| 2023-05-03 | Golden Plover (Pluvialis apricaria) | 3 | bird | passage birds | |
| 2023-05-03 | Great Skua (Stercorarius skutilensis) | | bird | | |
| 2023-05-03 | Black-headed Gull (Chlidonias niger) | | bird | | |
| 2023-05-03 | Common Tern (Sterna hirundo) | | bird | | |
| 2023-05-03 | Arctic Tern (Sterna paradisaea) | | bird | | |
| 2023-05-03 | Harbour Porpoise (Phocoena phocoena) | | mammal | | |
| 2023-05-03 | Long-tailed Skua (Stercorarius longicaudatus) | 1 | bird | adult bird low over village | |
| 2023-05-03 | Little Gull (Larus minutus) | 1 | bird | adult with Common Gulls from the ferry in the Sound of Mull | |
| 2023-05-03 | House Martin (Delichon urbicum) | 3 | bird | passage birds in the village, less than annual on Coll | |
| 2023-05-03 | Basking Shark (Cetorhinus maximus) | 1 | fish | from the ferry between Mull and Coll | |
| 2023-05-03 | Minke Whale (Balaenoptera acutorum) | 1 | mammal | from the ferry between Mull and Coll | |
| 2023-05-04 | Great Northern Diver | | bird | | |
| 2023-05-04 | Red-throated Diver (a pair) | | bird | | |
| 2023-05-04 | Shelduck | 2 | bird | | |
| 2023-05-04 | Dunlin | 35 | bird | | |
| 2023-05-04 | Sanderling | 3 | bird | | |
| 2023-05-04 | Whimbrel | 15 | bird | | |
| 2023-05-04 | Golden Plover | 7 | bird | | |
| 2023-05-04 | Honey Buzzard | | bird | a dark juvenile bird low over the village late afternoon! | Uncommon |
| 2023-05-04 | Hen Harrier | | bird | male | |
| 2023-05-04 | Sparrowhawk | | bird | a female | |
| 2023-05-04 | Corncrake | | bird | | |
| 2023-05-04 | Guillemots | 2 | bird | in the bay | |
| 2023-05-04 | Dunnock | 2 | bird | | |
| 2023-05-04 | White Wagtail | | bird | | |
| 2023-05-04 | Greenfinch | 2 | bird | | |
| 2023-05-05 | Great Northern Diver | | bird | | |
| 2023-05-05 | Whimbrel (x1+2+2) | 5 | bird | Multiple individuals observed. | |
| 2023-05-05 | Sparrowhawk (x2 migrant females) | 2 | bird | Two migrant female sparrowhawks observed. | Migrant |
| 2023-05-05 | Arctic Tern | | bird | | |
| 2023-05-05 | Little Tern | | bird | | |
| 2023-05-05 | Grasshopper Warbler | | bird | | |
| 2023-05-06 | Great Northern Diver | 2 | bird | | |
| 2023-05-06 | Red-throated Diver | 2 | bird | +2 | |
| 2023-05-06 | Teal | 2 | bird | pairs on a moorland loch | |
| 2023-05-06 | Eider | | bird | | |
| 2023-05-06 | Red-breasted Merganser | 1 | bird | | |
| 2023-05-06 | Whimbrel | 5 | bird | | |
| 2023-05-06 | Great Skua | 2 | bird | | |
| 2023-05-06 | Arctic Skua | 5 | bird | | |
| 2023-05-06 | Woodpigeon | | bird | | |
| 2023-05-06 | Dunnock | | bird | | |
| 2023-05-06 | Chiffchaff | | bird | | |
| 2023-05-06 | Whitethroat | | bird | | |
| 2023-05-06 | Grasshopper Warbler | | bird | | |
| 2023-05-06 | Green Tiger Beetle | | invertebrate | | Uncommon |
| 2023-05-06 | Eristalis intricaria | | moth | (a new dronefly for Coll?) | New species sighting |
| 2023-05-06 | Northern Eggar | | moth | a moth caterpillar | |
| 2023-05-06 | Orange-tip | | insect | (a butterfly not knowingly recorded on Coll previously) | First of year |
| 2023-05-06 | Marsh Violet | | plant | | |
| 2023-05-06 | Bog Beacon | | fungi | a rare aquatic fungus | Rare sighting |
| 2023-05-07 | Great Northern Diver | | bird | | |
| 2023-05-07 | Whimbrel | 7 | bird | | |
| 2023-05-07 | Hen Harrier | | bird | a pair | |
| 2023-05-07 | Black-headed Gull | | bird | | |
| 2023-05-07 | Little Tern | | bird | | |
| 2023-05-07 | Corncrake | 5 | bird | | |
| 2023-05-07 | Whitethroat | | bird | | |
| 2023-05-07 | Greenfinch | | bird | | |
| 2023-05-07 | Twite | | bird | | |
| 2023-05-07 | Silver Y | | moth | a migrant moth | |
| 2023-05-07 | Grey Seal | | mammal | | |
| 2023-05-07 | Basking Shark | | fish | in Crossapol Bay. Looks like it may be a great year for these leviathans... | Uncommon |
| 2023-05-07 | _Silpha tyrolensis_ | | insect | a rare carrion beetle in black and brass whose range is restricted to Coll and Tiree | Rare |
| 2023-05-07 | Early Purple Orchids | | plant | the first orchids of the spring | Early |
| 2023-05-07 | Dune Pansy | | plant | | |
| 2023-05-07 | Spring Squill | | plant | | |
| 2023-05-07 | _Taraxacum obliquum_ | | plant | a very rare species of Dandelion growing in abundance on the machair | Rare |
| 2023-05-08 | Canada Goose (Branta canadensis) | 2 | bird | | |
| 2023-05-08 | Hen Harrier (Circus cyaneus) | 1 | bird | a male hunting | |
| 2023-05-08 | Dunlin (Calidris alpina) | 3 | bird | | |
| 2023-05-08 | Golden Plover (Pluvialis fulva) | 8 | bird | | |
| 2023-05-08 | Twite (Pyrrhulus pyrrhulus) | 2 | bird | a pair in the road | |
| 2023-05-08 | Minke Whale (Balaenoptera musculus) | 1 | mammal | from ferry towards Mull | |
| 2023-05-08 | Juniper (Juniperus communis) | 1 | plant | a huge ‘tree’ growing down a cliff-face | |
| 2023-05-11 | Eider | | bird | | |
| 2023-05-11 | Curlew | | bird | | |
| 2023-05-11 | Hen Harrier (Circus cyaneus) | | bird | | |
| 2023-05-11 | Merlin (Falco columbarius) | | bird | a female hunting | |
| 2023-05-11 | Arctic Skua (Stercorarius arctica) | | bird | | |
| 2023-05-11 | Corncrake (Crex crebrosa) | 8 | bird | | |
| 2023-05-11 | Woodpigeon (Columba palumbus) | | bird | a pair - not a regular bird on Coll | |
| 2023-05-11 | Grasshopper Warbler (Locustella naevia) | | bird | | |
| 2023-05-11 | Goldcrest (Regulus regulus) | | bird | | |
| 2023-05-11 | Greenfinch (Carduelis chloris) | 4 | bird | x2 pairs across the island | |
| 2023-05-11 | Green Hairstreak (Callophrys astragalis) | | insect | | Uncommon |
| 2023-05-13 | Hen Harrier (male) | | bird | | |
| 2023-05-13 | Merlin (a female again same place as two days ago) | | bird | | |
| 2023-05-13 | Corncrake | 6 | bird | | |
| 2023-05-13 | Whitethroat | | bird | | |
| 2023-05-16 | Eider | 6 | bird | | |
| 2023-05-16 | Dunlin | 15 | bird | | |
| 2023-05-16 | Sanderling | 10 | bird | | |
| 2023-05-16 | Ringed Plover | 70 | bird | | |
| 2023-05-16 | Little Tern | | bird | | |
| 2023-05-16 | Corncrake | 5 | bird | calling males away from the usual places | Unusual |
| 2023-05-16 | Grasshopper Warbler | | bird | | |
| 2023-05-16 | Common Carpet moth | | moth | | |
| 2023-05-16 | _Cryptocephalus aureolus_ | | invertebrate | a tiny electric green flower beetle | Rare |
| 2023-05-17 | Arctic Skua (Scolopha islandica) | 2 | bird | | |
| 2023-05-17 | Chiffchaff (Phylloscopus collybita) | | bird | passage bird singing weakly in the local plantation | |
| 2023-05-17 | Sedge Warbler (Locustella luscinia) | 2 | bird | singing males locally | |
| 2023-05-17 | Grasshopper Warbler (Locustella naevia) | | bird | | |
| 2023-05-17 | Twite (Podiceps cristatus) | 7 | bird | seven birds around the village | |
| 2023-05-17 | Greenfinch (Carduelis chloris) | | bird | a pair new in our garden, the male singing boldly | |
| 2023-05-19 | Red-throated Diver | | bird | | |
| 2023-05-19 | Hen Harrier (male) | | bird | | |
| 2023-05-19 | Dunlin | 20 + 12 | bird | | |
| 2023-05-19 | Turnstone | 6 | bird | | |
| 2023-05-19 | Black-headed Gull | | bird | | |
| 2023-05-19 | Little Tern | 4 | bird | | |
| 2023-05-19 | Flea Sedge | | plant | | |
| 2023-05-19 | Pignut | | plant | | |
| 2023-05-19 | Early Purple Orchid | | plant | | |
| 2023-05-20 | Great Northern Diver | | bird | | |
| 2023-05-20 | Shelduck (Bucephala clangula) | 3 | bird | One with x3 ducklings | |
| 2023-05-20 | Dunlin (Calidris alpina) | 10 | bird | _artica_ race | |
| 2023-05-20 | Sanderling (Calidris alba) | 5 | bird | | |
| 2023-05-20 | Turnstone (Arenaria interpres) | 5 | bird | | |
| 2023-05-20 | Golden Plover (Pluvialis fulva) | 16 | bird | fly over | |
| 2023-05-20 | Merlin (Falco columbarius) | | bird | male - a nice spring record | Nice spring record |
| 2023-05-20 | Hen Harrier (Circus cyaneus) | | bird | male | |
| 2023-05-21 | Minke Whale (from Arinagour) | | mammal | | |
| 2023-05-30 | Sparrowhawk (Accipiter nisus) | | bird | | |
| 2023-05-31 | Hen Harrier (a ring-tailed juvenile male) | | bird | | |
