There are two species of bunting in the Gainsborough area.
Reed Buntings are fairly common, and I have often seen them all along the riverside, from Gainsborough as far as Walkerith. I recently saw a male on the riverside by Mercer Wood on April 5th 2018, and again two days later.
The field at the Morton end of the riverside path is a good place to see Reed Buntings, I have seen several there. I have also seen them along Field Lane beyond Morton.
Beckingham Marsh is another good place to see Reed Buntings. There were several there on April 18th 2018.
male and female Reed Bunting (pictures from Wikipedia)
The other species of bunting in the Gainsborough area is the Yellowhammer, which doesn’t seem to be as common now as it once was. They are more frequent on the other side of the river, and I sometimes see or hear them along the road from the riverside to Beckingham Marsh or on the reserve itself. There were 12 on the road not far from the woodyard on November 23rd 2014.
On our side of the river, the best chance of seeing, or at least hearing Yellowhammers is beyond Morton. There were three on Laughton Lane on June 12th 2017, two on Field Lane on November 8th 2017, five on Walkerith Road on May 1st 2018, and one on Field Lane on July 3rd 2018.
male and female Yellowhamer (pictures from Wikipedia)