Save that from yonder ivy-mantled tow'r
The moping owl does to the moon complain.
-Thomas Gray Elegy Written in a Country Churchyard, 1750.
Asian mythology tells us that owls have been linked to thunder and the summer solstice. In other parts of the word owls have been coupled with old forests and contemporary natural resource organizations see them as key indicators of the vigor and fortune of such locations. These owls are identified as "management indicator species" by organizations such as USDA Forest Service, who has identified the Northern Spotted Owl (Strix occidentalis caurina) as such an indicator of old-growth conifer forests of northwestern United States. Could the Pygmy owls of the southwestern US hold the same position?
Owling.com notes that these small owls lack ear tufts and that male and female are similar in plumage. Adding:
“The eyebrows and lores are white and are bolder than the other white markings. Chest is white with rufous-brown streaks; iris of the eyes are lemon yellow; bill is yellow to greenish or grayish-yellow. The Ferruginous Pygmy-Owl is very similar to the Northern Pygmy-Owl with the distinctions of habitat, call, color, white crown streaking and usually tail band color.
Scope of Glaucidium brasilianum cactorum
As the name implies (ferruginous is defined as reddish-brown or rust in color), a major distinctive field mark of this owl is the rufous or reddish-brown tail bars (the Northern Pygmy-Owl having white barring) and over all color (Note: there is a grayish phase in Mexico that is gray with white tail bars and a rarer red phase with no tail bars).
The Ferruginous Pygmy also has white streaking on the forehead and head, where the Northern Pygmy's markings are more rounded spots. The backside of both Pygmy-Owls have similar white markings, but the over all color is more reddish-brown for the Ferrug (Texas birds are more gray-brown).
The, so called, "false eyes" of the Pygmy-Owls are a distinctive pair of black patches bordered with white on the nape. The only actual overlap of range, between the two Pygmy-Owls, is in a very small area of Southern Arizona so the possibility of mistaking their identification is slight. In addition to this, the Ferrug is a lowland bird and the Northern Pygmy is a mountain bird (some overlap "might" occur only in winter when the Northern Pygmy may move down slope).
The different calls of the Pygmy Owls may be the single best method of field separation. The male Ferruginous Pygmy's advertising call is described as a whistled "popping" sound and has a shorter interval between the notes than there is in the Northern Pygmy's. The female Ferrug, if present, may also respond to the male with a rapid "chitter."
Geographically Glaucidium brasilianum range from my back yard in Northwest Tucson along the western coast of Mexico. Additionally the Pygmy owl (Glaucidium brasilianum ) can be found from southern Texas and southern Mexico all the down into Panama. There are two subspecies of the Ferruginous Pygmy Owl within the United States. Biologists have noted up to four other owls that could be considered additional races in Central America but additional study needs to be done for these classifications to be established. While G. b. ridgwayi ranges across Texas, Mexico and into Panama, the tip of the G. b. cactorumis habitat is found from Arizona and southward along the Mexican coast.
Common Names of Glaucidium brasilianum
Familiar names for the little critters are Ferruginous Owl, Cactus Pygmy-Owl, Gnome Owl and the Streaked Pygmy-Owl .
Field Identifications of Glaucidium brasilianum cactorum
This small, uncommon rufous feathered avian likes to hang out in wooded river bottoms and saguaro deserts. It can be distinguished from Elf owls (Micrathéne whitneyi) and Burrowing owls (Speótyto cuniculária) by its plain rusty back, rusty streaks on the sides and a tail faintly barred with black on rust. Its call is a long series of single notes. “The whistled hoots of the (Ferruginous Pygmy Owl ) are a rapid whi-whi-whi-whi-,says Larry Liese in his article Dastardly Duos, Pygmy-Owls”... typically three per second with rising inflection, continuing for what seems like minutes, the Energizer Bunny of the owl world.” Their diminutive wingspan is fourteen to sixteen inches; they stand between six to seven inches tall with a tail length average of two inches. The males weigh and average of 2.2 ounces and the females weigh in at a heftier average of 2.7 ounces.
Because they hunt during the day they lack the feather adaptations of their nocturnal compatriots—a leading edge with a downy comb and fuzzy upper surfaces that typically quiet their approach. Since their predatory habits are diurnal birds frequently mob them. To confuse the pack of marauding protectors the tiny owl has dark eyespots on their napes. Their territories can be up to a mile in length and the attack in a rapid pursuit flight. They frequently pick on comparatively large prey such as the American Red Robin and Gamble’s quail. There are even records of assailing captive Guan, large chicken size birds with “the owl grabbing on firmly to the Guan and tearing at it, eventually wearing it out and killing it” reports one birder.
Pygmy-Owls are cavity nesters usually a tree, stump or “in old woodpecker holes, tree forks or depressions, occasionally in a sand bank or termite mound.” Courtship begins in early April and ends in mid-June. Clutch size can range from two to five eggs with 3 or 4 eggs being average. The female incubates and broods the eggs until they hatch about 28 days later. The male supplies the brooding female with food during incubation. The hatchlings are fed by both parents for approximately three weeks when fledgling occurs followed by another three weeks of parental care. Fierce competition among the brood over food can result in fatalities. The younglings have a high-pitched rattle begging call and white streaking on the brow and temple. While there are no distinctive head feathering on the juvenile Ferruginous, the rust tail bars are visible making classification possible.
Glaucidium brasilianum cactorum Watching
The best time to look for the owls is at dawn and dusk as this is their primary hunting times. If you live in the Tucson area be sure to bring binoculars and a camera. The best way to establish a sighting would be to get a picture that includes the dorsal area of tail since it’s the barring that clearly distinguishes it from other small animals. Pygmy owl calls elicit a strong mobbing response from various passerines like warblers and vireos. Simulation of this bird song frequently draws more small passerines than pishing does.
Glaucidium brasilianum Study
Previous studies of New World pygmy-owls, “revealed that the diversity of this group has been grossly underestimated (Vielliard 1989, Konig 1991, Heidrich et al. 1995, Howell and Robbins 1995, Robbins and Howell 1995). This is not surprising given that morphological and vocal variation in these owls are on the same order as the equally cryptic, but better-studied Empidonax flycatchers (Stein 1958, Johnson 1980, Lanyon and Lanyon 1986, Johnson and Marten 1988). However, unlike the diurnal, relatively numerous, and highly vocal Empidonax, pygmy-owls often occur in low densities in tall, humid forest and are notoriously difficult to locate and collect.”
Why did they start declining?
“Experts think the Arizona owls were more numerous,” reports Mitch Tobin and Tony Davis of azstarnet.com , “and widespread a century ago. They point to the loss of vegetation along streams and rivers as a major cause of the decline. In Arizona, the owls are at the northern end of their range, so their population has probably always waxed and waned here.” “But in the last century, major portions of their Arizona habitat has been lost, “says Bill Mannan, a professor in the University of Arizona's School of Natural Resources and member of the owl-recovery team. Fish and Wildlife biologist Scott Richardson continues that,” As of August 6, 2005 only two adult owls are thought to live there now - down from 12 in 1996 - so the neighborhood supplies just a sliver of the overall population. But a few years ago the area had the state's highest density of birds, and it still provides a link to unoccupied habitat in Pinal County.
Another recovery team member who has studied the owls since the 1950s, biologist Roy Johnson, disagrees saying, “the birds, which prefer riverside habitats, have only recently come to depend on the Northwest Side's saguaro-studded uplands. “ And finally Aaron Flesch, an owl researcher offers the opinion that while the region might have lesser value to the birds as far as habitat, the exception is that it's always been significant to the owls. "Animals don't go and settle where they haven't historically survived and reproduced," he said.
Are the Pygmy owls of Arizona vital to the whole subspecies?
Margins between species and subspecies are frequently fuzzy. When covering large distances of habitat an animal's activities, appearance and genetics can vary. Species and subspecies can meet the criteria for safeguarding under the Endangered Species Act. Subsequently unusual groups of animals, known as "distinct populaThe Endangered Species Acttion segments” can too. This is where biology and the law are especially gray and is how the owl became listed in 1997. A number of the better known species have been protected this way, counting bald eagles, grizzly bears and gray wolves. “To qualify,” Fish and Wildlife regulations state that, “ an animal must have a backbone and the population must be both "discrete" and "significant." With these regulations in mind, Fish and Wildlife divided the owl into western and eastern populations, and then further separated them at the U.S.-Mexico border. The effect was four groups: Arizona, western Mexico, Texas and eastern Mexico with only the Arizona section listed as endangered. This impeeded construction and raised costs as well as complaints from the building industry and by 2003, federal judges began to side with home builders saying that Fish and Wildlife hadn't proven the population's "significance."
”Genetic studies have found the birds living in Arizona and southward are a distinct subspecies from the owls living in Texas and below the border there, says Glenn Proudfoot, co-author of a Fish and Wildlife study. Adding. “…there's no significant difference in the DNA of owls in Arizona and Sonora, Mexico,” But to the majority of the environmentalists like Jenny Neeley of Defenders of Wildlife, the Northwest area of Tucson’s expansion “not only proves that developers' fears about the owl were wrong, it shows that the federal government failed to protect the bird adequately there as its numbers dropped.”
Nature vs. development; feathers flying to protect Pygmy Owls
Since 1997, the Ferruginous pygmy owls of Arizona have hunted and hooted happily under the protection of their classification as an endangered species. Members of the genus Glaucidium - are found in Africa and Asia and from Western Canada to the tip of South America. Only the Arizona population of one subspecies was listed as endangered in 1997. Like his cousins, the Ferruginous Pygmy-Owl is a “diurnal and crepuscular owl feeding mostly on insects, such as grasshoppers, crickets, caterpillars, other large insects and scorpions.” Other preys that make up their diet include “birds, small mammals, amphibians, and reptiles (often lizards). Like the Northern Pygmy-Owl, the Ferruginous Pygmy-Owl is a bold and ferocious daytime predator, sometimes attacking prey larger than itself, such as American Robins or young domestic fowl.”
According to the U.S. Fish and Wildlife Service, "Recovery is the process by which the decline of an endangered or threatened species is arrested or reversed, and threats neutralized so that its survival in the wild can be ensured. The goal of the Endangered Species Act is the recovery of listed species to levels where protection under the Act is no longer necessary." Initially listed as an endangered species on March 10th of that year with the intentions to recover the birds as an independent species, today the owls are no longer assigned a critical habitat.
As of August 2005 the Pygmy Owls that once dwelt among the mesquite lined river beds were “delisted” with no recovery plan established. The 1997 surveys confirmed only a dozen birds. The following year a total of thirty one birds were found through the survey process. Many of these endangered owls are located in the northwest Tucson/Marana area. Under the Endangered Species Act, the Secretary of the Interior is supposed to develop and implement “recovery plans for the conservation and survival of endangered and threatened species.” Unfortunately this never happened and because there aren’t enough remaining Pygmy Owl’s in this area to form a discrete population, or in simpler terms there aren’t adequate numbers to form a group and denote them as a specific species. “This is unprecedented. In the 32-year history of the |The Endangered Species Act|Endangered Species Act] (ESA), a court ruling that a species population is insignificant has never prompted a delisting proposal from the government,” said National Association of Home Builders (NAHB) President Dave Wilson. “The government is heading down the right path with its delisting proposal,” continues Wilson,“ It should be devoting its scarce resources on wildlife that qualifies for protection under the ESA and that has a meaningful chance of recovery.”
In 2001 the NAHB filed a suit challenging the validity of the listing and the designation of the critical habitat for the bird reasoning that almost similar species “can be found in abundant numbers to the south in Mexico.” They questioned whether the Arizona population was “discrete and significant to the survival of the species,” two official necessities for shielding by the Endangered Species Act. The National American Home Builders, “also contended that an initial designation of 1.2 million acres as critical habitat was excessive and would damage the home building industry and the local economy.” Additionally they claimed that “the designation would add $7,000-$12,000 to the price of a home, which NAHB calculated could take a $500 million toll on local economic activity over 10 years.”
The Ninth Circuit Court of Appeals found that the “listing did not prove the significance of Arizona’s distinct population of owls for the survival of the entire subspecies.” The Arizona owl population was removed from the Endangered Species List, but ongoing legal actions over the question is likely.
Arizona’s acting Southwest deputy regional director, Larry Bell foresees "very little" decline in safeguarding for the owls since they are still covered by the Migratory Bird Treaty Act. He notes that, “The 1918 federal law outlaws the killing of certain birds and possession or trade of their parts, nests and eggs.” The problem is that while the Endangered Species Act can shelter areas that a listed species calls home, courts have ruled the Migratory Bird Treaty Act doesn't prohibit damage to their habitation, such as blading desert for new subdivisions. The difference is important: in Northwest Tucson, the developers versus the owls clash has revolved on alterations of the owl's territory, rather than express hunting of them.
Glaucidium brasilianum Summary of Study
Despite its small stature and low numbers, in the beginning the pygmy-owl listing generated important regional habitat conservation planning around Tucson
Today it has come to represent the extreme conflict in southern Arizona between desert conservation and urban sprawl development. Even as its numbers in Arizona continue to plunge this court verdict could jeopardize other species of local owls, however the bird's heritage will live on in tighter development regulations.
Due to habitat loss, this owl now only occurs between Tucson and the Mexican border and less than fifty exist in Arizona. The majority of these losses are due to the destruction and modification of riparian and desert habitats or to bluntly out, the desert was bladed and prepared for construction. For many years the debate has raged on between environmentalists and the construction industry. At one point the dispute called a halt to the building of a nearby school, but today sits a fast food mart and gas station. Some environmentalists are so adamant about counting the creatures that biologists eventually refused to make their current nesting sites public to avoid having scores of people traipsing through their habitat and disturbing the few that remain.
For some really terrific pictures of the Ferruginous owl you may want to visit Greg Lasley’s web site:
There is also a nice close up of one in my home node for the next few days.
Auk, The: A new species of pygmy-Owl :
Accessed January 5, 2006.
Dastardly Duos, Tucson Audubon Society:
Accessed January 5, 2006.
Pygmy owl: Little bird casts very big shadow:
Accessed February 23, 2006.
U.S. seeks to delist Arizona's pygmy owl:
Accessed January 3, 2006
Endangered Species Delisting Proposed for Pygmy Owl:
Accessed January 3, 2006.
Ferruginous Pygmy Owl
Accessed January 3, 2006.
Mr. and Mrs. Cactus Ferruginous Pygmy-owl, Meet the Feds:
Accessed January 3, 2006
Ferruginous Pygmy-Owl Biology:
Accessed January 3, 2006.