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At least 55 records · Page 3Linked to original sources
USGS2009

The reintroduction of the Andean condor into Colombia, South America: 1989-1991

From 1989 to 1991,22 captive-reared Andean condors Vultur gryphus were released into three protected areas in the Andes of Colombia, South America. The goals of this reintroduction programme were to re-establish populations of these birds in protected habitat where the species had been extirpated, and to train local biologists in the conservation techniques necessary to recover their native condor. All birds were hatched, reared and released according to the protocols established by the US Fish and Wildlife Service and the California Department of Fish and Game for the California condor Gymnogyps californianus. At the time of release, the birds ranged in age from 11 to 26 months. Each bird was fitted with individually numbered wing tags and wing-mounted radio transmitters. Of the 22 released animals, 19 currently survive – a substantial increase to the wild population in Colombia, which had been estimated by Colombian biologists to number only 20 individuals.

Oryx↗
USGS2022

Drivers of flight performance of California Condors (Gymnogyps californianus)

Flight behavior of soaring birds depends on a complex array of physiological, social, demographic, and environmental factors. California Condors ( Gymnogyps californianus ) rely on thermal and orographic updrafts to subsidize extended bouts of soaring flight, and their soaring flight performance is expected to vary in response to environmental variation and, potentially, with experience. We collected 6298 flight tracks described by high-frequency GPS telemetry data from five birds ranging in age from 1 to 19 yr old and followed over 32 d in summer 2016. Using these data, we tested the hypothesis that climb rate, an indicator of flight performance, would be related to the topographic and meteorological variables the bird experienced, and also to its age. Climb rate was greater when condors were flying in faster winds and during environmental conditions that were conducive to updraft development. However, we found no effect of age on climb rate. Although many of these relationships were expected based on flight theory, the lack of an effect of age was unexpected. Our work expands understanding of the relationship condors have with the environment, and it also suggests the potential for as-yet unexplored complexity to this relationship. As such, this study provides insight into avian flight behavior and, because flight performance influences bird behavior and exposure to anthropogenic risk, it has potential consequences for development of conservation management plans.

California↗
USGS2013

Distribution and movement of Big Spring spinedace ( Lepidomeda mollispinis pratensis ) in Condor Canyon, Meadow Valley Wash, Nevada

Big Spring spinedace (Lepidomeda mollispinis pratensis) is a cyprinid whose entire population occurs within a section of Meadow Valley Wash, Nevada. Other spinedace species have suffered population and range declines (one species is extinct). Managers, concerned about the vulnerability of Big Spring spinedace, have considered habitat restoration actions or translocation, but they have lacked data on distribution or habitat use. Our study occurred in an 8.2-km section of Meadow Valley Wash, including about 7.2 km in Condor Canyon and 0.8 km upstream of the canyon. Big Spring spinedace were present upstream of the currently listed critical habitat, including in the tributary Kill Wash. We found no Big Spring spinedace in the lower 3.3 km of Condor Canyon. We tagged Big Spring spinedace ≥70 mm fork length (range 70–103 mm) with passive integrated transponder tags during October 2008 (n = 100) and March 2009 (n = 103) to document movement. At least 47 of these individuals moved from their release location (up to 2 km). Thirty-nine individuals moved to Kill Wash or the confluence area with Meadow Valley Wash. Ninety-three percent of movement occurred in spring 2009. Fish moved both upstream and downstream. We found no movement downstream over a small waterfall at river km 7.9 and recorded only one fish that moved downstream over Delmue Falls (a 12-m drop) at river km 6.1. At the time of tagging, there was no significant difference in fork length or condition between Big Spring Spinedace that were later detected moving and those not detected moving. We found no significant difference in fork length or condition at time of tagging of Big Spring spinedace ≥70 mm fork length that were detected moving and those not detected moving. Kill Wash and its confluence area appeared important to Big Spring spinedace; connectivity with these areas may be key to species persistence. These areas may provide a habitat template for restoration or translocation. The lower 3.3 km of Meadow Valley Wash in Condor Canyon may be a good candidate section for habitat restoration actions.

Nevada↗
USGS2012

Patterns of mortality in free-ranging California condors (Gymnogyps californianus)

We document causes of death in free-ranging California Condors (Gymnogyps californianus) from the inception of the reintroduction program in 1992 through December 2009 to identify current and historic mortality factors that might interfere with establishment of self-sustaining populations in the wild. A total of 135 deaths occurred from October 1992 (the first post-release death) through December 2009, from a maximum population-at-risk of 352 birds, for a cumulative crude mortality rate of 38%. A definitive cause of death was determined for 76 of the 98 submitted cases, 70% (53/76) of which were attributed to anthropogenic causes. Trash ingestion was the most important mortality factor in nestlings (proportional mortality rate [PMR] 73%; 8/11), while lead toxicosis was the most important factor in juveniles (PMR 26%; 13/50) and adults (PMR 67%; 10/15). These results demonstrate that the leading causes of death at all California Condor release sites are anthropogenic. The mortality factors thought to be important in the decline of the historic California Condor population, particularly lead poisoning, remain the most important documented mortality factors today. Without effective mitigation, these factors can be expected to have the same effects on the sustainability of the wild populations as they have in the past.

Journal of Wildlife Diseases↗
USGS1986

Nest-site biology of the California condor

A study of 72 historical and recent nests of the California Condor (Gymnogyps californianus) has revealed considerable variability in nest-site characteristics. This paper primarily summarizes the data on nest elevations and dimensions, entrance orientations, nest longevity and re-use, vulnerability of sites to natural enemies, and use of sites by other species. Although all known nests have been natural cavities, some have been little more than overhung ledges on cliffs, while others have been deep, dark caves with nest chambers completely concealed from the outside. Two sites have been cavities in giant sequoias (Sequoiadendron giganteum). Contrary to previous assumptions, condors do modify the characteristics of their nest sites significantly and commonly construct substrates of coarse gravel on which to rest their eggs. Many nests have been completely accessible to terrestrial predators, many have been poorly protected from avian predators, and some have had structural flaws leading directly to nesting failure. The use of suboptimal sites has not been clearly related to a scarcity of better quality sites.

Condor↗
USGS1974

Supplemental feeding program for California condors

A 2-year supplemental feeding program for the endangered California condor ( Gymnogyps californianus ) was of insufficient length to definitely show that a dependable food supply will stimulate additional breeding; however, production did increase during the study, and food supply appears a likely cause. Because no undesirable effects of feeding were noted, and because condor production is now critically low, an expanded supplemental feeding program is recommended.

California↗
USGS1972

Copulation by California condors

Koford (Res. Rept. No. 3, Natl. Audubon Soc., 1953) observed sexual display among California Condors ( Gymnogyps californianus ) on more than 30 occasions, yet only once did he see what he thought was copulation. Some of the displays he watched were quite intricate, with considerable posturing and "male" aggression, but no such activity preceded this copulation. The birds sat several feet apart for over 1 hour, then one climbed onto the other's back, staying there 1/2 minute and flapping gently at the apparent moment of coition. Afterward they sat quietly 1/2 hour before flying away. This led Koford to state (p. 79) that "possibly in Gymnogyps copulation is not immediately preceded by display." We have records of 8 California Condor copulations, 5 of which are similar to that described above. The three other occasions began similarly, with the birds sitting quietly, but then the "male" displayed briefly before the "female" with wings half spread and head drooping forward. This elicited no apparent response, but the male immediately walked behind and mounted the female. The apparent moment of coition was accompanied by gentle wing flapping in all instances.

The Auk↗
USGS1985

Replacement-clutching and annual nesting of California condors

Observations since 1981 have conclusively documented the capacity of California Condors (Gymnogyps californianus) to lay replacement clutches within breeding seasons and to nest successfully on an annual basis. Deliberate encouragement of these capacities led to a better than three-fold increase in reproduction of the remnant population in 1983 and 1984.

Condor↗
USGS1985

The California condor

The California condor ( Gymnogyps californicus ), with a weight of 18 to 22 pounds and a wingspan of approximately nine feet, is one of the largest land birds in the Western Hemisphere. It is one of seven species of New World vultures in the family Cathartidae, which includes the more familiar and much smaller North American species, the turkey vulture ( Cathartes aura ). 1

Audubon Wildlife Report↗
USGS1989

Lead contamination of golden eagles Aquila chrysaetos within the range of the California condor Gymnogyps californianus

Blood samples were taken from 66 golden eagles from June 1985 to January 1986 and analyzed for their lead content. Thirty-nine percent had blood lead levels greater than 0.2 ppm, indicating exposure to environmental lead. Within the exposed group, 3 had blood levels exceeding 0.6 ppm and one exceeded 1.0 ppm. These data suggest that lead, probably in the form of shot, bullets, or bullet fragments, poses a hazard to scavenging birds within the range of the California condor.

Book chapter↗
USGS1975

California condor plumage and molt as field study aids

An analysis is made of the reliability of plumage and molt characteristics of the California condor for estimating age and identifying individual birds. Neither character seems sufficiently reliable to use in more than a general way.

California Fish and Game↗