Spring is an exciting time for those of us that enjoy watching birds in our backyards.  At this time of the year scores of songbirds, visit our backyards that we rarely see at any other time of the year.  Ornithologists have long believed that migrating songbirds use stopover areas, like our backyards, to simply rest and refuel before resuming their arduous migration back their breeding grounds.  However, the results of research conducted by Swedish and German biologists suggest there is another important reason why birds drop in and stay in a location before moving on.

       Ornithologists have long realized that the rest stops used by migratory birds provide an opportunity to replenish fat needed to complete their journeys.  At these stops, birds try to consume as much food as possible in a least amount of time.  They also use this time to rejuvenate tired muscles and reduce their heart rates.  Researchers have recently discovered that the birds use these rest stops to build up their immune systems as well.

       This is the conclusion made by researchers with Sweden’s Lund University and the Institute of Avian Research in Germany.

       This finding is based on blood samples taken from a number of different species during migration.  When they compared the immune systems of birds soon after they arrived at a stopover site with those of birds that have rested and refueled for a as little as a few days, they found the birds were able to restore many parameters of their immune systems.  This, in turn, helps the birds maintain good health.

       Arne Hegemann, a biologist from Lund University put it this way, “It is fascinating just how much we are still to learn about avian migration and exciting things emerge regularly.  This provides an important part of the puzzle of how migratory birds cope with the physiological challenges they are faced with on their long journeys.”