At first, they thought it was a brand new species of bird. They even named it after an Australian bird expert, John B. Cox. But later, they discovered it was actually a hybrid. Most of the Cox's sandpipers found so far have been males.

How Was This Bird Discovered?

The first Cox's sandpiper was seen in Australia in 1955. At first, people thought these birds were dunlins, another type of sandpiper. But as more of these birds appeared, especially between 1968 and 1975, people started to wonder if they were something different.

By 1986, at least 20 of these mystery birds had been seen. They were mostly along the southern and eastern coasts of Australia. No one was sure what they were. Some thought they were unusual individuals. Others thought they were a new type of dunlin. Some even thought they were a special kind of hybrid that always looked the same.

To help figure it out, John Cox collected two of these birds in 1975 and 1977. He sent them to a museum in America to compare them with other birds. They found out these birds were not the same as other known species. In 1981, a live bird was caught and photographed. Then, in 1982, a scientist named Shane A. Parker officially described it as a new species.

For a while, many people believed the Cox's sandpiper was its own species. It was even listed in bird guides. But scientists still wondered if it might be a hybrid.

What Does a Cox's Sandpiper Look Like?

Cox's sandpipers are about the same size and shape as pectoral sandpipers and sharp-tailed sandpipers. Their bill, which is their beak, is quite long and blackish. It usually droops down a little, and sometimes has a yellowish color at the bottom. Their legs are a dull brownish-green. When the birds are resting, their wings stick out just a bit past their tail.

Plumage and Colors

Scientists have never seen a Cox's sandpiper in its full breeding plumage. This is the special, colorful feathers birds get when they are ready to mate. All the adult Cox's sandpipers seen so far have been in their non-breeding plumage. This means they have their regular, less colorful feathers. However, some have started to get a few breeding feathers.

When they are not breeding, these birds are brown-grey on top and white underneath. They have a brown-grey band across their chest. They do not have streaks on their sides. When they start to get breeding feathers, their chest and ear areas get a bit rusty. Some streaks appear on their sides. Also, the feathers on their upper body change. They get black centers, grey tips, and buff or light brown edges.

Only two young Cox's sandpipers have been seen. One was in Massachusetts, USA, and the other in Japan. Scientists think they were Cox's sandpipers because of how they looked. These young birds looked a lot like young pectoral sandpipers. But they did not have a clear chest band. The bird from Japan did have strong streaks on the sides of its chest. These young birds also had a lot of white feathers on the top of their tail.

Where Are These Birds Found?

Most of the Cox's sandpipers found so far have been in the more populated southern and southeastern parts of Australia.

Sightings Outside Australia

In September 1987, a mysterious young sandpiper was seen in Massachusetts, USA. Scientists thought it might be a Cox's sandpiper. They watched the bird in nature and also caught it to examine it closely. They even put a band on its leg. Several reports were written about this bird.

In August 2001, another young sandpiper was found in Japan. This bird also had features of both pectoral and curlew sandpipers. It was believed to be another young Cox's sandpiper. Pictures of this bird were published in a bird magazine.

The Mystery Is Solved!

The big mystery of the Cox's sandpiper was finally solved in 1996. Scientists used special tests to prove that these birds were indeed hybrids. They looked at the DNA of three Cox's sandpiper specimens. DNA is like a blueprint for living things.

They found that the DNA from the mother's side of the Cox's sandpiper was exactly the same as that of a curlew sandpiper. They also looked at other genetic markers. These markers showed a mix that matched curlew and pectoral sandpipers. This mix did not match any other bird species that were thought to be possible parents.

Since the mother's DNA comes only from the mother, scientists figured out the parents. They concluded that a male pectoral sandpiper and a female curlew sandpiper are the parents of the Cox's sandpiper. This solved the long-standing mystery of this unique bird!