Although it probably evolved to live on steppe grassland and salt marshes, the Skylark has long been the epitome of a farmland bird. Many non-birdwatchers who have never had a close-up view of a Skylark will know its distinctive, endlessly variable song as a cornerstone of farmland and the British countryside. Since widespread bird declines were identified in the 1990s, however, it has become emblematic in the cause of the recovery of the farmland environment.
A truly agricultural bird
Skylarks are characteristic of semi-natural grassland systems from sand dunes through heathland to marginal upland, but are most common in arable farmland, making use of the nesting cover and bare ground for feeding that crops themselves provide throughout the year. Males are highly territorial, using long song flights at high altitude to broadcast to rivals and potential mates because the open landscapes they prefer are devoid of high perches. The stamina required to sustain long song flights has led to song flight length being used as an “honest signal” of male quality by females, allowing male Skylarks to advertise themselves without bright plumage, so they have kept the cryptic, brown and streaked coloration that affords them protection from predators on the ground.
Although migratory in much of northern Europe, British breeding Skylarks are believed not to move far between seasons, although upland birds move to lower latitudes. They can then often begin to breed in March and continue into July, making up to three breeding attempts. In winter, they mostly use crop stubble and fallow fields, in which they forage for weed seed and spilled grain, often in large flocks. Throughout the year, the Skylark’s heritage as a steppe species is apparent in its avoidance of vertical structures, which restricts the suitability of farmland with a high density of hedgerows.
The standard-bearer of farmland bird decline
The Common Birds Census showed that the Skylark’s decline began in the late 1970s. Research at the time revealed an intriguing switch from eating seed in winter to eating more green shoots of winter-sown cereals; with the benefit of hindsight, perhaps an early warning of food shortages. A reduction in over-winter seed availability from the loss of over-wintered crop stubbles, plus the use of more efficient herbicides, meant fewer weed seeds were available in winter for seed-eaters like the Skylark. Autumn-sown crops also meant that the vegetation was generally too tall and too dense to allow skylarks to nest later in the season. Given usual rates of nest losses, this meant that they were unable to raise enough chicks to maintain stable populations. Such a role for breeding success in driving population change is unusual among farmland passerines.Knowledge of Skylark ecology is much better in the breeding season than in winter, chiefly because they are seldom ringed and still more rarely recovered or recaptured, whereas nests are quite easy to find. However, both the breeding success and winter food mechanisms above ultimately involved the shift from spring- to autumn-sown cereal crops, which transformed the landscape in the mid-1970s.
Agri-environment – a solution?
The Skylark’s decline led to widespread conservation concern and then to policy measures to allow recovery. To date, however, they have not worked. New management options have been introduced via agri-environment schemes, encouraging farmers to improve habitat quality for species like Skylark. Leaving stubbles unsprayed over winter – so enhancing weed seed availability, providing fallow land in spring for nesting and creating bare patches in crops to allow access for breeding birds are all supported by government funding.
So why has the decline continued? We do not yet know for sure, but there could be more than one reason. Firstly, many farmers do not like agri-environment management that interferes with crop production, so most tends to be along field edges – places that Skylarks avoid; fallows and bare patches are unpopular. Secondly, some options have not had the intended effects, perhaps concentrating birds and encouraging predators or diseases. Some recent changes in agri-environment schemes may not have taken effect yet, but a culture-shift amongst farmers about what makes “good farming” may be needed, along with more research into the reasons why some management is failing, without whichfewer and fewer people will see and hear this icon of the British countryside in the future.
How can I help?
Our new Farmland Bird Appeal will fund the next generation of research to improve the fortunes of farmland birds. We intend to investigate how Skylarks and other species, including predators, are using these farmland environments and how these have adapted since the measures were implemented. Find out more about how the research we plan to undertake to reverse the declines of farmland birds here.
What's next for our waders?
Recent BTO work focuses on understanding the variation in Curlew and other UK wader populations so that we can help suggest actions to conserve them.