Reintroduced Channel Islands eagles thrive on a diet of seabirds and fish
2015-07-23
(Press-News.org) Reintroducing a species into an area where it has vanished can be a great tool for conservation, but for reintroduction to be successful it's crucial to understand how the habitat has changed in the interim and whether the reintroduced species will be able to thrive in its former home. Extirpated in the 1960s as a result of human activity, Bald Eagles (Haleiaeetus leucocephalus) have been reintroduced to California's Channel Islands over the last 35 years. A study published this week in The Condor: Ornithological Applications examined the diets of these reestablished eagles in 2010 and 2011 to see how they compared to the diets of historical population. Like historical eagle populations, the reintroduced eagles in the Northern Channel Islands rely heavily on seabirds, according to authors Seth Newsome of the University of New Mexico, Paul Collins of the Santa Barbara Museum of Natural History, and Peter Sharpe of the Institute for Wildlife Studies. They also found that eagles on nearby Santa Catalina Island eat mostly fish, likely due to differences in human activity and a lack of seabird colonies on the island.
Newsome and his colleagues used two independent approaches to see what the eagles were eating--they collected the remains of prey from eagle nests, and they analyzed carbon and nitrogen isotopes in the eagles' feathers. The isotope findings were then compared to those from potential prey to determine what animals the eagles were eating. Both methods found the same results. "Generally speaking, the northern islands are much more pristine, and a larger fraction of their coastlines includes areas where fishing is strongly regulated or banned. Santa Catalina, on the other hand, has a larger human footprint, especially in the form of recreational fishing," explains Newsome. "We believe that the differences in diversity of fish consumed by eagles in these two areas is actually a product of recreational fishing, and that eagles on Santa Catalina have learned to follow recreational fishing boats and scavenge discards thrown overboard."
The Northern Channel Islands eagles' reliance on seabirds shows that successful seabird conservation efforts in the region have had benefits across the ecosystem. "As a community ecologist, I feel that the re-establishment of species at all trophic levels, including top predators like Bald Eagles, is the ultimate goal for animal conservation," says Newsome. "Preserving diversity is wonderful, but you need to preserve diversity at all levels in the food chain. At present, such intact fully-functioning food webs are relatively rare in the United States, but to see that happen in a place like the Channel Islands that is adjacent to an area with one of the highest human population densities in the U.S. (southern California) is exciting."
The number of eagles currently nesting on the islands is still below historic levels, so this fledgling population likely has room to expand. Exploiting both historical food sources and new ones made available by human activity, Channel Islands eagles are a success story for ecosystem recovery.
INFORMATION:
"Foraging ecology of a reintroduced population of breeding Bald Eagles on the Channel Islands, California, USA, inferred from prey remains and stable isotope analysis" is available at http://www.aoucospubs.org/doi/full/10.1650/CONDOR-14-213.1.
About the journal: The Condor: Ornithological Applications is a peer-reviewed, international journal of ornithology. It began in 1899 as the journal of the Cooper Ornithological Club, a group of ornithologists in California that became the Cooper Ornithological Society.
[Attachments] See images for this press release:
ELSE PRESS RELEASES FROM THIS DATE:
2015-07-23
People who grew up in a working class family are more satisfied in later life than those from a higher class background according to new research from The University of Manchester.
The study by Dr Bram Vanhoutte and Professor James Nazroo, published in the Journal of Population Ageing, also found that English people who climb the social ladder are more content and happy when they get older than people in the States who are similarly upwardly mobile.
The research sought to find out whether social mobility makes people happier in later life while taking into account ...
2015-07-23
Investigators affiliated with VIB and UGent recently achieved great success with a study involving biomedical research on mouse models. The research group of Prof Peter Vandenabeele (VIB/UGent) recently used tangible examples to demonstrate how the side effects of genetic modification of mice can complicate the interpretation of biomedical research. The team developed a web tool that allows scientists to estimate the impact of this phenomenon more accurately. Their findings were recently published in the medical journal Immunity and received ample attention by a preview ...
2015-07-23
Mangrove forests could play a crucial role in protecting coastal areas from sea level rise caused by climate change, according to new research involving the University of Southampton.
A joint study between researchers at the University of Southampton along with colleagues from the Universities of Auckland and Waikato in New Zealand used leading-edge mathematical simulations to study how mangrove forests respond to elevated sea levels.
Taking New Zealand mangrove data as the basis of a new modelling system, the team were able to predict what will happen to different types ...
2015-07-23
The U.S. Supreme Court's recent ruling legalizing marriage between same-sex couples in all 50 states follows on the heels of national polls showing rapid cultural changes in attitudes toward lesbian and gay people. A new University of Virginia study confirms this, showing that not only are Americans' conscious and unconscious biases against lesbian women and gay men decreasing across all demographic groups, but the trend also appears to be accelerating.
"Many people have this gut feeling that our culture has changed," said lead researcher Erin Westgate, a doctoral psychology ...
2015-07-23
ROCHESTER, MINN. - A group of 118 of the nation's leading cancer experts have drafted a prescription for reducing the high cost of cancer drugs and voiced support for a patient-based grassroots movement demanding action on the issue. Their recommendations and support are outlined in a commentary, co-authored by the group, in the journal Mayo Clinic Proceedings.
"High cancer drug prices are affecting the care of patients with cancer and our health care system," says lead author Ayalew Tefferi, M.D., a hematologist at Mayo Clinic. "The average gross household income in ...
2015-07-23
WASHINGTON, DC (July 23, 2015) -- Chicken, turkey and pork sold in grocery stores harbors disease-causing bacteria known as Klebsiella pneumoniae, according to a new study. The research, which was published online today in the journal Clinical Infectious Diseases, shows that contaminated meat may be an important source of human exposure to Klebsiella.The U.S. food safety system has traditionally focused on a few well-known bacteria like Listeria, Salmonella and Campylobacter, which cause millions of cases of food poisoning every year. The research published today suggests ...
2015-07-22
The Middle East is called the "Cradle of Civilization" because it is where our hunter-gatherer ancestors first established sedentary farming communities. Recently, the traditional dating of humans' first agricultural attempt was shaken up by the discovery of the earliest-known example of plant cultivation in the Levant, 11,000 years earlier than previously accepted.
The team of archaeologists, botanists, and ecologists from Bar-Ilan University, Haifa University, Tel Aviv University, and Harvard University published their work in the scientific journal Plos One on July ...
2015-07-22
Until now, researchers believed farming was "invented" some 12,000 years ago in the Cradle of Civilization -- Iraq, the Levant, parts of Turkey and Iran -- an area that was home to some of the earliest known human civilizations. A new discovery by an international collaboration of researchers from Tel Aviv University, Harvard University, Bar-Ilan University, and the University of Haifa offers the first evidence that trial plant cultivation began far earlier -- some 23,000 years ago.
The study focuses on the discovery of the first weed species at the site of a sedentary ...
2015-07-22
Family members who make major medical decisions for relatives in an intensive care unit (ICU) may suffer posttraumatic stress disorder (PTSD) if they cope by avoiding the situation, according to a new study by scientists at Case Western Reserve University's Frances Payne Bolton School of Nursing.
The patient isn't the only one affected by the long stay, according to Amy Petrinec, from the school of nursing. Family members may suffer, especially if they're required to make medical decisions with long-range consequences they may not understand, or are reluctant to question.
Family ...
2015-07-22
(NEW YORK CITY - July 22, 2015) Is it possible that too much iron in infant formula may potentially increase risk for neurodegenerative diseases like Parkinson's in adulthood -- and are teeth the window into the past that can help us tell? This and related theories were described in a "Perspectives" article authored by researchers from the Icahn School of Medicine at Mount Sinai and the University of Technology Sydney and Florey Institute of Neuroscience and Mental Health in Australia, and published online recently in Nature Reviews Neurology.
"Teeth are of particular ...
LAST 30 PRESS RELEASES:
[Press-News.org] Reintroduced Channel Islands eagles thrive on a diet of seabirds and fish
