POP QUIZ: What is the leading cause of death of California condor nestlings here in the Golden State?
If you guessed lead poisoning, clearly you know much about the threats to successful condor recovery – nice work! But while lead poisoning is the #1 cause of mortality in adult condors, something else is causing condor chicks to die here in our state. And you just might be surprised by the little things that are taking down our continent’s largest land-based birds.
According to the most recent 5-year status review on the California Condor Recovery Program issued by the U.S. Fish and Wildlife Service, breeding condors sometimes ingest then feed their nestling little pieces of garbage like bottle caps, nuts, bolts, washers, shards of glass, plastic, wire and spent ammunition cartridges – collectively referred to as “microtrash.” And while condor chicks can tolerate small quantities of microtrash, large amounts can result in a variety of negative effects, including digestive tract impaction, internal cuts and bleeding, and even death. More than 40% of known deaths in wild condor nestlings in California have been from microtrash ingestion. And unfortunately, condors in the southern part of our state are most affected by this problem, reflecting the increased human impact in the wild public lands that condors frequent.
You may be wondering, why do condors feed their chicks microtrash? No one knows for sure, but leading researchers believe they may be mistaking these small, shiny pieces of garbage for calcium-rich food sources needed for egg-laying and chick growth and development. Other researchers have suggested that the condors are trying to fill the need for roughage that helps digestion, which is common in other bird species.
So what can be done about this problem? There are several approaches that are currently being used to address microtrash ingestion. The first method, called nest guarding, is when members of the condor recovery team actually climb into and clean active nests of all trash and also assess the nestling for any microtrash-related distress. Another way biologists are addressing this issue is by offering bone chips at condor feeding stations. These stations are used to ensure condors have a clean food source that is not contaminated with lead fragments from spent ammunition. A third way to help tackle the microtrash problem is to reduce the amount available by simply cleaning up areas where condors are known to congregate, like mountaintops high in the Los Padres National Forest.
I’ve had a deep interest in helping condors return from the brink of extinction. I’m proud to have worked to fight new oil & gas development in condor territory and help pass legislation here in California that requires hunters to use non-lead ammunition for taking any wildlife. So when I learned of a way that I could help condors on the microtrash issue, I jumped at the opportunity.
I traveled down to southern California and met up with our partners at Los Padres ForestWatch for two microtrash clean-up events: one on McPherson Peak, the other on Frazier Mountain, both known to be popular hangout spots for condors in the Los Padres National Forest. Small but dedicated crews headed to the top of these mountains, both of which host several communications towers – and surprising amounts of little bits of garbage, especially washers, bolts, wire and glass.
I’m pleased to report that between the two events, we managed to remove a whopping 120 pounds of microtrash from McPherson Peak and Frazier Mountain – and believe me, it takes a lot of microtrash to weigh 120 pounds!
While microtrash has been identified as the main source of mortality for wild condor chicks in California, important steps – like these cleans-ups – are being taken to reduce the threat. Nesting success is showing signs of improvement and the cleaner we can keep our wild places, the better the chances for condors to continue to soar towards a brighter future.
Pamela Flick is the California Representative for Defenders of Wildlife