Habitat loss is affecting wildlife populations worldwide. Although the loss of forests has received the most attention, the loss of native grasslands is even more devastating. Scientists estimate that 99% of our native prairie is gone.
Here in Pennsylvania grassland bird populations have declined significantly in the southeast and south central parts of the state during the last 30 years because of development and changing farm practices that have eliminated hedgerows from farmland. According to Scott R. Klinger, wildlife biologist for the Pennsylvania Game Commission, ring-necked pheasants, eastern meadowlarks and vesper sparrows have declined by 80%, grasshopper sparrows by 83%, field sparrows by 67%, and northern bobwhite by a whopping 94%.
The northern bobwhite statistic was of particular interest to me after a visit to south central Arizona last winter. My husband Bruce and I had come to the Buenos Aires National Wildlife Refuge on a cool, clear day in search of the masked bobwhite, also known as “Arizona’s passenger pigeon,” according to our host, Michael Goddard, the assistant director of the refuge.
Like our passenger pigeon, the masked bobwhite was thought to be extinct when Arthur Cleveland Bent published his Life Histories of North American Gallinaceous Birds in 1932. “This bobwhite has now disappeared entirely from Arizona and is nearly, or quite, extinct in Sonora,” Bent concluded.
How had a bird first collected by the scientific community a mere 48 years previously vanished so quickly? Herbert Brown, a knowledgeable amateur ornithologist from West Virginia and an early expert on the bird, blamed it on too many cattle and too little rain.
Early historians reported that the Altar Valley in south central Arizona, which supported most of Arizona’s masked bobwhites, was covered with native perennial grasses when European settlers entered the area. This fragile subtropical grassland provided essential food and cover for masked bobwhites, but with the introduction of cattle, the grasslands were quickly overgrazed.
In a little over 20 years, cattle went from 5,000 to one and a half million on Arizona range land, most of which was in southern Arizona. The following two years (1892-93) a devastating drought killed tens of thousands of cattle but not before they totally denuded the landscape.
Cattle ranching in Sonora, Mexico, didn’t expand quite as quickly as in Arizona, and so it was not until the mid 1930s that the Mexican range was similarly overgrazed. By then the masked bobwhite, a quintessential habitat specialist, seemed to be gone forever from this earth.
At the time of its supposed demise, the masked bobwhite was still a separate species although ornithologists continued to debate the issue well into the twentieth century. As far as they could determine both northern bobwhites (Colinus virginianus) of the eastern and midwestern United States and masked bobwhites (Colinus ridgwayi) had identical calls, and a female masked bobwhite looked exactly like a female northern bobwhite. The only difference seemed to be the appearance of the male masked bobwhite which sported a rich, dark chestnut breast and a black throat and head instead of the mottled breast, white throat and prominent white eye stripe of the northern bobwhite.
Finally, in 1944, long after its extirpation in Arizona and supposed extinction in Sonora, the American Ornithologists’ Union declared it the subspecies Colinus virginianus ridgwayi, and so it has remained.
One ornithologist, J.W. Ligon, insisted that the masked bobwhite was still fairly numerous in central and southern Sonora as late as 1937, but when he returned to the area in 1950 he could find no trace of the bird.
“Ranch men who had formerly known of the presence of the birds advised that they seemed to have vanished overnight,” he wrote.
During the next fourteen years not one masked bobwhite was observed in Mexico or Arizona.
Then, in 1964, Steve Gallizioli, an Arizona Game and Fish biologist, and naturalists Jim and Seymour Levy of Tucson, rediscovered a small population in Sonora. Having been granted a reprieve that passenger pigeon advocates never received here in the East, masked bobwhite enthusiasts were determined to reintroduce the bird to its previous haunts in Arizona.
Ligon had first tried this with Sonoran birds in the late 1930s, but they had been released into the wrong habitat and quickly disappeared. The sixties attempt also failed. Vandals broke into the breeding pens and killed many captive birds. Furthermore, the niggling problem of habitat continued to sabotage reintroduction efforts because there was no ungrazed native grassland left within the former Arizona range of the masked bobwhite.
Nevertheless, with the passage of the Endangered Species Act, the masked bobwhite was listed and the United States Fish and Wildlife Service began its long battle to reintroduce the masked bobwhite to Arizona. In fact, according to Goddard, “The masked bobwhite came to symbolize endangered species in Arizona.”
During the seventies, the USFWS only had altered habitat to work with–the privately owned, Buenos Aires Ranch near Sasabe on the Arizona/Mexican border, where cattle still grazed. First they captured wild birds from Sonora as breeding stock to create populations of captive-reared birds. Then, the captive-reared birds were provided with wild-caught, sterilized, male northern bobwhites from Texas as foster parents to teach them how to adapt to the dangers of a free-ranging life. In 1977 researchers confirmed natural reproduction, and two years later located 74 calling males on the ranch.
Then, once again, disaster struck in the form of a two-year drought and excessive overgrazing. By 1983 only a few male masked bobwhites survived. But the Victoria Land and Cattle Company, which had bought the ranch in the seventies, was put out of business by the recession in the early eighties. When the ranch came up for bids, the USFWS bought it for the sole purpose of restoring the masked bobwhite to Arizona.
Almost immediately, the 117,000-acre refuge was closed to livestock, a move that made the refuge and its employees extremely unpopular with neighboring ranchers. Then began the long, and still unfinished, task of restoring a native grassland to benefit not only the masked bobwhite but other grassland-dependent birds such as Baird’s and Cassin’s sparrows, horned larks, and western meadowlarks, as well as mammals that had been squeezed out of most privately owned ranch lands by cattle-friendly practices. Pronghorn, mule deer and white-tailed deer were reintroduced to the refuge and recently another endangered species–the ferruginous pygmy owl–has been discovered there.
“We’re making it up as we go along,” Goddard freely admits, “because we are dealing with a lot of unknowns regarding the masked bobwhite’s life history.” What is known is that masked bobwhites remain in coveys where pair bonds are formed until late June or early July. The calling of the males from elevated perches heralds the start of the breeding season between June 25 and July 15. Actual breeding is triggered by the summer rains in mid-July, and nesting is dependent on abundant ground cover that conceals both the nest and the young from predators. The rains also produce a flush of invertebrate prey and plant food for the parents and their five to 15 chicks. Hatching starts in late July, peaks in September, and tapers off by late October. Throughout late fall, winter and spring, the masked bobwhites form coveys consisting of family groups that are usually no larger than 20 birds.
In an effort to produce more birds each year, a captive breeding program speeds up the natural process by controlling the temperature and humidity in the quail-breeding facility so that captive masked bobwhites are ready to start breeding in mid-March and are producing eggs by early April.
Until 1996 the breeding was done at Patuxent Wildlife Research Center in Maryland and the resultant young quail were shipped to Buenos Aires NWR every year. Since 1997 the refuge has had its own breeding facility and hatches them out at their quail barn. Once they hatch, surplus masked bobwhite adults act as foster parents. In an ordered sequence, the young move from brooders to small runs to outside release pens. In the brooders and small runs they receive food pellets and water, but when they are put in outside release pens, they are encouraged to eat insects and scratch feed and they get their water from dew.
They remain in the outside pens for at least three months before their release in September, October and November. This way the birds are older and bigger than those that are naturally hatched in the wild. Predation is the primary problem and chief biologist Sally Gall, who has been working with the quail for six years, believes that they are not predator smart and are quickly picked off by their major predators–northern harriers, red-tailed and Cooper’s hawks, and great horned owls.
On the other hand, she has found evidence that they are pairing up in the wild and have produced chicks.
“There are more seen and in larger groups of ten to 25 during the covey season,” she says. Gall and her assistants walk one mile by one mile transects in search of masked bobwhite but censusing them is very difficult. Instead of flushing, they hide in the grass and move only if they are in danger of being stepped on so counting calling males is still the most reliable method. In the summer of 1998, they counted 57.
Keeping cattle off the refuge has not altered the habitat enough to encourage the return of masked bobwhites. Much of the refuge is still covered by Lehmann’s lovegrass, an introduced species from South Africa that was used to hold soil in place and feed cattle back in the fifties and earlier and provides little food or cover for the masked bobwhites. They much prefer alkali-sacatone and side oats gramma, both native grasses. To encourage the return of native grasses and revitalize the soil, the refuge is using fire management, burning 14,000 acres at a time on a five year rotation plan, but do not know how it will work out in the long run. They have also been replanting native grasses in selected areas.
After spending hours talking about masked bobwhites and touring their breeding facilities, we did have a chance to see several dozen in a release pen. They were extraordinarily wary of us, piling up in a corner of the pen and hiding as best they could. Perhaps, in the long run, “Arizona’s passenger pigeons” will be a success story.
Whether or not they succeed in establishing a self-sustaining population of masked bobwhites, though, the refuge is one of the best examples of an ecosystem approach to management in the National Wildlife Refuge system. Its combination of grasslands, wetlands, cottonwood-lined streambeds, and sycamore and live oak mountain canyons is already home to five endangered species, ten species of special concern, and a wide variety of other native plants and animals including 314 species of birds. It is a beautiful piece of primeval Arizona that is wonderful to visit at any time of year and proof that saving habitat for one species benefits many more.
This lesson is one that we in Pennsylvania are also learning as we reintroduce extirpated species such as fishers and elk. Without suitable habitat, wildlife cannot survive. We need to ask ourselves, as the Arizonans have, whether we are willing to make room for grassland species in our increasingly urbanized and heavily farmed state. If not, the northern bobwhite may be extirpated in Pennsylvania just as the masked bobwhite was in Arizona.