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This is the 81st 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 collected and processed in 2017. Demographic data contributed to several research studies during the year, including a review of the conservation status of Raven Corvus corax and the impacts of licensed control. This quantified the extent to which non-breeding birds could be removed without impacting overall population sustainability, as well as the data permitted, but noted that a better understanding of age-specific survival rates was required. Nest Record Scheme data contributed to a large-scale collaborative study investigating the impact that temperature and rainfall have on the timing of events throughout the annual cycles of 10 000 animal and plant species across different trophic levels. The results indicated that the speed of response was greatest at low trophic levels. Future changes under a range of emission scenarios were estimated; these results indicated that advances in timing would be greatest for primary consumers. A statistical method was developed, using nest record data, to quantify nest failure, taking into account uncertainties generated during data collection. The method was applied to Blackbird Turdus merula records to compare survival rates of nests in gardens with those in the wider countryside. Survival in suburban areas was found to be higher than in urban or rural areas, and nests survived better in wetter conditions across all habitats. In order to quantify any welfare impacts of capturing wild birds, we examined the frequency with which passerines were reported to have died either whilst in the net or during handling. Analyses of capture data submitted from 2005 to 2013 indicated that the average mortality rate is around 0.1%, and that this is consistent between years. Most fatalities occurred before individuals had been extracted from the nets and juveniles appeared to be at greater risk than adults. In 2017, 135 CE sites submitted data. Long-term (1984–2016) declines in abundance were observed in four migrant, one partial migrant and one resident species and concurrent increases in abundance continued to be recorded in two short-distance migrants and four resident species. There was no change to the 10 species which exhibited significant long-term declines in productivity; only one species, Chaffinch Fringilla coelebs, exhibited a significant long-term increase in productivity. Compared to the five-year mean (2012–16), the abundance of six species increased significantly in 2017; Treecreepers Certhia familiaris were seen in greater numbers in 2017 than in any other year since CES monitoring began. Conversely, the abundance of six species fell significantly in 2017, with Chaffinch and Greenfinch Chloris chloris numbers at their lowest since CES monitoring began. Productivity increased significantly for three species in 2017 and decreased for eight species. The only significant change in survival rates between 2017 and the five-year mean was for Wren Troglodytes troglodytes, although the survival rate for Song Thrush Turdus philomelos was at its highest. The number of Retrapping Adults for Survival submissions fell slightly in 2017 to 195; 11 projects ran for the first time. In total, 58 species were monitored, with Pied Flycatcher Ficedula hypoleuca (20 projects), House Sparrow Passer domesticus (16), Starling Sturnus vulgaris (15) and Sand Martin Riparia riparia (11) continuing to be the most-studied species. Once again, over a million birds (1 020 356) were ringed during the year, comprising 165 565 nestlings, 500 580 first-year birds, 321 945 adults (birds in their second calendar year or older) and 32 266 birds where the age could not be determined. In addition, there were 242 719 recaptures of ringed birds at or near the ringing site. In total, 41 049 recoveries (birds found dead, recaptured or resighted at least 5 km from the place of ringing) of BTO-ringed birds were reported in 2017. The Appendix highlights a selection of recoveries that have extended our knowledge of movements, as well as longevity records established during the year. NRS submissions in 2017 exceeded 4 0 000 for the eighth consecutive year, with a total of 43 570 records received. Mean laying dates for 22 species were significantly earlier than the five-year mean (2012–16) with none of the 52 species analysed laying significantly later. There was a significant increase in breeding success (fledglings per breeding attempt) for two species in 2017, 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 580 ringers and nest recorders in 2017. During 2017, the use of special methods was authorised for 584 marking projects and 67 trapping projects, a 4% decrease from 2016. [ABSTRACT FROM AUTHOR]

The article reports on the 2009 bird Ringing Scheme of the British Trust for Ornithology (BTO) covering Great Britain and Ireland to better understand population change. Due to low productivity in 2007 and 2008 and freezing winters, there were decreases in species such as Wren Troglodytes troglodytes, Sedge Warbler Acrocephalus schoenobaenus and Reed Warbler A. scirpaceus. The number of birds ringed was the highest recorded at 935,867 and recovery total was also high at 14,643.

The article presents a study which identifies some of the key opportunities and challenges that must be prioritized by large-scale bird-making programmes in the next 10 to 20 years in the British and Irish Ringing Scheme. It mentions various issues such as the global environmental change and disease control. It also states that the technologies for bird studies have capabilities to facilitate study designs that require fewer birds to be marked, and provides rapid collation, sharing, and analysis.

Understanding demography is critical for understanding the causes underlying population declines, and for initiating and monitoring policies to reverse them. A method of fitting demographic models directly to avian count data recorded at a sample of census sites is described. The model is applied to national and regional counts of Common Starling Sturnus vulgaris in Britain for the period 1965–2000. Starlings have declined markedly during this time and are now on the list of birds of highest conservation concern. Although there have been small changes in various aspects of breeding success over this time, the analysis shows that these are unlikely to have made much impact on the long-term status of the species. By incorporating estimates of survival, based upon recoveries of ringed birds, the model suggests that the pronounced national decline in Starling numbers since a period of stability in the 1970s is most likely to be due to changes in the survival of first-year birds. This narrows the candidate range of environmental factors which might influence the decline and implicates changes in resource availability. [ABSTRACT FROM AUTHOR]

Long-distance migrants have evolved complex strategies for the timing of their annual moult, fattening and migration cycles. These strategies are likely to vary at different stages of a bird's life. Ringing data on 6079 Grey Plovers Pluvialis squatarola, caught on the Wash, England, between 1959 and 1996, were analysed to relate migratory strategies to patterns of primary moult and body mass changes. Adults returning from breeding grounds had a shorter and delayed primary moult (duration 90 days, starting date 19 August) in comparison with over-summering birds (duration 109 days, starting date 5 June). Three categories of migrant adults were identified on the basis of primary moult and body mass: (1) birds which did not moult, but increased body mass and migrated further south; (2) birds which moulted 1–3 inner primaries, suspended moult, increased body mass and migrated; and (3) birds which completed or suspended moult and wintered locally. In birds of the second category, timing of primary moult and body mass increase overlapped. Among wintering birds, 38% were in suspended moult. Ninety-six per cent of birds that suspended moult at the beginning of winter were males and almost all completed moult in spring. Grey Plovers which left Britain in autumn had an average body mass of 280 g, enough to reach southern Morocco without refuelling. Both wintering adults and first-year birds showed a prewinter body mass increase, peaking in December. Adults had a synchronized premigratory body mass increase in May, which suggested a negligible presence of African migrants. The average departure mass for spring migration, estimated at 316 g, would allow birds to fly non-stop to the Siberian breeding grounds in western Taymyr. [ABSTRACT FROM AUTHOR]

The article focuses on British Trust for Ornithology's (BTO) addition of ringing totals for Great Britain and Ireland from 1909 onwards to the online ringing reports, in which data are available on the BTO website (www.bto.org/ringing). It states that the total number of birds ringed was recorded from 1909-1930, with no breakdown by age class. It also mentions that the grand total of birds ringed for the said countries were 1,819,057 millions.

The article discusses the effects of the winter season on the mortality rate of barn owls in Great Britain from 2008 to 2010. It mentions that this kind of bird experience a hard time finding food whenever there is snow and it also became prone to poor health conditions if it hunts during the day. According to the author, the season also decreases the chances that it will nest successfully in the months ahead.

The article reports that figures from the British Trust for Ornithology's (BTO) Constant Effort Sites Scheme (CES) showed the increase in birds ringed in Great Britain in 2009. About 920,000 birds were ringed in 2009. The increase in the number of birds ringed is also attributed to the rise in the number of ringers who joined the scheme.