This report details pilot work in Wensleydale to test methods for involving farmers and gamekeepers in the survey and monitoring of breeding waders, and consider how such methods could be applied more widely.

The time that birds decide to breed has a strong impact upon the likely success of raising their young to independence. Pairs of birds will generally time egg laying to maximise the availability of food for their chicks. However, one of the strongest impacts of climate change so far has been to alter the timing of spring. In response to milder temperatures, flowers and insects are all appearing earlier than they used to. Songbirds struggling to match their timing to the changing climate could be facing population declines. To test this, BTO, in collaboration with The Woodland Trust, Rothamsted Research, Butterfly Conservation and the Centre for Ecology and Hydrology (CEH), have collated some of the most comprehensive long-term data on the timing of spring from across the UK. They have related changes in the timing of leaf and flower emergence as well as aphid, butterfly and moth emergence, to changes in the timing of egg-laying, tracked by the BTO/JNCC Nest Record Scheme. As expected, in warmer springs, birds do tend to breed late relative to the timing of spring. However, by using data from the BTO/JNCC ringing scheme to monitor changes in the number of fledglings produced by each species per year, the study’s authors found no evidence that these mismatched species were also suffering a long-term decline in breeding success. This suggests that the population declines observed in many British songbirds are not directly caused by the effect of mismatch on breeding success. These results significantly increase our understanding of the impacts of climate change upon birds by showing there is not a strong link between changes in the timing of spring and long-term trends in breeding success. The heroic efforts of thousands of volunteers recording information on birds, insects and plants were vital in providing the long-term data required to understand the impacts of climate change upon bird populations, and we thank them for their hard work and dedication.

There is growing use of full-spectrum bat detectors to survey bats and other taxa. When used in conjunction with call identification software and validation, these detectors have the potential to transform large-scale bat monitoring in the UK. However, there are several questions to be answered regarding how these detectors should be best deployed.

Responding to a request for information on the status of deer in Scotland, BTO researchers Dario Massimino and John Calladine analysed data on Red Deer and Roe Deer distribution and abundance, collected through the BTO/JNCC/RSPB Breeding Bird Survey. This research note describes the derivation of maps of abundance and change in abundance for the two species, from the late 1990s to the present day, and illustrates recent changes in distribution and abundance.

Research commissioned by Scottish Natural Heritage (SNH) and led by the British Trust for Ornithology (BTO) demonstrates the power of volunteers in helping to better understand the distribution of rare and vulnerable bat species. The Southern Scotland Bat Survey was a pioneering citizen science project run in 2016. It aimed to engage the public by allowing people to borrow bat monitoring equipment for a few days to record bat activity. This approach enables the collection of high-quality data on bats, from a wider range of sites, than could feasibly be achieved by professional researchers alone. Focusing on the southern third of Scotland, over 1,500 complete nights of bat recording were carried out across 715 one-kilometer squares, resulting in the collection of just under 400,000 bat recordings. Whilst data were collected for all bat species in the region, more detailed analyses were carried out on three species of bats, Leisler’s bat, noctule and Nathusius’ pipistrelle, because their preferred habitat and foraging behaviour make them particularly vulnerable to wind farms. Of the three species, Leisler’s bat and noctule were found to be more widespread and abundant than previously thought, although they remain localised and amongst the five most scarce species of bats in Scotland. Southern Scotland has one of the highest densities of wind farms in the country. The study has produced detailed data and mapping which will be invaluable in assisting decisions in the region, including assessing future onshore wind energy construction.