| MINK | Weasel-like mammal, a non-native species in the UK |
| COYPU | Rodent eradicated as a non-native species in the UK |
| TREELILY | Attempt to capture elusive creature, one living initially as native species in Brazil |
| SPARROW | With two species in the UK, a finch-like bird known collectively as a host, quarrel or tribe (7) |
| GOLDCREST | Bird with a claim to be the smallest species in the UK |
| NEWTS | Forming the aquatic ecosystem of many ponds, salamander-like amphibians with three species in the UK - common, palmate and great crested (5) |
| SQUIRREL | Bushy-tailed rodent that has two species in the UK, the red and the grey (8) |
| OWLET | Young of a bird with five species in the UK, associated with wisdom (5) |
| WAGTAIL | Bird with three species in the UK, namely the pied, grey and yellow (7) |
| SWAN | Waterbird whose smallest species in the UK is the Bewick's (4) |
| GOOSE | A large waterbird whose species in the UK include Canada and greylag (5) |
| INVASIVE | Term for a proliferating non-native species (8) |
| POPLAR | A tall, fast-growing tree whose species in the UK include aspen, white and grey (6) |
| OWLS | Nocturnal birds with five species in the UK including barn, little and tawny (4) |
| DEER | Hoofed grazing animal whose species in the UK include fallow and sika (4) |
| OAKS | The English and the sessile are native species of these trees in the UK (4) |
| ARNO | Italian river, notable for its populations of non-native species (4) |
| WELS | Non-native species of catfish (4) |
| EXOTIC | Non-native, ... species |
| HAOLE | A non-native, in Hawaii |
