WHY IS IT IMPORTANT ?
THIS DAY IS AN AWARENESS CAMPAIGN THAT HIGHLIGHTS THE IMPORTANCE OF CONSERVING MIGRATORY BIRDS AND THEIR HABITATS. IT’S AN EFFECTIVE TOOL TO HELP RAISE GLOBAL AWARENESS OF THE THREATS TO MIGRATORY BIRDS, THEIR ECOLOGICAL IMPORTANCE AND THE NEED FOR INTERNATIONAL COOPERATION TO CONSERVE THEM.
ALMOST HALF OF BIRD SPECIES MIGRATE EACH YEAR. THE BIRDS FLEE TO AVOID THE COLD AND HARSH WINTER, BUT ABOVE ALL THEY FLEE THE LACK OF FOOD RESOURCES THAT OCCURS AT THIS TIME OF YEAR, AND GO LOOK ELSEWHERE FOR FOOD. BIRDS ARE ALWAYS LOOKING FOR WARMER PLACES AND A PLACE WHERE FOOD IS AVAILABLE AND SAFE FOR THE MATING PROCESS.
AROUND 4000 SPECIES OF BIRDS MIGRATE REGULARLY, AND THIS REPRESENTS AROUND 40% OF THE TOTAL NUMBER OF BIRD SPECIES IN THE WORLD.
SOME SPECIES OF MIGRATORY BIRDS CAN TRAVEL THOUSANDS OF MILES ON THEIR ANNUAL FLIGHT, AND SOMEHOW THEY CAN FIND THEIR WINTER HOME AND RETURN THE FOLLOWING SPRING TO WHERE THEY WERE BORN.
DURING MAJOR MIGRATORY FLOWS, THERE IS GENERALLY A PEAK IN MIGRATORY ACTIVITY FROM SUNSET UNTIL MIDNIGHT OR EVEN 1 A.M., FOLLOWED BY A DECREASE IN THIS ACTIVITY THE REST OF THE NIGHT. AT DAWN, THE NUMBER OF BIRDS IN FLIGHT INCREASES AGAIN, FOR DIURNAL MIGRANTS THIS TIME.
A BETTER PROTECTION OF THESE ANIMALS REQUIRES A GOOD KNOWLEDGE OF THEIR MIGRATIONS
THE TRAJECTORY OF MIGRATORY BIRDS
IN EARLY FALL, MANY BIRDS MIGRATE LONG DISTANCES, MAINLY FROM TEMPERATE ZONES, SOUTHWARD, THEN RETURN NORTHWARD DURING SPRING.
MIGRATORY BIRDS CROSS CONTINENTS AND OCEANS WITHOUT EVER GETTING LOST. SCIENTISTS HAVE TRIED TO DECIPHER THESE ABILITIES. RESULT: LIKE THE GREAT NAVIGATORS, THEY LOOK AT THE SKY. THESE MARKERS ALLOW THEM TO POSITION THEMSELVES IN THE RIGHT DIRECTION, BUT ALSO TO REGULATE THEIR ANNUAL MIGRATION: WHEN THE DURATION OF DAYLIGHT DECREASES, IT’S TIME TO LEAVE. THEY ARE ALSO ABLE TO KNOW THE TIME OF DAY, BY ANALYZING THE POSITION OF THE SUN, THUS JUDGING THE TIME REMAINING BEFORE IT SETS. NOCTURNAL INDIVIDUALS FLY LOOKING AT THE STARS. SCIENTISTS HAVE PROVEN THIS BY PLACING BIRDS IN A PLANETARIUM AND ARTIFICIALLY MOVING THE STARS.
TO GUIDE THEMSELVES, BIRDS THAT MIGRATE BY DAY CAN ALSO USE LANDMARKS ON THE GROUND SUCH AS MOUNTAINS, RIVERS, COASTS, ETC. AS WELL AS TERRESTRIAL MAGNETISM. SOME BIRDS HAVE MAGNETIC SENSORS IN THEIR EYES AND LODESTONE (A MINERAL THAT ACTS LIKE A MAGNET) IN THEIR BEAKS, WHICH HELP THEM ORIENT THEIR FLIGHT. THIS MODE OF NAVIGATION IS FACILITATED AT THE POLES, WHERE THE LINES OF THE EARTH'S MAGNETIC FIELD CONVERGE, BECOMING STRONGER. ON THE OTHER HAND, NEAR THE EQUATOR, IT IS DIFFICULT TO RELY ON THIS NATURAL GPS.