By Jon Friedman
Introduction
Last month’s newsletter article about the uncertain future facing birds and the three previous serial articles about the demise of the Passenger Pigeon may have led readers to question why I wrote about extinction of species and the loss of important habitat for local birds. These are not easy subjects to consider in light of the fact that birding is usually associated with being a positive, uplifting, and enjoyable way to learn, understand and be involved in the natural world. We live in a world today where, it seems, birding should be an escape from the negative news that informs us of war, political upheaval, social unrest, destabilization of the climate, mass extinctions and a host of other problems. Yet globally, some of these problems can affect, directly or indirectly, our local birding experiences.
Tucson August, 2016 by Doris Evans
Local research
Locally, we can track trends in bird conservation, population increases and decreases, diseases, migration, habitat trends, and a host of other considerations. Due to the fact of advanced technology and that there are many groups that monitor occurrences in the natural world, we have access to the knowledge they accumulate at nearly the rate they gather this information. Moreover, locally, Southern Arizona provides a base for headquarters and large chapters for these organizations to operate. A sympathetic and supportive public acknowledges the research conducted here, and an informed populace grows and is benefitted by these activities.
State Resources
On the state level, the Arizona Land and Water Trust is mandated to manage these precious resources in conjunction with other state interests, such as education and transportation. Arizona Game and Fish Department is officially tasked with the overseeing of the management of all wildlife, especially game animals and fish. They operate in conjunction with some conservation organizations that are dedicated to game animals and fish. They are the source for buying hunting and fishing licenses for public properties and the funds they collect further their rather limited efforts. Private groups that work with Game and Fish include, but are not limited to: Ducks Unlimited, Arizona Elk Society, Arizona Antelope Foundation, Volunteers for Outdoor Arizona, Arizona Wildlife Federation, Arizona Wilderness Coalition and others.
Local Non-profit Organizations
More importantly, several non-profit conservation organizations operate in our region with great results and outreach. Each has a specialty area of concern, but all are interested in protecting natural lands and the living entities that call a wide variety of Southern Arizona habitats home. All are deserving of increased public awareness and support as more and more pressure is asserted by private interests (mining, timber, urban sprawl, increasing human population, pollution, large-scale agriculture, ranching, etc.).
Southwest Center for Biodiversity
Among my favorites is the Southwest Center for (Biological) Biodiversity. This is a highly effective professional organization that coordinates field research and pressures politicians to enact conservation laws and to enforce existing laws. I think of this group as the leading edge in directing conservation efforts where they are most necessary. And, while they were founded and headquartered in Tucson, their vision and efforts now span the globe. They are an excellent example of an activist organization.
The Audubon Society
The Tucson chapter of the National Audubon Society is one of the largest in the country. While primarily a volunteer-powered organization, they have a strong presence in both the local and national political and conservation communities. While they were founded primarily for the protection of birds over one hundred years ago, they have expanded their reach considerably with the passing of the years. In addition to seeking realizable results in the area of conservation, it is also their mission to educate the public. They have a long history of working within school districts to introduce the importance of nature to children. Their conservation efforts have helped industry and commerce work within the bounds of preserving nature, rather than the old attitude of “conquering nature”. Their work has prevented the extinction of many species. In modern times, their mission has expanded into protecting the American landscape and its wide variety of habitats necessary to support the rich diversity of species that also call North America home. The Audubon Society’s educational outreach operates on all levels with their regular field trips into the natural world, providing group trips geared for beginners, intermediate and experienced nature lovers.
The Nature Conservancy
The Nature Conservancy has long had a strong presence in our region as well. They operate in several important and critical locations where, without their efforts, large swaths of habitat and landscape would be lost to private interests. Most notably, their collaborative work with the Malpai Borderlands Group in extreme Southeastern Arizona and the southwestern boot heel of New Mexico has resulted in the permanent conservation of thousands of square miles of nearly pristine desert grasslands, mountain ranges and valleys, and riparian corridors. By partnering with and entering into long-time and permanent agreements with ranching families, they are insuring that large ranches are managed in sustainable ways that discourage over-grazing and denuding the landscape, deny the ability of these ranches to be divided up and sold as private parcels, and enable the natural habitat and inhabitants to flourish. Another prime example of Nature Conservancy work is the ongoing work at the Muleshoe Ranch Preserve, north of Benson in the Galiuro Mountains. This is a prime example of riparian habitat conservation on what was a former private cattle ranch and health resort, Hooker’s Hot Springs. Naturally, the local Apaches inhabited this site long before the arrival of white settlers and probably as a year-round permanent stronghold. This is unusual land in that it contains hot springs and has five creeks with mature riparian habitat and a wealth of wildlife. Some of my fondest birding moments occurred at Muleshoe.
Other Conservation Organizations
There are many other organizations operating in this region that also deserve attention, funding, and recognition of their many accomplishments thus far. The Sky Island Alliance, Wildlife Defenders, the Sierra Club (Rincon Group), the Coalition for Sonoran Desert Protection, the Wildlands Project, The Wilderness Society, the Coalition for Sonoran Desert Protection, the Southeastern Arizona Bird Observatory, Save the Scenic Santa Ritas, Friends of the San Pedro River, Friends of Sonoita Creek, and numerous others.
The University of Arizona
Additionally, the University of Arizona has numerous departments that are involved in continually gathering conservation research information and making it available to the public. I have often consulted with experts at the U of A for respected and up to date opinions and facts.
Inca Dove by Richard at SearchNet Media
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Inca Doves
I originally intended this article to be about the recent but substantial decline of one of my favorite species, the Inca Dove. Incas are the smallest of the dove family and have been one of the most numerous and beloved of our native birds. Not much larger than the largest sparrows, they are wonderful birds that are rarely spoken of in negative terms. Many backyard birders resent the large White-wing Doves that migrate north from Mexico, beginning in April, and tend to dominate non-doveproof feeders in our backyards until they depart in August. The large Mourning Doves also present problems for some backyard birders, mostly if their numbers reach peak limits in any given backyard. The much smaller Inca Doves have always been considered welcomed guests in our yards. They did not congregate in the large numbers that White-wing and Mourning Doves do, they did not dominate feeders as they are true ground-feeding birds, and their overall good looks and charming behavior made them favorite birds in many backyards. However, nowadays, Inca doves are proving very difficult to find at all. I began wondering about this and started discussing this with other birders and bird experts. There seems to be no definitive answer to this question, so I began researching this topic. Many of the conservation organizations I spoke about earlier in this article have not researched this topic well or thoroughly and cannot offer any conclusive evidence to explain the virtual disappearance of this species.
Causes for the Decline
Nevertheless, I did hear several possible explanations but few seemed plausible. While they are generally acknowledged to be a Mexican species, and where they are found north of the border, they are really a resident species. So, while they do not migrate, the theory of migrating off-schedule, possibly tied to global warming, doesn’t seem logical. Loss of habitat I also think is not accurate as Inca Doves are especially found in and around human habitation. City parks, empty lots, cemeteries, golf courses, home lawns, and backyard feeding stations were all more likely to yield Inca Doves than further out in the raw desert. The urban habitat has not changed much with the exception of its sprawling out to encompass a larger area yet. The growing population of invasive Eurasian Collared Doves outcompeting the native Inca Doves, likewise, does not make sense to me either. While the invasive species may be dominating other dove species in certain locations, such as Durango, Colorado, I do not believe their numbers in our region have been great enough to cause the relatively rapid depletion of our local Inca Doves.
Cooper's Hawk by Doris Evans
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Cooper’s Hawks
This leaves one more potential explanation, the one that seems most plausible to me and can be backed up with research results. The upsurge of urban Cooper’s Hawks in the Tucson basin certainly, and reasonably, can explain, at least in part, the diminished Inca Dove population.
For the past two decades, the University of Arizona has been conducting a long term study of urban Cooper’s Hawks. It seems the Tucson urban area has become the largest city in the nation to host noticeably increasing numbers of Cooper’s Hawks. They belong to the accipter family of raptors and most accipters are found in wooded areas and forests. They are known for their hunting prowess and their ability to fly at high speeds in pursuit of prey and easily maneuver over, under, around and through thick woods and branches chasing birds, their major food. The term “accipiter” means bird hawk.
The U of A researchers know that doves represent about 80% of the Cooper’s Hawk diet. Inca Doves are known to be more docile than other species, less wary, and therefore easier for the hawks to capture than the larger, heavier Mourning and White-winged Doves. So, most of the U of A researchers point to the ever-expanding population of urban Cooper’s Hawks as the most likely cause of the steep decline in the population numbers of the Incas.
Support for the Theory
Troy Corman, the chief coordinator of avian monitoring for Arizona Game and Fish, agrees with this theory. He’s also noted that the Inca Dove population has remained stable, or even slightly increased, at Southern Arizona locations that do not have heavy concentrations of Cooper’s Hawks. He noted that Inca Dove populations remain relatively stable, and the species is considered common, in various desert locations in Southern Arizona and Southern California. This is true especially south of Parker Dam on the lower Colorado River and in towns like Needles and Bullhead City. The late Alexander Skutch, one of my favorite ornithologists, whose research focused on birds that breed in Tucson and winter in Costa Rica, notated that in relatively recent years, Inca populations were stable or growing, except for the Tucson area. While he didn’t live long enough to analyze the U of A research, I find it interesting that his general observations were correct.
Juvenile Cooper's Hawk out of nest by Richard at SearchNet Media
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Christmas Bird Count (CBC)
In addition, the local Audubon Chapter organizes the annual Christmas Bird Count (CBC). Each year, for a single day, large numbers of Tucson and Southern Arizona birders work within tight grid lines and census the exact numbers of all species seen and heard. While volunteer driven, this research has proven invaluable to our local knowledge base. Also, this CBC has been in operation longer than the U of A Cooper’s Hawk study. In essence, after reviewing the annual numbers, and making appropriate comparisons where possible, there emerges a distinct correlation between the increase of Cooper’s Hawks and the decrease of Inca Doves over the same 20-year period.
Research Results
Twenty years ago, there were slightly over 70 Cooper’s Hawk nests in mid-town Tucson. That comfortably translates to three to four times the number of actual individual hawks, or approximately 250. Research has shown that the population has increased today by a factor of three. (This past summer’s extremely hot temperatures took a serious and unusual toll on juvenile Cooper’s, however.)
Twenty years ago, the CBC recorded approximately 7,000 Inca Doves in the Tucson area. Last year, over 6,000 Mourning Doves were counted while only twelve Inca Doves were recorded! I’ve questioned many birders about their observations regarding the rapid decline of Incas they have seen, both in the field and in backyard feeding stations. Without exception, all Tucson birders responded with negative reports. Many haven’t seen Incas for several years. The birders who live outside the city also report none or a relative handful of Incas, whereas a decade or two ago, they were numerous and one of the most common species in urban Tucson.
Last Year’s Results
Last year’s CBC revealed at total of 79,934 individual birds within 153 species. Pretty amazing, especially considering this was a one-day tally! As a result, we learned that a number of very rare birds (at least to this area) were unexpectedly seen. Chief among them were Gray Hawk, Bonaparte’s Gull (Silverbell Lake), Gray Catbird, Rufus-capped Warbler (upper Ventana Canyon), Montezuma Quail (upper Finger Rock trail), Louisiana Waterthrush (Santa Cruz River), Pine Warbler and Neotropic Cormorant.
Additionally, interesting species that are somewhat less rare or out of season were also recorded. Included in this group were Northern Parula, Greater Pewee, American Goldfinch, Clay-colored Sparrow, Ring-billed Gull, Merlin, Gray Flycatcher, Yellow-bellied Sapsucker, Eastern Bluebird, Black and White Warbler, Snowy Egret and Summer Tanager.
Conclusion
Tucson remains one of the best urban birding areas in the country, in any season. We will always experience increases and decreases in populations of certain species, for a variety of reasons. Most of the organizations discussed in the earlier parts of this article contribute to the totality of local birding knowledge, some more than others. But, all deserve our respect, admiration and support for their unique work that helps keep Tucson and Southern Arizona on the cutting edge of contemporary bird research and understanding. This is something we can all take pride in.
