Royal Society for the Protection of Birds

About: Royal Society for the Protection of Birds is a nonprofit organization based out in Sandy, United Kingdom. It is known for research contribution in the topics: Population & Biodiversity. The organization has 670 authors who have published 1425 publications receiving 88006 citations. The organization is also known as: RSPB & Plumage League.

Postfledging survival, movements, and dispersal of ring ouzels (turdus torquatus)

Abstract: . Recent evidence suggests that avian population growth rates may be constrained by low postfledging survival. Therefore, quantifying postfledging mortality and understanding the ecological factors that influence it are fundamental for assessing the relative importance of this life-history stage for population growth and identifying the ecological drivers of population dynamics. We radiotracked 110 juvenile Ring Ouzels (Turdus torquatus), a species of high conservation concern in the United Kingdom, to test hypotheses regarding the timing and causes of postfledging mortality and to quantify the timing and magnitude of local movements and dispersal. Juveniles fledged from early-season broods had higher survival during each 4-day period over 116 days postfledging (0.952 ± 0.011 [SE]) than juveniles fledged from late-season broods (0.837 ± 0.021). Most mortality occurred within the first 3 weeks postfledging, and predation by raptors and mammals was the main apparent cause of mortality, accounting fo...

Annual abundance of common Kestrels (Falco tinnunculus) is negatively associated with second generation anticoagulant rodenticides

Abstract: Rats and mice can damage food and agricultural products as well as transmit diseases, thereby requiring control of their numbers. Application of Second Generation Anticoagulant Rodenticides (SGARs) often reduces rodent numbers locally. However, predators eating rodents, including non-target species, that have consumed SGARs may be secondarily exposed and potentially lethally poisoned. Here we study whether SGARs may have contributed to the widespread population declines of a rodent-eating raptor, the Common Kestrel (Falco tinnunculus) in the UK. We show that 161 (66.8%) of the 241 Kestrels submitted for ecotoxicology tests between 1997 and 2012 had detectable levels of at least one SGAR in their livers. Adult Kestrels had significantly higher prevalence of SGARs than juveniles, suggesting accumulation of SGARs through time. The prevalence and concentrations of individual SGARs in Kestrels were significantly higher in England than in Scotland. SGAR prevalence in Kestrels were positively associated with some land cover types, primarily arable cereals and broad-leaved woodland, and negatively associated with mainly mean elevation, probably reflecting variation in SGAR usage across land cover types. By using volunteer-collected data on national Kestrel abundance 1997-2012, we show that there is a negative correlation between the Kestrel population index in a specific year and the concentration of bromadialone as well as the total SGAR concentration in the same year. Although correlative, this is the first study to provide evidence for a potential population-limiting effect of SGARs on a raptor.

Survival of chicks and adults explains variation in population growth in a recovering red grouse Lagopus lagopus scotica population

Abstract: Understanding demographic mechanisms is key to managing animal populations, both in conservation and game management. We examine which life-stages contributed most to population growth in a recovering red grouse Lagopus lagopus scotica population following restoration of management aimed at resuming economically viable harvesting. Demographic parameters derived from biannual grouse counts and from radio-tagged individuals were analysed using ‘standard demographic accounting’. When parameter estimates were based on counts, a combination of adult summer and winter survival appeared to contribute most to population change. When based on radio-tagged birds, deemed more reliable because of independence between parameters and years, adult summer survival and chick survival contributed most to population change. The contributions of clutch size, nesting success (i.e. the proportion of nests with ≥1 egg hatching) and hatching success (proportion of eggs hatching in successful nests) were negligible. Overall, the survival rate of adults and chicks contributed most to annual population change and reduced the rate of population recovery. Analysis of grouse carcasses found that 82% were associated with signs of predation or scavenging by raptors. Rates of juvenile production exceeded those of adult mortality, allowing modest population growth, but insufficient to resume economically viable harvesting.