Site maintenance

Submitted by admin on 2 November 2025.

We are currently working on the site kvismaren.org. Things might look a bit messy from time to time.

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The summer 2020 at the Observatory

Submitted by admin on 15 April 2025.

In June... månad avslutades en intensiv vårsäsong med ett stort antal projekt. Trots en kall vår och första del av sommaren så fångar vi mycket ungfåglar. Studierna av jordbruksarter har utökats med intensiva studier av bl.a. sånglärkor. Den utsatta populationen av ortolansparv fortsätter att följas. I år var det också dags för kråkinventeringen som genomförs vart femte år.

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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.

Black-headed gull

At the beginning of the 1990's attention was drawn to the fact that the Black-headed Gull population declined in all of Sweden, a national project was initiated to investigate the causes and Kvismare Bird Observatory participated in a study in Rysjön’s colony. The production of juveniles was measured, nestling weight at different ages and predation was studied. It was found that too few young birds survived and these results were applied to more places around Sweden.