Oak Apple Gall Causer
- Group
- Bees, wasps and ants
- Peak month
- May
- Records since 2000
- 1,088
Oak Beauty
- Group
- Butterflies and moths
- Peak month
- March
- Records since 2000
- 1,661
Oak Blackhead
- Group
- Fungi
- Peak month
- January
- Records since 2000
- 1,074
Oak Bolete
- Group
- Fungi
- Peak month
- August
- Records since 2000
- 96
Oak Bush Cricket
- Group
- Grasshoppers and crickets
- Peak month
- August
- Records since 2000
- 5,193
Oak Carl
- Group
- Butterflies and moths
- Peak month
- October
- Records since 2000
- 626
Oak Crust
- Group
- Fungi
- Peak month
- January
- Records since 2000
- 1,269
Oak Curtain Crust
- Group
- Fungi
- Peak month
- October
- Records since 2000
- 1,194
Oak Curved-leaf Gall Wasp
- Group
- Bees, wasps and ants
- Peak month
- September
- Records since 2000
- 672
Oak Eggar
- Group
- Butterflies and moths
- Peak month
- July
- Records since 2000
- 1,652
Oak Fern
- Group
- Ferns and horsetails
- Peak month
- July
- Records since 2000
- 435
Oak Hook-tip
- Group
- Butterflies and moths
- Peak month
- August
- Records since 2000
- 2,249
Oak Leaf-roller
- Group
- Beetles
- Peak month
- May
- Records since 2000
- 201
Oak Lutestring
- Group
- Butterflies and moths
- Peak month
- September
- Records since 2000
- 157
Oak Mildew
- Group
- Fungi
- Peak month
- September
- Records since 2000
- 1,679
Oak Mining Sawfly
- Group
- Bees, wasps and ants
- Peak month
- July
- Records since 2000
- 649
Oak Nycteoline
- Group
- Butterflies and moths
- Peak month
- July
- Records since 2000
- 1,159
Oak Pin-Hole Borer
- Group
- Beetles
- Peak month
- July
- Records since 2000
- 151
Oak polypore
- Group
- Fungi
- Peak month
- July
- Records since 2000
- 140
Oak-tree Pug
- Group
- Butterflies and moths
- Peak month
- May
- Records since 2000
- 1,116
Oakbug Milkcap
- Group
- Fungi
- Peak month
- October
- Records since 2000
- 1,463
Oakmoss
- Group
- Lichens
- Peak month
- March
- Records since 2000
- 7,937
Oarweed
- Group
- Seaweeds and algae
- Peak month
- September
- Records since 2000
- 3,533
Oaten Pipes Hydroid
- Group
- Jellyfish, corals and anemones
- Peak month
- June
- Records since 2000
- 7,697
Obedient plant
- Group
- Flowering plants
- Peak month
- August
- Records since 2000
- 193
Obelia longissima
- Group
- Jellyfish, corals and anemones
- Peak month
- June
- Records since 2000
- 326
Oberwinklerozyma silvestris
- Group
- Fungi
- Peak month
- August
- Records since 2000
- 540
Oblique carpet
- Group
- Butterflies and moths
- Peak month
- August
- Records since 2000
- 399
Oblique striped
- Group
- Butterflies and moths
- Peak month
- May
- Records since 2000
- 77
Oblong-leaved Dandelion
- Group
- Flowering plants
- Peak month
- April
- Records since 2000
- 106
Oblong-leaved Sundew
- Group
- Flowering plants
- Peak month
- July
- Records since 2000
- 344
Obrium brunneum
- Group
- Beetles
- Peak month
- May
- Records since 2000
- 56
Obscure Earwort
- Group
- Liverworts
- Peak month
- July
- Records since 2000
- 500
Obscure shield lichen
- Group
- Lichens
- Peak month
- September
- Records since 2000
- 139
Obscuriphantes obscurus
- Group
- Spiders
- Peak month
- June
- Records since 2000
- 62
Obtusella intersecta
- Group
- Molluscs
- Peak month
- July
- Records since 2000
- 387
Ocean Quahog
- Group
- Molluscs
- Peak month
- May
- Records since 2000
- 2,449
Oceanic Bonito
- Group
- Fish
- Peak month
- June
- Records since 2000
- 102
Oceanspray
- Group
- Flowering plants
- Peak month
- July
- Records since 2000
- 142
Ochreous pug
- Group
- Butterflies and moths
- Peak month
- May
- Records since 2000
- 242
Ochrolechia microstictoides
- Group
- Lichens
- Peak month
- May
- Records since 2000
- 547
Ochrolechia subviridis
- Group
- Lichens
- Peak month
- March
- Records since 2000
- 734
Ochrolechia turneri
- Group
- Lichens
- Peak month
- July
- Records since 2000
- 273
Ochthebius dilatatus
- Group
- Beetles
- Peak month
- June
- Records since 2000
- 376
Ochthebius marinus
- Group
- Beetles
- Peak month
- May
- Records since 2000
- 145
Ochthebius minimus
- Group
- Beetles
- Peak month
- April
- Records since 2000
- 1,655
Ochthephilum fracticorne
- Group
- Beetles
- Peak month
- June
- Records since 2000
- 106
Ochthephilus aureus
- Group
- Beetles
- Peak month
- June
- Records since 2000
- 79
Ochthephilus omalinus
- Group
- Beetles
- Peak month
- June
- Records since 2000
- 188
Ochthera manicata
- Group
- True flies
- Peak month
- June
- Records since 2000
- 102
Ochthera mantis
- Group
- True flies
- Peak month
- June
- Records since 2000
- 213
Ocnus lacteus
- Group
- Starfish and sea urchins
- Peak month
- August
- Records since 2000
- 59
Octactis speculum
- Group
- Seaweeds and algae
- Peak month
- July
- Records since 2000
- 239
Octotemnus glabriculus
- Group
- Beetles
- Peak month
- May
- Records since 2000
- 269
Ocydromia glabricula
- Group
- True flies
- Peak month
- June
- Records since 2000
- 384
Ocypus aeneocephalus
- Group
- Beetles
- Peak month
- July
- Records since 2000
- 128
Ocypus brunnipes
- Group
- Beetles
- Peak month
- July
- Records since 2000
- 127
Ocypus ophthalmicus
- Group
- Beetles
- Peak month
- August
- Records since 2000
- 66
Ocys harpaloides
- Group
- Beetles
- Peak month
- June
- Records since 2000
- 345
Ocys tachysoides
- Group
- Beetles
- Peak month
- December
- Records since 2000
- 134
Ocytata pallipes
- Group
- True flies
- Peak month
- July
- Records since 2000
- 252
Ocyusa maura
- Group
- Beetles
- Peak month
- May
- Records since 2000
- 210
Ocyusa picina
- Group
- Beetles
- Peak month
- June
- Records since 2000
- 316
Odacantha melanura
- Group
- Beetles
- Peak month
- June
- Records since 2000
- 469
Odeles marginata
- Group
- Beetles
- Peak month
- May
- Records since 2000
- 233
Odiellus spinosus
- Group
- Mites, harvestmen and other arachnids
- Peak month
- October
- Records since 2000
- 274
Odontella aurita
- Group
- Seaweeds and algae
- Peak month
- March
- Records since 2000
- 282
Odontella regia
- Group
- Seaweeds and algae
- Peak month
- April
- Records since 2000
- 238
Odonthalia dentata
- Group
- Seaweeds and algae
- Peak month
- August
- Records since 2000
- 743
Odontomyia angulata
- Group
- True flies
- Peak month
- July
- Records since 2000
- 72
Odontomyia argentata
- Group
- True flies
- Peak month
- May
- Records since 2000
- 151
Odontophora exharena
- Group
- Roundworms
- Peak month
- May
- Records since 2000
- 51
Odontophora longisetosa
- Group
- Roundworms
- Peak month
- May
- Records since 2000
- 105
Odontoscelis lineola
- Group
- True bugs
- Peak month
- June
- Records since 2000
- 133
Odontoschisma elongatum
- Group
- Liverworts
- Peak month
- July
- Records since 2000
- 147
Odontosyllis ctenostoma
- Group
- Worms (annelids)
- Peak month
- August
- Records since 2000
- 280
Odontosyllis fulgurans
- Group
- Worms (annelids)
- Peak month
- August
- Records since 2000
- 1,175
Odontosyllis gibba
- Group
- Worms (annelids)
- Peak month
- August
- Records since 2000
- 1,800
Odostomia acuta
- Group
- Molluscs
- Peak month
- March
- Records since 2000
- 647
Odostomia plicata
- Group
- Molluscs
- Peak month
- May
- Records since 2000
- 170
Odostomia turrita
- Group
- Molluscs
- Peak month
- May
- Records since 2000
- 303
Odostomia unidentata
- Group
- Molluscs
- Peak month
- May
- Records since 2000
- 202
Odynerus spinipes
- Group
- Bees, wasps and ants
- Peak month
- June
- Records since 2000
- 341
Oecetis furva
- Group
- Caddisflies
- Peak month
- July
- Records since 2000
- 198
Oecetis lacustris
- Group
- Caddisflies
- Peak month
- July
- Records since 2000
- 685
Oecetis notata
- Group
- Caddisflies
- Peak month
- May
- Records since 2000
- 91
Oecetis ochracea
- Group
- Caddisflies
- Peak month
- July
- Records since 2000
- 2,139
Oecetis testacea
- Group
- Caddisflies
- Peak month
- April
- Records since 2000
- 1,496
Oecothea fenestralis
- Group
- True flies
- Peak month
- February
- Records since 2000
- 51
Oedalea holmgreni
- Group
- True flies
- Peak month
- June
- Records since 2000
- 58
Oedemera femoralis
- Group
- Beetles
- Peak month
- October
- Records since 2000
- 1,144
Oedemera virescens
- Group
- Beetles
- Peak month
- May
- Records since 2000
- 712
Oeder's map lichen
- Group
- Lichens
- Peak month
- September
- Records since 2000
- 408
Oedothorax agrestis
- Group
- Spiders
- Peak month
- June
- Records since 2000
- 51
Oedothorax apicatus
- Group
- Spiders
- Peak month
- July
- Records since 2000
- 127
Oedothorax fuscus
- Group
- Spiders
- Peak month
- June
- Records since 2000
- 604
Oedothorax gibbosus
- Group
- Spiders
- Peak month
- June
- Records since 2000
- 314
Oedothorax retusus
- Group
- Spiders
- Peak month
- July
- Records since 2000
- 386
Oegoconia quadripuncta
- Group
- Butterflies and moths
- Peak month
- July
- Records since 2000
- 134
Oenanthe hispanica
- Group
- Birds
- Peak month
- June
- Records since 2000
- 59
Oenothera fallax
- Group
- Flowering plants
- Peak month
- July
- Records since 2000
- 76
Oerstedia dorsalis
- Group
- Other invertebrates
- Peak month
- September
- Records since 2000
- 374
Oestergrenia digitata
- Group
- Starfish and sea urchins
- Peak month
- May
- Records since 2000
- 451
Oidiodendron majus
- Group
- Fungi
- Peak month
- June
- Records since 2000
- 52
Oil beetle
- Group
- Beetles
- Peak month
- April
- Records since 2000
- 2,548
Oily Waxcap
- Group
- Fungi
- Peak month
- October
- Records since 2000
- 2,250
Oithona similis
- Group
- Crustaceans
- Peak month
- June
- Records since 2000
- 555
Olavius ilvae
- Group
- Worms (annelids)
- Peak month
- January
- Records since 2000
- 97
Old Growth Rag lichen
- Group
- Lichens
- Peak month
- April
- Records since 2000
- 100
Old Lady
- Group
- Butterflies and moths
- Peak month
- August
- Records since 2000
- 1,493
Old Man of The Woods
- Group
- Fungi
- Peak month
- September
- Records since 2000
- 59
Old World Swallowtail
- Group
- Butterflies and moths
- Peak month
- June
- Records since 2000
- 1,486
Old-wood Lichen
- Group
- Lichens
- Peak month
- May
- Records since 2000
- 1,626
Oldfashioned weigela
- Group
- Flowering plants
- Peak month
- May
- Records since 2000
- 83
Oldrose Bolete
- Group
- Fungi
- Peak month
- August
- Records since 2000
- 59
Oleolophozia perssonii
- Group
- Liverworts
- Peak month
- February
- Records since 2000
- 87
Olethreutes schulziana
- Group
- Butterflies and moths
- Peak month
- June
- Records since 2000
- 95
Olibrus aeneus
- Group
- Beetles
- Peak month
- August
- Records since 2000
- 541
Olibrus affinis
- Group
- Beetles
- Peak month
- June
- Records since 2000
- 423
Olibrus corticalis
- Group
- Beetles
- Peak month
- April
- Records since 2000
- 325
Olibrus flavicornis
- Group
- Beetles
- Peak month
- June
- Records since 2000
- 108
Olibrus liquidus
- Group
- Beetles
- Peak month
- June
- Records since 2000
- 218
Oligia versicolor
- Group
- Butterflies and moths
- Peak month
- July
- Records since 2000
- 228
Oligolophus hansenii
- Group
- Mites, harvestmen and other arachnids
- Peak month
- October
- Records since 2000
- 216
Oligolophus tridens
- Group
- Mites, harvestmen and other arachnids
- Peak month
- August
- Records since 2000
- 304
Oligonema affine
- Group
- Microorganisms and protists
- Peak month
- October
- Records since 2000
- 76
Oligoporus wakefieldiae
- Group
- Fungi
- Peak month
- November
- Records since 2000
- 58
Oligotricha striata
- Group
- Caddisflies
- Peak month
- June
- Records since 2000
- 102
Oligotrophus juniperinus
- Group
- True flies
- Peak month
- June
- Records since 2000
- 114
Oligotrophus panteli
- Group
- True flies
- Peak month
- March
- Records since 2000
- 91
Olindia schumacherana
- Group
- Butterflies and moths
- Peak month
- June
- Records since 2000
- 114
Olisthopus rotundatus
- Group
- Beetles
- Peak month
- August
- Records since 2000
- 442
Olive Beard Moss
- Group
- Mosses
- Peak month
- March
- Records since 2000
- 3,036
Olive Bog-moss
- Group
- Mosses
- Peak month
- June
- Records since 2000
- 50
Olive Pearl
- Group
- Butterflies and moths
- Peak month
- June
- Records since 2000
- 2,251
Olive Scribble Lichen
- Group
- Lichens
- Peak month
- May
- Records since 2000
- 1,611
Olive Upright
- Group
- Mayflies
- Peak month
- April
- Records since 2000
- 4,445
Olive-backed Pipit
- Group
- Birds
- Peak month
- October
- Records since 2000
- 674
Olivegreen calcareous moss
- Group
- Mosses
- Peak month
- April
- Records since 2000
- 317
Olophrum fuscum
- Group
- Beetles
- Peak month
- June
- Records since 2000
- 65
Olophrum piceum
- Group
- Beetles
- Peak month
- September
- Records since 2000
- 206
Omalium caesum
- Group
- Beetles
- Peak month
- May
- Records since 2000
- 71
Omalium laeviusculum
- Group
- Beetles
- Peak month
- June
- Records since 2000
- 58
Omalium rivulare
- Group
- Beetles
- Peak month
- May
- Records since 2000
- 137
Omalogyra atomus
- Group
- Molluscs
- Peak month
- August
- Records since 2000
- 124
Omaloplia ruricola
- Group
- Beetles
- Peak month
- June
- Records since 2000
- 159
Omonadus formicarius
- Group
- Beetles
- Peak month
- September
- Records since 2000
- 86
Omophron limbatum
- Group
- Beetles
- Peak month
- May
- Records since 2000
- 111
Omosita discoidea
- Group
- Beetles
- Peak month
- May
- Records since 2000
- 78
Omphalapion hookerorum
- Group
- Beetles
- Peak month
- June
- Records since 2000
- 188
Omphale lugens
- Group
- Bees, wasps and ants
- Peak month
- April
- Records since 2000
- 144
Omphalina pyxidata
- Group
- Fungi
- Peak month
- October
- Records since 2000
- 100
Oncocera semirubella
- Group
- Butterflies and moths
- Peak month
- July
- Records since 2000
- 239
Oncopsis alni
- Group
- True bugs
- Peak month
- June
- Records since 2000
- 149
Oncopsis subangulata
- Group
- True bugs
- Peak month
- June
- Records since 2000
- 103
Oncopsis tristis
- Group
- True bugs
- Peak month
- June
- Records since 2000
- 203
Oncousoecia dilatans
- Group
- Bryozoans
- Peak month
- August
- Records since 2000
- 844
Ondina diaphana
- Group
- Molluscs
- Peak month
- May
- Records since 2000
- 97
Ondina divisa
- Group
- Molluscs
- Peak month
- April
- Records since 2000
- 214
Ontholestes murinus
- Group
- Beetles
- Peak month
- July
- Records since 2000
- 81
Ontholestes tessellatus
- Group
- Beetles
- Peak month
- August
- Records since 2000
- 53
Onthophagus joannae
- Group
- Beetles
- Peak month
- May
- Records since 2000
- 395
Onthophagus nuchicornis
- Group
- Beetles
- Peak month
- May
- Records since 2000
- 120
Onygena equina
- Group
- Fungi
- Peak month
- April
- Records since 2000
- 77
Ooctonus hemipterus
- Group
- Bees, wasps and ants
- Peak month
- July
- Records since 2000
- 391
Ooctonus notatus
- Group
- Bees, wasps and ants
- Peak month
- August
- Records since 2000
- 58
Oodes helopioides
- Group
- Beetles
- Peak month
- May
- Records since 2000
- 223
Oomorphus concolor
- Group
- Beetles
- Peak month
- May
- Records since 2000
- 96
Opacifrons coxata
- Group
- True flies
- Peak month
- July
- Records since 2000
- 367
Opacifrons humida
- Group
- True flies
- Peak month
- July
- Records since 2000
- 247
Opal Thread-moss
- Group
- Mosses
- Peak month
- July
- Records since 2000
- 839
Opatrum sabulosum
- Group
- Beetles
- Peak month
- April
- Records since 2000
- 96
Opegrapha cesareensis
- Group
- Lichens
- Peak month
- August
- Records since 2000
- 98
Opegrapha dolomitica
- Group
- Lichens
- Peak month
- May
- Records since 2000
- 52
Opegrapha lithyrga
- Group
- Lichens
- Peak month
- March
- Records since 2000
- 58
Opegrapha vermicellifera
- Group
- Lichens
- Peak month
- February
- Records since 2000
- 505
Opeltia flavorubescens
- Group
- Lichens
- Peak month
- May
- Records since 2000
- 73
Opetia nigra
- Group
- True flies
- Peak month
- June
- Records since 2000
- 756
Ophelia borealis
- Group
- Worms (annelids)
- Peak month
- July
- Records since 2000
- 5,763
Ophelia celtica
- Group
- Worms (annelids)
- Peak month
- August
- Records since 2000
- 307
Ophelia limacina
- Group
- Worms (annelids)
- Peak month
- June
- Records since 2000
- 119
Ophelia rathkei
- Group
- Worms (annelids)
- Peak month
- September
- Records since 2000
- 90
Ophelia roscoffensis
- Group
- Worms (annelids)
- Peak month
- April
- Records since 2000
- 53
Ophelina acuminata
- Group
- Worms (annelids)
- Peak month
- June
- Records since 2000
- 2,953
Ophelina cylindricaudata
- Group
- Worms (annelids)
- Peak month
- October
- Records since 2000
- 448
Ophelina modesta
- Group
- Worms (annelids)
- Peak month
- August
- Records since 2000
- 427
Ophelina norvegica
- Group
- Worms (annelids)
- Peak month
- January
- Records since 2000
- 116
Ophiactis balli
- Group
- Starfish and sea urchins
- Peak month
- May
- Records since 2000
- 730
Ophiobolus acuminatus
- Group
- Fungi
- Peak month
- June
- Records since 2000
- 50
Ophiocten affinis
- Group
- Starfish and sea urchins
- Peak month
- July
- Records since 2000
- 1,795
Ophiognomonia alni-viridis
- Group
- Fungi
- Peak month
- March
- Records since 2000
- 88
Ophiognomonia intermedia
- Group
- Fungi
- Peak month
- March
- Records since 2000
- 53
Ophion brevicornis
- Group
- Bees, wasps and ants
- Peak month
- June
- Records since 2000
- 60
Ophion minutus
- Group
- Bees, wasps and ants
- Peak month
- May
- Records since 2000
- 81
Ophion obscuratus
- Group
- Bees, wasps and ants
- Peak month
- April
- Records since 2000
- 138
Ophion scutellaris
- Group
- Bees, wasps and ants
- Peak month
- March
- Records since 2000
- 74
Ophiostoma novo-ulmi
- Group
- Fungi
- Records since 2000
- 265
- NBN Atlas records since 2000
- 265
Ophiostoma ulmi
- Group
- Fungi
- Peak month
- July
- Records since 2000
- 67
Ophiura sarsii
- Group
- Starfish and sea urchins
- Peak month
- September
- Records since 2000
- 81
Ophlitaspongia papilla
- Group
- Sponges
- Peak month
- September
- Records since 2000
- 211
Ophonus ardosiacus
- Group
- Beetles
- Peak month
- August
- Records since 2000
- 456
Ophonus azureus
- Group
- Beetles
- Peak month
- May
- Records since 2000
- 111
Ophonus puncticeps
- Group
- Beetles
- Peak month
- August
- Records since 2000
- 289
Ophonus rufibarbis
- Group
- Beetles
- Peak month
- May
- Records since 2000
- 325
Ophonus schaubergerianus
- Group
- Beetles
- Peak month
- May
- Records since 2000
- 283
Ophryotrocha hartmanni
- Group
- Worms (annelids)
- Peak month
- July
- Records since 2000
- 1,754
Ophryotrocha puerilis
- Group
- Worms (annelids)
- Peak month
- June
- Records since 2000
- 85
Ophrys pietzschii
- Group
- Flowering plants
- Peak month
- April
- Records since 2000
- 80
Ophyiulus pilosus
- Group
- Millipedes
- Peak month
- June
- Records since 2000
- 228
Opilio canestrinii
- Group
- Mites, harvestmen and other arachnids
- Peak month
- August
- Records since 2000
- 1,560
Opilio saxatilis
- Group
- Mites, harvestmen and other arachnids
- Peak month
- August
- Records since 2000
- 202
Opilo mollis
- Group
- Beetles
- Peak month
- June
- Records since 2000
- 178
Opitutus terrae
- Group
- Microorganisms and protists
- Peak month
- January
- Records since 2000
- 89
Opium Poppy
- Group
- Flowering plants
- Peak month
- June
- Records since 2000
- 5,832
Opius irregularis
- Group
- Bees, wasps and ants
- Peak month
- July
- Records since 2000
- 77
Opomyza germinationis
- Group
- True flies
- Peak month
- June
- Records since 2000
- 2,572
Opomyza petrei
- Group
- True flies
- Peak month
- July
- Records since 2000
- 929
Opomyza punctata
- Group
- True flies
- Peak month
- August
- Records since 2000
- 136
Opostega salaciella
- Group
- Butterflies and moths
- Peak month
- June
- Records since 2000
- 101
Opposite-leaved Golden-saxifrage
- Group
- Flowering plants
- Peak month
- April
- Records since 2000
- 7,171
Opposite-leaved Pondweed
- Group
- Flowering plants
- Peak month
- July
- Records since 2000
- 123
Orange Balsam
- Group
- Flowering plants
- Peak month
- August
- Records since 2000
- 3,382
Orange Birch Bolete
- Group
- Fungi
- Peak month
- September
- Records since 2000
- 499
Orange Bonnet
- Group
- Fungi
- Peak month
- October
- Records since 2000
- 589
Orange Crest
- Group
- Butterflies and moths
- Peak month
- July
- Records since 2000
- 592
Orange daylily
- Group
- Flowering plants
- Peak month
- July
- Records since 2000
- 56
Orange Dot Lichen
- Group
- Lichens
- Peak month
- July
- Records since 2000
- 3,144
Orange Footman
- Group
- Butterflies and moths
- Peak month
- May
- Records since 2000
- 1,557
Orange Foxtail
- Group
- Flowering plants
- Peak month
- June
- Records since 2000
- 90
Orange fruited elm lichen
- Group
- Lichens
- Peak month
- September
- Records since 2000
- 58
Orange Hawkweed
- Group
- Flowering plants
- Peak month
- June
- Records since 2000
- 4,109
Orange lights seasquirt
- Group
- Sea squirts
- Peak month
- June
- Records since 2000
- 527
Orange Mosscap
- Group
- Fungi
- Peak month
- October
- Records since 2000
- 1,826
Orange moth
- Group
- Butterflies and moths
- Peak month
- June
- Records since 2000
- 174
Orange Mullein
- Group
- Flowering plants
- Peak month
- July
- Records since 2000
- 139
Orange peel bryozoan
- Group
- Bryozoans
- Peak month
- September
- Records since 2000
- 57
Orange Pine Twist
- Group
- Butterflies and moths
- Peak month
- July
- Records since 2000
- 678
Orange Pixie-hair Lichen
- Group
- Lichens
- Peak month
- May
- Records since 2000
- 1,636
Orange sallow
- Group
- Butterflies and moths
- Peak month
- September
- Records since 2000
- 255
Orange Sea Grapes
- Group
- Sea squirts
- Peak month
- July
- Records since 2000
- 1,707
Orange Sea Lichen
- Group
- Lichens
- Peak month
- August
- Records since 2000
- 509
Orange Swift
- Group
- Butterflies and moths
- Peak month
- August
- Records since 2000
- 3,650
Orange underwing
- Group
- Butterflies and moths
- Peak month
- March
- Records since 2000
- 172
Orange-ball-tree
- Group
- Flowering plants
- Peak month
- June
- Records since 2000
- 1,595
Orange-belted Plumehorn
- Group
- True flies
- Peak month
- June
- Records since 2000
- 593
Orange-Clubbed Sea Slug
- Group
- Molluscs
- Peak month
- July
- Records since 2000
- 1,616
Orange-legged Furrow Bee
- Group
- Bees, wasps and ants
- Peak month
- May
- Records since 2000
- 2,303
Orange-marked cranefly
- Group
- True flies
- Peak month
- May
- Records since 2000
- 1,414
Orange-peel Fungus
- Group
- Fungi
- Peak month
- October
- Records since 2000
- 865
Orange-shinned Blacklet
- Group
- True flies
- Peak month
- May
- Records since 2000
- 489
Orange-sided comb-horn
- Group
- True flies
- Peak month
- May
- Records since 2000
- 520
Orange-spined Drone Fly
- Group
- True flies
- Peak month
- August
- Records since 2000
- 5,815
Orange-spot Piercer
- Group
- Butterflies and moths
- Peak month
- June
- Records since 2000
- 481
Orange-spotted plant bug
- Group
- True bugs
- Peak month
- June
- Records since 2000
- 3,898
Orange-striped Stonefly
- Group
- Stoneflies
- Peak month
- September
- Records since 2000
- 1,953
Orange-tip
- Group
- Butterflies and moths
- Peak month
- May
- Records since 2000
- 203,747
Orange-tipped sea squirt
- Group
- Sea squirts
- Peak month
- July
- Records since 2000
- 1,182
Orange-vented Mason Bee
- Group
- Bees, wasps and ants
- Peak month
- June
- Records since 2000
- 949
Orangeman
- Group
- Beetles
- Peak month
- June
- Records since 2000
- 86
Orbilia auricolor
- Group
- Fungi
- Peak month
- April
- Records since 2000
- 82
Orbilia coccinella
- Group
- Fungi
- Peak month
- September
- Records since 2000
- 70
Orbilia eucalypti
- Group
- Fungi
- Peak month
- April
- Records since 2000
- 58
Orbilia xanthostigma
- Group
- Fungi
- Peak month
- September
- Records since 2000
- 326
Orbinia armandi
- Group
- Worms (annelids)
- Peak month
- July
- Records since 2000
- 93
Orbinia latreillii
- Group
- Worms (annelids)
- Peak month
- June
- Records since 2000
- 92
Orbinia sertulata
- Group
- Worms (annelids)
- Peak month
- May
- Records since 2000
- 922
Orca
- Group
- Mammals
- Peak month
- May
- Records since 2000
- 647
Orchard Ermine
- Group
- Butterflies and moths
- Peak month
- July
- Records since 2000
- 860
Orchesella villosa
- Group
- Springtails
- Peak month
- March
- Records since 2000
- 336
Orchesella villosa
- Group
- Springtails
- Peak month
- April
- Records since 2000
- 250
Orchesia micans
- Group
- Beetles
- Peak month
- July
- Records since 2000
- 104
Orchesia minor
- Group
- Beetles
- Peak month
- July
- Records since 2000
- 168
Orchesia undulata
- Group
- Beetles
- Peak month
- July
- Records since 2000
- 367
Orchestes hortorum
- Group
- Beetles
- Peak month
- June
- Records since 2000
- 355
Orchestes pilosus
- Group
- Beetles
- Peak month
- June
- Records since 2000
- 207
Orchestes quercus
- Group
- Beetles
- Peak month
- June
- Records since 2000
- 304
Orchestes rusci
- Group
- Beetles
- Peak month
- July
- Records since 2000
- 307
Orchestia gammarellus
- Group
- Crustaceans
- Peak month
- June
- Records since 2000
- 220
Orchid Beetle
- Group
- Beetles
- Peak month
- June
- Records since 2000
- 1,692
Orchomene humilis
- Group
- Crustaceans
- Peak month
- September
- Records since 2000
- 353
Oregon-grape
- Group
- Flowering plants
- Peak month
- April
- Records since 2000
- 1,230
Oreodytes septentrionalis
- Group
- Beetles
- Peak month
- September
- Records since 2000
- 249
Oreojuncus trifidus
- Group
- Flowering plants
- Peak month
- July
- Records since 2000
- 148
Oreoneta frigida
- Group
- Spiders
- Peak month
- August
- Records since 2000
- 53
Orfelia nemoralis
- Group
- True flies
- Peak month
- June
- Records since 2000
- 290
Orfelia pallida
- Group
- True flies
- Peak month
- June
- Records since 2000
- 71
Oriental Plane
- Group
- Flowering plants
- Peak month
- June
- Records since 2000
- 68
Oriental Poppy
- Group
- Flowering plants
- Peak month
- May
- Records since 2000
- 1,180
Oriental Pratincole
- Group
- Birds
- Peak month
- May
- Records since 2000
- 62
Oriental Turtle Dove
- Group
- Birds
- Peak month
- February
- Records since 2000
- 217
Orimarga juvenilis
- Group
- True flies
- Peak month
- June
- Records since 2000
- 50
Orimarga virgo
- Group
- True flies
- Peak month
- June
- Records since 2000
- 52
Orius laevigatus
- Group
- True bugs
- Peak month
- August
- Records since 2000
- 242
Orius majusculus
- Group
- True bugs
- Peak month
- August
- Records since 2000
- 160
Orius niger
- Group
- True bugs
- Peak month
- July
- Records since 2000
- 310
Orius vicinus
- Group
- True bugs
- Peak month
- August
- Records since 2000
- 118
Orkney Notchwort
- Group
- Liverworts
- Peak month
- July
- Records since 2000
- 871
Ormosia depilata
- Group
- True flies
- Peak month
- May
- Records since 2000
- 157
Ormosia hederae
- Group
- True flies
- Peak month
- May
- Records since 2000
- 388
Ormosia lineata
- Group
- True flies
- Peak month
- April
- Records since 2000
- 392
Ormosia nodulosa
- Group
- True flies
- Peak month
- June
- Records since 2000
- 1,129
Ormosia pseudosimilis
- Group
- True flies
- Peak month
- June
- Records since 2000
- 86
Ormyrus nitidulus
- Group
- Bees, wasps and ants
- Peak month
- September
- Records since 2000
- 64
Ornate Brigadier
- Group
- True flies
- Peak month
- June
- Records since 2000
- 503
Ornate Tailed Digger Wasp
- Group
- Bees, wasps and ants
- Peak month
- July
- Records since 2000
- 1,429
Ornithomya avicularia
- Group
- True flies
- Peak month
- July
- Records since 2000
- 125
Ornithomya chloropus
- Group
- True flies
- Peak month
- July
- Records since 2000
- 83
Ornithomya fringillina
- Group
- True flies
- Peak month
- August
- Records since 2000
- 95
Orobitis cyaneus
- Group
- Beetles
- Peak month
- June
- Records since 2000
- 72
Orpine
- Group
- Flowering plants
- Peak month
- August
- Records since 2000
- 360
Orsillus depressus
- Group
- True bugs
- Peak month
- September
- Records since 2000
- 255
Orsodacne cerasi
- Group
- Beetles
- Peak month
- June
- Records since 2000
- 123
Orsodacne humeralis
- Group
- Beetles
- Peak month
- May
- Records since 2000
- 61
Orthocentrus spurius
- Group
- Bees, wasps and ants
- Peak month
- September
- Records since 2000
- 88
Orthocephalus coriaceus
- Group
- True bugs
- Peak month
- July
- Records since 2000
- 61
Orthocephalus saltator
- Group
- True bugs
- Peak month
- July
- Records since 2000
- 212
Orthochaetes setiger
- Group
- Beetles
- Peak month
- June
- Records since 2000
- 158
Orthocis alni
- Group
- Beetles
- Peak month
- June
- Records since 2000
- 132
Orthocladius consobrinus
- Group
- True flies
- Peak month
- April
- Records since 2000
- 55
Orthocladius fuscimanus
- Group
- True flies
- Peak month
- February
- Records since 2000
- 60
Orthocladius rubicundus
- Group
- True flies
- Peak month
- May
- Records since 2000
- 62
Orthocladius thienemanni
- Group
- True flies
- Peak month
- February
- Records since 2000
- 448
Orthocladius van-der
- Group
- True flies
- Peak month
- May
- Records since 2000
- 530
Orthodicranum montanum
- Group
- Mosses
- Peak month
- February
- Records since 2000
- 459
Orthodicranum tauricum
- Group
- Mosses
- Peak month
- March
- Records since 2000
- 1,532
Orthonama obstipata
- Group
- Butterflies and moths
- Peak month
- October
- Records since 2000
- 113
Orthonevra geniculata
- Group
- True flies
- Peak month
- May
- Records since 2000
- 60
Orthonevra nobilis
- Group
- True flies
- Peak month
- July
- Records since 2000
- 269
Orthonevra splendens
- Group
- True flies
- Peak month
- June
- Records since 2000
- 1,063
Orthonotus rufifrons
- Group
- True bugs
- Peak month
- July
- Records since 2000
- 210
Orthoperus nigrescens
- Group
- Beetles
- Peak month
- May
- Records since 2000
- 70
Orthops basalis
- Group
- True bugs
- Peak month
- July
- Records since 2000
- 211
Orthops campestris
- Group
- True bugs
- Peak month
- July
- Records since 2000
- 1,003
Orthops kalmii
- Group
- True bugs
- Peak month
- July
- Records since 2000
- 151
Orthopyxis sargassicola
- Group
- Jellyfish, corals and anemones
- Peak month
- August
- Records since 2000
- 1,080
Orthotaenia undulana
- Group
- Butterflies and moths
- Peak month
- June
- Records since 2000
- 273
Orthothecium moss
- Group
- Mosses
- Peak month
- July
- Records since 2000
- 338
Orthotrichia costalis
- Group
- Caddisflies
- Peak month
- June
- Records since 2000
- 166
Orthotrichum anomalum
- Group
- Mosses
- Peak month
- February
- Records since 2000
- 286
Orthotylus ericetorum
- Group
- True bugs
- Peak month
- August
- Records since 2000
- 300
Orthotylus flavosparsus
- Group
- True bugs
- Peak month
- August
- Records since 2000
- 158
Orthotylus marginalis
- Group
- True bugs
- Peak month
- June
- Records since 2000
- 327
Orthotylus moncreaffi
- Group
- True bugs
- Peak month
- July
- Records since 2000
- 68
Orthotylus ochrotrichus
- Group
- True bugs
- Peak month
- July
- Records since 2000
- 103
Orthotylus tenellus
- Group
- True bugs
- Peak month
- June
- Records since 2000
- 144
Orthotylus virescens
- Group
- True bugs
- Peak month
- July
- Records since 2000
- 103
Ortolan Bunting
- Group
- Birds
- Peak month
- September
- Records since 2000
- 547
Orygma luctuosum
- Group
- True flies
- Peak month
- June
- Records since 2000
- 56
Oscarella lobularis
- Group
- Sponges
- Peak month
- March
- Records since 2000
- 155
Oscillatoria acuminata
- Group
- Microorganisms and protists
- Peak month
- January
- Records since 2000
- 68
Oscinella nitidissima
- Group
- True flies
- Peak month
- August
- Records since 2000
- 133
Oscinella pusilla
- Group
- True flies
- Peak month
- August
- Records since 2000
- 90
Oshurkovia littoralis
- Group
- Bryozoans
- Peak month
- August
- Records since 2000
- 182
Osier
- Group
- Flowering plants
- Peak month
- August
- Records since 2000
- 2,328
Osmia cornuta
- Group
- Bees, wasps and ants
- Peak month
- March
- Records since 2000
- 206
Osmundea oederi
- Group
- Seaweeds and algae
- Peak month
- June
- Records since 2000
- 98
Osmundea truncata
- Group
- Seaweeds and algae
- Peak month
- July
- Records since 2000
- 113
Osmylus fulvicephalus
- Group
- Lacewings
- Peak month
- June
- Records since 2000
- 54
Osphya bipunctata
- Group
- Beetles
- Peak month
- May
- Records since 2000
- 63
Osprey
- Group
- Birds
- Peak month
- August
- Records since 2000
- 28,915
Ossicaulis lignatilis
- Group
- Fungi
- Peak month
- October
- Records since 2000
- 67
Ostearius melanopygius
- Group
- Spiders
- Peak month
- August
- Records since 2000
- 54
Ostrich fern
- Group
- Ferns and horsetails
- Peak month
- April
- Records since 2000
- 58
Ostrich-plume Feather-moss
- Group
- Mosses
- Peak month
- July
- Records since 2000
- 786
Oswaldia muscaria
- Group
- True flies
- Peak month
- May
- Records since 2000
- 108
Othius laeviusculus
- Group
- Beetles
- Peak month
- June
- Records since 2000
- 82
Othius punctulatus
- Group
- Beetles
- Peak month
- June
- Records since 2000
- 160
Othius subuliformis
- Group
- Beetles
- Peak month
- July
- Records since 2000
- 97
Othomaera othonis
- Group
- Crustaceans
- Peak month
- August
- Records since 2000
- 4,405
Otidea alutacea
- Group
- Fungi
- Peak month
- October
- Records since 2000
- 283
Otidea bufonia
- Group
- Fungi
- Peak month
- October
- Records since 2000
- 205
Otidea onotica
- Group
- Fungi
- Peak month
- October
- Records since 2000
- 431
Otiorhynchus arcticus
- Group
- Beetles
- Peak month
- July
- Records since 2000
- 60
Otiorhynchus armadillo
- Group
- Beetles
- Peak month
- May
- Records since 2000
- 185
Otiorhynchus crataegi
- Group
- Beetles
- Peak month
- September
- Records since 2000
- 131
Otiorhynchus ligneus
- Group
- Beetles
- Peak month
- June
- Records since 2000
- 156
Otiorhynchus porcatus
- Group
- Beetles
- Peak month
- August
- Records since 2000
- 77
Otiorhynchus raucus
- Group
- Beetles
- Peak month
- April
- Records since 2000
- 60
Otiorhynchus rugifrons
- Group
- Beetles
- Peak month
- June
- Records since 2000
- 71
Otiorhynchus rugosostriatus
- Group
- Beetles
- Peak month
- September
- Records since 2000
- 126
Otites guttata
- Group
- True flies
- Peak month
- May
- Records since 2000
- 73
Otophorus haemorrhoidalis
- Group
- Beetles
- Peak month
- July
- Records since 2000
- 280
Ougia subaequalis
- Group
- Worms (annelids)
- Peak month
- August
- Records since 2000
- 75
Oulema duftschmidi
- Group
- Beetles
- Peak month
- July
- Records since 2000
- 253
Oulema gallaeciana
- Group
- Beetles
- Peak month
- July
- Records since 2000
- 596
Oulimnius major
- Group
- Beetles
- Peak month
- May
- Records since 2000
- 61
Oulimnius rivularis
- Group
- Beetles
- Peak month
- May
- Records since 2000
- 71
Oulimnius troglodytes
- Group
- Beetles
- Peak month
- August
- Records since 2000
- 54
Oulimnius tuberculatus
- Group
- Beetles
- Peak month
- September
- Records since 2000
- 1,909
Oval Cockle
- Group
- Molluscs
- Peak month
- September
- Records since 2000
- 1,682
Oval Sedge
- Group
- Flowering plants
- Peak month
- June
- Records since 2000
- 2,462
Oval venus
- Group
- Molluscs
- Peak month
- August
- Records since 2000
- 7,943
Oval-leaved Pottia
- Group
- Mosses
- Peak month
- February
- Records since 2000
- 63
Ovate harp ground beetle
- Group
- Beetles
- Peak month
- May
- Records since 2000
- 979
Overleaf Pellia
- Group
- Liverworts
- Peak month
- July
- Records since 2000
- 13,066
Owenia borealis
- Group
- Worms (annelids)
- Peak month
- May
- Records since 2000
- 256
Oxalis stricta
- Group
- Flowering plants
- Peak month
- July
- Records since 2000
- 67
Oxeye Daisy
- Group
- Flowering plants
- Peak month
- June
- Records since 2000
- 12,477
Oxford Ragwort
- Group
- Flowering plants
- Peak month
- April
- Records since 2000
- 3,206
Oxlip
- Group
- Flowering plants
- Peak month
- April
- Records since 2000
- 146
Oxycera morrisii
- Group
- True flies
- Peak month
- July
- Records since 2000
- 225
Oxycera pardalina
- Group
- True flies
- Peak month
- July
- Records since 2000
- 173
Oxydromus flexuosus
- Group
- Worms (annelids)
- Peak month
- June
- Records since 2000
- 4,148
Oxydromus pallidus
- Group
- Worms (annelids)
- Peak month
- July
- Records since 2000
- 454
Oxyethira falcata
- Group
- Caddisflies
- Peak month
- August
- Records since 2000
- 277
Oxyethira flavicornis
- Group
- Caddisflies
- Peak month
- July
- Records since 2000
- 503
Oxyethira frici
- Group
- Caddisflies
- Peak month
- July
- Records since 2000
- 53
Oxygen-weed
- Group
- Flowering plants
- Peak month
- July
- Records since 2000
- 363
Oxyloma sarsii
- Group
- Molluscs
- Peak month
- June
- Records since 2000
- 54
Oxyopes heterophthalmus
- Group
- Spiders
- Peak month
- July
- Records since 2000
- 57
Oxypoda alternans
- Group
- Beetles
- Peak month
- September
- Records since 2000
- 94
Oxypoda brevicornis
- Group
- Beetles
- Peak month
- June
- Records since 2000
- 120
Oxypoda elongatula
- Group
- Beetles
- Peak month
- May
- Records since 2000
- 251
Oxypoda haemorrhoa
- Group
- Beetles
- Peak month
- July
- Records since 2000
- 72
Oxypoda procerula
- Group
- Beetles
- Peak month
- August
- Records since 2000
- 61
Oxyporus populinus
- Group
- Fungi
- Peak month
- October
- Records since 2000
- 181
Oxypselaphus obscurus
- Group
- Beetles
- Peak month
- May
- Records since 2000
- 1,525
Oxypteryx atrella
- Group
- Butterflies and moths
- Peak month
- July
- Records since 2000
- 86
Oxystoma cerdo
- Group
- Beetles
- Peak month
- June
- Records since 2000
- 184
Oxystoma craccae
- Group
- Beetles
- Peak month
- June
- Records since 2000
- 104
Oxystoma pomonae
- Group
- Beetles
- Peak month
- May
- Records since 2000
- 620
Oxystoma subulatum
- Group
- Beetles
- Peak month
- June
- Records since 2000
- 220
Oxytelus laqueatus
- Group
- Beetles
- Peak month
- June
- Records since 2000
- 179
Oxythyrea funesta
- Group
- Beetles
- Peak month
- June
- Records since 2000
- 84
Oyster Drill
- Group
- Molluscs
- Peak month
- September
- Records since 2000
- 1,227
Oyster gall, April-bud gall
- Group
- Bees, wasps and ants
- Peak month
- September
- Records since 2000
- 1,306
Oyster Mushroom
- Group
- Fungi
- Peak month
- October
- Records since 2000
- 2,176
Oysterplant
- Group
- Flowering plants
- Peak month
- June
- Records since 2000
- 121
OysterThief
- Group
- Seaweeds and algae
- Peak month
- June
- Records since 2000
- 969
Ozyptila atomaria
- Group
- Spiders
- Peak month
- June
- Records since 2000
- 76
Ozyptila brevipes
- Group
- Spiders
- Peak month
- July
- Records since 2000
- 92
Ozyptila praticola
- Group
- Spiders
- Peak month
- June
- Records since 2000
- 97
Ozyptila simplex
- Group
- Spiders
- Peak month
- May
- Records since 2000
- 50
Ozyptila trux
- Group
- Spiders
- Peak month
- June
- Records since 2000
- 232