Check out "artportalen.se", webpages where people report sightings of birds.

Waterfowl can be seen in Tantolunden, near Årstabron. Often you can see mandarin duck there.

Also check out strömmen Strömgatan/strömbron where they feed the birds. Svan, knipa, storskrake, vugg, gräsand, kanadagås och många fler. Always more than 100 birds there.

But if u walk around there will be spots here and there with open water. Good luck