Increasing species

Population changes of species for which our best long-term trend estimate from CBC/BBS (usually over 48 years) or from WBS/WBBS (a maximum of 40 years) shows an increase of more than 50% are shown in Table C1. There are 29 species listed, one more than in BirdTrends 2016; the increase for Coal Tit is now below the 50% cut-off, but the increases for Goldcrest and Robin are now both just above the cut-off. Twenty-two of the species have more than doubled their population size over the periods in which they have been monitored (22–48 years).

Table C1 Long-term population increases of greater than 50% from CBC/BBS (1967-2015) or WBS/WBBS (1975-2015), using the best survey for each species

Species Period
(yrs)
Source Change
(%)
Lower
limit
Upper
limit
Alert Comment
Buzzard 48 CBC/BBS England 792 477 1892    
Greylag Goose 22 WBS/WBBS waterways 512 166 1297    
Great Spotted Woodpecker 48 CBC/BBS UK 387 235 708    
Collared Dove 43 CBC/BBS UK 311 168 500    
Shelduck 31 CBC to 1999 300 94 787   Small sample
Blackcap 48 CBC/BBS UK 291 215 387    
Nuthatch 48 CBC/BBS UK 254 162 393    
Mute Swan 48 CBC/BBS UK 246 55 679    
Stock Dove 48 CBC/BBS England 212 111 347    
Green Woodpecker 48 CBC/BBS England 182 110 296    
Mallard 48 CBC/BBS UK 169 105 246    
Woodpigeon 48 CBC/BBS UK 160 36 462    
Canada Goose 34 WBS/WBBS waterways 159 42 560    
Coot 48 CBC/BBS UK 159 67 544    
Carrion Crow 48 CBC/BBS England 134 94 193    
Jackdaw 48 CBC/BBS UK 131 51 269    
Goosander 34 WBS/WBBS waterways 122 41 272    
Wren 48 CBC/BBS UK 114 87 142    
Goldfinch 48 CBC/BBS England 109 58 158    
Sparrowhawk 40 CBC/BBS England 108 37 281    
Chiffchaff 48 CBC/BBS UK 105 68 162    
Magpie 48 CBC/BBS UK 101 61 147    
Great Tit 48 CBC/BBS UK 99 76 127    
Long-tailed Tit 48 CBC/BBS England 97 40 186    
Reed Warbler 48 CBC/BBS UK 87 21 272    
Pheasant 48 CBC/BBS England 85 49 161    
Pied Wagtail 48 CBC/BBS UK 73 26 136    
Goldcrest 48 CBC/BBS England 56 -21 233    
Robin 48 CBC/BBS UK 50 35 64    

Table C1 is led by Buzzard, by a wide margin, but it should be noted that seven of the fastest-increasing species in this report are actually not included here, because their monitoring data cover too short a period. The UK's non-native population of Ring-necked Parakeets is estimated to have risen by 1455% (more than a 15-fold increase) over the 20 years 1995–2015. Arguably, however, this is more a conservation problem than a success! Mandarin Duck (+405%) is another fast-increasing non-native species. Unmitigated successes are the growth during 1995–2015, estimated through BBS, of Barn Owl (+217%), Gadwall (+131%) and the reintroduced Red Kite (+1231%). Little Egret has increased by almost 30-fold during 1995–2015. Though the trajectory has been moderated by recent cold-weather-related setbacks, attention should also be drawn to the rapid rise of Cetti's Warbler, a recently established native species, which CES now estimates to have increased by 1115% during 1990–2015.

Four groups stand out among the increasing species: corvids – especially Carrion Crow, Magpie and Jackdaw; doves – Collared Dove, Stock Dove and Woodpigeon; woodpeckers and other smaller species of woodland and gardens; and some waterbirds. Corvids appear to have benefited from changed gamebird management practices in recent years, and the larger doves from the increased acreage of brassica crops (particularly oilseed rape).

The majority of the third group are species primarily of woodland that are also common in gardens in some areas: Great Spotted Woodpecker, Green Woodpecker, Nuthatch, Blackcap, Wren, Great Tit, Long-tailed Tit and Robin. The reasons for these increases are presently unclear but may, in many cases, relate to improved feeding opportunities in gardens. Pied Wagtail has increased in numbers by 73% on CBC/BBS plots over 48 years, but declined by 61% on WBS/WBBS plots over the past 40 years, although the CBC/BBS index is likely to be most representative of the UK population as a whole. Reed Warbler, also an insectivore, has been expanding its range northwards and westwards and might be benefiting from climate change. Declines on CES plots suggest the benefits might not be universal, with the habitat quality in 'core' sites possibly decreasing, while warming climates facilitate the colonisation of new sites.

A number of species associated with freshwater habitats are becoming more abundant, although differences between their ecological requirements make it unlikely that the major causal factors are common to all. For Mallard, the CBC/BBS increase was matched by a WBS/WBBS increase of 181% over 40 years. The long-term increases recorded for Mute Swan on both CBC/BBS and WBS/WBBS plots are likely to be the result, at least in part, of banning the use of lead weights by anglers, which took effect in 1986. Greylag Goose, Shelduck, Canada Goose, Coot and Goosander are other wildfowl among this report's increasing species.

Two widespread raptors have shown remarkable recoveries from low population levels after the banning of certain poisonous farmland pesticides in the early 1960s, assisted by lower levels of illegal predator control. Buzzards increased in England by a remarkable 792% between 1967 and 2015, with a rapid increase of 59% over the last ten years alone. Sparrowhawks, too scarce for CBC to monitor until the mid 1970s, showed a 108% increase over the 40-year period from 1975 to 2015. However, their recovery appears to have been completed earlier than Buzzard's, with the population currently in shallow decline.

While Pheasant holds a place in this table, its increase in census data has been driven largely by the hugely increasing scale of releases of artificially reared poults for shooting, from which the corvids may also have benefited.