Bird Ringing

Bird ringing is the most time consuming activity at the bird observatory, starting after midsummer and continuing for the remainder of the season until the end of September. When the weather is favourable, ringing takes place every morning from sunrise to noon.

The ringing is standardised which means that the same number of mist nets are used at the same sites year after year. Through this standardisation it is possible to compare different years and analyse changes in the bird populations.

Moult in adult birds

Started in 1968 rather tentatively, a study of the moulting adult birds caught in Kvismaren began; this is when birds are replacing feathers completely after nesting. As of 1973, almost all the specimens caught in this category are investigated according to their moult. This take place on a special form; a schematic diagram of the wing and tail.
To date, over 10 000 moult cards have been completed.

Hooded crow

This species has been surveyed at regular intervals since 1968. Nowadays, the species is an important predator in the bird community at Kvismaren. Therefore, it has always been valuable to have knowledge of the population size. There was a strong focus on the crows being associated with mercury poisoning in the 1960s. A 1964 census showed that there were only nine pairs in an approximately 5000-acre survey area around Kvismare lakes. Thereafter, there has been a strong increase and stabilization in recent years.