The first thing that strikes you compared to London is the different composition of species - first and foremost, Fieldfares. Displaying, whirring their wings as well as feeding young, this species was present on pretty much every area of parkland. Cracking birds, severely underrated: -
Black Redstarts were also around central Krakow too, even in the Wawel Castle grounds and feeding young in a small church just off the main square.
While I tried my best to endure one of Krakow's museums, after an hour the tedium got too much, and so leaving Karen to it I walked to some nearby riverside bushes where I was happy to find both Marsh and Great Reed Warblers singing. This area was on the south side of the River Wisla; head south on Starowislna and over the bridge and then immediately left (east) and along the river path a couple of hundred metres to an area of bushes and reeds near a turning circle where the asphalt road stops. Nothing ground breaking, but a real bonus within this urban environment.
Meanwhile, Jackdaws are a common sight in the city, and seem to be rather mixed in their appearance - too dull for 'eastern race' soemerringii and lacking the obvious neck collar (though remarkable how this varies in changeable light), but still more contrasting that British birds with a greyish hue to the mantle in many birds - presumably these birds are of the race turrium according to this and this.