Traffic noise reduces birds' response to alarm calls

Pollution can take many forms--including noise. Excess noise in the environment from sources such as traffic can have negative effects on animals that rely on sound to communicate and get information about their surroundings. A new study from The Condor: Ornithological Applications shows that traffic noise makes birds less responsive to alarm calls that would otherwise alert them to dangers such as predators.

Alaska's shorebirds exposed to mercury

Shorebirds breeding in Alaska are being exposed to mercury at levels that could put their populations at risk, according to new research from The Condor: Ornithological Applications.Thanks to atmospheric circulation and other factors, the mercury that we deposit into the environment tends to accumulate in the Arctic. Mercury exposure can reduce birds' reproductive success and sometimes even be lethal. Shorebirds may be particularly vulnerable because they forage in aquatic environments where mercury is converted into methylmercury, its most dangerous form. Marie Perkins of the Biodiversity Research Institute (BRI) and her colleagues investigated the level of mercury in Alaska's shorebirds and found that some birds breeding near Barrow, at the state's northern end, have mercury concentrations upwards of two micrograms per gram of blood.

Coastal birds understand tides and the moon's phases

Coastal wading birds shape their lives around the tides, and new research in The Auk: Ornithological Advances shows that different species respond differently to shifting patterns of high and low water according to their size and daily schedules, even following prey cycles tied to the phases of the moon.Many birds rely on the shallow water of the intertidal zone for foraging, but this habitat appears and disappears as the tide ebbs and flows, with patterns that go through monthly cycles of strong "spring" and weak "neap" tides. Leonardo Calle of Montana State University (formerly Florida Atlantic University) and his colleagues wanted to assess how wading birds respond to these changes, because different species face different constraints--longer-legged birds can forage in deeper water than those with shorter legs, and birds that are only active during the day have different needs than those that will forage day or night.