More than ruffled feathers: Mockingbirds show heightened aggression after lead exposure

Date:  January 23, 2019

Source:  Morris Animal Foundation

Mockingbirds exposed to sub-lethal levels of lead in urban areas display significantly heightened aggression, said Morris Animal Foundation-funded researchers at Tulane University. The team said their findings highlight the possibility that sub-lethal lead exposure may be common among other wildlife living in urban areas and more work is needed to better understand its full effects. Their study was published in Science of the Total Environment.

"There's considerable lead contamination in soils around the world and that means literally billions of animals, both urban wildlife and pets, are likely exposed at sub-lethal levels," said Dr. Jordan Karubian, Associate Professor at Tulane University's Department of Ecology and Evolutionary Biology. "The levels aren't killing them, but they may affect their behavior or physiology. Heightened aggression among mockingbirds may just be the tip of the iceberg."

For the study, the team used simulated territorial intrusion on dozens of northern mockingbirds in urban New Orleans neighborhoods with either low or high levels of lead in the soil. Researchers placed a taxidermized mockingbird on a tripod, 25 feet away from nests that pairs of mockingbirds were constructing, a situation in which the birds act most territorial. The researchers also played recorded songs of singing males to alert the mockingbirds and make the intrusions more realistic.

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Big game hunters in Africa urged to drop the lead to help save vultures

Lead bullet fragments in carcasses left by hunters are poisoning endangered African vultures, a new study has found

Date:  March 15, 2018

Source:  University of Cape Town

A third of all vultures caught and tested in the Botswana study showed elevated levels of lead in their blood, most likely due to ingesting lead bullet-contaminated flesh. Hunters' bullets shatter inside their prey and can then be absorbed into the blood stream of the vultures when they feed on these animals or their remains. This ingested lead is highly toxic to birds.

"We were all shocked by how widespread lead poisoning was for this population and just how clearly these elevated levels were associated with recreational hunting activity," said Dr Arjun Amar, Associate Professor from the University of Cape Town's FitzPatrick Institute of African Ornithology, who supervised the research.

The study, published this week in the international journal Science of the Total Environment, is based on tests of nearly 600 critically endangered African White-backed Vultures. Higher lead levels were found in the blood of vultures in the hunting season and in hunting areas, suggesting that the source of the lead in their blood stream was lead bullets used for hunting.

"The only logical explanation for the patterns of lead poisoning we observed is if lead bullets were the source of this contamination" said the study's lead author Beckie Garbett, who conducted the research as part of her PhD.

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Griffon vultures are exposed to high concentrations of lead in their diets

Date: May 19, 2015

Source: Plataforma SINC

Summary: Because of their position on the food chain and their dietary habits, Griffon vultures from the Iberian Peninsula are exposed to accumulation of heavy metals in their tissues. A study reveals that, due to their diets, wild populations of Griffon vultures in Catalonia show the presence of a high amount of lead, which affects their immune systems and reproductive function.

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Lead continues to be a serious threat to California condor populations

Date:

April 9, 2014

Source:

Zoological Society of San Diego

Summary:

The California condor was one of the first species to be listed under the Endangered Species Preservation Act in 1966 when the population was reduced to a handful of birds. Through a massive collaborative effort, the condor population has grown to more than 400 birds, more than half of which are now free-flying in the wild. Unfortunately, there is overwhelming evidence that lead poisoning from accidental ingestion of spent ammunition is the leading cause of death in the wild population.

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