Migration Flights Test Bird Stamina
It has long been known that migrating birds embark on particularly long and grueling journeys when they cross the oceans. What hasn’t been known for sure is whether or not they somehow stop along the way – until now that is. A Bar-tailed Godwit has been bestowed with the title ‘endurance champion of the animal kingdom’ after completing his epic 7,200 mile flight across the Pacific Ocean nonstop.
It’s no secret that Bar-tailed Godwits undertake an annual migration from Alaska to Australia and various islands in the southern hemisphere each year to breed. What scientists really wanted to know was if they made pit-stops along the way. That was the goal behind a recent study wherein nine Bar-tailed Godwits (Limosa lapponica baueri) were fitted with electronic tags before setting off into the sunset on their mammoth migration flights. The birds flew between 4,355 miles and 7,258 miles, depending on which route they chose to take, with their journeys lasting 6-9 days correspondingly. What makes the research particularly interesting is that the flight paths reveal the birds were unlikely to sleep during the time and even more significantly – that they did not feed along the way. That means that their wings did not stop flapping from their point of departure to their point of arrival! This makes their journey even more remarkable, since it sets new precedents for endurance in animals. According to scientists, the energy required to complete this sort of migratory journey is the greatest in the animal kingdom.
The international scientific team, under the leadership of Bob Gill of the US Geological Survey, has said: “These extraordinary nonstop flights establish new extremes for avian flight performance and have profound implications for understanding the physiological capabilities of vertebrates.” According to Theunis Piersma of the University of Groningen (Netherlands) who worked on the study, the energy requirements of the birds was the greatest known energy requirement in the animal kingdom. During their week-long, non-stop journey, the birds would have been consuming energy at around eight times their resting basic metabolic rate (BMR). This is in sharp contrast with other measurements, such as a professional cyclist who may manage to function at around five times BMR for just a few hours. Piersma appropriately summed up the results with this remark: “There is something special going on here. For a vertebrate this kind of endurance is just extraordinary.”
