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.

Using a Random Forest Model and Public Data to Predict the Distribution of Prey for Marine Wildlife Management

Abstract: Modern wildlife management relies on studies investigating the distribution patterns and habitat selection of wildlife at appropriately large scales for decision-making. One important aspect to consider in the assessment of habitat suitability and the underlying mechanism of animal distribution is the spatial distribution of their food resources. In marine areas, where many mammal and bird species occur over large spatial scales, the analysis of habitat use and distribution patterns requires information on the distribution of food resources at appropriately large scales (Huettmann and Diamond 2006). An important food resource for several species of marine birds and mammals are invertebrate organisms that live on the bottom of the sea and are collectively described as the benthos, a community that is especially productive and diverse at high latitudes (Carey 1991; Piepenburg 2005; Starmans et al. 1999). The distribution and productivity of benthic foragers such as ice seals, walrus (Odobenus rosmarus), sea ducks (Somateria spp., Melanitta spp.), and gray whales (Eschrichtius robustus) is influenced by the distribution of accessible benthic prey resources (Kaiser et al. 2006; Lovvorn et al. 2003; Moore et al. 2003). Benthic invertebrates thus form a key component in the trophic structure of marine ecosystems, and the distribution of marine benthic invertebrates is of major interest to wildlife managers (Solan et al. 2004). Most of the species mentioned above are of management concern, and either are (Spectacled Eider, Somateria fischeri; Steller's Eider, Polysticta stelleri) or have been proposed (walrus, ice seals) to be listed as ‘threatened’. Therefore, the identification and delineation of critical habitat providing sufficient food resources for these species will become extremely important in the near future.

The impact of raptors on the abundance of upland passerines and waders

Abstract: The issue of predator limitation of vertebrate prey populations is contentious, particularly when it involves species of economic or conservation value. In this paper, we examine the case of raptor predation on upland passerines and waders in Scotland. We analysed the abundance of five wader and passerine species on an upland sporting estate in southern Scotland during an eight-year period when hen harrier, peregrine and merlin numbers increased due to strict law enforcement. The abundance of meadow pipit and skylark declined significantly during this time. Golden plover also showed a declining trend, whereas curlew increased significantly and there was a near significant increase in lapwings. Contrasting the local population trends of these species with trends on nearby areas revealed higher rates of decline for meadow pipit and skylark at the site where raptors increased, but no differences in trends for any of the three wader species. There was a negative relationship between the number of breeding harriers and meadow pipit abundance the same year and between total annual raptor numbers and meadow pipit abundance. Predation rates of meadow pipit and skylark determined from observations at harrier nests suggested that predation in June was sufficient to remove up to 40% of the June meadow pipit population and up to 34% of the June skylark population. This ‘quasi-natural’ experiment suggests that harrier predation limited the abundance of their main prey, meadow pipit, and possibly the abundance of skylark. Thus, high densities of harriers may in theory reduce the abundance of the prey species which determine their breeding densities, potentially leading to lower harrier breeding densities in subsequent years. We found no evidence to suggest that raptor predation limited the populations of any of the three wader species. We infer that concerns over the impact of natural densities of hen harriers on vulnerable upland waders are unjustified.

Differential survival throughout the full annual cycle of a migratory bird presents a life-history trade-off.

Abstract: Long-distance migrations are among the most physically demanding feats animals perform. Understanding the potential costs and benefits of such behaviour is a fundamental question in ecology and evolution. A hypothetical cost of migration should be outweighed by higher productivity and/or higher annual survival, but few studies on migratory species have been able to directly quantify patterns of survival throughout the full annual cycle and across the majority of a species' range. Here, we use telemetry data from 220 migratory Egyptian vultures Neophron percnopterus, tracked for 3,186 bird months and across approximately 70% of the species' global distribution, to test for differences in survival throughout the annual cycle. We estimated monthly survival probability relative to migration and latitude using a multi-event capture-recapture model in a Bayesian framework that accounted for age, origin, subpopulation and the uncertainty of classifying fates from tracking data. We found lower survival during migration compared to stationary periods (β = -0.816; 95% credible interval: -1.290 to -0.318) and higher survival on non-breeding grounds at southern latitudes (<25°N; β = 0.664; 0.076-1.319) compared to on breeding grounds. Survival was also higher for individuals originating from Western Europe (β = 0.664; 0.110-1.330) as compared to further east in Europe and Asia, and improved with age (β = 0.030; 0.020-0.042). Anthropogenic mortalities accounted for half of the mortalities with a known cause and occurred mainly in northern latitudes. Many juveniles drowned in the Mediterranean Sea on their first autumn migration while there were few confirmed mortalities in the Sahara Desert, indicating that migration barriers are likely species-specific. Our study advances the understanding of important fitness trade-offs associated with long-distance migration. We conclude that there is lower survival associated with migration, but that this may be offset by higher non-breeding survival at lower latitudes. We found more human-caused mortality farther north, and suggest that increasing anthropogenic mortality could disrupt the delicate migration trade-off balance. Research to investigate further potential benefits of migration (e.g. differential productivity across latitudes) could clarify how migration evolved and how migrants may persist in a rapidly changing world.

The effects of rainfall on different components of seasonal fecundity in a tropical forest passerine

Abstract: Seasonal fecundity is a composite metric that is determined by component parameterssuch as clutch size, nest survival and re-nesting probability. Many of these componentparameters are known to vary with environmental conditions, in particular rainfall priorto or during the breeding season. In some species, seasonal fecundity is positively relatedto rainfall, but little is known about which component parameters of seasonal fecundityrespond most strongly to rainfall. We used intensive nest monitoring of a multi-broodedtropical forest passerine, the Montserrat Oriole Icterus oberi, to examine the effects ofrainfall during the pre-breeding season on component parameters of annual fecundity.We monitored all nests of a total of 42 pairs over 5 years in which rainfall varied sub-stantially. We then related clutch size, nest survival, onset and length of the breedingseason, re-nesting probability and re-nesting interval to pre-breeding season rainfall usinggeneralized linear mixed models that accounted for random variation across sites andindividual pairs, and incorporated other variables known to affect the response. Higherpre-breeding season rainfall led to an increase in clutch size and a decrease in re-nestinginterval, but nest survival, re-nesting probability and length of the breeding season werenot affected by variation in rainfall. The onset of the breeding season was delayed in verydry years. We conclude that higher rainfall is likely to increase food availability and thusbody condition of female Montserrat Orioles, leading to an increase in fecundity due tolarger clutch sizes.Keywords: clutch size, Heliconia, Icterus oberi, Montserrat Oriole, productivity, re-nesting.Seasonal fecundity, defined as the number of off-spring produced by a female bird over a singlebreeding season, is a key demographic parameterthat affects the fitness of individuals and the statusof populations (Roper et al. 2010, Etterson et al.2011). Seasonal fecundity is determined by severaldistinct demographic processes acting in sequenceover a breeding season: the timing of breeding,clutch size, the survival of eggs and chicks, re-nestingprobability and interval, and the length of thebreeding season (Ricklefs & Bloom 1977). Many ofthese processes can respond to environmental varia-tion, such as changes in temperature or rainfall, butthe responses of different component parametersmay vary considerably over a given environmentalgradient (Mattsson & Cooper 2009). Thus, studiesthat relate variation in environmental conditions tovariation in just a single fecundity parameter maynot be sufficiently powerful to resolve the fitnessimplications of environmental variation (Mattsson& Cooper 2007, Etterson et al. 2011). Similarly,studies that demonstrate an effect of environmentalvariation only on overall fecundity are less informa-tive than those that identify those components ofthe reproductive process that are most affected byenvironmental variation.

Land sparing to make space for species dependent on natural habitats and high nature value farmland.

Abstract: Empirical evidence from four continents indicates that human food demand may be best reconciled with biodiversity conservation through sparing natural habitats by boosting agricultural yields. This runs counter to the conservation paradigm of wildlife-friendly farming, which is influential in Europe, where many species are dependent on low-yielding high nature value farmland threatened by both intensification and abandonment. In the first multi-taxon population-level test of land-sparing theory in Europe, we quantified how population densities of 175 bird and sedge species varied with farm yield across 26 squares (each with an area of 1 km2) in eastern Poland. We discovered that, as in previous studies elsewhere, simple land sparing, with only natural habitats on spared land, markedly out-performed land sharing in its effect on region-wide projected population sizes. However, a novel 'three-compartment' land-sparing approach, in which about one-third of spared land is assigned to very low-yield agriculture and the remainder to natural habitats, resulted in least-reduced projected future populations for more species. Implementing the three-compartment model would require significant reorganization of current subsidy regimes, but would mean high-yield farming could release sufficient land for species dependent on both natural and high nature value farmland to persist.