The last Hertfordshire Tree Sparrow colony at Tyttenhanger became extinct in 2021.
Photo © Andrew Steele
This video, created for the HNHS 150th anniversary exhibition, contrasts species that have become extinct or threatened in Hertfordshire during recent decades with new arrivals and other that are spreading rapidly across the county.
Video editor: Eleanor Utting.
The Tree-lichen Beauty Moth was a rare migrant from southern Europe, but is now widespread.
Photo © Ben Sale