Corn Bunting

This species can be found on the following statutory and conservation listings and schedules.

UK Birds of Conservation Concern	Red listed
Species of European Conservation Concern	Least Concern
IUCN Red List of Threatened Species (global)	Least Concern
Schedule 1 license required (to disturb)	No
Birds Directive Annex 1	No
Listed on the Annexes of	Bern(III), NERC (41)

Following an earlier, historical decrease, Corn Buntings declined very steeply between the mid 1970s and mid 1980s, with local extinctions across large sections of their former range. The decline has continued, but at a reduced rate until around 2000, since when numbers have remained relatively stable but there have been no signs of recovery. There has been a decline across Europe since 1980 (PECBMS: PECBMS 2020a>), and the species has recently declined to extinction in Ireland (Taylor & O'Halloran 2002). Studies of the now isolated eastern Scottish population stress the importance of providing uncut or late-cut grasses or cereals, 30-100 cm tall, with a dense ground layer of weeds or crop vegetation, as nesting habitat (Perkins et al. 2015).

UK breeding population

-83% decrease (1967–2022)

Corn Buntings have undergone a severe population decline in many parts of Britain. In Ireland they ceased to breed in the late 1990s and none were recorded during the 2008–11 atlas. In 2007–11 the distribution in Britain was highly fragmented, with populations on the machair of Uists, arable farmland in northeast Scotland, on downland, chalk ridges and some arable farmland in south and central England. Many areas of superficially suitable arable farmland are no longer occupied.

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Occupied 10-km squares in UK

No. occupied in breeding season	596
% occupied in breeding season	20
No. occupied in winter	557
% occupied in winter	18

European Distribution Map

European Breeding Bird Atlas 2

Breeding Season Habitats

Most frequent in

Arable Farmland

Relative frequency by habitat

Relative occurrence in different habitat types during the breeding season.

In Britain the Corn Bunting's winter range has contracted by 27% since the 1981–84 Winter Atlas, and its breeding range by 56% since the 1968–72 Breeding Atlas. Losses in southern Scotland and northern England mean the remnant Scottish populations are highly isolated. Losses from the Northern Isles, Lewis, Coll and Tiree mean the only remaining island population is that in the machair of the Uists.

Corn Bunting is recorded throughout the year, although detections peak in late spring and summer when this late breeder is most easily seen and heard.

View a summary of recoveries in the Online Ringing Report.

Foreign locations of birds ringed or recovered in Britain & Ireland

View number ringed each year in the Online Ringing Report

Maximum Age from Ringing	8 years 1 months 21 days (set in 2014)
Typical Lifespan	3 years with breeding typically at 1 year
Adult Survival	0.58±0.04

Wing Length	Adults	96.3±5.3 | Range 89–104mm, N=545
	Males	101.2±2.4 | Range 97–105mm, N=249
	Females	91.6±2.2 | Range 88–95mm, N=265

Body Weight	Adults	47.4±6 | Range 39.1–57.4g, N=409
	Males	52.7±3.9 | Range 47.0–59.0g, N=182
	Females	42.5±2.9 | Range 37.4–47.3g, N=198

Feather measurements and photos on featherbase

Ring size	B+
Field Codes	2-letter: CB | 5-letter code: CORBU | Euring: 18820

For information in another language (where available) click on a linked name

Causes of change

Changes in farming practice are believed to have been responsible for declines, through impacts on reduced seed and/or invertebrate abundance. The demographic causes are unclear and there is conflicting evidence as to whether breeding or wintering effects have been the primary driver.

Further information on causes of change

Modelling suggests that climate change may have had a positive impact on the long-term trend for this species, resulting in less negative trends than would have occurred in the absence of climate change (Pearce-Higgins & Crick 2019).

National-scale evidence gives no indication of a historical role for breeding success, but there are contemporary local correlations between agricultural practices and breeding success, including a notable effect on numbers of breeding attempts. Causes of change may be different in different populations, as some of this species' breeding habitats are completely different and isolated from each other. There is no way to test for effects of survival. Conversely, it is easy to test for effects on breeding success, especially locally and with respect to contemporary as opposed to historical land-use. This leads to a big imbalance in the evidence available.

Breeding performance per nesting attempt increased considerably while population numbers were declining (Crick 1997, Siriwardena et al. 2000a), but it is also reported that fewer birds now raise a second brood, thus reducing productivity overall (Brickle & Harper 2002). More recent demographic data show curvilinear trends in nest failures at the chick stage and in clutch and brood sizes, but no trend in productivity per nesting attempt (see above). Ring-recovery sample sizes do not permit an analysis of survival rates, meaning that it is impossible to test for effects of survival (Siriwardena et al. 1998b, 2000a). Any decrease there has been in survival rates is probably a result of the reduction in winter seed availability that has followed from agricultural intensification (Donald 1997, Wilson et al. 2007). Donald & Evans (1994) found that 60% of Corn Buntings fed on winter stubbles, which were the only field type for which a consistent preference was detected.

Spring-sown cereals have been found to be a particularly important habitat for Corn Bunting (Brickle & Harper 2000, Fox & Heldbjerg 2008), and hence its reduction may have contributed to declines, as they provide long-lasting stubbles during the winter and abundant food in the form of surface grain when first sown. In the breeding season, spring cereals were among the most frequently used habitats for nesting and for collecting chick food; territory associations with overhead wires (for songposts) and fallow (positive in early summer, negative in late summer) became stronger in later years as the population declined (Perkins et al. 2012). A study in Germany, suggested that territories with mixed farming, including at least 10% fallow, and with song-posts, were favoured (Altewischeret al. 2016). Siriwardena et al. (2000b) provide evidence that mixed farming at the territory scale supported better breeding performance. However, Donald & Forrest (1995) found little evidence for breeding-season effects in their study using CBC data and suggest that numbers are more likely to have declined due to reduced winter food supplies resulting particularly from the loss of spring tillage, increased pesticide usage and improved harvesting and storage techniques.

A reduction in food availability has been implicated in the declines of this species. In arable-dominated areas in Scotland, Perkins et al. (2011) provide evidence showing that AES management (agri-environment schemes) that increased food availability reversed population declines. However, where a high proportion of Corn Buntings nested in grasslands, an additional AES option that delayed mowing was essential to achieving population increase. Setchfield et al. (2012) have further demonstrated that AES management of cereals can boost productivity and emphasise the importance of delayed harvest to the number and success of late nests. In a subsequent re-survey by Perkins et al. (2017), the study population remained stable, but a link between AES schemes and population trends could no longer be found; however one potential explanation for this was that positive effects of AES had affected a wider area including birds breeding on non-scheme farms.

As part of a PhD study, Brickle (1999) modelled the population dynamics of Corn Buntings in Sussex, concluding that productivity was the most likely cause of decline in the South Downs, also finding evidence of indirect effects of pesticides. Brickle & Harper (1999) identified the main food items of chicks, most of which have declined in abundance on lowland farmland (Campbell et al. 1997). Boatman et al. (2004) further analysed the data from Brickle et al. (2000) and found that arthropod abundance in the vicinity of the nest had a significant effect on the survival of broods, although this was based only on two years' data, whilst Ewald et al. (2002) found that densities of Corn Bunting were higher where the number of pesticide applications was low. Brickle et al. (2000) found that chick weight and nest survival at the nestling stage were respectively positively and negatively correlated with invertebrate food availability, and chick food abundance was negatively correlated with the number of insecticide applications to cereal fields. However, the authors state that the contribution of this reduction in breeding performance to the Corn Bunting's decline depends on the mortality rates for fledged chicks and older birds, information on which is sparse.

An experimental study by Setchfield & Peach (2016) found that nest site selection was influenced by crop density and that a disproportionate numbers of nests were close to field edges where regular seed sowing overlaps creating a denser sward. Nests close to the field edge are subject to high predation rates so they suggest that patches of denser sward should be deliberately created away from crop edges by double-drilling during sowing. Brickle & Harper (2002) found that, although predation accounted for the majority of nest failures in their Corn Bunting study population, there was a seasonal decline in the nest survival rate during incubation, which was largely due to increased losses through farming operations. Furthermore, they speculated that harvesting of cereal crops may reduce the availability of suitable breeding habitat late in the season, thus curtailing the length of the breeding season, and preventing double-brooding. A reduction in fecundity via these mechanisms provides one explanation for the collapse of the Corn Bunting population (Donald 1997, Brickle & Harper 2002). A more recent agri-enviroment scheme trail has confirmed that delayed mowing can increase nest success (Perkins et al. 2013).

Information about conservation actions

The sharp decline during the 1970s and 1980s is believed to be linked to agricultural intensification. However it is unclear whether breeding or wintering effects were the most important and therefore which conservation actions are most likely to benefit the Corn Bunting.

Actions to increase the availability of seeds during winter could help increase overwinter survival, and can be encouraged by policies within agri-environment schemes (Perkins et al. 2011; Setchfield et al. 2012). As well as the direct provision of supplementary food, they can also include other options such as the planting of wild bird seed cover mixes, the retention of stubble fields and the provision of semi-natural habitats, e.g. through the provision of buffer strips, conservation headlands or areas of set-aside and through less intensive farmland management practices.

During the breeding season, conservation actions should aim to provide nesting habitat and invertebrate prey for nestlings. Territories with mixed farming including at least 10% fallow were favoured in Germany (Altewischer et al. 2016) and mixed farms support better breeding performance in the UK (Siriwardena et al. 2000b) . Spring-sown cereals are a particularly important habitat (see Causes of Change section, above). Perkins et al. (2012) recommended the provision of weed-rich or under-sown spring cereals and winter barley along with late-cut hay and fallow areas. Corn Buntings prefer field boundaries without hedges but require other song posts (Mason & McDonald 2000) such as overhead wires (Perkins et al. 2012).

Other specific breeding season recommendations include: delaying mowing to prevent nest and habitat destruction (Brickle & Harper 2002; Perkins et al. 2013); reducing pesticide usage to increase invertebrate prey numbers (Brickle & Harper 1999; Ewald et al. 2002); deliberately creating patches of denser sward away from crop edges as Corn Buntings are currently nesting in denser sward at the edge of fields where they are more vulnerable to predators (Setchfield & Peach 2016); and providing sown arable field margins and nectar flower mixtures to provide foraging habitat (Burgess et al. 2015).