Bird ringing and nest recording in Britain and Ireland in 2018

This is the 82nd annual report of the British Trust for Ornithology’s Ringing Scheme, incorporating the report of the Nest Record Scheme and covering work carried out and data processed in 2018. We reviewed the literature on tracking devices to assess the impact of their use on individual birds. More than 3400 studies were identified, the first dating back to the early 1960s. The ecological questions being studied varied, with migration being the most common study subject. The frequency of effects was significantly related to attachment type and the likelihood of adverse effects was related to device weight. The proportion of studies reporting adverse effects has declined over time and the research highlighted the need for systematic documentation of potential effects. NRS and CES data were used in a collaborative study which investigated mismatches between the timing of breeding for 21 British songbirds and the availability of food for their chicks. Results indicate that birds did breed later in warmer springs relative to the timing of spring; however, this did not have a significant impact on long-term breeding success. In 2018, 135 CE sites submitted data. Long-term (1984–2017) declines in abundance were observed in six migrant, one partial migrant and three resident species while long-term increases in abundance continue to be recorded in two short-distance migrants and four resident species. Seven species are exhibiting significant long-term declines in productivity; only two species, Reed Warbler Acrocephalus scirpaceus and Chaffinch Fringilla coelebs, are exhibiting a significant long-term increase in productivity. Long-term trends in survival indicate increases for 12 species and declines for eight. Compared to the five-year mean (2013–17), the abundance of 14 species decreased significantly in 2018 with five species being recorded in lower numbers than in any previous year since CES monitoring began. No significant increases in abundance were recorded. Productivity increased significantly for six migrant and four resident species in 2018 and decreased for only two species (both residents). Significant declines in survival rates were observed in 10 species in 2018 compared to the five-year mean. The number of Retrapping Adults for Survival submissions fell slightly in 2018 to 190; eight projects ran for the first time. In total, 58 species were monitored, with Pied Flycatcher Ficedula hypoleuca (23 projects), House Sparrow Passer domesticus (18), Starling Sturnus vulgaris (17), Sand Martin Riparia riparia (13) and Reed Warbler (10) the most-studied species. A total of 982 858 birds were ringed during the year, comprising 170 619 nestlings, 465 610 first-year birds, 319 955 adults (birds in their second calendar year or older) and 26 674 birds whose age could not be determined. In addition, there were 236 314 recaptures of ringed birds at or near the ringing site. In total, 54 324 recoveries (birds found dead, recaptured or resighted at least 5 km from the place of ringing) of BTO-ringed birds were reported in 2018. The Appendix highlights a selection of recoveries that have extended our knowledge of movements, as well as longevity records established during the year. A total of 38 269 NRS submissions were received in 2018, the lowest total since 2009. Mean laying dates for four species were significantly earlier than the five-year mean (2013–17) with eight of the 52 species analysed laying significantly later. Eight species displayed a significant increase in breeding success (fledglings per breeding attempt) in 2018 compared to the five-year mean, with one decreasing significantly. Permits or licences to disturb breeding birds on Schedule 1 of the Wildlife and Countryside Act 1981 (as amended), were prepared and issued to 502 ringers and nest recorders in 2018. During 2018, the use of special methods was authorised for 557 marking projects, 66 trapping projects and 52 sampling projects.