Chaffinches, Greenfinches and Goldfinches are very common, and can be seen or heard singing throughout the Gainsborough area. All three are resident in Mercers Wood, and can be seen regularly along the riverside.
male and female Chaffinch (pictures from Wikipedia)
male and female Greenfinch (pictures from Wikipedia)
Goldfinch (picture from Wikipedia)
Bullfinches are also resident in Mercers Wood, where I frequently see them. I once saw six there (3 males, 3 females) in a single tree. They are also resident in Castle Hill Wood (especially at the Leisure Centre end of the wood), and I have seen them occasionally in other places, including along the riverside.
There was a single female outside the Old Hall on Dec 30th 2013, and a single male was seen around Morton during February and March 2018.
male and female Bullfinch (pictures from Wikipedia)
Linnets are also resident in the area, and I have frequently seen them in the scrub area between Mercers Wood and Bowling Green Road. There were three in the wood itself on January 5th 2017.
Linnets are also a common sight along the riverside, and on Field Lane beyond Morton. I have occasionally seen a few on the Levellings in Gainsborough.
Linnets also occur in small numbers at Beckingham Marsh.
The overgrown field at the Morton end of the Riverside path is an important habitat for finches. There are large numbers of chaffinches, greenfinches, goldfinches and linnets and a few bullfinches inhabiting this area (as well as many other species).
Large numbers of linnets gather there in the winter months. Walk along the Morton end of the riverside path just before dusk in late autumn or winter and you will see a large flock of linnets, as many as 75 or more, circling around and around until finally settling down in the bushes to roost.
male Linnet (picture from Wikipedia)
Bramblings, a close relative of the Chaffinch, are winter visitors, and can sometimes be found in the Gainsborough area.
Several spent the winter of 2016-2017 in the Field Lane area of Morton (around where the allotments are).
Brambling (picture from Wikipedia)
A flock of between 40 and 50 Siskins were in the Parish Churchyard in Gainsborough on November 7th 2013. It is the only time I have seen Siskins in the Gainsborough area.
Siskin (picture from Wikipedia)
On October 30th 2017, nine Lesser Redpolls roosted in the trees bordering the Riverside end of Rose’s Sports Field. The next evening there were thirteen. They were still there on November 1st, and then they disappeared. It is the only time I have seen Redpolls in the Gainsborough area.
Lesser Redpoll (picture from Wikipedia)