Brave New World

Golden Eagle Chick. Photo by Ron Kellermueller

Perhaps it was a tussle over a food delivery. Or sibling rivalry. Maybe it was an ordinary exercise session gone amok, the furious pre-flight flapping that strengthens flight muscles in preparation for the aerial maneuvers that will come later. We will never know the real cause of the eaglet’s premature descent from her lofty nest. The wise biologist who had been watching the nest all season knew, however, that there should have been two eaglets still inside the safety of the sizeable stick fortress in which they had been born. The biologist began his search, and easily located the large female chick huddled in natal position on the ground, a behavior common to most unfledged nestlings. With only half-grown flight feathers, she was definitely too young to be out, yet putting her back was a physical impossibility. She would not be flighted for another week or so. Her chances for survival? Reasonable, particularly because she was already quite large, and few animals would attempt to prey on a chick of this size, particularly with defensive parents in the immediate vicinity.

Great Horned Owls do not build nests. As the earliest nesting species other than eagles, they merely select their preferred nest, add a nest lining, and set up housekeeping. Unfortunately, they are not known for their ability to select structurally sound nests. Many disintegrate as the young begin to move around. Such was the case of the nest watched by the female biologist, but its demise was particularly early, when the nestlings were only about 2 weeks old, still covered in gray down, and far too early to expect survival of the young. Two diligent searches a week apart failed to reveal any evidence of survival and this nesting attempt was declared failed. One month later, however, a songbird biologist conducting a survey in the same area called to ask if there had been a Great Horned Owl nest because he had seen two fledged owls and their attentive mother. Interestingly, the sighted trio was within 50 feet of the original nest.

The transmission line that runs through Ted Turner’s Armendaris Ranch bears a special name, “Maternity Row”, bestowed by ranch manager, Tom Waddell. Nearly every transmission tower holds at least one nest, and on average, there is an active nest on one of every two towers. Most are ravens, but Swainson’s and Red-tailed Hawks also crowd into the premium high-rise district. Management practices on this expansive ranch, just east of Elephant Butte Reservoir, are intended to foster healthy populations of all wildlife. The Chihuahuan desert ranch positively teams with life in all shapes and sizes, from large ungulates including Oryx, pronghorn, and bison, to endangered turtles, prairie dogs, Burrowing Owls, bats, and cicadas. In fact, I had never before seen so many cicadas in my life. It was a smorgasbord of food, enough for everyone even the sizeable families of quail with golf ball-sized young speeding along on invisible legs.

We were there to look for a particular nest, one that held two very precious nestlings, the first of their kind in New Mexico – Aplomado Falcon – another species that does not build nests, but generally uses existing nests in oversized yuccas. However, when a bird is reared on a wooden structure, perhaps it views that as the most desirable nest location. One tower held a smallish nest, located in the shade of the crossarms above. It was insignificant in size compared to the others, but I got the scope out just in case. As I watched through the lens, one tiny white fuzzy head bobbed above the nest rim, soon joined by another. Precious cargo here, watched and loved by ranch management and biologist alike, a success story just one year following the first release of 11 young, by the Peregrine Fund in August 2006. Chances of survival for these two chicks are mixed. Birds that attempt nesting when they, themselves, are less than one year old, may not be sufficiently skilled hunters to provide for their young. Here, however, watchful human eyes keep a close, but distant eye on the nest, and food limitations are certainly not a problem.

The woman called to tell me that she and her family had discovered a nest with five featherless nestlings on their boat. She wasn’t asking for information, just telling me about her discovery. As politely as possible, I asked how they had handled the situation and suggested that the best thing to do was to either return the nest to an area very near where the boat had been or to transport them to a wildlife rehabilitator. Her response was to say that they had already driven five miles before the discovery and did not want to take the time to put them back. Instead, they had placed the nest on the ground under the shade of a tree (five miles away from the original location). The disastrous phone call continued as the woman went on to tell me that ‘these birds’ need to learn not to build their nests on people’s boats. So ‘these young’, species unknown, had no chance for survival, and indeed the woman reported that by the next morning only the centermost nestling was still alive. I still haven’t figured out why she felt the need to display her ignorance in this way.

Many chicks of all species end up on the ground before they can fly. It is a stage called ‘branching’ and the young are indeed quite vulnerable at this stage even though it is part of their normal life cycle. The parents continue to feed and care for their young, while at the same time, teaching them to find and consume appropriate food. Most baby birds, especially those that have almost all of their feathers do not need to be rescued.

Another myth is that a mother will reject a baby that has been handled by humans because of the human scent. This is not true. If you can find the nest, the best thing to do is to put the youngster back into the nest. If you cannot find the nest, which is probable because birds hide their nests for protection, then you can build a nest to hold the baby bird.

Find a margarine tub, or similar shape and puncture it with drainage holes. Line it with tissue for support and warmth. Nail the container to the tree as close as possible to where the bird was found, making sure that the location will remain shaded and protected as the sun moves. Watch for a parent to find the nestling and continue to care for it. Monitor for at least two hours. If you still have concerns, contact a wildlife rehabilitator. Two different groups are within an hour’s drive of Jemez Springs. The Wildlife Center, (505-753-9505) located in Espanola, takes all kinds of animals including bears, mountain lions, reptiles, bats, and birds. In Albuquerque, Wildlife Rescue (505-344-2500) takes all species of birds, as well as some small mammals. If you have an injured or orphaned raptor, Hawks Aloft (505-828-9455) will assist you in making sure that the bird gets to a rehabilitator.

Of the four vignettes above, three sets of young were not in need of human interference. Only in the case of the last incident, should humans have taken a different course of action.

Hairy Housepecker and Co.

Hairy Woodpecker photo by David Powell

Aah! A beautiful spring morning, about dawn actually. Jemez locals know only too well how peacefully quiet a mountain home can be at that time of the morning. It was perfect for a little extra snoozing, resting my weary body after a long hike the previous day. I snuggled deeper under the covers. Sheer bliss!

Bam! Bam! Bamm-bamm-bamm!

I tried to ignore the familiar sound, hoping it would go away. No such luck. Apparently my friend, Hairy, was an early riser. It sounded like he was going to drill right through the walls and into my bedroom! Maybe even into the side of my skull! In the spring, the ever increasing daylight brings out the lust in all things feathered. Male songbirds sing to attract a mate, while raptors engage in elaborate courtship flights.

Bam! Bam! Bamm-bamm-bamm!

But woodpeckers . . . well they impress the ladies by drumming! Obviously, the biggest noise is most impressive and the greatest measure of a male’s physical prowess, as well as his ability to provide for a nesting female and their subsequent progeny. I rose from my bed to see what was the object of such intense pounding. Sneaking quietly around the corner, all trees seemed to be devoid of Hairy. Then, I looked up. Surely, he was not actually attacking the house!

Bam! Bam! Bamm-bamm-bamm!

And there he was! Clinging to the protective screening on the metal chimney, this magnificent specimen was loudly proclaiming his virility, for he had discovered the ultimate magnification device - the metal stovepipe of my chimney top. I smiled as I chased him off, knowing that he would return to his drum of choice soon after I disappeared. He and others of his kind had been feasting on the suet cakes and black oil sunflower seeds that adorned various trees near the house all winter long, so they were quite familiar with this territory. The Hairy Woodpecker is the most frequent visitor in the Jemez, followed by the larger Northern Flicker, and the smaller Downy Woodpecker, a lookalike of the Hairy. During the winter, many woodpecker species comfortably coexist in mixed feeding flocks; however, come spring with its attendant raging hormones, battles ensue. Dueling drums reverberate throughout the forest. In the end, only the most dominant male and his mate remain for the breeding season, while others have to settle for less desirable nesting territories.

Woodpeckers have particularly stiff tails that enable them to balance on the sides of trees, and specially adapted feet with two forward- and two backward-facing toes that allow them to cling to the sides of trees. As a group, these birds fill several valuable niches in nature. Primarily insectivorous, they use their exceptionally long tongues to probe for insects in the bark and crevices of trees; some species also eat a variety of fruits and seeds, and occasionally even forage on crops such as corn. They rely on a number of adaptations to locate food, including searching visually, and probing with their tongues. They also find insects within the wood by listening. Most woodpeckers also cache, or store food during times of abundance for later retrieval. One species, the Acorn Woodpecker, drills regularly spaces holes for food storage in a granary tree, placing a single acorn in each hole. They are a communal, cooperative breeder, with groups of birds filling, using, and defending the granaries.

All woodpeckers are cavity nesters, excavating their own cavities in living or dead wood. A pair will often create two cavities, one for nesting, and one for roosting in the fall. In fact, these birds are the primary excavators of nest burrows in the forest. Abandoned woodpecker cavities provide important nesting habitat for other species that lack the ability to excavate. This includes many species of small owls such as the diminutive Flammulated Owl, the Northern Saw-whet Owl, and the Western Screech-Owl. Other birds that utilize these cavities include Western and Mountain Bluebirds, Violet-Green Swallows, and even Mountain Chickadees.

However, even an extremely beneficial species can be annoying on occasion, especially when they are engulfed in a hormone-induced noisemaking frenzy, not to mention the extra holes drilled along the eaves of the roof. Bam! I looked the other way, went back inside, and silently welcomed Hairy and Harriet for the summer.

Big Black Birds a.k.a. Nature’s Clean-up Detail

Photo by David Powell


In my mind, they are among the first harbingers of spring. Each year, beginning in mid-March, my eyes are drawn skyward daily, searching for their dark form, soaring aimlessly above. I record this event faithfully each year, and my records show that our Turkey Vulture (Cathartes aura) friends return from their wintering grounds around March 15 each year, just in time for Saint Patrick’s Day celebrations. This year it happened on March 17, only not in the cerulean blue open sky, but on KOAT-TV, on the news! They ran a wonderful story, showing one of the first big black birds to return. My first sighting occurred a few days later, on March 21, at 8:30 a.m. in the Rio Grande bosque during a songbird survey. First one large black shape caught my eye, followed by another. Ultimately, ten birds took flight from their night roost in snag along the river bank. I knew that spring was on the way despite the dreadfully windy days of late.

Often unappreciated, vultures perform a vital role in the Earth’s food chain, that of the scavenger. Their scientific name, Cathartes, means purifier. Until very recently, they were considered to be a raptor even though they almost never kill their food, preferring instead to eat carrion. DNA studies conducted within the last ten years have proven that this species is more closely related to the stork family. Unlike other birds of prey, Turkey Vultures have a highly developed sense of smell, and can locate concealed carcasses beneath the forest canopy. Vultures tend to forage alone, but keep a keen watch on the activities of other vultures nearby. A discovered carcass may attract numerous vultures to the site, along with the other, much smaller western scavenger, the Common Raven. Even Golden Eagles are sometimes found at carcasses, and indeed, nearly all species of raptors scavenge when live food is scarce. Vultures, including the Black Vulture which does not occur in New Mexico, are responsible for the removal of tons of animal carcasses in North America each year.

Generally acknowledged as a beneficial scavenger, Turkey Vultures were accorded protection in many states even before the Migratory Bird Treaty Act was passed in 1918. They are; however, still persecuted in some areas and have been trapped, shot, and poisoned by ill-informed humans who fear that they may spread disease among livestock, or kill newborn calves, although direct kills of young are almost certainly due to another avian predator. Over 100,000 vultures were killed in Texas in the mid-1900's by baiting walk in traps with carrion, and the species is also vulnerable to steel leg-hold traps such as the ones that were responsible for the deaths of two gray foxes in Jemez Springs in February 2006.

The population of Turkey Vultures is generally stable in the U.S., particularly as increased education about the benefits of this species has reduced persecution. The greatest causes of mortality for this species today are collisions with automobiles and aircraft, and electrocution on power poles. Collisions with military aircraft are particularly serious, costing the U.S. Air Force 21.6 million dollars, 3 crashed aircraft, and 2 fatalities between 1989-1992. Records of collisions with power lines are rare, and Turkey Vultures often forage directly beneath power lines on carcasses of other less adept species; however, electrocutions occur when the bird perches on power poles, and two body parts, such as wings, or a wing and a foot, touch separate energized portions of the structures, causing electricity to arc between them. Their winspan (63-71 inches), which is smaller only than that of eagles, makes them particularly susceptible to electrocution when the fleshy wrist tissue spans two energized wires.

One of my first and most memorable close encounters with Turkey Vultures happened in the Jemez Mountains. A friend and I were attempting yet again, to find a way to hike to the top of Virgin Mesa without driving around to the west side. We struggled through the increasing steep terrain of the tent rocks, where each step forward was countered by a half slide back. Then, just as we were about to admit defeat, several vultures took flight right over our heads. Their presence was impressive as they wheeled buoyantly on the wind, above and around us oblivious to the limitations of the land-locked humans below. I wondered then, if they nested on the cliffs above us, and they may have been doing just that. They do not build nests, but utilize caves and crevices in cliffs, like the escarpment on Virgin Mesa, and other mesas in the Jemez Mountains. By the time this reaches you, these remarkable black birds should have returned to their mountain home.

Watching and Feeding Wild Birds

Photo of Pine Siskin by David Powell. Niger seed is a favorite of this small finch.


The stereotypical birder, or birdwatcher, is an elderly, eccentric woman dressed in very odd attire. However, recent birdwatching demographics belie this myth. Today’s birder may easily be a teenager, middle-aged, or senior, male or female, rich or poor. There is no question that birding is big business worldwide, with an estimated 46 million bird watchers in the United States. Of this total, 88% consider themselves backyard birders. In New Mexico, 28% of the state’s residents participated in bird related activities in a study conducted in 2001. How does that add up economically? In 2001 (the last year for which figures are available), birding generated $32 billion in retail sales, $85 billion in overall economic output, $13 billion in state and federal income taxes, and 863,406 jobs were created!

To some, the thrill is traveling to special locations in search of unusual birds. To others, gaining insight into bird behavior is most gratifying. But, to the vast majority of bird lovers, the greatest pleasure is derived from attracting birds to their back yards. Some birds are naturally bolder, and easy to attract, like the ever-present Steller’s Jay and their smaller cousin, the Western scrub-jay. These colorful birds can become regular visitors to your back yard through frequent feedings of raw peanuts, still in the shell, one of their favorites. They also like whole and cracked corn, and will eat black oil sunflower when all the other, more desirable seeds are gone.

Black oil sunflower is without doubt, the all-around favorite for many birds. It has a high meat-to-shell ratio and a high fat content. It is small, and thin shelled, so even small birds can easily crack and eat. This type of seed can be offered in a platform type of feeder, or simply spread along a deck rail. Striped sunflower seeds are larger, and have thicker seed coats. If you are using bird feeders made from hardware cloth, striped sunflower will clog the openings.

Many ground feeding birds, such as mourning dove and dark-eyed junco prefer white millet or red milo. Beware of commercial seed mixes. Often, these are a blend of sunflower, plus a high proportion of less desirable filler seeds. Birds pick through the mix, feasting on the prized sunflower, and leaving the rest. You can make your own birdseed mix to suit the birds in your back yard. Combine 25 pounds of black oil sunflower, 10 lbs. of white proso millet, and 10 lbs. of cracked corn.

Smaller birds, like the pine siskin and lesser goldfinch simply adore niger, or thistle seed. This can be offered in a hanging, tube-type feeder or a cheesecloth bag which holds the seed but is loosely woven to allow the bird to pull the seeds from the bag. These types of feeders permit the smaller birds to avoid competition with jays, black-headed grosbeaks, and woodpeckers which take over platform feeders.

Some people feed only during the winter, which attracts good numbers of birds, and also helps birds survive the rigors of cold, icy, and snowy weather. However, year-round feeding bolsters the wild bird population and provides hours of entertainment to the watcher. Because naturally produced seeds are uncommon in the spring and summer, mixed flocks of birds visit feeders filled with oil-type sunflower seeds in the growing season. Chickadees, jays, nuthatches, and mourning doves will visit daily. Young birds, often with clumps of down still attached, follow their parents, begging. Seeing an adult black-headed grosbeak stuffing food into the incessantly begging, flapping youngster is a thrill to new or experienced birdwatcher alike.

Your neighborhood birds are not completely dependent on you for a food source. They visit several feeding sites daily and waste little time at an empty feeder. Occasional periods of emptiness are unlikely to result in starvation.

Just like the birds that you want to attract to your yard, other less desirable birds, and even avian and mammalian predators will be attracted to your yard. Fortunately, species such as house sparrow, starlings, and rock pigeons are not very numerous in the Jemez Valley. At some point in your bird feeding activities though, a sharp-shinned or Cooper’s Hawk will visit. The primary diet of these two forest dwelling hawks is small birds, and the abundance of songbirds in your back yard provides a food source for the hawk as well, who coincidentally, also needs to eat to survive. If this becomes a big problem, remove your feeders for a few days. The hawk will get hungry, and move on to another area.

Squirrels, although fun to watch, are persistent, and can seem to outsmart every human built squirrel baffle. One way to distract them is to feed them peanuts or dried ears of corn in a location far from the bird feeders. There are a number of commercially available non-lethal squirrel deterrents that can help to reduce damage from this furry, agile mammal.

Bears often become a problem in New Mexico’s mountain communities during the summer and fall, particularly during drought years when little natural food is available. To deter bears: bring all of your feeders in each night; hang all feeders at least 10’ above ground and 6’ away from tree trunks; clean up spilled birdseed; and don’t hang your feeder on your front porch. If you do see a bear, do not approach it.

The family cat is one of the biggest avian predators, killing millions of wild birds each year. Ground feeding, ground nesting, and fledgling birds are at the greatest risk. While kitty may be very well fed, cat’s natural instincts cause them to hunt other animals. If you do own a cat, keep it indoors to reduce the senseless loss of bird lives. For more information about cats and wildlife, visit Cats Indoors, created by the American Bird Conservancy at www.abcbirds.org/cats/

An Irruption of the Natural World

Red-breasted Nuthatch, photo by David Powell

It was along the Rio Grande, in mid-August, that I saw my first Red-breasted Nuthatch heralding the onset of fall migration 2007. With his characteristic, “Yank, Yank” call, there was no mistaking this bird for anything else. A careful scan of the nearby cottonwoods revealed the little fellow climbing head first down the tree trunk, typical behavior of all nuthatches, picking the choicest of insect morsels from the bark. With a dark gray back, a bold white eyebrow, and brilliant red breast, the Red-breasted Nuthatch is the most colorful of the three North American nuthatches. The other two nuthatches found in New Mexico, are the smaller Pygmy Nuthatch, and the larger White-breasted Nuthatch.

It seemed a little early, but perhaps that was due to the unseasonably warm temperatures that tricked my body and mind into thinking that summer would stretch deliciously on for many more months. When I announced my observation to the rest of the songbird department later that day, they also had a few observations of Red-breasted Nuthatch. Typically a bird of coniferous forest, and one that remains on or near its breeding grounds year-round, we generally detect only a handful of individuals during migration. As days progressed though it began to appear that a veritable herd of little red-breasted birds were making their way south.

I noticed a change in bird numbers and behavior at the cabin too. Following a summer with lower than normal feeder activity, September was marked by packed feeders and what appeared to be voraciously hungry birds. There didn’t seem to be any one dominant species, rather a wide assemblage, all foraging together. The big feeder that holds about 10 pounds of black oil sunflower seemed to be empty every few days. The suet disappeared at record pace. Pine Siskins stuck to the thistle sock like frenzied ants whose nest had been disturbed, aggressively pecking at any errant newcomers vying for a feeding position. All birds seemed to share in a universal need for sustenance, feeding as if they had never before or would never again comfortably fill their bellies.

Being the responsible bird nerd, the seed bills began to mount. First it was the extra 20 pounds of thistle, then the 50 pound bag of black oil sunflower, and the 25 pound bag of raw peanuts in the shell. Suet began to be purchased by the case, and it seemed that every week at least one of the staples in my bird kitchen was missing. The wild bird store received increasingly larger checks, first $25-$40, then rising to $60-$90. Just like a teenager, my feathery friends were never full.

I began to hear stories from afar in early October. Apparently, the change is not unique to New Mexico. From Nebraska, a story about a mountain of Mountain Chickadees hanging out in the grasslands. From Colorado, it was nuthatches arriving in the eastern plains from more mountainous environs. Just what might be going on to drive all these birds to seek new wintering grounds?

Irruptions, or mass movements of certain animals including birds and mammals, to lower altitudes or more temperate climates, are thought to be caused by mass food shortages. These events occur irregularly, likely in response to the failure of a major food crop such as coniferous cones, or other seeds.

Years with high crop production for birds result in greater nesting success and adult survival, thus increasing overall populations. If a crop failure occurred in the year immediately following one of abundant food resources, then the bird populations might be larger than normal, adding pressure on scarce food reserves. This increases the pressure on individuals to migrate in search of a more reliable food source. Often, the birds that leave are the young birds, less experienced at foraging. However, because different species of birds feed on varying foods, crop failure might only impact a few species.

Interestingly, songbirds are not the only birds that might be affected by a failed seed crop. The avian predators that rely on these smaller birds for sustenance may also be driven from their normal range in search of adequate food. Such was the case in the winter of 2005-06, when large numbers of rodent-feeding boreal owls including the Great Gray, Snowy, and Northern Hawk Owl irrupted southward into northern Minnesota. The site was a birder’s bonanza as one could count up to 75 owls in one day near Duluth. Unfortunately for the owls, most were young of the year and starving. Other hazards faced by the owls of the remote Canadian forest were cars, cats, and even the loving humans that traveled so far to view them. Most of these owls had never before been exposed to humans or our accoutrements, and had not yet learned a healthy fear of us. An estimated 62% of the owls that came to Minnesota that winter never saw their homes again.

Irruptions occur only when conditions are so severe that survival is not possible in an animal’s natural habitat. Soon, we will begin to hear of more irruptions, this time from California, a state not known for severe cold during winter, but fire. So, if you notice a few extra birds at your feeders this winter, be generous.

The Bald Eagle - A Tumultuous Journey

Photograph by David Powell


“For my own part, I wish the Bald Eagle had not been chosen the representative of our Country. He is a bird of bad moral character. He does not get his living honestly. You may have seen him perched on some dead tree near the river, where, too lazy to fish for himself, he watches the labour of the fishing hawk; and when that diligent bird has at length take a fish, and is bearing it to his nest for the support of his mate and young ones, the Bald Eagle pursues him and takes it from him.”

“With all this injustice, he is never in good case but like those among men who live by sharping and robbing he is generally poor and often very lousy. Besides, he is a rank coward: The little King Bird, not bigger than a sparrow, attacks him boldly and drives him out of the district. He is by no means a proper emblem for the brave and honest Cincinnati of America who have driven all the King Birds from our Country . . .”

“I am on this account not displeased that the figure is not known as a Bald Eagle, but looks more like a Turkey. For the truth, the Turkey is in comparison a much more respectable bird, and withal a true original Native of America . . . He is besides, though a little silly and vain, a bird of courage, and would not hesitate to attack a grenadier of the British Guards who should presume to invade his farm yard with a red coat on.”

Benjamin Franklin
January 26, 1784

So began the rocky road of the National Bird of the United States, the majestic Bald Eagle. Unappreciated and feared, all raptors were viewed as varmints by the general populace, even after the Migratory Bird Treaty Act was passed in 1918, and the 1940 passage of the Bald and Golden Eagle Protection Act. Humans have been the most significant cause of mortality for the Bald Eagle and other raptors, and it has only been in the past 35 years that their persecution has declined. Early settlers shot and trapped Bald Eagles because of their perceived threat to livestock, competition for game, or tradition such as the use of feathers by Native Americans. This practice continued; however, even after the above laws were in place. Shooting, trapping, and intentional or accidental poisonings were responsible for 38% of the mortality of Bald Eagles recovered from 1963 to 1984 (Wood et al. 1990). Over 128,000 bounties were paid in Alaska from 1917 to 1952 because Bald Eagles were thought to impact salmon fishing. Significant numbers of Bald, and especially Golden Eagles, were shot by ranchers in western states earlier in the 20th century because of suspected livestock depredations. One such incident, which occurred in Wyoming, involved the shooting of >770 Bald Eagles for which the shooters were paid $25 per dead eagle.

The eagles were further persecuted by those that collected their eggs, a common practice up until 1940. Bald Eagles also suffered from reduced reproductive success due to eggshell thinning related to DDT poisoning. Population declines of eagles, Osprey, and Peregrine Falcons particularly in the eastern US lead to the ban of this pesticide in 1972, but not before the Bald Eagle (1966 and 1978) ) and Peregrine Falcon were listed under the Endangered Species Act of 1973. Since then; however, population trends have increased for the three species most affected by this chemical. In the early 1980s the nationwide population of Bald Eagles was estimated to be 70-80 thousand birds, and that number had grown to 100,000 by 1999.

This recovery represents on of our nation’s most successful conservation stories. By the late 1990s, Bald Eagles were successfully nesting in all but 2 of the contiguous United States. Interestingly, although most citizens now revere our national symbol, today lead poisoning is considered a significant cause of mortality, and has been reported in 34 states. The source of the lead is the pellets and bullets in hunter- shot waterfowl, deer, and other game species. Other factors continue to affect populations such as collisions with vehicle, electrocution on utility structures, and an unknown number that are killed annually for their feathers which are sold on the illegal feather market.

The adults are easily distinguished by the characteristic white heads and tails, and bright yellow bills and feet. The youngsters; which are very similar in appearance to their cousin, the Golden Eagle, often defy identification. Beginning life as a mostly dark brown bird with a black bill, they undergo a variety of plumage changes before they acquire the adult plumage at age 4, when they are sexually mature. The record longevity in the wild is 28 years, with a captive Bald Eagle surviving until age 36. It is likely that, similar to other raptors, mortality is high the first year, with increasing survival to adulthood.

In New Mexico, we generally see the Bald Eagle only during the winter months, where they are primarily feeding on waterfowl, particularly wintering ducks. The numbers of eagles present here during the winter is largely affected by the weather up north. If those lakes are frozen, forcing ducks and other waterfowl further south, likewise the eagles follow their food source. By the time you read this, most of our birds will be heading north for nesting areas located near large bodies of water. Fewer than 8 pairs of Bald Eagles nest in New Mexico, mostly in the northernmost counties, but during the winter months they might be observed just about anywhere, even far from the nearest river or lake. I’ve seen them calmly roosting in canyon country far from any water source, not surprising for a bird that can go 5-7 days between meals.

Speaking of meals, this article would probably have been much different had Benjamin Franklin has his way with our fledgling country. Thanksgiving might have been celebrated in a very different style!

Life After Dark

Photograph by David Powell


“Whoo-hoo-o-o, whoo-hoo-o-o, who” reverberated from the snow-topped tree, only to be answered a few moments later by a higher-pitched, more elaborate response from the nearby forest. One of the birds flew to the top of a utility pole, where he continued his elaborate duet with the female of his choice. Apparently she returned his affection, as the hooting continued throughout much of the night. Among the earliest of nesters, Great Horned Owls may already be incubating this year’s clutch of eggs. Widespread throughout North America, and occurring locally south to Tierra del Fuego, South America, this highly adaptable species might be considered the supreme generalist among birds. The word variable personifies the species as a whole; as a result the population is reported to be robust without a need for special management in scientific literature.

Great Horns have many advantages that contribute to their overall success. As one of the largest owls in North America (the other is the Snowy Owl of the Arctic tundra), adults have few predators and are long-lived. Some studies have reported non-captive owls 21-28 years old. Monogamous pairs remain on territory year-round, and aggressively defend it from other owls. They do; however, often nest in close proximity to other diurnal (daytime hunting) raptors such as hawks and eagles. In 2003, we documented a Great Horned Owl nest and a Red-tailed Hawk nest on opposite sides of the same promontory in northwestern New Mexico, a total distance between nests of about 25'. Our raptor biologist speculated that only one nest would succeed, and wondered which it would be. In the end, only the owl nest was successful, fledging two young, while the hawk nest failed. There was no evidence of predation by the owls on the other nest, and we speculated the more visible hawk nest might have failed due to human disturbance while the more camouflaged, cryptically colored owls may have escaped detection. The pair successfully nested at the same spot in 2004 and 2005, but the hawk paired move on to another location. Other studies report owl nests in close proximity to other species such as Golden Eagle, Harris Hawk, and in one instance a Great Horned Owl and a Turkey Vulture nested in different cavities in the same tree. There is an apparent benefit to the nesting birds due to additional protection afforded by two separate species, one active during the day and the other at night. At the same time, there is little competition for food.

The prey taken by the Great Horned Owl varies according the occupied habitat. For instance, desert dwelling owls consume a greater number of reptiles than birds living near ponds and marshes that take waterfowl and muskrats. Documented prey includes everything from earthworms, crickets, and scorpions to mice, rabbits, and even skunks. Free-ranging house cats often fall victim to the talons of this owl. Other species of birds are routinely hunted by some owls. Indeed, I once located an owl nest in the cavity of a cottonwood tree after finding the headless body of an adult Red-tailed Hawk at the base of the tree.

Several remarkable biological adaptations make all owls supremely adapted to their inconspicuous nightlife. Their feathers are very soft, with comblike fringes along the leading edge of each feather, and a fuzzy surface that muffles sounds, enabling them to fly almost silently. They have large, forward facing eyes with binocular vision like us. But, unlike humans, they are unable to move them in their eye-sockets. They compensate for this limitation by bobbing their heads up and down and from side to side. Possessing more vertebrae in their necks than humans, they also can rotate their heads about 270 degrees!

The feathered tufts atop their heads, often called ears, are used for communication between owls and to break up the owl’s silhouette when it is roosting during the day. Their true ears are asymmetrically located on their heads within the feathered facial disk that helps direct sound into the ear canal. Some owls, such as the Barn Owl, can hunt in nearly total darkness. Owls use a combination of hearing and vision to locate prey. Cryptic coloration serves this species particularly well, and the birds are often indistinguishable from the tree in which they are sleeping, unless a mobbing actions of a flock of crows, ravens, or jays draws attention to them. Even within New Mexico, the plumages of Great Horned Owls vary by habitat with soft browns and tans characterizing the lowland desert dwellers setting them apart from the charcoal gray and dark brown of those that live in the coniferous forest.

Truly a remarkable species, survivors in a tough world, these owls adapt well to human activities, and often nest close to our dwellings. One might then wonder then, why it is that the bird chooses to nest in the dead of winter when little food is available and keeping eggs warm might present a greater problem. Owls do not build their own nests, but instead occupy nests constructed by other birds or cavities in cliffs or trees. Because they remain on territory year-round, they have ample opportunity to select the best nest site within the area without interference from the original nest builder who may be spending the winter further south. In the Middle Rio Grande bosque, they often choose the largest Cooper’s Hawk nest of the previous year! Their offspring leave the nest about May 1, the time when most of the migrant songbirds are returning to their nesting territories. Fed by their owl parents for another 30-45 days, the young owlets begin learning to hunt and catch their first live food at about the time that young, vulnerable songbirds are just hatching and leaving their nests. It makes perfect sense, from an owl’s point of view!