Newly published research, carried out by staff at BTO Scotland, has investigated the response to wintering waterbirds to drones, and shown that they can be easily scared into flight by drone use. Drone use has increased sharply in recent years, facilitated by mass production and much-reduced retail prices. The mass proliferation of drones and the likelihood of commercial and recreational drone use taking place in proximity to wildlife creates a new and potentially significant source of disturbance to wild birds. Such disturbance causes birds to waste energy and reduces their feeding time. In extreme cases, birds might stop using an area altogether, and be forced to feed elsewhere, where feeding opportunities may be poorer or the risk of predation higher. This could be particularly harmful during the cold winter months. BTO scientists flew a commercially available quadcopter drone towards waterbird flocks in coastal, freshwater and arable farmland habitats. While one researcher flew the drone at a standardised speed and height towards the flock, another observed the flocks through a telescope to record any responses to the drone as it approached, including alarm calls, signs of heightened alert levels and taking flight. The results showed that larger flocks were more likely to take flight than smaller flocks, and large flocks also took flight at a greater distance from the drone than smaller flocks. This is probably because the larger the flock, the more likely there is to be a sensitive individual present – in almost all cases, once one bird had responded to the drone, the rest of the flock followed. Habitat type also had a strong effect on birds' responses to drones. Birds at inland lochs, which were already subject to lots of human activity, were very unlikely to respond to drone presence, while birds at coastal sites were more likely to respond. Birds in arable farmland were particularly sensitive – flocks feeding in this habitat are probably more susceptible to disturbance because of the need to be vigilant to potential predators. Britain hosts internationally important flocks of waterbirds outside the breeding season. While it has been thought that drones could be useful in monitoring their numbers, the disturbance caused by such monitoring would have to be carefully evaluated. If drone use were to become more frequent at important sites for our wintering waterbirds, and birds did not become accustomed to this novel form of disturbance, then the resulting increases in energy expenditure and stress would be likely to negatively affect their population. The results of this research could be used to help inform guidance and regulations on drone use in proximity to birds and other wildlife.

Climate change is now widely recognised as having a large impact on biodiversity, affecting species distributions at a large spatial scale. Previous BTO research has demonstrated a change in species’ ranges within Britain, with a shift northwards and, less frequently, towards higher altitudes. However, the importance of a species’ microclimate – the climate experienced by individual animals, which may be at a scale of metres or smaller – and changes is not well understood. New research led by the BTO has used data collected by volunteers taking part in the Breeding Bird Survey (BBS) to investigate the effect of microclimate on Meadow Pipits, a globally Red-listed, declining species with important populations concentrated in northern and western upland parts of the UK. Although it was already known that Meadow Pipits are more likely to be found on wet, cool, high-altitude slopes, this work quantified how strongly the species is associated to these locations. Crucially, the analyses also showed that microclimates which are typical of these locations have an even stronger influence on the Meadow Pipit presence than larger-scale (macro) climate has. This is probably linked to the abundance of their cranefly prey, which is positively associated with soil moisture and negatively associated with high summer temperatures. The importance of these analyses goes well beyond a statistical exercise. With increasing temperatures, the British macroclimate will become progressively unsuitable for this, and other, upland bird species. At lower elevations and latitudes, wet and northerly exposed slopes could become refuges where Meadow Pipits are able to persist, in a similar way to glacial relict species which only survive in enclaves surrounded by otherwise unsuitable environment. Understanding the importance of microclimate for Meadow Pipits and similar upland species has therefore strong implications for species’ conservation in the face of ongoing large scale climate change. Refuges consisting of areas of suitable microclimate could become the future focus for the conservation and protection of cold-adapted species that will be rapidly losing large areas with suitable macroclimate. This study of the humble Meadow Pipit not only adds to the evidence required to inform conservation in the UK, but by highlighting the importance of microclimate, is also relevant to the future conservation of many other mountain bird species around the world that are threatened by climate change.