14 DAY TRIAL // According to a new scientific investigation, it would appear that small-sized migrating birds may actually be better off if they are a bit on the chubby side. Researchers say that a little extra fat may be very beneficial for the winged creatures, seeing how long-distance migrations tend to take a huge toll on their bodies. The same investigation seems to suggest that fatter birds also tend to stop less while flying long distances, in order to replenish their fuel reserves. Details of the research appear in the February 17 online issue of the respected scientific journal Biology Letters, LiveScience reports.
The new work was conducted on a species of small birds, known as the garden warbler. These animals migrate annually from the southern and central parts of Africa, where they spend most of their year, to their spawning grounds in Europe. Because of the relatively large distances involved in their flight, the birds need to make a number of stops along the way, so as to replenish their fat reserves. Curious to see whether there was any difference in stop patterns between fat and skinny birds, scientists mounted 10 fat birds and 10 thin birds with temporary adhesive radio transmitters, to see the routes they take.
When the study began, the birds were making a pit stop on the Italian island called Ventotene. The scientists set up a number of listening posts, so as to capture the signal emitted by the transmitters. They listened in at regular intervals in order to determine which of the animals left earliest. They discovered that 9 of the 10 birds that were outfitted with radios left the island the same night as they arrived, whereas the skinny birds spent at least 40 hours on the island in total, before gathering enough fat to resume their flight.
According to Max Planck Institute for Ornithology researcher Wolfgang Goymann, the leader of the investigation, the work proves once and for all that there are many more factors at work in determining how much time birds spend during their migration, other than the influence of natural and environmental factors. He explains that until now researchers thought that wind and weather conditions were among the only things that determined how birds migrate. Areas laden with insects, nectar and pollen therefore make the ideal pit stop for small birds on the road.