Steve Portugal, researcher in the School of Biosciences at the University of Birmingham, carried out a study to find out the reason behind the sudden weight loss of geese six weeks before migration. His study suggested that the waterfowl lose their weight during wing moult as the lighter birds are considered to be able to fly more than heavier one. Portugal found that captive barnacle geese lose weight at the same time during the wing moult even when they have unlimited to restricted access to food. He noted that birds tend to rest and stay put a lot more than before the wing moult and together with their vulnerability, hamper foraging opportunities thereby resulting in inevitable weight loss. He also utilized the satellite monitoring for his study on about 6 geese by supervising their heart beat per flight and found that they stop periodically along the coasts and flew for 24 hours a day non-stop.
