If you try to see Herdla from a bird's perspective, you will understand why: Herdla is a flat, green, attractive oasis between the west coast's rocky moors, fjords and mountains. For a tired migrant, who still has many hundreds of miles to go, it is not just tempting to take a closer look at this place. It is in fact entirely necessary, for there is very little of this type of natural haven in this part of western Norway. For several bird species, Herdla is in fact the only place between Vigra and Sunnmøre and the beaches of Jæren in Rogaland where they can hope to secure an essential meal.
Many of the migrating birds have to travel far away to find suitable conditions when winter approaches. Flying demands much energy. A duck uses five times as many calories for each unit of time she flies, as compared with wandering by foot around land. Birds surely get tired when they fly far, and it is very important that they don't run out of fuel. Before the long migrations start, most of them go on a "fat cure". They stock up on their fat reserves as this is their way of "filling up with fuel". If this supply runs out, there will be a crisis, if they don't find a haven for an emergency landing within reach.
For such tired and hungry birds on their autumn migrations, Herdla has an important function. It is fully possible to "top up" their tanks, but then one must have ample access to the right kind of food. They shall preferably eat most possible in the least possible amount of time, such that they can be on their way again as soon as the wind and weather allow. The soil, beaches and the shallow sea areas around Herdla are biologically highly productive. If one studies wading birds at low tide in Prestevika or in a pond on Valen, you tend to see hectic activity as they search for food.
