California Condor

Characteristics

They are notoriously massive birds, and have the longest wingspan of any bird of continental North America. They are predominantly black, with mostly bald heads. Their baggy, wrinkled skin is grey in the juvenile form, and varies from cream to reddish orange in adults. Long, white triangular stripes on the undersides of their wings distinguish them from other raptors in flight, e.g. Bald Eagles and Turley Vultures. The stripes appear mottled grey on juveniles. Conservation Society of California/Oakland Zoo works with other zoos, institutions and Ventana Wildlife Society to test wild condors for lead, conduct full lead poisoning/chelation treatments, and when ready, release them back into the wild through our California Condor Recovery Program.

Species Specifics

California Condors are one of two species of condors in the world, and one of six New World vultures. Among several salient features that distinguish the species from the Andean Condor of South America, they are the smaller of the two. The California condor is the largest soaring bird of continental North America. They are mostly black, with bald heads and baggy, wrinkled skin (bright orange in adults and dark gray in juveniles). In flight, they have distinctive long, white feather triangles on the undersides of their wings.

Physical Characteristics

They have the ability to soar and glide for hours without beating their wings and can glide at more than 55 mph, allowing them to travel long distances in search of food. Because their food source is never reliable, they can hold approximately 3 pounds of meat in their crop, though they only eat about 1 pound of food a day. Their bald heads allow for sanitation; scavenger behavior means they have their head inside of carcasses, and with feathers on their head cleanliness would be impossible (which could lead to infection and/or disease).

Ecology

Habitat

Rocky, open-country scrubland, coniferous forest, deserts, beaches, and oak savannah.

Distribution

Foraging ranges of nonbreeding birds have been documented at about 4,350 mi2. While nesting, birds have been documented traveling up to 112 miles from the nest for a single foraging trip.

Diet

These scavengers often look for large carcasses to feed on and they prefer fresh kills.

Ecological Web

The condor's role in communities has been as a highly social scavenger, feeding mainly on carcasses found from soaring flight. Predators: Condors do not have many predators hunting them as adults, but eggs and nestling condors are threatened by common ravens, golden eagles, and many large, terrestrial animals, most notably the black bear in recent years. Prey: Feed almost entirely on carcasses of large mammals, notably deer, cattle, sheep, and horses as well as marine mammals. But have been found feeding on CA ground squirrels. In addition, food remains in nests indicate that CA condors commonly consume shells of marine mollusks and barnacles, possibly to increase their calcium intake (collected from ocean shores or subfossil deposits on inland hillsides).

Activity and Behavior

Activity Pattern

Considered diurnal, but as scavengers, condors have to deal with a food supply that is often highly unpredictable in terms of abundance and distribution. Condors normally forage only during the midday hours, perhaps because the winds and thermals necessary for extended soaring flight are often not present at other times. They roost overnight and commonly stay preening and sunning themselves until mid-morning.

Behavior

They are rarely the first scavengers to discover a carcass, and rely mainly on observing activities of other scavengers such as common ravens and turkey vultures to find food. They will generally displace other scavengers upon arrival except golden eagles (they wait at a distance until the eagle finishes before moving in), probably because golden eagles are highly aggressive regarding food.

Social Behavior

Condors are highly gregarious in feeding and most other activities, with the exception of nesting, which occurs in caves in cliffs or natural cavities on nesting territories defended by pairs. Prior to their extinction in the wild, non-breeding birds would roost in groups of up to ~20.

Reproductive Behavior

Generally condors can start breeding at 6 years of age. Pairs are monogamous, but if one mate dies the survivor generally will find a new mate in a year or two. Cliffs, rocky outcrops, or large trees are used as nest sites, with no nesting material. CA condors have exceedingly low reproductive rates, with breeding pairs having the ability to produce 2 fledglings every 3 years. (Low reproductive rates and high survival rates are typical for animals with long-lived life histories like CA condors.) Eggs are generally laid between February- May for the species.

Offspring

1 egg per clutch, averaging 1 chick every other year. Chicks fledge after 6-7 months, but chick may leave the nest at 5 months.

Conservation

Status

Critically endangered by IUCN. U.S. and California Endangered Species Lists, Population trend: Increasing. As of February 2012, the total population stood at 173 individuals in captivity and 213 in the wild, primarily in southern and central California. The birds in California occur regularly in San Bernardino, Los Angeles, Ventura, Kern, Santa Barbara, San Luis Obispo, Monterey, San Benito, and probably Santa Cruz mountains. As of 2010, there were 104 adults in the wild that are old enough to breed and 44 have produced viable offspring.

Historical

California Condors came back from the edge of extinction! There were once 22 birds left in the wild, as populations plummeted due to DDT poisoning. Thanks to the help of the California Condor Recovery Program they have come back from the brink, and over 440 soar on warm thermals. California Condors were widely distributed in North America in ancient times, from the West Coast to small populations in Florida and New York. The California Gold Rush had a huge impact on the condors, because so many settlers came to the West and upended the ecology of the land. Lack of reproduction, inadequate food supply, contaminants, habitat loss, human disturbance, and direct persecution by humans were thought to be contributing to the condor population decline. Today, lead poisoning is the number one cause of death for California condors. Lead bullets fragment into hundreds of tiny pieces when they strike an animal and Condors feed on the remains left by hunters. Ingestion of lead fragments can lead to paralysis, seizures, blindness and sometimes death. Micro-trash is another challenge. Tiny bright pieces are brought to the nest, regurgitated by an adult condor, and ingested by condor chicks. The micro-trash can get stuck in the gastrointestinal track of young condors and cause impaction, preventing the birds from digesting food, resulting in starvation and death.

Current Threats

Our Role

California Condor Recovery Program. CSC works with other zoos, institutions and Ventana Wildlife Society to test wild condors for lead, conduct full lead poisoning/chelation treatments, and when ready, release them back into the wild. CSC also treats condors sick with other ailments, or injured condors. Support for Ventana Wildlife Society: Funds support the resources to be able to test all the condors in their areas that are vulnerable to lead poisoning twice a year. Oakland Zoo supplies food for their wild populations. Oakland Zoo provides field video cameras for biologists to easily monitor health and locations. Plans include campaigns to inspire hunters to move to copper bullets.