Mute Swan
- Group
- Birds
- Peak month
- April
- Records since 2000
- 679,735
Described in 1789
63 species
Rock Pigeon
- Group
- Birds
- Peak month
- April
- Records since 2000
- 571,038
Common Brittlestar
- Group
- Starfish and sea urchins
- Peak month
- June
- Records since 2000
- 11,342
Ruddy Duck
- Group
- Birds
- Peak month
- January
- Records since 2000
- 10,294
Grass Snake
- Group
- Reptiles
- Peak month
- May
- Records since 2000
- 8,979
Sooty shearwater
- Group
- Birds
- Peak month
- September
- Records since 2000
- 8,460
An acorn barnacle
- Group
- Crustaceans
- Peak month
- June
- Records since 2000
- 7,641
Small Red Damselfly
- Group
- Dragonflies and damselflies
- Peak month
- July
- Records since 2000
- 7,101
Palmate Newt
- Group
- Amphibians
- Peak month
- May
- Records since 2000
- 6,154
Early Grey
- Group
- Butterflies and moths
- Peak month
- April
- Records since 2000
- 4,715
Rosy Rustic
- Group
- Butterflies and moths
- Peak month
- August
- Records since 2000
- 4,443
Black Brittlestar
- Group
- Starfish and sea urchins
- Peak month
- September
- Records since 2000
- 4,267
Lesser Yellowlegs
- Group
- Birds
- Peak month
- October
- Records since 2000
- 2,959
Mueller's pearlside
- Group
- Fish
- Peak month
- February
- Records since 2000
- 2,476
American Wigeon
- Group
- Birds
- Peak month
- January
- Records since 2000
- 2,340
Gregarious fanworm
- Group
- Worms (annelids)
- Peak month
- August
- Records since 2000
- 2,081
Volcano Barnacle
- Group
- Crustaceans
- Peak month
- September
- Records since 2000
- 1,653
Hairy Spiny Doris
- Group
- Molluscs
- Peak month
- July
- Records since 2000
- 1,006
Rove beetle
- Group
- Beetles
- Peak month
- June
- Records since 2000
- 985
Pill Millipede
- Group
- Millipedes
- Peak month
- April
- Records since 2000
- 787
Tawny-speckled Pug
- Group
- Butterflies and moths
- Peak month
- August
- Records since 2000
- 675
Pacific Golden-Plover
- Group
- Birds
- Peak month
- July
- Records since 2000
- 577
Staph beetle
- Group
- Beetles
- Peak month
- June
- Records since 2000
- 531
Eastern Yellow Wagtail
- Group
- Birds
- Peak month
- December
- Records since 2000
- 516
Livia junci
- Group
- True bugs
- Peak month
- August
- Records since 2000
- 467
Gull billed Tern
- Group
- Birds
- Peak month
- May
- Records since 2000
- 428
Two-Barred Crossbill
- Group
- Birds
- Peak month
- July
- Records since 2000
- 418
Tawny cockroach
- Group
- Other insects
- Peak month
- August
- Records since 2000
- 408
Ptinus sexpunctatus
- Group
- Beetles
- Peak month
- May
- Records since 2000
- 376
Stigmatogaster subterranea
- Group
- Centipedes
- Peak month
- April
- Records since 2000
- 373
Cicadula quadripunctata
- Group
- True bugs
- Peak month
- September
- Records since 2000
- 306
Anthrenus fuscus
- Group
- Beetles
- Peak month
- July
- Records since 2000
- 293
Northern Waterthrush
- Group
- Birds
- Peak month
- January
- Records since 2000
- 293
Cape Shelduck
- Group
- Birds
- Peak month
- August
- Records since 2000
- 271
Leucothoe spinicarpa
- Group
- Crustaceans
- Peak month
- May
- Records since 2000
- 263
Black-winged Kite
- Group
- Birds
- Peak month
- July
- Records since 2000
- 256
Textrix denticulata
- Group
- Spiders
- Peak month
- June
- Records since 2000
- 256
Greater Yellowlegs
- Group
- Birds
- Peak month
- November
- Records since 2000
- 251
Brackish cockle
- Group
- Molluscs
- Peak month
- July
- Records since 2000
- 239
Swammerdamia pyrella
- Group
- Butterflies and moths
- Peak month
- August
- Records since 2000
- 230
American Yellow Warbler
- Group
- Birds
- Peak month
- December
- Records since 2000
- 217
Synanthedon myopaeformis
- Group
- Butterflies and moths
- Peak month
- June
- Records since 2000
- 201
White-throated sparrow
- Group
- Birds
- Peak month
- April
- Records since 2000
- 184
Philonthus varians
- Group
- Beetles
- Peak month
- June
- Records since 2000
- 181
Atrecus affinis
- Group
- Beetles
- Peak month
- July
- Records since 2000
- 175
Cassida vittata
- Group
- Beetles
- Peak month
- May
- Records since 2000
- 145
Sardinian Warbler
- Group
- Birds
- Peak month
- October
- Records since 2000
- 143
Esymus pusillus
- Group
- Beetles
- Peak month
- May
- Records since 2000
- 142
Omalium rivulare
- Group
- Beetles
- Peak month
- May
- Records since 2000
- 137
Filefish
- Group
- Fish
- Peak month
- September
- Records since 2000
- 120
Barrow's Goldeneye
- Group
- Birds
- Peak month
- May
- Records since 2000
- 117
Welsh Clearwing
- Group
- Butterflies and moths
- Peak month
- July
- Records since 2000
- 108
American Coot
- Group
- Birds
- Peak month
- January
- Records since 2000
- 104
Ero furcata
- Group
- Spiders
- Peak month
- September
- Records since 2000
- 102
Rugilus orbiculatus
- Group
- Beetles
- Peak month
- March
- Records since 2000
- 97
Green-winged teal
- Group
- Birds
- Peak month
- January
- Records since 2000
- 83
Short-billed Dowitcher
- Group
- Birds
- Peak month
- September
- Records since 2000
- 80
Bordered grey
- Group
- Butterflies and moths
- Peak month
- July
- Records since 2000
- 76
Antarctic Giant-Petrel
- Group
- Birds
- Peak month
- October
- Records since 2000
- 74
Atlantic yellow-nosed albatross
- Group
- Birds
- Peak month
- October
- Records since 2000
- 74
Tromatobia lineatoria
- Group
- Bees, wasps and ants
- Peak month
- April
- Records since 2000
- 74
Megarthrus depressus
- Group
- Beetles
- Peak month
- August
- Records since 2000
- 61
Rhizotrogus aestivus
- Group
- Beetles
- Peak month
- May
- Records since 2000
- 52