In the 1950s, the San Diego Zoo was believed to have the only thick-billed parrots in captivity in the world. Starting in 1951, we had but one female bird at a time. But a male was confiscated by U.S. Customs and arrived at our zoo in 1956. He was paired with a female that had been found in a Los Angeles pet store the previous year.
Over nine years, the pair was given a variety of nesting facilities, foods, and care—all to no avail, until a new wooden nesting box was filled with soil and pine shavings and suspended by wire from the top of the aviary. A chick hatched in 1965, giving the zoo world a known incubation period of 28 days for this species. This historic event earned us the Association of Zoos and Aquariums’ 1966 Edward H. Bean Award for the first captive hatch of a thick-billed parrot.
The thick-billed parrot population has dropped since the early 1900s. Although its range once included southern areas of Arizona and New Mexico south to Venezuela in South America, it is now found mostly in the Sierra Madre Occidental Mountains of northern Mexico. Estimates suggest there are just 3,000 to 6,000 of the parrots in the wild, with fewer than 1,000 breeding pairs. What has happened? Hunting and logging in the parrots' pine forest habitat, disease, and the illegal capture of birds for the pet trade are the greatest threats facing thick-billed parrots today.
It is believed that half of the world's thick-billed parrots live in a 6,000-acre (2,400 hectares) tract of forest in Chihuahua, Mexico, which is the birds' most important nesting area. In 2000, a private group that owned the land agreed to stop logging in the area, and plans are underway to develop a certified sustainable timber harvest and build cabins for ecotourists.
San Diego Zoo Global participates in the Association of Zoos and Aquariums’ Species Survival Plan for the thick-billed parrot and is part of a group of conservation organizations supporting field studies and working to save the birds' remaining habitat. Artificial nest boxes have been installed to provide suitable nest sites for the birds, and we are now studying health issues affecting the parrots to help with their recovery.
To date, the most concerning observation has been the presence of ectoparasites on chicks and in the nest cavities. Four different types of parasites have been identified. These parasites can be devastating to newly hatched chicks, as many of the bugs are hematophagous (a nice way of saying blood-sucking). It’s thought that increased temperatures and rainfall, often linked to climate change, may be increasing the number of parasitic fly larvae that feed on chicks. This has been recently documented in many species of chicks in South America and is very concerning.
Our veterinarians have developed treatments for individual birds and their nest cavities, using only organic compounds so as to have the least impact on the forest and all its inhabitants. Obviously, treatment of all chicks and all nest cavities in the nesting area is not possible, but increasing chick survival is a first step in halting population declines.
With their noisy habits and eye-catching plumage, thick-billed parrots are hard to ignore. Today, with a breeding program in place, habitat protection undertaken, and public awareness on the rise, our western mountains just might echo again with the riotous calls of flocking thick-billed parrots!
You can help us bring thick-billed parrots and other species back from the brink by supporting the San Diego Zoo Global Wildlife Conservancy. Together we can save and protect wildlife around the globe.