Birdwatchers in Kansas are seeing a bright yellow visitor that, until recently, wasn’t expected to breed in the state.

The bird is the Prothonotary Warbler – sometimes referred to as the PROW – a small, brilliantly colored songbird that has established breeding populations in parts of southeast Kansas. Researchers are now using tiny tracking devices to learn where these birds go when they leave – and the results are revealing just how extraordinary their annual journey can be.

For anyone in eastern Kansas with a bird feeder, nest box, or patch of woodland nearby, this species is well worth looking out for. 

Image credit: Karlus Morales

A bright yellow bird is making itself at home in Kansas

The Prothonotary Warbler – not to be mistaken with the Northern Yellow Warbler – is roughly palm-sized, with striking golden-yellow bodies, blue-gray wings and a distinctive appearance that has earned them plenty of attention from local birdwatchers, especially those in the state of Kansas.

A population has become established in southeast Kansas, with researchers describing the area as the possible westernmost part of the species’ breeding range. The birds have been recorded as far west as Wichita, although the main breeding activity is concentrated farther east.

Image Credit: Birdlife Datazone

According to one news report, a local resident (Kathy Fox) near Pittsburg, Kansas, discovered the birds nesting in bluebird boxes back in 2023. She initially assumed the yellow birds were simply “migrating through” before realizing that they were actually staying to raise their young. Now researchers want to understand why.

Why are Prothonotary Warblers breeding in Kansas?

Prothonotary Warblers are strongly associated with forests and wooded wetlands. Researchers studying the Kansas population believe that changes in the landscape have created suitable wooded habitat in areas that were previously used as strip mines. This alone could be helping the birds establish themselves farther west than they traditionally would have.

If the birds continue to thrive in southeast Kansas, researchers may be able to learn more about how bird populations expand into new areas and how changes to habitat can affect where a species breeds.

The birds appear to be doing relatively well in eastern Kansas, with researchers noting that their numbers are better than in many other parts of their breeding range.

Scientists are tracking the birds on a 5,000-mile journey

The Kansas population has also given researchers a remarkable opportunity to study their impressive migratory journey. A team led by Pittsburg State University graduate student Gabe McClain has been fitting male Prothonotary Warblers with tiny geolocators – lightweight tracking devices that record information about the bird’s movements – since June, 2025.

As you can imagine, researchers are careful about the weight of the tracker to ensure it doesn’t impact the bird’s migratory journey, making sure the devices account for a minute percentage of the bird’s overall body weight. The devices collect data at regular intervals, but the information cannot be downloaded until researchers recapture the bird and remove the tracker – similar to the trackers you see on many fish species caught with. 

Fortunately, after an incredible 5,000-mile journey, one male Prothonotary Warbler returned to the exact same bird box where its journey began. The bird, named Hydrogen, gave researchers a remarkable insight into its migration.

His journey began in June of 2025 around Kansas City and ended in late October as far south as Bolivar, Columbia – where he enjoyed the rich resources of food from the warmer climate before heading back north. That’s an incredible journey for a bird small enough to fit comfortably in the palm of your hand.

Since then, the number of birds being tracked has increased exponentially, giving researchers a broader range of data to conclude from. 

The perfect time to spot a Prothonotary Warbler before they head south

The timing of this research is particularly interesting because late summer marks the beginning of the fall migration period for many North American birds.

Prothonotary Warblers that breed in Kansas don’t remain there year-round. They eventually head south toward their wintering grounds in South America. That means birdwatchers in Kansas and surrounding states are entering a period when they could potentially see these striking yellow birds before they disappear for the winter.

Fall migration is already starting across parts of the United States, with more species expected to move south as August gives way to September. Recent observations from Kansas wetlands, for example, show early migrants beginning to appear while summer residents remain in the area.

For birdwatchers, that makes the next few weeks particularly interesting.

How to spot a Prothonotary Warbler

If you’re in southeast Kansas, look for a small bird with bright golden-yellow plumage and blue-gray wings, particularly around wooded areas and wetlands.

The species is also unusual among warblers because it readily uses cavities for nesting. In Kansas, researchers have been monitoring hundreds of nest boxes across multiple locations to study the birds’ breeding behavior. The current research project has expanded considerably, too.

Researchers placed 36 trackers on birds this year, compared with just six the previous year, giving them a much larger amount of information to work with.

For local birders, that means the seemingly ordinary yellow bird appearing around a nest box could actually be part of a much bigger scientific story.

A tiny yellow bird is revealing how migration is changing

The Prothonotary Warbler’s growing presence in Kansas is more than just an interesting new bird sighting.

It gives scientists a chance to watch a population establish itself near the western edge of its breeding range while simultaneously tracking individual birds across thousands of miles.

And as fall migration gets underway, some of those birds will soon leave Kansas on another remarkable journey south.

So if you’re in southeast Kansas and spot a flash of brilliant yellow around a woodland or nest box, take a closer look.