California condors return to Pacific Northwest skies, with lead the threat

A bird with a wingspan of 2.8 metres is being brought back to skies it left a century ago. This National Park Service "Featured Creature" article, from the March 2022 edition by the Klamath Inventory and Monitoring Network, describes the California condor, why lead ammunition is its main threat, and why northern California and Oregon are next.

A California condor flying below a turkey vulture; note the wing tag and the bright red patches of skin on its neck and crop. Photo: NPS/Gavin Emmons.

The biggest soaring land bird in North America

The California condor (Gymnogyps californianus) stretches 2.8 m (9.5 ft) wing to wing and weighs about 8.5 to 10 kg (18 to 22 lbs). It is a New World vulture whose closest relative is the Andean condor. An adult has brownish-red eyes in a bare, yellow to reddish-orange head, a mostly black body, and a long white triangle under each wing. Juveniles are dark overall and take several years to reach adult colouring. A ruff of neck feathers covers or exposes the neck to regulate temperature, and the legs can look white because the bird coats them with its own excretions to cool by evaporation, called urohydrosis.

In flight it can be mistaken for an eagle or vulture, but it soars steadily on flat wings like a small airplane, unlike the rocking flight of the smaller turkey vulture, and bald and golden eagles are about 2.5 ft shorter in wingspread. The giveaway is a large numbered tag on one or both wings, used by researchers to track birds.

From Lewis and Clark to a few dozen birds

Fossils show condors once ranged across North America, including southern Canada and the eastern United States, before the extinctions of large animals about 13,000 years ago. Lewis and Clark recorded them along the Columbia River and coast in 1804 to 1806; by the early 1900s they were mostly gone, and by 1940 only a small population in the coastal mountains of southern California remained. Reintroductions now give populations in southern and central California, Baja, Mexico, and the Grand Canyon area of northern Arizona. The Yurok Tribe is leading efforts to reintroduce condors to its ancestral territory and the Pacific Northwest; the first birds were released in 2022, and the article says they were soaring over Pacific Northwest skies for the first time in a century.

Condors are habitat generalists that glide great distances over very large home ranges, searching by sight for carcasses. Studies suggest the Pacific Northwest looks favourable: mature forests with big redwoods, open prairies and woodlands for foraging, plentiful marine mammal carcasses and relatively low lead and DDT.

Food, family and the lead problem

Radiograph of a condor with lead fragments visible in its body. Photo: NPS/PINN.

Condors are obligate scavengers. They eat deer, elk, livestock and marine mammals, mostly soft tissue, since they cannot break the bones, so they take calcium from bone chips of small prey. That need may explain a lethal habit: carrying bottle caps, spent bullet casings, glass and plastic back to the nest, where nestlings can swallow them. The most significant dietary threat, though, is poisoning from lead ammunition remnants in hunter-killed animals, and lead poisoning is currently the main threat to recovery.

They are social birds that roost, bathe and feed together. Pairs bond for years. The female lays a single pale egg between January and April directly onto the nest site, adding no nesting material, and both adults take turns incubating it. If the nest fails, the female can lay a replacement egg, "double clutching", which has been crucial to the species' recovery. The chick hatches after 8 weeks, fledges after 5.5 to 6 months and stays with its parents for 6 to 12 more months, so females breed no more than 2 years in 3. Maturity takes 6 to 8 years. Condors are thought to live to 60 or 70 years.

A California condor nesting in a redwood tree in Big Sur, California. Photo: NPS/Gavin Emmons.

Why they matter

Condors break carcasses into pieces for smaller scavengers. Vultures' guts resist bacterial toxins such as botulism, so by eating carcasses they help prevent disease outbreaks. Condors are culturally important to the Hupa, Karuk, Wiyot, Chilula and Tolowa Dee-ni' tribes, and sacred to the Yurok, for whom the bird is prey-go-neesh.

Recovery

In 1967 the federal government listed the 60 or so remaining condors as endangered, and a recovery team led by the U.S. Fish and Wildlife Service began implementing the recovery plan in 1975. By the early 1980s numbers had plummeted to about 23 birds, and all remaining free-flying birds were captured for breeding by 1987. The programme relies on captive breeding, double clutching, training young birds to avoid power poles, and regular clean, lead-free food for released birds. In 2020, 329 free-flying condors of 504 living birds were in California, Arizona and Mexico.

Free-flying condors are still ingesting toxic levels of lead and dying at rates too high to sustain a wild population without help. The article asks hunters to switch to non-lead ammunition such as steel or copper, everyone to keep microtrash out of the environment, and visitors to keep their distance from wild condors. It says to watch for condors in the Pacific Northwest soon, starting at Redwood National and State Parks.

Sources

• National Park Service, Klamath Inventory and Monitoring Network, "California Condor in the Pacific Northwest", Featured Creature edition of March 2022, prepared by Sonya Daw (https://www.nps.gov/articles/000/california-condor-in-the-pacific-northwest.htm). The Network's logo and one foraging-area figure whose unit was lost are left out.
• National Park Service; rewritten in hubnx's own words.