Up Close with Cranes

Sandhill cranes have been returning to the Platte River in central Nebraska for centuries. (Photo by Ariana Brocious, NET News)
Wet meadows form part of the critical habitat cranes depend upon each spring. (Photo by Ariana Brocious, NET News)
The Crane Trust is using small, camoflauged cameras like this one to capture thousands of up-close images of the cranes. (Photo by Ariana Brocious, NET News)
Sandhill cranes return to the Platte River at night to roost and keep themselves safe from predators. Nighttime river behavior will be the focus of the camera research this spring. (Photo by Ariana Brocious, NET News)
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March 20, 2014 - 6:30am

For decades, scientists have studied the annual migration of sandhill cranes through central Nebraska. A new project is using time-lapse cameras to capture and study crane behavior.

Much of the ground was still frozen on a recent March afternoon on Mormon Island in central Nebraska. This “island” runs for several miles between two channels of the Platte River. Mary Harner, director of science at the Crane Trust, leads the way to a wet meadow: low-lying, undulating grasslands near the Platte, carved by older flows of the river.

Photo by Ariana Brocious, NET News

Wet meadow habitats are very rare and important for cranes, said Mary Harner, director of science at the Crane Trust.

"It’s difficult to take a close look at what the birds are doing because just by physically being there as a human we disrupt their natural behavior. This kind of camera technology is a way to get in close with the birds without altering their behavior."

Standing on an ice-covered portion of the slough roughly 20 feet across, Harner explained once the ice melts, this area will have flowing water. These aptly-named wet meadows are closely connected to the groundwater just below the surface, and usually marsh-like in spring and summer. Their moist soil makes it easier for birds to find bugs and plants to eat.

Last spring, Harner and other researchers set up 10 game cameras over multiple sites in the meadow. The small, camouflaged cameras were set up to take pictures every half hour or when they detected motion.

“We had cameras paired between the low wet areas and the nearby drier areas going from south to north across this island,” Harner said.

More than half a million sandhill cranes depend upon this shallow river, its sandbars and nearby wetlands to rest and feed on during their annual spring migration, Harner said. But much of their critical habitat has disappeared. The Crane Trust is one of several organizations working on conserving what remains along the central Platte, using methods that mimic historic forces on this river habitat — like fire and grazing.

Greg Wright is wildlife biologist at the Crane Trust: "There’s a lot of preconceived notions about what these birds do in these wet meadows, but no one has ever done a study of this type so we didn’t exactly know what to expect."

The Crane Trust left one camera in the field year-round, elevated and with a fence to protect it from grazing cattle. Now that it's spring, Wright will remove the fence and drop the camera back down to crane height, about two to three feet from the ground.

Photos by Ariana Brocious, NET News

“These wet meadow habitats are very rare. They’re one of the first habitats to be lost when river flows are diminished and floodplains are converted from their natural state. So we’re here to first and foremost protect the remaining grasslands and meadows like this,” Harner said.

Harner and her colleagues think these cameras might help them learn more about how and why the birds use these areas, which will help their conservation work.

Paul Johnsgard, a renowned ornithologist and retired biology professor at the University of Nebraska-Lincoln, has spent his career studying cranes and other birds.

“Spring biology of cranes is really important because these six weeks or so that the birds spend in the Platte Valley are critically important for them to acquire the amount of fat, energy, that the need for the rest of their spring and summer activities. So it really is important to get this kind of data,” Johnsgard said.

Crane video cameras have been around for a while, but most of the information about cranes has come from aerial surveys, thermal imaging, and people watching from wildlife blinds. Using the cameras to get thousands of up-close images offers a different way to study sandhill crane biology.

“You get an enormous sample of thousands of data points and from that you can look at them statistically and figure out exactly what percentage of time birds are doing different things. It gives a set of real data instead of general perceptions,” Johnsgard said.

That data would be almost impossible to get without human presence affecting crane behavior, according to Greg Wright, wildlife biologist at the Crane Trust. Part of the initial study involved figuring out where to put the cameras, said Wright, “We didn’t know exactly how they would respond to these cameras being out there. The camera is small and fairly discreet, and it’s camouflaged but still, in a grassland, anything sticks out.”

Crane Watching in Nebraska: 

There are numerous crane-related events in Nebraska in March and April. Here's a small sample:

The Crane Watch Festival: March 21-30

This year's festival will continue the tradition with a calendar of fun-filled, educational, family activities, entertainment and community-wide events taking place in Kearney, Gibbon, and Minden. 

Audubon's Nebraska Crane Festival: March 21-23

Current festivals focus on wildlife and environment education in general, with family-friendly activities and famous field trips to crane blinds along the Platte River and bird migration stopovers in central and southern Nebraska.

Visitors can also arrange crane viewing blind tours through the Crane Trust and Audubon's Rowe Sanctuary.

Events at the Ian Nicolson Audubon Center at Rowe Sanctuary:

March 29, 3 pm & 7 pm - Heather Henson's FLIGHT: A Crane's Story

"FLIGHT: A Crane's Story" explores nature's deepest mysteries and the spiritual essence in the cycle of life on earth through the story of an orphaned crane named Awaken. This is an interactive performance using puppetry, kiting, and music from indigenous North America.

March 29, 2 pm - Migrating with the Sandhill Cranes

Join photojournalists, birders and adventurers, Erv Nichols and Sandra Noll on their eight month photo-journey following sandhill cranes from their wintering grounds at Bosque del Apache National Wildlife Refuge in New Mexico to northern Alaska. Cost is $5 per person.

April 5, 10 am to 4 pm -  Crane Carnival 

Audubon's Rowe Sanctuary is hosting the tenth annual Family Crane Carnival, a one-of-a-kind carnival for all ages with an emphasis on fun and learning. This is a great opportunity to learn about cranes and their habitat in a hands-on setting. Free to the public.

Wright said their time-lapse photography approach builds on previous wildlife studies, and cranes make an ideal subject for this kind of technology because of their “fidelity” to the Platte River, where they’ve returned year after year, for centuries.

“The nature of cameras, when you can’t move them, you need a bird that has some sort of fidelity to a site. Other than nests there’s not too many places that birds return to again and again in a way that you’d have enough images to be able to discover a pattern. Cranes fit that bill,” Wright said.

The idea for the study came from an existing partnership with the University of Nebraska’s and NET Television’s Platte Basin Timelapse project, which has been collecting time-lapse images across the river system for the past three years.

Harner said changing technology has recently made these kinds of studies much cheaper and easier for researchers. Photos and videos are also more accessible for the general public than papers or graphs, Harner said, “being able to show how the groundwater is pulsing and how these grasslands are essentially breathing … it just brings it to life in ways that are nearly impossible to visualize otherwise.”

Student interns helped classify more than 67,000 unique behaviors from tens of thousands of images collected last March and April. Wright said their initial findings show cranes tend to congregate in the wetter parts of the meadows, where they did more bathing and resting, compared to drier upland areas, where they mostly ate and moved around.

“I think we were surprised that there were these strong differences between the uplands and the sloughs — the water areas,” Wright said.

Camera data also offered rare glimpses of birds spending the night in the meadows, rather than returning to the river as they normally do. This spring the Crane Trust will use the cameras to study nighttime behavior of cranes on the river, Wright said.

“We don’t know what the birds are necessarily doing. We know they stay on the river. But to be able to have a camera right there on the roost and see those birds throughout the night … We’ll be able to see their activity pattern through the night,” Wright said.

The project should help researchers and the public alike learn more about Nebraska’s annual winged travelers.

Watch NET Television's high-definition documentary "Crane Song," a stunning visual essay of the sandhill crane's migration through Nebraska.



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