in the UK i would be pretty sure its the Golden Eagle in Scotland
As for owls recently we have been getting breeding pairs of the Eurasian/European Eagle owl, which was native until around 200 yrs ago when the hunting/shooting of them got rid of them all. but now they are making a come back to the UK :)
research will help you find more detail but here is a list from the top of my head of the most common or well known
golden eagle
osprey
kestral
sparrowhawk
peregrine falcon
red kite
hen harrier
marsh harrier
buzzard
merlin
tawny owl
barn owl
short eared owl
The white tailed eagle is the largest resident very scarce only a few pairs live in the extreme Nortth West of Scotland. The golden eagle is the 2nd largest only slightly smaller.
Mute Swan in both wingspan and size
The Golden Eagle.
capercaille
Eagle.
The Ostrich is the largest bird.
Is the Largest bird the Ostrich
The flamingo is NOT the largest bird in Africa, That would be the ostrich. Find your information first.
The Emu would be the largest bird
the largest livening bird is cody jensen
The second largest bird (by height) is the emu.
The largest bird that is not extinct is the kiwi bird. Maybe it's the Royal Albatross.
The ostrich is the largest bird on Earth, and it is also a flightless one.
The ostrich, which is also the largest bird on Earth not currently extinct.
California Condor is the largest of the "flight" birds. The Ostrich is the largest bird
The ostrich lays the largest eggs of all birds.
The smallest bird in the UK is generally accepted as the wren. This is probably not the smallest bird in the world.