A scarce visitor to the UK.
No interactions present.
I'm not familiar with these but note that they are decribed as a passage migrant, and you have an observation date of jan 1st. Is this correct?.
Two wonderful photographs show the diagnostic features beautifully, top marks.
Serins, although fairly common just across the channel, are very scarce visitors to Britain, and are most frequently encountered as off course migrants during the spring and autumn. They do also occur at other times of year though - some have bred occasionally, and very rarely they are present during the winter.
Up to 2 have been seen at Rainham this winter (there were also some present last winter), but they are still a very scarce visitor, and not one that any birdwatchers are likely to see regularly in this country (although they still have the potential to colonise).
Google 'Rainham Serin' and you will get quite a few hits for more information on these sightings!
Lat/Lng: 51.4, 0.2
OS grid ref: TQ5479