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Watching The Nests

The Dramatic Recovery and Wide-Open Future of the Southwestern Bald Eagle

By Tony Padegimas

Arizona Game and Fish/James Driscoll

Eyes on Luna Lake - When the Luna Lake fledglings are 6 weeks old, biologists from Arizona Game and Fish will come out to give them their check-up. Ken Jacobson (see main article) or biologist Kyle McCarty makes his way with rope and harness up the 113-foot Ponderosa pine tree to the nest. There, he places a hood and some booties over one of the chicks, places the chick in a special duffel bag, and lowers it down to Joe Peddie, who is going on his sixth season as the Luna Lake nest-watcher. Peddie then helps do the health check: weighing the bird, checking the craw to see if and what the fledgling has eaten, and measuring the length of the beak and talons. They also measure the ankle to affix an identification band, and also to determine the sex of the bird. Eagles have no external sex organs. The only way to tell boys from girls is at the ankle. Due to the reverse dimorphism of the species, the females will have larger ankles. All of this data will eventually lands in a national database. The fledgling is then affixed with metal bands: the silver USF&WS band and a color-coded AZGF band with prominent number codes. At least 75 percent of Southwestern Bald Eagles have been banded. Juveniles wearing these bands have been spotted as far north as Wyoming, and nesting adults from northern Mexico, across Arizona and into the lakes of northeastern New Mexico. "Anything that can get me out in nature is something I want to do," Peddie said. "The most exciting thing I've seen was when the male jumped out of his favorite perch to come blazing after some geese," he recalled. The eagle broke the back of the first goose with one strike. As the goose sank into the lake, the eagle dove in after it. "A lot of people do not know this, but eagles are good swimmers," explained Peddie, a former biology teacher. "The eagle swam back to shore with the dead goose, bigger than he was, in tow." Peddie sets up his observation post in the parking lot near the boat ramp. The eagle nest sits in a small meadow on the opposite shore of the lake. Bird watchers are invited to join him on his side, but the meadow across the water is closed to entry by foot or boat throughout the nesting season. Peddie says he has to chase out people who violate the closure two or three times a year. He has the power to issue .U.S. Forest Service tickets but rarely does so, assuming the trespassers leave when asked. "There's no set time when they forage," Peddie explained, "but if you're out there for three or four hours, you're bound to see something. In deep winter, when ice covers much of the lake, the eagles hunt the coots (and sometimes geese), which gather by the open pools of water. As the lake thaws, their diet becomes mostly fish. By the end of July, though, the fledglings will have flown off to begin their five-year fly-about, and Peddie will go even higher up the slopes to watch the pair at Crescent Lake. Crescent Lake sits at a lung-busting 9,400 feet elevation, and the pair living there starts their breeding a month later than their relations on the balmy shores of Luna Lake. The male at Crescent, according to his band, hatched at Luna Lake. - T. P.

The eagle swoops down from where he has been circling to glide within a yard of the cold, steel-blue surface of the lake. He slows his speed with two half-flaps of his 6-foot wings, and then thrusts his talons into the water. He takes several more swift, determined flaps, before he begins to pull away from the lake, a silvery fish dangling from his talons.
The eagle circling over the waters of Luna Lake near Alpine, Ariz., is exceptional in several ways. While eagles have always migrated south to this lake and many like it every winter, this 20-year-old male, and his 17-year-old mate, have lived here year round since 1994. They represent the first known breeding couple of the Southwestern Bald Eagle in the White Mountains, which hug the border between Arizona and New Mexico.
Bird lovers obviously hope that many more will follow, and while there are reasons to be optimistic about this, there are just as many reasons to doubt not only the growth but the very survival of the southwestern sub-population of this iconic raptor.
A Distinct Species
In Apache lore, giant eagles once grew large enough to prey upon mankind. A warrior tricked one of these eagles into capturing him and, while the warrior feigned death, the great eagle dropped him into the nest for the fledglings to eat. There, he managed to ambush and kill both of the adult eagles. Then he cursed the fledglings to never grow any bigger than they already were. In general, desert eagles are smaller than their northern counterparts.
Ornithologist Robert Mesta of Tucson explains, "Any species within a hotter, dryer climate tends to be smaller. The Southwestern Bald Eagle definitely averages smaller in size compared to the northern Bald Eagle."
"There is definitely a separation of habitats; [they are] primarily an isolated population in the Sonoran Desert," he said.
Banding and tracking data [see sidebar, left] indicate that the Southwestern bald eagle, clustered mostly along the rivers and reservoirs of the central Arizona deserts, breed only among themselves, and are becoming a sub-species in their own right.
Also, Southwestern bald eagles breed in the winter to avoid the extreme temperatures of summer, as opposed to the northern branch, which breeds in the summer to avoid the snows of winter. There is ample and sad evidence that heat will kill an eagle chick every bit as fast as freezing cold.
Not even the adults are immune. Adult mortality in the Southwest runs 12 to 16 percent, while it is less than 10 percent among bald eagles that live elsewhere.
In Arizona, the bald eagles typically start laying one to three eggs in December. Those hatch in about 35 days, but the mottled gray fledglings won't leave the nest until May. Meanwhile, the parents take turns guarding them and hunting, providing meals of fish, rodents and carrion, but mostly fish.
Once able to fly and feed for themselves, the juveniles migrate north, sometimes as far as Canada, and will continue to wander back and forth, following the freeze line for 4 or 5 years. Only at full adulthood, when they have grown the distinct white head and tail-feathers, do they settle down near a river or lake to breed.
Once a pair starts breeding, typically after five years or so, they stay put year round, operating out of nests which can consist of as much as 60 pounds of sticks and twigs. They build nests in the tops of cottonwoods or pine trees, or on cliffs, but they prefer trees. From there, they produce an average of .75 offspring a year (compared to a .96 average in the northern populations). Do the math for a moment . . . raising an eagle is never a sure thing.
Bob Witzman, of the Maricopa Audubon Society, offered this as a prime example of why preserving and respecting the nesting sites is so crucial. He explains that humans approaching too closely to the nest will frighten off the adult birds, leaving them vulnerable to other predators, mostly other raptors.
"And that's true in all predatory bird nests. It's a horribly vicious war bringing up young." Witzman added.

Snowbirds that Just Stayed?
While the migratory range of bald eagles extends from Canada to Mexico, a breeding population in the central deserts of Arizona may be a new thing.
"The government has maintained in the past that there were no nesting bald eagles here (prior to the construction of the reservoirs)," complained Robin Silver of the Center for Biological Diversity. "The U.S. Fish & Wildlife Service has not respected this population as much as they would if they were here in historically large numbers."
"How many eagle biologists were here before 1850?" asked Witzman. "None!"
Ken Jacobson, who manages the bald eagle program for the Arizona Game & Fish Department, explained, "The historical status of the eagle in Arizona is not really well known. Our first sighting of a nesting eagle was in 1890, and that was up at Stoneman Lake. It wasn't until 1927, I believe, that the first eagles were found actually nesting in the desert."
Bald eagles (Haliaeetus leucocephalus) are essentially water-fowl. They hardly ever nest farther than a mile away from a large body of water. There are no natural lakes and very few perennial rivers in central Arizona. As canyon after canyon flooded with water held back by dams, bald eagles settled to nest.
Or maybe not:. The Apache and other local tribes claim eagles, giant and otherwise, have always been soaring around the river canyons.
Silver noted, "At one point we had 900 percent more riparian areas, and those have been destroyed by the reservoirs." Large sections of the Salt and Gila rivers, once perennial all the way to the Colorado, now remain dry due to impoundment upstream.
Recent history, though, is more agreed upon. As development increased around the reservoirs, highways, marinas and diversion pumps, the eagles flew out. In 1971, there were only three known nesting sites.
Now, however, the highest concentration of breeding pairs (one every 3.1 miles) is on the lower Verde River, between its confluence with Fossil Creek, and the chain of reservoirs it feeds. This portion of the river, where green water snakes through steep-walled desert canyons, has been designated "Wild and Scenic," and is bordered on either side by huge wilderness areas, so it runs, largely, as it has always.
For all we know, eagles could have been nesting here since the end of the last ice age.

Victims of Their Own Success
The comeback of the bald eagle is well celebrated and publicized, as the U.S. Fish and Wildlife Service (USFWS) removed it from the Endangered Species list in 2007. The change in status applied to all bald eagles, including the desert population, despite petitions from environmental groups and nativeNative American tribes.
When the USFWS rejected that petition, the Center for Biological Diversity and the Maricopa Audubon Society (with support from the tribes) took them to court. In March of 2006, Federal District Judge Mary Murguia ruled that the USFWS had made that decision arbitrarily, ignoringand in spite of clear scientific evidence that the central desert eagles qualify as a "discreet and significant" population under federal guidelines. She directed the USFWS to do the status report they should have done in the first place, which is due in October of 2009.
Meanwhile, the Southwestern bald eagle remains classified as a threatened species under the Endangered Species Act.
Jacobson is not worried.
"As far as how (the Endangered Species Act status) is going to affect the eagle here in Arizona, and affect the eagle program and all the work that we've been doing over the last 30 years on the eagles, it's not going to affect that at all. Arizona Game and Fish is continuing with their closures and their active management. . . . We see the benefit of that program, and that will continue regardless of what the Fish and Wildlife Service decides," he said.
The Nest Watchers
In 1978, volunteers from the Maricopa Audubon Society and the U.S. Forest Service started going out on weekends watching and counting nesting bald eagles. This year, 20 paid Nest Watchers will be dispatched to observe and protect nesting areas."It's part of a program that has saved the lives of over 50 eagle nestlings since it began in 1978," informed Jacobson. "That's equal to 10 percent of all the eagles that have lived to fly on their own in Arizona since the program started."
Some 20 to 25 areas throughout the state are closed, typically from January through June, to foot and boat traffic, to give the raptors the peace they need.
Watchers actually camp out in the breeding areas, on a 10-day-on, four-day-off rotation, for four months, keeping watch on the nests, and confronting (they use the word "educating") intruders into the nesting area.
"This is a pretty unique operation. I can't think of any others that would compare to it, especially not with bald eagles." Jacobson said.
The conditions are primitive, and the pay is marginal, but this year Jacobson expects 60 to 80 applicants for 20 positions.
Twenty-three different agencies, governmental, tribal and environmental, form the Southwestern Bald Eagle Management Committee, which funds the Nest Watch program. Since 1991, Arizona Game and Fish has been the "implementing" member, meaning that they organize the Nest Watchers, among other things.
"With the 23 organizations on that committee there's a ton of resources at our fingertips," said Jacobsen, "and when we need to do something, we can act fast . . . and keep them from becoming a big problem."
Arizona Game and Fish also has an aggressive banding program. Nest Watchers will climb or repel to nests, measure the fledglings and fix them with ID bands: the silver USFWS band and a color-coded Arizona Game and Fish band with prominent number codes. Birds wearing these bands have been spotted from southern California, though northern Mexico, and into the lakes of northeastern New Mexico.
As of 2008, Arizona Game and Fish has identified 56 breeding areas. Forty-eight have breeding pairs, for 53 total breeding pairs. They produced 52 fledglings last year - a record. According to the 2008 mid-winter bald eagle count, covering 105 standard routes by foot and helicopter, there were 325 bald eagles in Arizona last winter. The survey identifies an average of three new nesting areas every year.
"It will take about five years before we start seeing that effect (of record fledglings) in the breeding population. So here in the next few years we'll start seeing those more sparsely populated breeding sites get filled in,." said Jacobson.

Pressure from Every Direction
The eagles aren't the only species whose population is increasing dramatically across the central parts of Arizona. Prescott may double in size and Phoenix could triple in size over the next few decades, threatening the aquifers that feed both the Verde and the Salt Rivers. Not to mention increasing development along the shrinking reservoirs.
While the birds themselves are protected by multiple layers of state and federal law, only the Endangered Species Act, and land management policies of the scattered agencies and tribes which own the land, protects their habitat.
Asked about the biggest threats, and the eagle experts have a hard time deciding.
"Cattle grazing is the worst thing of all for the bald eagles, because they eat the saplings that grow along the river bank like they were ice cream," said Witzman.
Silver notes that loss of the natural riparian flood cycle has also devastated riverside saplings. Currently, many eagles nest in old-growth trees, but there are few if any new trees to replace them.
"The biggest threat over the eagle's head right now is the Prescott Pipeline," said Silver, referring to the huge water-diversion project proposed to provide the growing communities of Prescott and Prescott Valley with water. "If and when that pipeline is completed, it would suck dry the upper Verde River."
"Last year I would have had a different answer," added Mesta, "but today I'll say climate change. They've been able to adapt, but every year young bald eagles die from heat."
They all point out that eagles face constant danger from more localized hazards such as fishing line and random gunfire.
"We need to recognize that this population has increased because of intense human management. It requires our vigilance in order to survive," said Silver.
Yet Jacobson, the eagle vigilante, is still not worried, noting that all their population models have been "blown out of the water."
"In 1971, we still only knew of three breeding areas. In 1978 we only knew of 11. Today we're up to 56 breeding areas," he said. "I've invested seven years of my life into it at this point, and I've been real happy and surprised at the effectiveness . . . I don't see the eagles in the Southwest having a whole lot of trouble as long as we keep these strong partnerships. They're doing amazingly great right now."

Tony Padegimas is a freelance writer based alternately in Phoenix, Ariz., or in his hammock strung up in some random spot in the national forest. His book, Day and Overnight Hikes in the Tonto National Forest, is available from Menasha Ridge Press.