Tag Archives: Birds

 

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Birding

Better Know a Bird: The Clark’s Nutcracker and Its Obsessive Seed Hoarding

Hiding away tens of thousands of pine seeds every year makes the nutcracker a prolific natural forester.

One sunny day in California’s Sierra Nevada Mountains, Diana Tomback met her first Clark’s Nutcracker. As she rested under a pine tree, she noticed a bird wrenching scales from a pinecone. Its persistence in stabbing the cone with its bill, peeling off the scales, and extracting individual pine seeds mesmerized her. She had to know more, and when a park ranger ambled by, Tomback demanded information. That bird, the ranger said, was a ‘pine crow,’ and the tree was a whitebark pine.

When she returned to graduate school, she was determined to find out more. “I was utterly consumed by this bird, its behaviors, and the interaction with the whitebark pine,” Tomback says. A bit of research revealed this ‘pine crow’ to be a Clark’s Nutcracker. But she couldn’t find much else. The Eurasian Nutcracker had been studied in Russia, Germany, and France, but there was little known about its North American cousin.

“I realized: My gosh, what an incredible bird and interaction to study,” she says. So Tomback devoted herself to the cause. Since the 1970s, Tomback, who’s now an ecologist at the University of Colorado, Denver, has published dozens of papers about the Clark’s Nutcracker. Along the way, she’s discovered that the birds are more remarkable than she imagined. Clark’s Nutcrackers are winged foresters, whose penchant for hoarding seeds contributes to the growth of new pine forest.

A Craving for Cones
Clark’s Nutcrackers are experts at the difficult art of freeing seeds from pinecones. Each cone contains dozens of seeds, which are inaccessible to most animals until autumn when the cones open and spread their protective scales. But nutcrackers don’t have to wait. As stiff, unripe cones become available each July, they jab their strong, piercing bills between scales to loosen and tear out bits of seeds.

It’s not easy work. Clark’s Nutcrackers spend so much time hacking apart pinecones that sticky resin sometimes dyes their grey feathers a reddish-purple color. But the prize is worth the effort: Pine seeds are a nutritious food, packed with fats, proteins, and carbs. They are so rich that it doesn’t take many to satiate a nutcracker’s appetite—and it’s then that the bird’s habits get really interesting.

Photo: Marshal Hedin/Flickr CC (BY- SA 2.0)Hide and Seek
While other birds prepare for winter by feasting and fattening up for lean times, these sleek gray corvids use their landscape as a larder. After a Clark’s Nutcracker eats its fill of pine seeds, it stores the rest—upwards of 100 pine seeds at a time—in an expandable pocket below its tongue.

The bird then flies around the forest, burying clusters of four or five seeds in the soil; during peak pinecone season, it will cache up to 500 seeds per hour. By the end of the fall, each nutcracker has stashed tens of thousands of seeds, a food source it relies on throughout the winter.

Remarkably, the birds manage to find their caches later. They often hide seeds near the base of tree trunks, a tendency “that may play an important role in their spatial memory system,” Tomback says. Landmarks help nutcrackers remember the precise locations of caches, so they can retrieve and eat seeds when trees are coneless and the weather turns cold.

“These birds probably remember up to 10,000 caching locations” at a given time, says ecologist Mario Pesendorfer of the Cornell Lab of Ornithology. But their memory fades over time. Within nine or 10 months, many uneaten seeds lie forgotten beneath the forest floor.

Foresters with Wings
Nutcrackers often bury their seeds at the perfect depth for germination, and given time and a bit of luck, abandoned seeds will sprout and grow into new trees. In this way, their overzealous seed hiding means that Clark’s Nutcrackers play a critical role as foresters, planting new generations of pine trees that conveniently spring up from the oversupply.

Crucially, the birds will hide seeds as far as 20 miles away from their source trees. In doing so, they help trees expand their territory into new areas. As development continues to fragment forests and climate change demands rapid migration, “animals that move between patches of habitat are increasing in importance,” Pesendorfer says.

Nutcrackers have an especially close relationship with the whitebark pine. Even in the fall, whitebark pinecones don’t open on their own; the seeds remain trapped behind tightly locked scales. It’s largely up to Clark’s Nutcrackers to free those seeds with their hammering beaks and then help spread them. Also unlike other pines, whitebark seeds don’t have “wings” that let them ride gusts of wind across the landscape. Instead, the seeds and cones seem optimized for a nutcracker’s bill, and as such, the trees rely on the birds’ forgetfulness to reproduce.

The relationship has served both species well, but researchers are growing worried because whitebark pines are now in decline. A deadly fungus called white pine blister rust is spreading through the West’s pine forests. Simultaneously, mountain pine beetles are chewing through the trees, a problem made worse by climate change. The loss of pinecones shouldn’t threaten Clark’s Nutcrackers; they can feed on a variety of seeds and cones along with insects and fruits, so they are safe for now. But as whitebark pines vanish from the landscape, they will produce fewer seeds, and the birds that once helped them proliferate might not be able to cache enough to sustain the tree.

However, it’s possible that the birds could play a part in helping the whitebark pine recover. Human foresters are now studying how to attract Clark’s Nutcrackers to aid in forest restoration. As fantastical as it sounds, this isn’t an unprecedented effort. Since at least the 1950s, German foresters have harnessed the abilities of another scatter-hoarding corvid, the Eurasian Jay, to their advantage. Instead of doing the hard labor of replanting oak trees, they put out buckets of acorns and “let the jays do their thing,” Pesendorfer says. It’s estimated that the jays plant up to 1,600 oaks per acre. If Clark’s Nutcrackers could do the same—but with whitebark pine seeds resistent to blister rust—they could be the savior’s of the West’s pine forests.

 REPOSTED FROM AUDUBON

 

Whooping Cranes

Should the Whooping Crane Shooter’s Fine Have Been Higher?

The Texas man who killed two of the endangered birds will pay $25,810—one-fifth the cost of raising a single Whooping Crane to adulthood.

On Tuesday, a 19-year-old man received his sentence in the case of two dead Whooping Cranes, marking a victory for the Endangered Species Act. Earlier this year, Trey Joseph Frederick from Beaumont, Texas pleaded guilty to shooting and killing two of the endangered birds near the Louisiana border, a misdemeanor under the act.

U.S. Magistrate Judge Zack Hawthorn sentenced Frederick to five years probation, during which time he’s not allowed to hunt, fish, or own firearms. The judge also ordered Frederick to serve 200 hours of community service, the most in the court’s history, with either the Texas Parks and Wildlife Department or the U.S. Fish and Wildlife Service, and pay a $25,810 fine that will be divvied up between the Texas Parks and Wildlife Foundation and the International Crane Foundation (ICF).

“This ruling has set a powerful precedent for the future of Whooping Crane conservation,” ICF president Rich Beilfuss wrote in a press release. “This was not hunting. This was an act of criminal vandalism.”

With successful prosecutions under the Endangered Species Act a rarity, the sentence is being championed as a victory for conservationists. But when the staggering cost of raising Whooping Cranes in captivity is considered, it might not be quite the victory that it appears.

Whooping Cranes are expensive. The price tag to raise and release just one bird from an egg can exceed $110,000. That money pays for food, housing, caretaking staff, and breeding—and for some birds, there’s also the cost of flight school. Before young birds are released to the wild to join a migratory flock, they go to Wisconsin, where they are trained to follow ultralight aircraft to prepare for fall migration—a process that isn’t cheap. (The two cranes killed by Frederick did not attend flight school; they were part of a non-migratory flock of 46 young cranes.)

Based on the costs of raising a single Whooping Crane to adulthood, the ICF proposed a fine of $113,886 per bird to the judge, a proposal that gained the support of the U.S. Probation Office. In comparison, the judge’s fine of $12,905 per bird is paltry. “The fine that he got was significant, but of course we would have liked to see something higher,” says Lizzie Condon, ICF’s outreach specialist. In the only other Endangered Species Act case in which a Whooping Crane was shot, a South Dakota man was forced to pay $85,000 in 2013.

More than the money, Condon is concerned about losing additional whoopers to gunfire. “In the most recent decade, there has been an alarming increase in the number of Whooping Crane shootings,” she says. Between 1967 (which was the year the species was listed under the Endangered Species Act) and 1999, there were only 5 documented shooting cases, Condon says. But in the past 5 years, more than 20 birds have been shot.

To better understand why shootings are on the rise, Condon surveyed Alabama residents to gauge the level of knowledge about the endangered birds. She found that people were completely unfamiliar with the bird and its status. “People in Alabama don’t know what Whooping Cranes are because they only started encountering them in 2004,” she says. “They didn’t know what they were, and we weren’t telling them. We’re working hard to try and change that.”

The problem, Condon says, is that in the past decade efforts to save the species from extinction became the primary concern, and raising awareness and public knowledge about Whooping Cranes fell behind. She wants the Whooping Crane to be viewed with the same respect and appreciation as the Bald Eagle, a bird with which no gunowner could claim unfamiliarity. To that end, the ICF reaches out to schools and hunting groups, displays billboards featuring the birds, and have released public service announcements on the radio.

As community outreach efforts continue, Condon says the ICF’s main goal is to get the shootings down to a “sustainable level.” That is to say, a level that current populations can handle. Shootings account for 19 percent of known mortality in eastern migratory Whooping Crane populations, and 24 percent of mortality in Louisiana non-migratory populations. Condon hopes to reach a day where shootings only account for 5 percent of known mortality, though even that number is still too much for her. “I don’t like saying that because, for me, shooting a Whooping Crane is never going to be acceptable,” she says.