Currently non-native species are being introduced to countries at an unprecedented rate. These species can have severe detrimental effects on native biodiversity, human health and the economy. Due to population growth, increases in trade and tourism and global warming the likelihood of non-native species arriving and establishing in the UK will be higher in the future. A new study by BTO investigates whether it is possible to predict which non-native species are likely to establish in the UK based on the climate in their native range, thereby enabling early preventative action to be taken. Invasive species can have serious effects in their new home turf; they can be economically expensive, potentially cause health hazards, and they can have a large impact on the native biodiversity. Predicting whether invasive species are likely to colonise the UK is therefore an important priority. This study compared the suitability of the climate in the UK against the native range of 167 potentially invasive, or already established non-native bird species to see which species would be able to expand their range into the UK. Climate parameters that were used included temperature, precipitation and moisture. Values were used for both the current climate and the projected future climate. Results predicted that in the future, the UK climate will be suitable for more non-native species. Currently the UK climate was deemed suitable for 69 out of the 167 species included, but only 44 of those species actually currently occur in the UK. The results also showed that 85% of species that have colonised the UK successfully were found in climatically unsuitable areas. Many of these were usually found in areas that were wetter than their native range. In conclusion, there was no overall support that climate suitability is a reliable predictor of non-native bird species’ ranges, as there are many other contributing factors. Non-native populations are highly dependent on when and where introductions take place. Additionally, local availability of resources and competition with native flora and fauna may prevent establishment. Similarly, some birds which may not be climatically suited to the UK may be able to evolve rapidly to adjust to a different climate, or human influence (such as feeding) may provide them with the resources they need to survive. Regular surveying will be necessary to determine the effect climate change has on bird populations, and on where they may go in future.

The return of breeding Peregrines to former haunts, and the colonisation of urban sites such as industrial buildings and cathedrals, has not gone unnoticed by birdwatchers. It is only now, however, with the publication of the results from the latest national Peregrine survey, that we can put figures on the changing fortunes of this stunning bird of prey. The Peregrine breeding population in the UK and Isle of Man has been surveyed at intervals of 10 years since 1961/62. The first four surveys documented the recovery of the Peregrine population from the ‘crash’ of the 1960s (when numbers fell to less than half of the pre-war population) to the highest levels since recording began. The new national survey, carried out in 2014, sought to secure a new national population estimate and, in particular, to improve our knowledge of the species in lowland areas not traditionally regarded as being part of the Peregrine’s breeding range. The 2014 survey, co-ordinated by the BTO in partnership with many other raptor monitoring individuals and organisations, was made possible by the hard work of hundreds of volunteers. These fieldworkers surveyed a combination of known sites and randomly selected survey squares to secure evidence of occupation and breeding by Peregrines. The population estimate derived from the survey puts the UK Peregrine population at 1,769 breeding pairs, an increase of 22% on the previous survey (carried out in 2002). Most of the increase is accounted for by population growth in lowland England, with breeding Peregrines continuing to occupy new sites. Most of the inland breeding pairs utilise large cliffs, smaller crags or quarries, but an increasing proportion of pairs occupy man-made structures such as buildings, bridges, pylons and communication masks. Examination of the regional results reveals contrasting fortunes in Scotland, where there the population has declined overall. Worryingly, Peregrine populations are not doing well in the upland SPAs (Special Protection Areas) established to protect them, a pattern evident in both Scotland and northern England. Further losses of Peregrines from such areas might not pose a grave threat to the UK population, but could be important at a regional level. Possible factors associated with the poor performance of upland Peregrine populations may include prey abundance and availability, and illegal killing associated particularly with management of upland gamebirds for shooting, but also with recreational breeding and racing of domestic pigeons. Other factors may have affected Peregrine numbers at a local level; these include avoidance of Golden Eagles, oiling by Fulmars and exposure to a wide range of environmental pollutants. The findings of this survey provide an opportunity to investigate the effects of these and other issues, with complementary data sets – such as Bird Atlas 2007-11 or the RSPB’s data on upland land use – potentially of great value here.

A three-year study, supported by EDF Energy and the British Trust for Ornithology (BTO), has been able to identify that dry summer weather may be putting some of our favourite bird species at risk as it triggers a significant drop in the availability of earthworms close to the soil surface during the breeding season. The research was undertaken by thousands of schoolchildren in a nationwide science project to understand the effects of climate change on our soils and ecosystems, helping to inspire the next generation of ecologists. Nearly 15,000 school children from over 500 schools across the UK have been digging up small sections of their playing fields once a term in October, March and June, and counting and identifying the creatures they found living in the top 5cm of the turf. The results show that the invertebrate groups varied based on season and small-scale habitat factors. Earthworms were the most present group (93.1% of total invertebrate biomass) and were strongly associated with soil moisture, and therefore season. Other groups that were monitored included slugs and snails, woodlice, centipedes, spiders, beetles, ants, earwigs, Diptera larvae, beetle larvae and caterpillars, most of which became more common in spring and summer. The results suggest that climate change will not necessarily have large-scale impacts on soil invertebrate populations, but rather affect their availability through time. The project shows that large-scale citizen science at schools can be of tremendous value to scientific data collection. As the project continues, we hope to further expand our knowledge on the UK’s soil invertebrate communities with the help of schools across the country and link this knowledge to bird populations.

Ecology and Conservation of Forest Birds is a unique review of current understanding of the relationships between forest birds and their changing environments. Large ecological changes are being driven by forest management, climate change, introduced pests and pathogens, abiotic disturbances, and overbrowsing. Many forest bird species have suffered population declines, with the situation being particularly severe for birds dependent on attributes such as dead wood, old trees and structurally complex forests. With a focus on the non-tropical parts of the northern hemisphere, the text addresses the fundamental evolutionary and ecological aspects of forest birds using original data analyses and synthesising reviews. The characteristics of bird assemblages and their habitats in different European forest types are explored, together with the macroecological patterns of bird diversity and conservation issues. Ecology and Conservation of Forest Birds provides a valuable reference for ecologists, ornithologists, conservation professionals, forest industry employees, and those interested in birds and nature.

Large-scale population estimates of species are used for several reasons, including the assessment and protection of important sites. However, determining a national population requires extensive surveying and using methods that allow counts to be scaled up to the number of birds actually present and across a larger area. This new BTO study looks at different methods used to estimate the population of Nightingales in the UK. Nightingales have declined by 61% in the last 25 years and therefore determining which sites contain the largest populations is vital. The study focused on 2733 2x2 km squares, 2356 where Nightingales were known to be, as well as randomly-chosen squares whose selection was stratified based on habitat suitability. By using different analytical methods, the final population was estimated to be between 5094 and 5938 territorial males, of which only 55-65% were counted during the surveys. It is therefore important to consider how to fully control for variability in detection and for birds outside of surveyed areas when estimating national populations. The study also highlighted the importance of Lodge Hill SSSI for breeding Nightingales, which was designated for its nationally important population of the species, based on the results presented in this paper.

Initial findings suggest that Lesser Black-backed Gulls in north-west England fly within wind farms, but may avoid wind turbines once there. Offshore wind farms may affect birds in many ways, such as stopping them moving between places, or restricting access to areas where they feed. Collision risk is a key concern for seabirds, yet there has been little study to date of the use of wind farms by birds from known breeding colonies. This study, led by BTO, provides a first look at the movements of Lesser Black-backed Gulls at a colony in north-west England and their interaction with five operational offshore wind farms. The birds were tracked with GPS tags which recorded location, speed and height. Out of the 24 birds tracked, 15 visited wind farms, and in total spent 1.3% of their time there. A detailed look at the movements of two birds that visited wind farms most often, showed that their flight heights were greater within wind farms than outside, particularly during the day, potentially placing them at greater risk of collision. However, within wind farms, their use of the zone swept by the rotor blades was significantly less than expected. Although preliminary, these results suggest that Lesser Black-backed Gulls at this site may not avoid wind farms, but could avoid individual wind turbines once inside the wind farms. Further work is now being conducted to verify these patterns, which will be important in improving our understanding of the likely collision risk for seabirds.

A new paper, resulting from a collaborative study between BTO and Lancaster University showed that monitoring nests has no effect on daily survival rates of Whinchat nestlings. To ensure that monitoring efforts do not affect survival rate of nestlings and young birds, it is important to assess their impact. Nest monitoring could potentially lead predators to the nest or cause parents to desert or reduce parental care effort to their nestlings. This paper investigated 39 nests to determine whether monitoring has an adverse effect on daily survival rate in Whinchats at Salisbury Plain, Wiltshire. Nests were either visited only once upon their initial detection, or every two days during the incubation period. The visited nests did not have a lower survival rate than the non-visited nests, suggesting that there are no adverse effects of monitoring on incubation. During the nestling stage, the nests were monitored once a day on three consecutive days, by using a video camera to record the parents’ behaviour. This part of the study found that nest disturbance by setting up monitoring equipment temporarily reduced the feeding behaviour of the parents, but this only added up to 0.52% of total nestling time; a non-significant portion of the total time a nestling spends with its parents. In conclusion, this study found that monitoring Whinchat nests every two to three days has no negative effect on survival rate, and although birds can become slightly disturbed, they will soon resettle into normal behaviour. The authors emphasise that precautions to minimise potential impact on nests should always be taken and that guidelines for nest monitoring should always be adhered to.