The Strugle For The California Condor Lorin McNulty McNulty 1 Environmental Biology Biology Mid-Term 10 April 2000 THE STRUGGLE FOR THE CALIFORNIA CONDOR The natural environment of the modern world has been under siege for the better part of the past century. This has been due to many factors.
The waste produced by an ever-expanding human population has tainted much of the natural resources available to both humans and animals alike. Efforts to curb this waste output and to more effectively dispose of the waste have failed in the mainstream. The constant change of the common environment instituted by humans who have collectively sought to modify their own habitat has exacted a high toll on the available habitat for lesser creatures.
Constant waste production, poor disposal, and habitat encroachment have combined to render the balance of the natural world asunder. The delicate and intricate balance of the natural world has been damaged by a dominant species that has commonly disregarded its inherent responsibility to garnish its actions concurrent with the world it shares with the rest of nature (Center for Reproduction of Endangered Species. p3).
An all too common result of this imbalance is the expiration of entire species of animals that are dependent on precious resources. Historically, the presence of humans McNulty 2 has exponentially accelerated the natural rate at which fringe species have met with extinction.Modern humans have followed their own ancient precedent in this regard.
Recorded evidence of early human settlement has shown that human presence alone had accelerated extinction rates to several times its natural rate (Center for the Reproduction of Endangered Species. p4). However, it is a different precedent that modern humans have sought with the advent of a new and more complete awareness of our collective role as the dominant species. Several recent advances in waste treatment are offering alternatives to the usual high-output, wasteful societal paradigm. Although habitat encroachment continues to be a source of great conflict between the human population and the animal world, the human race has begun in earnest to attempt restoration of some species that have fallen casualty to pollution, encroachment, or both. Although success has been limited, these restorative efforts represent a reckoning on the behalf of humans with their place in the natural order.
One of the most successful of these programs concerns the California Condor. This magnificent species had all but disappeared from its natural range due to the human presence. With the recently recorded demise of the California Condors natural population came the effort to repopulate selected areas of habitat with captively breed condors. McNulty 3 THE STUDY OF THE CALIFORNIA CONDOR The California Condor is a remarkable species of scavenging birds indigenous primarily to California. Early studies showed populations of condors ranging from the rocky coastal areas to the interior mountains. In the early 1900s, sightings of these majestic birds, although reclusive in nature, were commonplace.
Early in the 1900s, serious scientific studies began on the California Condors. There were many successful studies in the wild, and there was increasing interest from the scientific community. In 1939, the naturalist Carl Koford first began a careful scientific study of these condors in the wild. Carefully documented field studies yielded a wealth of information about a species in the American West that had previously eluded the scientific eye. One development resulting from the study of Carl Koford was the establishment of the exact nature of the diet of these birds. Although known to be primarily scavengers, it was learned just how well adapted these birds are at finding and discriminating suitable prey.
It was learned that the primary feeding times were during daylight hours, with most activity centering near noon. They were observed feeding on carcasses in all states of decay, and even competing with other more aggressive species for rights to a kill. Their bills are exquisitely adapted to tearing animal flesh, and their digestive systems are specially suited to digesting rotting flesh. Condors were not known to have attacked live prey, and the diet of condors was found to have been an assortment McNulty 4 of carcasses found throughout the feeding range.
Condors were found to have spent an average of fifteen hours a day at the roosting site, and even more hours on days of inclement weather (Grossman. p38). These studies also produced the first scientific measure of the social structure of these birds.Their population had come under suspicion during this time, and the population count during this time seemed to prove their decline. The territories of these birds were found to be wide stretching, often including several hundred miles. The ability of these birds to roam these territories in search of food was found to be incredible, with some specimens gliding on large wings as far as ten miles with no wing movement. Poor weather and still air had been found to restrict the birds to the nesting site. In optimum conditions, making use of thermal updrafts for efficient flying was found to be common among these birds.
This mobility was shown to provide another advantage with the remains of coastal marine molluscs found near some nesting sites during the study.In combination with the diet of these birds, this mobility led to conflict with the ranching efforts of humans. Many ranchers began making a misguided effort to protect their livestock by regularly shooting condors even though condors are scavengers, and are not hunters of live prey. Further, sport shooting went largely unregulated for years. Some other developments included establishing the nature of the reproductive biology of the condors. These birds were observed as cavity dwellers.Nesting in rocky caves, crevices, or among boulder formations, these condors were found to move to new sites between nesting attempts (The Encyclopedia of Birds).
This was deemed to be part McNulty 5 of the habitat needs these birds required. The incubation period of these birds was found to be fifty-four to fifty-eight days, with each parent taking turns guarding the nest. The fragility of these birds was attributed in part to their low birth rate. A mature female will lay one egg only every two years, and the young are fed throughout most of their eighteen to twenty month adolescence.Although a chic begins flight practice at five to six months of age, the dependency on the adults for food can continue into the second year (Audubons Birds of America.
). This reproductive profile rendered the condor population sensitive to hunting and encroachment because they required so long a period of time to regenerate losses in population. The effects of industrial chemical pollution further complicated regeneration of losses. Industrial chemical pollution has been proven to be destructive with studies having shown that the eggshells of condors were reduced in thickness by as much as thirty percent after the widespread use of DDT (MacMillan Illustrated Encyclopedia of Birds). CONSERVATION EFFORTS FOR THE CALIFORNIA CONDOR With the knowledge gained from successful field studies, scientists began to consider solutions to the dwindling wild population of California Condors. Captive breeding was an idea that garnished considerable attention from the general scientific McNulty 6 community. Two scientists from the San Diego Zoo proposed a captive-breeding program aimed specifically at regenerating the wild population of California Condors.
The San Diego Zoo Director Belle Benchley and Curator K.C. Lint had met with considerable success with a captive breeding program aimed at breeding Andean Condors through a technique known as double clutching. This involved removing eggs from captive breeding pairs, thereby stimulating the female to lay one egg every year.
The doubled egg laying rate offered potential for regeneration of numbers faster than a naturally breeding pair. Pressure from environmental groups eventually prevented the proposed program from going into action with the overriding concern being disturbance of the remaining pairs in the wild. The attention devoted to the preservation of the California Condor experienced a resurgence in nineteen sixty-six when the California Condor appeared on the first published list of endangered species.
The population estimates ranged from fifty to sixty birds. The population continued to decline and in nineteen seventy-nine estimates ranged from twenty-five to thirty-five …