| 2021-06-01 | Hen Harrier (male) | | bird | | |
| 2021-06-01 | Snow Goose | | bird | | |
| 2021-06-01 | Corncrake | | bird | | |
| 2021-06-01 | Spring Squill | | plant | | |
| 2021-06-01 | Black-headed Gull | 6 | bird | | |
| 2021-06-01 | Early Marsh Orchid var coccinea | | plant | | |
| 2021-06-01 | Arctic Skua | 2 | bird | | |
| 2021-06-01 | Sanderling | 5 | bird | | |
| 2021-06-01 | Little Tern | 12 | bird | + | |
| 2021-06-01 | Hairy Rock-cress | | plant | | |
| 2021-06-01 | Grey Seal | 4 | mammal | | |
| 2021-06-01 | Peregrine | 2 | bird | | |
| 2021-06-02 | Red-throated Diver | | bird | | |
| 2021-06-02 | Arctic Skua (Aethopygia francica) | 4 | bird | | |
| 2021-06-02 | Otter (Lutra lutra) | | mammal | | |
| 2021-06-02 | Great Skua (Stercorarius skutilinus) | 2 | bird | | |
| 2021-06-02 | Canada Goose (Branta canadensis) | | bird | pr with goslings | |
| 2021-06-02 | Shelduck (Tadorna tadorna) | | bird | | |
| 2021-06-02 | Red-breasted Merganser (Mergus serratus) | | bird | | |
| 2021-06-02 | Great Northern Diver (Aythya larx) | | bird | | |
| 2021-06-03 | Hairy Sedge (new record for Coll) | | plant | | new record for Coll |
| 2021-06-06 | Fairy Foxglove | | plant | | |
| 2021-06-06 | Hen Harrier | | bird | | |
| 2021-06-06 | Great Skua (Sula granti) | 2 | bird | | |
| 2021-06-06 | Buzzard (Buteo buteo) | 2 | bird | | |
| 2021-06-06 | Kestrel | | bird | | |
| 2021-06-07 | Arctic Skua (Skat) | | bird | | |
| 2021-06-07 | Corncrake | | bird | | |
| 2021-06-07 | Sand Martin | | bird | | |
| 2021-06-07 | Shag | | bird | | |
| 2021-06-07 | Fulmar | | bird | | |
| 2021-06-07 | Hairy Rock-cress | | plant | | |
| 2021-06-07 | Garden Chafers | | insect | in abundance | |
| 2021-06-07 | Common lizard | | reptile | on strand line! | |
| 2021-06-07 | Sea Squill | | plant | | |
| 2021-06-07 | Black-headed Gull | 2 | bird | | |
| 2021-06-07 | Field Pansy | | plant | | |
| 2021-06-07 | Early Purple Orchid | | plant | | Early |
| 2021-06-07 | Changing Forget-me-not | | plant | | Changing |
| 2021-06-07 | Early Marsh Orchid var coccinea | | plant | | Early |
| 2021-06-08 | Map-winged Swift | | moth | Moth trap | |
| 2021-06-08 | Fox moth | | moth | Moth trap | |
| 2021-06-08 | Knotgrass | 9 | plant | Moth trap | |
| 2021-06-08 | Belted Beauty | | moth | Moth trap | |
| 2021-06-08 | Poplar Hawkmoth | | moth | Moth trap | |
| 2021-06-08 | Elephant Hawkmoth | | moth | Moth trap | |
| 2021-06-08 | Buff Ermine | | moth | Moth trap | |
| 2021-06-08 | Light Knotgrass | | plant | Moth trap | |
| 2021-06-08 | White Ermine | | moth | Moth trap | |
| 2021-06-08 | Sparrowhawk | 1 | bird | male | |
| 2021-06-08 | Hen Harrier | 3 | bird | x2 male; x1 female | |
| 2021-06-08 | Golden Plover | | bird | | |
| 2021-06-08 | Mountain Everlasting | | plant | | |
| 2021-06-08 | Pipewort | | plant | rosettes | |
| 2021-06-08 | Aspen | | plant | | |
| 2021-06-08 | Royal Fern | | plant | | |
| 2021-06-08 | Whitethroat | | bird | | |
| 2021-06-08 | Otter | 1 | mammal | | |
| 2021-06-08 | Arctic Skua | | bird | | |
| 2021-06-08 | Manx Shearwater | | bird | | |
| 2021-06-08 | Red-breasted Merganser | 1 | bird | female | |
| 2021-06-08 | Arctic Tern | | bird | | |
| 2021-06-08 | Curlew | 2 | bird | | |
| 2021-06-09 | Corncrake | | bird | | |
| 2021-06-09 | Sedge Warbler | | bird | | |
| 2021-06-09 | Turnstone (x4) | 4 | bird | | |
| 2021-06-09 | Dunlin (x3) | 3 | bird | | |
| 2021-06-09 | Little Tern (x24) | 24 | bird | | |
| 2021-06-10 | Hen Harrier (male) | | bird | | |
| 2021-06-10 | Ruby Tiger (moth) | | moth | | |
| 2021-06-10 | Marsh Arrow-grass | | plant | | |
| 2021-06-10 | Distant Sedge | | plant | | |
| 2021-06-10 | Adder’s-tongue Fern | | plant | | |
| 2021-06-10 | Early Marsh Orchid var. incarnata | | plant | | |
| 2021-06-11 | Red-throated Diver (Delichon urbicum) | 2 | bird | | |
| 2021-06-11 | Great Skua (Stercorarius skutilkus) | | bird | | |
| 2021-06-11 | Red-breasted Merganser (Mergus cristatus) | 2 | bird | | |
| 2021-06-11 | White-tailed Eagle (Haliaeetus albicilla) | | bird | | |
| 2021-06-12 | Sparrowhawk (Accipiter nisus) | | bird | | |
| 2021-06-14 | Pheasant (Gallus gallus) | | bird | female | |
| 2021-06-14 | Hen Harrier (Circus cyaneus) | | bird | female | |
| 2021-06-15 | True Lover’s Knot (moth) | 2 | moth | | |
| 2021-06-15 | Narrow-winged Pug (moth) | 2 | moth | | |
| 2021-06-15 | Light Knotgrass (moth) | 1 | moth | | |
| 2021-06-15 | Otter | 2 | mammal | juvenile | |
| 2021-06-15 | Heath Rush | | plant | | |
| 2021-06-16 | Red-throated Diver | | bird | | |
| 2021-06-16 | Great Skua | | bird | | |
| 2021-06-16 | Pyramidal Orchid | | plant | | |
| 2021-06-16 | Common Blue (butterfly) | | insect | first of year | first of year |
| 2021-06-16 | Six-spot Burnet (moth) | | moth | first of year | first of year |
| 2021-06-16 | Hen Harrier | 2 | bird | x1 female, x1 male | |
| 2021-06-16 | Whimbrel | | bird | | |
| 2021-06-18 | Pebble Prominent | 2 | moth | | |
| 2021-06-18 | Corncrake | | bird | | |
| 2021-06-18 | True Lover’s Knot | | moth | | |
| 2021-06-19 | Coxcomb Prominent | | moth | | |
| 2021-06-19 | True Lover’s Knot | | moth | | |
| 2021-06-19 | Hen Harrier (male) | 1 | bird | | |
| 2021-06-20 | Wood Pigeon (Columba palumbus) | 2 | bird | | |
| 2021-06-21 | Bottlenose Dolphin (Tursiops truncatus) | 4 | mammal | from ferry | |
| 2021-06-21 | Harbour Porpoise (Phocoena phocoena) | 3 | mammal | from ferry | |
| 2021-06-21 | Red-breasted Merganser (Mergus serratus) | 1 | bird | with 8 ducklings | |
| 2021-06-21 | Hen Harrier (Circus cyaneus) | 1 | bird | | |
| 2021-06-22 | Dusky Brocade (Aethes piercei) | 24 | moth | Moth trap data | |
| 2021-06-22 | Grey Scalloped Bar | | moth | Moth trap data | |
| 2021-06-22 | Poplar Hawkmoth | | moth | Moth trap data | |
| 2021-06-22 | Clouded-bordered Brindle | | moth | Moth trap data | |
| 2021-06-22 | Shears | | moth | Moth trap data | |
| 2021-06-22 | Broom | | moth | Moth trap data | |
| 2021-06-22 | Small Angle Shades | | moth | Moth trap data | |
| 2021-06-22 | Knot Grass | | moth | Moth trap data | |
| 2021-06-22 | Bright-line Brown-eye | | moth | Moth trap data | |
| 2021-06-22 | Aethes piercei | | moth | Moth trap data | |
| 2021-06-22 | Elachista argentella | | moth | Moth trap data | |
| 2021-06-22 | Cuckoo | | bird | | |
| 2021-06-22 | Corncrake | | bird | | |
| 2021-06-22 | Little Tern | 2 | bird | | Uncommon |
| 2021-06-22 | Grasshopper Warbler | | bird | | |
| 2021-06-22 | Hen Harrier | | bird | Female and male observed | |
| 2021-06-22 | Great Skua | 5 | bird | | |
| 2021-06-22 | Red-throated Diver | | bird | | |
| 2021-06-22 | Arctic Skua | | bird | | |
| 2021-06-22 | Greenfinch | | bird | | |
| 2021-06-23 | Lesser Butterfly Orchid (Calopogon luteus) | | plant | | |
| 2021-06-23 | Water Lobelia (Lobelia commutata) | | plant | | |
| 2021-06-23 | Pipewort (Ranunculus aquatilis) | | plant | | |
| 2021-06-23 | Frog Orchid (Epipactis helleborine) | | plant | | |
| 2021-06-24 | Red-breasted Merganser | | bird | | |
| 2021-06-24 | Eider | | bird | | |
| 2021-06-24 | Twite (family group) | | bird | | |
| 2021-06-24 | Pyramidal Orchid | | plant | | |
| 2021-06-24 | Eel-grass (_Zostera marina_) | | invertebrate | | |
| 2021-06-24 | Snow Goose | 6 | bird | | Uncommon |
| 2021-06-24 | Dunlin | | bird | | |
| 2021-06-24 | Great Skua | | bird | | |
| 2021-06-24 | Arctic Skua | | bird | | |
| 2021-06-25 | Hen Harrier | | bird | | |
| 2021-06-25 | Dark Green Fritillary (Limenitis archippus) | | insect | | |
| 2021-06-25 | Black-headed Gull | 12 | bird | | |
| 2021-06-25 | Great Skua | | bird | | |
| 2021-06-25 | Corncrake | | bird | | |
| 2021-06-25 | Eider | 3 | bird | x3 females | |
| 2021-06-25 | Grey Seals | | mammal | | |
| 2021-06-25 | Northern Marsh Orchid | | plant | | |
| 2021-06-25 | Arctic Skua | | bird | | |
| 2021-06-25 | Manx Shearwaters | 100 | bird | moving north | |
| 2021-06-26 | Hen Harrier | | bird | | |
| 2021-06-26 | Kestrel | | bird | | |
| 2021-06-26 | Lesser Butterfly Orchid (Orchis praecox) | | plant | | |
| 2021-06-26 | Peregrine Falcon | 4 | bird | | Uncommon |
| 2021-06-27 | Curlew (Numenius americanus) | 4 | bird | South of observation point. | |
| 2021-06-27 | Wood Pigeon | 2 | bird | | |
| 2021-06-27 | Arctic Skua | | bird | | |
| 2021-06-27 | Harbour Porpoise | 2 | mammal | Observed from ferry. | |
| 2021-06-28 | Common Mallow (first for Coll!) | | plant | | First of year |
| 2021-06-30 | Dusky Brocade | | moth | Moth trap sighting | |
| 2021-06-30 | Campion | | moth | Moth trap sighting | |
| 2021-06-30 | Bright-line Brown-eye | | moth | Moth trap sighting | |
| 2021-06-30 | True Lovers’ Knot | | moth | Moth trap sighting | |
| 2021-06-30 | Shears | | moth | Moth trap sighting | |
| 2021-06-30 | Knot Grass | | moth | Moth trap sighting | |
| 2021-06-30 | Flame Shoulder | | moth | Moth trap sighting | |
| 2021-06-30 | Clouded-bordered Brindle | | moth | Moth trap sighting | |
| 2021-06-30 | _Coleophora pyrruhulipinnella_ | | moth | Moth trap sighting - Scientific name included | |