Missing San Francisco Sea Lions Move To Oregon
Scientists in the US believe they may have solved the riddle of San Francisco’s vanishing sea lions. The Californian city’s famous colony of sea lions all but disappeared over the past month, baffling experts. But now large numbers of the animals have been spotted further north, off the coast of Oregon. Scientists say the animals have probably migrated in search of food during the winter, although in unusually high numbers…. (continues @ BBC News)
Mystery of Amazon Manatee Migration Solved (via BBC Earth News)
Only in recent years did scientists find that the secretive aquatic mammal migrates from shallow to deep water. Now researchers can reveal that the manatees make this perilous journey to avoid being exposed to attack by predators during the low water season. That means the species maybe at greater risk than previously thought, say scientists, as migration and low water levels make them vulnerable to hunters….
Moving to the deeper habitat is not easy, as the large mammals must pass through narrow bottlenecks in the aquatic landscape, where human hunters wait for them. The perilous journey also has another downside; it forces the manatees to fast for several months due to a lack of aquatic plants….
Butterfly ‘GPS’ found in antennae (via BBC News)
North America’s Monarch butterflies use a 24-hour “clock” in their antennae to help navigate the 4,000km to overwinter in Mexico, say scientists.
Every autumn about 100 million Monarch butterflies migrate to the south. The insects navigate according to the position of the Sun, adjusting their calculations as it appears to move across the sky….
They removed the antennae from a group of butterflies and compared the way they flew with a control population in a flight simulator. The intact butterflies all flew southwest, as normal, but the insects without antennae, although they flew strongly, headed off in random directions….
North African Migrant Painted Lady Butterflies Invade UK
Monarch butterflies are not the only butterflies to migrate long distances:
From the Atlas Mountains of Morocco, millions of North African butterflies are arriving in Britain - expected to be the largest migration of the Painted Lady species ever seen in the UK.
With warm, southerly winds over the bank holiday weekend, the extraordinary annual journey of these fragile looking insects suddenly hit Britain and experts think it may break all records.
“We have all been stunned at how quickly it has all happened. We were expecting them to arrive and suddenly with the good weather - Bang!”, Dr Martin Warren from the charity Butterfly Conservation tells me.
“All the signs are that this will be the largest ever migration of Painted Ladies to the UK.”…. An estimated 18,000 were spotted flying past Scolt Head Island on the Norfolk coast on Monday, passing at 50-a-minute over a 400m front yesterday…. (continues @ BBC News)
