Yarrell's Blenny
- Group
- Fish
- Peak month
- July
- Records since 2000
- 480
Yarrow
- Group
- Flowering plants
- Peak month
- July
- Records since 2000
- 27,652
Yarrow Broomrape
- Group
- Flowering plants
- Peak month
- June
- Records since 2000
- 88
Yarrow pug
- Group
- Butterflies and moths
- Peak month
- July
- Records since 2000
- 65
Yellow and black longhorn
- Group
- Beetles
- Peak month
- July
- Records since 2000
- 8,578
Yellow Archangel
- Group
- Flowering plants
- Peak month
- April
- Records since 2000
- 14,460
Yellow Azalea
- Group
- Flowering plants
- Peak month
- May
- Records since 2000
- 1,527
Yellow barklouse
- Group
- Other insects
- Peak month
- October
- Records since 2000
- 1,515
Yellow belle
- Group
- Butterflies and moths
- Peak month
- May
- Records since 2000
- 97
Yellow bird's-nest
- Group
- Flowering plants
- Peak month
- July
- Records since 2000
- 225
Yellow bloodstain lichen
- Group
- Lichens
- Peak month
- May
- Records since 2000
- 1,241
Yellow Brain
- Group
- Fungi
- Peak month
- January
- Records since 2000
- 2,322
Yellow bush lupine
- Group
- Flowering plants
- Peak month
- May
- Records since 2000
- 343
Yellow Cereal Fly
- Group
- True flies
- Peak month
- July
- Records since 2000
- 1,900
Yellow Club
- Group
- Fungi
- Peak month
- October
- Records since 2000
- 2,502
Yellow Cluster Anemone
- Group
- Jellyfish, corals and anemones
- Peak month
- June
- Records since 2000
- 506
Yellow Crisp-moss
- Group
- Mosses
- Peak month
- March
- Records since 2000
- 1,160
Yellow Feather-moss
- Group
- Mosses
- Peak month
- March
- Records since 2000
- 4,490
Yellow Feathers
- Group
- Jellyfish, corals and anemones
- Peak month
- May
- Records since 2000
- 1,113
Yellow Fieldcap
- Group
- Fungi
- Peak month
- October
- Records since 2000
- 2,438
Yellow Foot Waxcap
- Group
- Fungi
- Peak month
- October
- Records since 2000
- 679
Yellow Footed Mining Bee
- Group
- Bees, wasps and ants
- Peak month
- May
- Records since 2000
- 96
Yellow foxtail
- Group
- Flowering plants
- Peak month
- September
- Records since 2000
- 151
Yellow Horned
- Group
- Butterflies and moths
- Peak month
- March
- Records since 2000
- 625
Yellow Horned Poppy
- Group
- Flowering plants
- Peak month
- June
- Records since 2000
- 1,664
Yellow Iris
- Group
- Flowering plants
- Peak month
- June
- Records since 2000
- 13,607
Yellow Legged Mining Bee
- Group
- Bees, wasps and ants
- Peak month
- April
- Records since 2000
- 2,875
Yellow Loosestrife
- Group
- Flowering plants
- Peak month
- July
- Records since 2000
- 3,088
Yellow Map Lichen
- Group
- Lichens
- Peak month
- May
- Records since 2000
- 3,025
Yellow May Dun
- Group
- Mayflies
- Peak month
- April
- Records since 2000
- 1,186
Yellow Mayfly
- Group
- Mayflies
- Peak month
- September
- Records since 2000
- 362
Yellow Meadow Ant
- Group
- Bees, wasps and ants
- Peak month
- June
- Records since 2000
- 3,810
Yellow monkswort
- Group
- Flowering plants
- Peak month
- April
- Records since 2000
- 123
Yellow Oak Button
- Group
- Butterflies and moths
- Peak month
- June
- Records since 2000
- 1,369
Yellow Oat-grass
- Group
- Flowering plants
- Peak month
- June
- Records since 2000
- 2,868
Yellow Pimpernel
- Group
- Flowering plants
- Peak month
- May
- Records since 2000
- 5,601
Yellow pot beetle
- Group
- Beetles
- Peak month
- July
- Records since 2000
- 570
Yellow Saxifrage
- Group
- Flowering plants
- Peak month
- July
- Records since 2000
- 1,231
Yellow sea-squirt, Tube sea-squirt, Sea vase
- Group
- Sea squirts
- Peak month
- June
- Records since 2000
- 4,422
Yellow Shell
- Group
- Butterflies and moths
- Peak month
- August
- Records since 2000
- 6,476
Yellow skirt slug
- Group
- Molluscs
- Peak month
- June
- Records since 2000
- 143
Yellow Slug
- Group
- Molluscs
- Peak month
- September
- Records since 2000
- 705
Yellow spotted sedge
- Group
- Caddisflies
- Peak month
- May
- Records since 2000
- 2,862
Yellow Stagshorn
- Group
- Fungi
- Peak month
- October
- Records since 2000
- 2,416
Yellow Stainer
- Group
- Fungi
- Peak month
- October
- Records since 2000
- 696
Yellow Star-of-Bethlehem
- Group
- Flowering plants
- Peak month
- March
- Records since 2000
- 295
Yellow Starry Feather-moss
- Group
- Mosses
- Peak month
- July
- Records since 2000
- 4,629
Yellow swamp brittlegill
- Group
- Fungi
- Peak month
- September
- Records since 2000
- 455
Yellow Thread-moss
- Group
- Mosses
- Peak month
- November
- Records since 2000
- 500
Yellow Vetchling
- Group
- Flowering plants
- Peak month
- June
- Records since 2000
- 125
Yellow Water-lily
- Group
- Flowering plants
- Peak month
- July
- Records since 2000
- 1,971
Yellow-barred Brindle
- Group
- Butterflies and moths
- Peak month
- August
- Records since 2000
- 2,078
Yellow-barred Long-horn
- Group
- Butterflies and moths
- Peak month
- June
- Records since 2000
- 1,205
Yellow-billed Loon
- Group
- Birds
- Peak month
- April
- Records since 2000
- 826
Yellow-bowed Smoothwing
- Group
- True flies
- Peak month
- July
- Records since 2000
- 591
Yellow-browed Warbler
- Group
- Birds
- Peak month
- October
- Records since 2000
- 13,959
Yellow-faced bell moth
- Group
- Butterflies and moths
- Peak month
- May
- Records since 2000
- 1,393
Yellow-faced Blowfly
- Group
- True flies
- Peak month
- July
- Records since 2000
- 789
Yellow-faced Fly
- Group
- True flies
- Peak month
- July
- Records since 2000
- 1,856
Yellow-flowered strawberry
- Group
- Flowering plants
- Peak month
- May
- Records since 2000
- 347
Yellow-girdled Brusheye
- Group
- True flies
- Peak month
- August
- Records since 2000
- 947
Yellow-juiced Poppy
- Group
- Flowering plants
- Peak month
- June
- Records since 2000
- 149
Yellow-legged Black
- Group
- True flies
- Peak month
- July
- Records since 2000
- 1,534
Yellow-legged Black Legionnaire
- Group
- True flies
- Peak month
- July
- Records since 2000
- 777
Yellow-legged Gull
- Group
- Birds
- Peak month
- August
- Records since 2000
- 31,327
Yellow-legged Water-snipefly
- Group
- True flies
- Peak month
- May
- Records since 2000
- 540
Yellow-line Quaker
- Group
- Butterflies and moths
- Peak month
- October
- Records since 2000
- 1,222
Yellow-line Quaker
- Group
- Butterflies and moths
- Peak month
- October
- Records since 2000
- 466
Yellow-necked mouse
- Group
- Mammals
- Peak month
- July
- Records since 2000
- 232
Yellow-rattle
- Group
- Flowering plants
- Peak month
- June
- Records since 2000
- 9,710
Yellow-ringed carpet
- Group
- Butterflies and moths
- Peak month
- July
- Records since 2000
- 99
Yellow-spot Tortrix
- Group
- Butterflies and moths
- Peak month
- June
- Records since 2000
- 1,507
Yellow-tail
- Group
- Butterflies and moths
- Peak month
- July
- Records since 2000
- 2,710
Yellow-tail
- Group
- Butterflies and moths
- Peak month
- July
- Records since 2000
- 605
Yellow-vetch
- Group
- Flowering plants
- Peak month
- June
- Records since 2000
- 62
Yellow-winged darter
- Group
- Dragonflies and damselflies
- Peak month
- July
- Records since 2000
- 294
Yellow-wort
- Group
- Flowering plants
- Peak month
- June
- Records since 2000
- 2,540
Yellowhammer
- Group
- Birds
- Peak month
- May
- Records since 2000
- 147,352
Yellowing Curtain Crust
- Group
- Fungi
- Peak month
- October
- Records since 2000
- 756
Yellowing Knight
- Group
- Fungi
- Peak month
- October
- Records since 2000
- 463
Yellowish Fork-moss
- Group
- Mosses
- Peak month
- July
- Records since 2000
- 663
Yellowish planthopper
- Group
- True bugs
- Peak month
- July
- Records since 2000
- 1,092
Yellowleg Bonnet
- Group
- Fungi
- Peak month
- October
- Records since 2000
- 912
Yersinia enterocolitica
- Group
- Microorganisms and protists
- Peak month
- February
- Records since 2000
- 127
Ylodes conspersus
- Group
- Caddisflies
- Peak month
- July
- Records since 2000
- 82
Yoldiella philippiana
- Group
- Molluscs
- Peak month
- September
- Records since 2000
- 172
Yorkshire-fog
- Group
- Flowering plants
- Peak month
- June
- Records since 2000
- 29,834
Yponomeuta cagnagellus
- Group
- Butterflies and moths
- Peak month
- May
- Records since 2000
- 348
Yponomeuta plumbella
- Group
- Butterflies and moths
- Peak month
- August
- Records since 2000
- 57
Yponomeuta vigintipunctata
- Group
- Butterflies and moths
- Peak month
- July
- Records since 2000
- 53
Ypsolopha alpella
- Group
- Butterflies and moths
- Peak month
- August
- Records since 2000
- 54
Ypsolopha horridella
- Group
- Butterflies and moths
- Peak month
- August
- Records since 2000
- 55
Ypsolopha mucronella
- Group
- Butterflies and moths
- Peak month
- March
- Records since 2000
- 55
Ypsolopha nemorella
- Group
- Butterflies and moths
- Peak month
- July
- Records since 2000
- 70
Ypsolophus sequella
- Group
- Butterflies and moths
- Peak month
- August
- Records since 2000
- 421
Ypsolophus ustella
- Group
- Butterflies and moths
- Peak month
- June
- Records since 2000
- 677