For Some Arctic Birds, Time of Day Is Irrelevant

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Arctic summers mean migrating animals, a bounty of breeding opportunities, and 24 hours of sunlight. Many plants and animals experience 24-hour cycles telling them when it's time to rest and when it's time to get up—called the circadian rhythm—that are often tied to light cues. So what happens when the sun never sets?

For four species of migrating birds that breed in the Arctic, new research shows that "anything goes," said Bart Kempenaers, a behavioral ecologist with the Max Planck Institute for Ornithology near Munich.

Lapland longspurs (Calcarius lapponicus) exhibit a 24-hour cycle, while semipalmated sandpipers (Calidris pusilla) and pectoral sandpipers (Calidris melanotos) are active around the clock. Red phalaropes (Phalaropus fulicarius) shift from a roughly 21-hour cycle to a 29-hour cycle.

The type of cycle each displays depends on the species, an individual's sex, and their social circumstances.

Arctic residents like the reindeer and a bird called the ptarmigan don't really have a 24-hour cycle, said Kempenaers, co-author of a recent study published this week in the journal Proceedings of the Royal Society B.

Scientists think this enables the permanent residents to take advantage of the midnight sun to feed around the clock. (Read about Scandinavians who walk with reindeer in National Geographic magazine.)

But Kempenaers and colleagues were curious to see what happened with Arctic migrants.

So the scientists studied the activity patterns of four bird species that migrated to the same area near Barrow, Alaska (map) to reproduce during the Arctic's five-week breeding season. (See pictures of other Arctic animals.)

They attached 0.03-ounce (one-gram) radio transmitters to 142 individuals of Lapland longspurs, semipalmated sandpipers, pectoral sandpipers, and red phalaropes.

The radio tags allowed researchers to continuously monitor individual activity levels, which the team then verified with behavioral observations in the field.

How Diving Mammals Stay Underwater for So Long

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Imagine holding your breath while chasing down a giant squid (Architeuthis dux)—multi-tentacled monsters wielding suckers lined with tiny teeth—in freezing cold water, all in the dark. That would take a lot out of anybody, yet sperm whales (Physeter macrocephalus) do this day in and day out.

The ability to dive underwater for extended periods is a specialized feat marine and aquatic mammals have evolved over millions of years. Diving mammals will slow their heart rate, stop their breathing, and shunt blood flow from their extremities to the brain, heart, and muscles when starting a dive. (Related: "Can Diving Mammals Avoid the Bends?")

But champion divers, such as elephant seals, can hold their breath for about two hours. "It was known that they rely on internal oxygen stores when they're down there," said Michael Berenbrink, a zoologist at the University of Liverpool, England, who specializes in how animals function.

But there was something else going on in the bodies of these animals that researchers were missing, until now.

So what's new? A study published June 13 in the journal Science reports that diving mammals—including whales, seals, otters, and even beavers and muskrats—have positively charged oxygen-binding proteins, called myoglobin, in their muscles.

This positive characteristic allows the animals to pack much more myoglobin into their bodies than other mammals, such as humans—and enables diving mammals to keep a larger store of oxygen on which to draw while underwater.

Why is it important? Packing too many proteins together can be problematic, explained Berenbrink, a study co-author, because they clump when they get too close to each other.

"This [can cause] serious diseases," he added. In humans, ailments like diabetes and Alzheimer's can result.

But myoglobin is ten times more concentrated in the muscles of diving mammals than it is in human muscles, Berenbrink said.

Since like charges repel each other—think of trying to push together the sides of two magnets with the same charge—having positively charged myoglobin keeps the proteins from sticking to each other.

Penguins support gorillas as biscuit makers respond to palm oil threat

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Penguins are coming to the aid of gorillas, according to a survey which reveals that the UK's leading biscuit manufacturers are responding to the environmental threats of palm oil production.

Many of the biggest names in biscuits including Marks & Spencer, Sainsbury's and United Biscuits – which makes some of the UK's most popular biscuits including McVitie's Digestive and Penguin – have pledged to reduce the amount of palm oil in their products.

The Rainforest Foundation UK (RFUK) and Ethical Consumer magazine together surveyed over 50 of the UK's biggest biscuit manufacturers about their use of palm oil or its derivatives.

The top scoring companies were the Co-op, M&S, Sainsbury's, Waitrose and United Biscuits. Those at the bottom of the ranking were mostly American-based companies including Asda/Walmart, PepsiCo and Kraft, makers of Ritz and Oreo biscuits.

The project was carried out in response to the increasing threat that palm oil production is posing to the world's rainforest and to the people that rely on these forests for their livelihoods. Palm oil is a core ingredient in many food products but companies are not required by EU law to label products containing it until December 2014.

Having destroyed vast areas of forest in countries including Indonesia, which is home to orangutans, the RFUK says palm oil companies are now planning to expand into the rainforests of the Congo basin in Africa, home to lowland gorillas and other threatened primates. Palm oil companies are also partly responsible for the recent devastating forest fires in Sumatra, which caused pollution episodes in Malaysia and Singapore.

Simon Counsell, executive director of The Rainforest Foundation, UK said: "UK biscuit manufacturers and retailers are showing that it is possible to outright reduce the use of palm oil, which is going to have to occur globally if large areas of Africa's rainforests are to be saved from conversion to palm plantations."

Leonie Nimmo, researcher at Ethical Consumer, added: "This survey clearly shows that environmental campaigning is having a positive impact on the palm oil policies of many companies which is something we wholeheartedly support. Consumers now have a choice in buying biscuits which are reducing the risks to both people and wildlife."

North American Birds Declining as Threats Mount

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Throughout the year, birders look forward to changing seasons and avian scenes as they explore woods, grasslands, and wetlands: the spectacle of spring migration, the songs of breeding birds, the autumn southward flight of wintering species from northern nesting grounds.

Increasingly, though, both casual bird-watchers and ornithologists note a steady decline in numbers—not just of endangered species, but also of common birds not usually considered to be at risk. Study after study, survey after survey show a worrisome downward trend in populations.

A National Audubon Society report called "Common Birds in Decline," for instance, shows that some widespread species generally thought to be secure have decreased in number as much as 80 percent since 1967, and the 19 others in the report have lost half their populations. The figures reflect an array of threats faced by birds throughout North America. (Read about the decline of European songbirds in National Geographic magazine.)

Migrants return from Central America to find that the brushy field where they nested the previous year is now a strip mall.

Millions of songbirds annually suffer bloody death in the claws of domestic cats. Millions more collide with city skyscrapers or communications towers, or fly into the glass windows of suburban houses.

And climate change could degrade or even eliminate habitats in ways that scientists have only recently begun to study and try to forecast.

Threats to songbirds occasionally make splashy headlines, as when Smithsonian scientists released a report in January indicating that free-ranging domestic cats kill far more birds than previously believed: between 1.4 and 3.7 billion birds annually in the lower 48 states.