It’s dusk at the Navopatia Field Station, and a cacophony of warblers, willets and other birds fills the otherwise calm, still evening.
Navopatia is a small fishing town on the Agiabampo Estuarynear the Sonoran border with Sinaloa. And it’s part of what’s known as the Pitayal Costera — the densest concentration of organ pipe cactus (Stenocereus thurberi) — or pitayo dulce — in the plants’ range.
“It is a unique ecosystem. It’s not particularly large, but it is found nowhere else on the planet,” said Michael Krzywicki, director of the Navopatia field station. “So we wanted to understand how and what birds and other animals are using this habitat.”
For four months every winter, Krzywicki comes here to study the diverse resident and migratory birds in the coastal pitayal — a coastal thornscrub habitat where not only organ pipes but hundreds of species of cactus, herbs, grasses and shrubs thrive.
“It’s kind of an unusual assemblage of birds here,” he said. “I can’t think of many other places where you can be looking at a group of snowy egrets, reddish egrets, white ibis and long bird curlew and whimbrel in front of you and then you’re hearing verdins and broad-billed and Costa's hummingbirds behind you, you know a cactus wren singing. You can see a roadrunner go by as you’re also seeing an osprey fishing over the water.”
Biologists opened the field station in Navopatia — an Indigenous Mayo word meaning something like "the place of many prickly pear" — nearly 20 years ago to collect basic data about an ecosystem that was poorly understood, Krzywicki said. Since then, they’ve recorded more than 250 bird species and hundreds of plants.
Bird counts
Each morning, the research team counts birds in plots scattered throughout the pitayal.
“So this is a 200 by 200 meter plot. And each time we visit we try to take a different route throughout it, but still covering the majority of the space,” Krzywicki said, as we stepped out into a remote area of pitayal.
As we walked, he looked and listened for birds, jotting them down on a clipboard.
“Cactus wren,” he said in a whisper. “There’s also a northern mockingbird calling off that way. There’s a cardinal singing in that direction.”
Within 20 minutes, we spotted 12 species, including Gila and ladder-backed woodpeckers, house finches, verdins and blue-gray gnatcatchers.
This plot had previously been clear cut for a failed shrimp farm. Some have been impacted by cattle grazing, and others are undisturbed. The comparison helps researchers understand how land use changes impact birds — and the ecosystem.
“So far a lot of the same reasons that people enjoy watching birds as a hobby, they make great organisms to study,” Krzywicki said. “They’re out during the daytime — you know, maybe a bit earlier than our interns would like — you can identify them visually, and you can also distinguish them by their vocalizations, so you don’t have to be able to see the birds to be able to tell what they are. And they are also very diverse.”
That diversity means that studying bird communities can also shed light on what’s happening at other levels of the food chain as well, he said. And that information can help efforts to preserve this unique habitat, where towering columnar cactus meet leafy coastal mangroves and calm waters where bottlenose dolphins dive just off the shore.
It’s stunningly beautiful, but rapidly disappearing.
“I believe 40% of the pitayal has been lost since the turn of the century,” Krzywicki said. “Which is unfortunate because pitayas are relatively slow growing, so it will be challenging to restore these landscapes if that is ever the goal or the mission. And it’s challenging because it is much simpler to quantify the value of an agricultural field or a shrimp farm than it is with native habitat.”
Changing Navopatia
“I arrived here in 1960,” said field station cook Guadalupe Mendivil Alvarez, as she kneaded tortillas for that night’s dinner.
She was a child when her family moved to this remote coastal town of just four houses on the edge of the dense pitayo forest, she said. Much has changed since then.
“I wish we could go back to the Navopatia of yesterday,” she said, when this was just an isolated fishing village visited from time to time by tourists and researchers.
Though still remote, clear cutting for shrimp farms and agricultural fields has eaten up many of native plants her family — and generations of Indigenous peoples in this region — use for foodand medicine. Now, irrigation from those fields regularly floods the dirt roads, making Navopatia harder than ever to access.
“Fewer tourists come here now,” said Luis Fortino Mendivil Alvarez, Guadaplupe's brother, known to all as Tino.
He was sitting on the shore of the estuary mending a mist net researchers use to catch birds so they can gather demographic information and tag them with tiny metal bands. A lifelong fisherman, he’s an expert at repairing the fine net, and in the natural flora and fauna of the pitayal.
His family has long depended on tourism for extra income — selling hand-crafted goods and food and guiding tours. Now, they work also with the field station.
“And it’s a good thing they came here,” he said. “They changed my life.”
The arrival of the field station offered him opportunities to visit new places and learn about birds and ecotourism from experts around the state, he said. It’s also the best chance they have to preserve what’s left of the pitayal.
“It deserves to be protected,” he said. “Out here, we don’t have electricity or anything, but it’s better. We don’t have many comforts, but we have a lot of peace. And we want to protect that.”
The value of Navopatia
The Navopatia Field Station is working with other groups to create a protected area in the pitayal, said Krzywicki. And part of that effort is raising awareness.
“It’s hard to understand the value of a place like this unless you spend time here,” he said.
So they bring in student groups, ecotourism and interns from both the U.S. and Mexico to learn about this habitat and why it needs protecting.
“We take a lot of pride in providing educational opportunities for people to come in and be immersed in the habitat and ecosystem here,” he said. “Our hope is that through that we’re going to create more advocates that want to protect places like this.”
Enrique Sanchez said it worked for him.
“Coming here was like … wow!” he said. “I had no idea there was something like this in Sonora.”
Sanchez is an ecology student at the Sonora State University (UES) and was an intern at Navopatia this winter. He called it a hidden treasure.
It’s 6:30 in the morning, and we are kayaking across the Agiabampo Estuary to Isla Masocarit where we’ll do a bird count on a remote plot of island pitayal surrounded by mangroves.
Roseate spoonbills and yellow-crowned night herons perch on the branches and a mangrove warbler flits through the long roots as we approach the shore.
As we walked through the grasses and shrubs to the study area, Sanchez said he will never forget holding — and being bitten — by his favorite bird, a cardinal, while doing bird banding.
“People need to come here, because you learn everything,” he said. “Everything, everything, everything.”
He said there are few opportunities in Sonora to get the kind of hands on experience he has had as an intern at Navopatia, and he wants more people to get that experience and to see just how special this place is — before its range shrinks much further.
Conserving the pitayal
“Our goal is not to create a reserve and exclude people,” Krzywicki said. “Our goal is to promote this ecosystem and find ways that all the different parties involved in a place like this can coexist and thrive.”
The pitayal has always been an important part of people’s lives in this region, he said. The plants here are used as medicine; the pitaya fruit is a seasonal staple food, often sold as ice cream throughout the state; and even the plant’s ribs are used for building.
“The importance of the pitayal goes beyond what the data can tell us,” Krzywicki said. “And the simple message is, it’s worth saving.”
“Because it’s a habitat type found nowhere else, I think it’s worth saving. Because it is a part of our global biological and cultural heritage, it’s worth saving,” he said. “Change is a part of life, but as things change, it’s important to acknowledge and appreciate and protect these places when we can.”
That’s what Navopatia is trying to do.
