Skylarks Alauda arvensis
Portland, Dorset May 2005

The Skylark has declined hugely throughout the UK (see below for details), but on Portland a combination of protected land and low-intensity farming has resulted in a relatively healthy population. Breeding birds - there are thought to be between 30 and 40 pairs - are augmented by migrants, particularly in the autumn, and the beautiful song is heard as early as March if the weather is mild and sunny.

All photographs © Charlie Moores.

Of all the farmland birds that have declined over the last 25 years, perhaps none is missed more than the Skylark. Although this species has declined less in percentage terms than some others, its abundance means that the number the UK has lost (more than two million) is greater than for any other species.

The reasons for the decline of the Skylark have been the subject of intense research over the last few years.

This research has focused on cereal crops, because a high proportion of the UK’s Skylarks nest in such crops and because Skylark nests in cereals produce more chicks on average than nests in any other habitat. Territory densities are consistently higher in traditional spring-sown crops than in the autumn-sown crops that have largely replaced them. This may be due entirely to differences in crop structure: the taller, more developed swards of winter cereals hold lower densities of Skylark than shorter, patchier spring cereal swards. Furthermore, as crop height increases over the summer, territory densities fall. The reasons for this are likely to be related to the availability of safe nesting sites. As the sward becomes thicker and taller during the growing season, access to nests becomes more difficult and Skylarks increasingly build their nests in tramlines, the unsown tractor tracks that never develop a sward. Unfortunately, survival rates of nests on tramlines are less than half as good as those of nests built further into the crop, as tramline nests are easily found by predators. (Adapted from RSPB Science/Skylark Ecology)

In pastoral systems, the switch from hay to silage has increased nest mortality due to cutting during the nesting season. Early silage cutting not only destroys nests directly but also exposes ones that are left to predators. Reseeding of pastures with pure stands of rye grass reduces the diversity of insect prey. Intensive grazing of pasture and saltmarsh can create a sward that is too short for nesting Skylarks .

On the urban fringes, in particular, there has been a loss of grassland habitat to development and tree-planting. The loss of breeding Skylarks from at least one site in Darwen (Lancashire) followed amenity tree-planting to ‘improve the environment’.

Additionally, intensive use of agrochemicals on arable fields tends to diminish the skylarks’ food sources (weed seeds and insect prey), in turn reducing breeding success. (Adapted from Lancashire Biodiversity Action Plan/Skylark)

This once abundant and familiar species has declined by more than 50% since the 1970s and now has the following conservation listings:

• Europe: SPEC category 3 (depleted)
• UK: red (>50% population decline)
• Long-term trend: England - rapid decline

(For more information BTO: Bird trends 2004/Skylark)