In Gainsborough, Buzzards can often be seen soaring high over both sides of the Trent, usually in ones, twos or threes. They are also frequently seen at Castle Hill Wood, and sometimes over the town centre.
There were two over Marshalls Yard on May 2nd 2013, with the many shoppers there oblivious to their presence (but not escaped by me).
They can also be seen over farmland outside of the town, and they are regular visitors to Beckingham Marsh (there were 8 there on Mar 11th 2018).
Buzzard (pictures from Wikipedia)
Kestrels are also very common all over the area, with a resident female currently hanging around the riverside near Mercer Wood. One can often be seen hovering all along the Riverside, and they are regularly seen at Beckingham Marsh also.
Kestrel (pictures from Wikipedia)
Sparrowhawks are also a regular sight in the skies over Gainsborough. They are often seen over the allotments on Love Lane, and the scrub area between Mercers Wood and Bowling Green Road.
There was one soaring over Trinity Street on Aug 15th 2017, and another trying to catch small birds outside the Old Hall on Feb 1st 2018.
The Levellings and Rose’s sports field are two more good places to look out for one, and there was one on the riverside at Morton Turn on June 18th 2018.
Sparrowhawk (pictures from Wikipedia)
A female Merlin has been visiting the Gainsborough area for the last few winters, and I saw her regularly along the riverside at Gainsborough from 2012 to 2017, disappearing in the spring only to return the following autumn. The North Warren Road allotments (next to Mercer Wood) seemed to be a favourite hunting ground and I have often watched her there. I saw her once perched on a TV ariel in Alfred Street. I last saw her on the riverside on Oct 18th 2017, but she seems to have disappeared since then.
A male Merlin was seen hunting on the riverside at Gainsborough on Sep 9th 2018.
Merlin (picture from Wikipedia)
Peregrines are very occasional visitors.
I saw one on Corringham Road on Feb 8th 2013, and there was one chasing Woodpigeons on Field Lane just outside Morton on Sep 6th 2017, and again on Oct 1st 2017.
A Peregrine flew between the houses at the Morton end of Ropery Road on Jun 18th 2018, heading west towards the river.
A Peregrine flew over Mercers Wood on Jul 8th 2018, and there was one chasing Woodpigeons on the riverside by Roses sports field on Aug 1st 2018.
Peregrine (picture from Wikipedia)
The RSPB have been releasing Red Kites in an attempt to reintroduce the species to England. They have been released in the East Midlands, apparently with some success, and I have sometimes seen one in Nottinghamshire.
A Red Kite was seen over Lea Road in Gainsborough (near the railway station) in June 2017. I never saw it myself at the time, but I have seen the photos posted online. But I did see a Red Kite (the same bird?) over Morton on Aug 20th 2017.
A Red Kite was flying around Mercers Wood on Jun 14th 2019
Red Kite (picture from Wikipedia)