Thomas McCabe: Britain Year List 2021 BOU, All records: Top Blockers Record(s) 1 to 67 of 67 total.
Seq.	Species	Scientific Name	Seen By Other Listers	Other Listers (%)	
1	Canada Goose	Branta canadensis	460	98.08	
2	Greylag Goose	Anser anser	449	95.74	
3	Mute Swan	Cygnus olor	461	98.29	
4	Shelduck	Tadorna tadorna	441	94.03	
5	Shoveler	Spatula clypeata	444	94.67	
6	Gadwall	Mareca strepera	442	94.24	
7	Mallard	Anas platyrhynchos	461	98.29	
8	Teal	Anas crecca	445	94.88	
9	Tufted Duck	Aythya fuligula	457	97.44	
10	Grey Partridge	Perdix perdix	294	62.69	
11	Pheasant	Phasianus colchicus	454	96.80	
12	Rock Dove (Feral Pigeon)	Columba livia	403	85.93	
13	Woodpigeon	Columba palumbus	463	98.72	
14	Collared Dove	Streptopelia decaocto	453	96.59	
15	Moorhen	Gallinula chloropus	458	97.65	
16	Coot	Fulica atra	456	97.23	
17	Oystercatcher	Haematopus ostralegus	448	95.52	
18	Lapwing	Vanellus vanellus	453	96.59	
19	Curlew	Numenius arquata	436	92.96	
20	Black-tailed Godwit	Limosa limosa	411	87.63	
21	Snipe	Gallinago gallinago	413	88.06	
22	Dunlin	Calidris alpina	418	89.13	
23	Common Tern	Sterna hirundo	407	86.78	
24	Bonaparte's Gull	Chroicocephalus philadelphia	107	22.81	
25	Black-headed Gull	Chroicocephalus ridibundus	460	98.08	
26	Mediterranean Gull	Ichthyaetus melanocephalus	366	78.04	
27	Herring Gull	Larus argentatus	457	97.44	
28	Great Black-backed Gull	Larus marinus	433	92.32	
29	Iceland Gull	Larus glaucoides	158	33.69	
30	Cormorant	Phalacrocorax carbo	457	97.44	
31	Little Egret	Egretta garzetta	444	94.67	
32	Cattle Egret	Bubulcus ibis	300	63.97	
33	Great White Egret	Ardea alba	387	82.52	
34	Grey Heron	Ardea cinerea	454	96.80	
35	Marsh Harrier	Circus aeruginosus	406	86.57	
36	Buzzard	Buteo buteo	457	97.44	
37	Tawny Owl	Strix aluco	364	77.61	
38	Kingfisher	Alcedo atthis	410	87.42	
39	Great Spotted Woodpecker	Dendrocopos major	443	94.46	
40	Kestrel	Falco tinnunculus	453	96.59	
41	Magpie	Pica pica	460	98.08	
42	Rook	Corvus frugilegus	453	96.59	
43	Carrion Crow	Corvus corone	460	98.08	
44	Raven	Corvus corax	415	88.49	
45	Coal Tit	Periparus ater	446	95.10	
46	Blue Tit	Cyanistes caeruleus	463	98.72	
47	Great Tit	Parus major	461	98.29	
48	Bearded Tit	Panurus biarmicus	299	63.75	
49	Skylark	Alauda arvensis	440	93.82	
50	Sand Martin	Riparia riparia	426	90.83	
51	Swallow	Hirundo rustica	437	93.18	
52	Cetti's Warbler	Cettia cetti	387	82.52	
53	Long-tailed Tit	Aegithalos caudatus	453	96.59	
54	Blackcap	Sylvia atricapilla	437	93.18	
55	Wren	Troglodytes troglodytes	458	97.65	
56	Nuthatch	Sitta europaea	431	91.90	
57	Starling	Sturnus vulgaris	458	97.65	
58	Blackbird	Turdus merula	462	98.51	
59	Robin	Erithacus rubecula	462	98.51	
60	Stonechat	Saxicola rubicola	432	92.11	
61	House Sparrow	Passer domesticus	458	97.65	
62	Dunnock	Prunella modularis	462	98.51	
63	Grey Wagtail	Motacilla cinerea	440	93.82	
64	Pied Wagtail	Motacilla alba	460	98.08	
65	Rock Pipit	Anthus petrosus	372	79.32	
66	Greenfinch	Chloris chloris	453	96.59	
67	Yellowhammer	Emberiza citrinella	407	86.78