Project Protho

This Prothonotary is named Trillium, and was banded at Beidler in 2016. Photo: Joan Eckhart
This Prothonotary is named Trillium, and was banded at Beidler in 2016. Photo: Joan Eckhart

Project Protho

Have you seen the yellow flash of a Prothonotary Warbler as it flies through the swamp at Beidler Forest? Have you visited and watched these beautiful “swamp canaries” take food to their nests in cypress knees? Have you heard that loud, ringing, “sweet-sweet-sweet” song?

These tiny, beautiful birds are one of the mascots of Beidler Forest, a species that perhaps best exemplifies Audubon’s work in the Four Holes Swamp watershed. Prothonotary Warblers arrive in South Carolina from their wintering grounds in Central and South America around the beginning of April each year. Over the course of the following four months, they are frequently seen visiting their nests in cypress knees and hollow trees. Much to the delight of the thousands of visitors that come to Beidler each spring and summer, these birds often nest close to the ground and near the boardwalk, offering close observations of their nesting activities.

Audubon South Carolina’s research on this species at Beidler Forest started in 2008 with the launch of “Project PROTHO.” A phrase coined by former Center Director Mike Dawson, “PROTHO” stands for Protecting Resident Ornitholically-Tantilizing Hole-dwelling Occupants! This eloquent name summarizes the 15-year long research and community science project that’s been led by Beidler staff and center visitors. Each year, staff, volunteers, and interns capture and band the Prothonotary Warblers nesting near the boardwalk. This ongoing project allows us to learn about the nesting ecology of this species, and it has turned the sanctuary as a long-term research station for this species.

Though Audubon’s research on this species was started in the swamp long ago, the secrets of the amazing migration undertaken each year by these birds first came to light with one special bird nicknamed “Longshot.” You can read about Longshot’s awe-inspiring journey here

Looking for more information on this project, contact Matthew Johnson at

A Project Protho slideshow by Aaron Angel
A long distance migrant: Prothonotary Warblers are a cavity nesting bird whose habitat has been declining to the point where they've been listed as a species of special conservation concern.
Long-term data collection: By banding birds with color bands on their legs we can identify them as individuals, which then allows us to collect data such as behavior, territory, and migration time. Other data collected at time of capture includes weight, sex, age, wing length, tail length, flight feather wear, fat, and tarsus (leg) length.
Banding nestling Prothonotary Warbelrs: Only about half of juveniles survive past their first year, but by banding them from the nest we can get a more accurate assessment for their age when they are recaptured. Because of size constraints, there is a short window for banding nestlings, only on five days after they've hatched to ten days, a few days longer than that and they fledge from the nest.
Spring thru Summer as a Bird Conservation Technician: Technicians scout on the property for unbanded male Prothonotarys, taking advantage of the warblers' territorial behavior for targeted capture. Technicians also document resightings, check over 25 nest boxes throughout the swamp and monitoring the ones in use, and helping to capture and band them. In 2021, 13 adults, 2 hatch years, and 18 nestlings were banded!
Meet the 2021 Prothonotary Warblers
From top left to right: A prothonotary checks out a hollow in a tree limb. A male raises its head and sings in its territory. A prothonotary clings to the side of a cypress knee. Four nestlings are crammed into a nest box. Bottom left to right: A prothonotary wrestles with an insect almost as large as it is. A fuzzy hatchling is held in cupped hands. A fledgling stands on a branch.
Azalea has a red over orange band and was banded here in 2019.
Tupelo (left, female) has a double green band and was banded in 2021, while Mistletoe (right, male) has a double white and was banded in 2020. They built a nest together in one of our nest boxes.
Maple (male) has double red bands and was banded this year, and often sang around the visitor center.
Magnolia (male) has a white over yellow band, was banded in 2020, and nested in a natural hole in a cypress knee.
Sparkleberry (male), has a white over blue band, was banded in 2020, and mated with Laurel, she has a red over white band.
Dogwood (male) has a double white band, and was banded as Beidler in 2018, making him presently the oldest warbler to return to nest here.
Violet (male) red over blue, banded in 2021, and is known for his odd song. We're curious to see if he finds a mate next year.
Scarlet (male) has orange over red, banded in 2021, and is named for both his band colors and for a young girl who got to witness him being banded firsthand.
Future work for the program: continue monitoring and recapturing banded birds, deploy Motus nanotags (tracking devices) to learn their migration route, and work with other groups located along the warblers' migration route to ensure they're protected start to finish.

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On April ‎16, ‎2014, this bird, named "Longshot" was the first Prothonotary Warbler in Four Holes Swamp to be equipped with a geolocator and released Photo: Richard Covey
On April ‎16, ‎2015, Longshot was caught again after returning from Colombia, South America on his annual migration. Here the sensor of the geolocator is visible. Photo: Marcie Daniels
Geolocators have to be extremely light, less than a quarter (5.7 grams, 0.2 ounces) or it's too heavy for the bird. Photo: Richard Covey
Here's the route Longshot took traveling down to Colombia.

Want more details?  Check out the press clips below.  Want to volunteer?  Please be in touch!

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