Fiskgjusen - Inventeringar i västra Mälaren 1971-2009. Rapport 2011:4 från Länsstyrelsen i Södermanlands län.
It means: Osbrey - Inventory in the western part of the lake Mälaren. Publ. 2011:4 from the regional country administration (In Södermanland). (53 pages)
It will probably very soon get published on its computorinformation.
During 1977-1986 and 2001-2005 were every (known) nest and every pull registrated.
Between the years 1977-1986 existed ordinary about 36 nests, During 2001-2005 had
it been reduced to 29 nests. During these years were all the pulls counted.
The other years we have had different anbitions. Total about 1000 breedings have been noticed which probably means that about 70 % of all breedings since 1971 have been registrated. For 97 % we have the knowledge if the breedings have been sucessful or not. (At least one pull in the nest means that the breeding was sucessful)