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Manipulation of clutch size during incubation has been used in a number of studies to investigate life‐history costs of incubation. We increased or decreased clutches of Common Terns Sterna hirundo during incubation and measured subsequent chick growth and productivity. Our results provide little support for the hypothesis that costs of incubation in Common Terns are substantially affected by the...
Several hypotheses have been proposed to account for the adaptive evolution of personality, defined as inter‐individual differences in behaviour that are consistent over time and across situations. For instance, the ‘pace‐of‐life syndrome’ hypothesis suggests that personality evolved as a behavioural correlate of life‐history trajectories that vary within populations. Thus, proactivity, corresponding...
Seasonal fecundity is a composite metric that is determined by component parameters such as clutch size, nest survival and re‐nesting probability. Many of these component parameters are known to vary with environmental conditions, in particular rainfall prior to or during the breeding season. In some species, seasonal fecundity is positively related to rainfall, but little is known about which component...
We report on an 11‐year study of floater interference in a population of Spanish Imperial Eagles Aquila adalberti. We analysed changes over the years in the productivity of 15 territories to test predictions of two hypotheses of density‐dependent productivity in relation to the presence of floaters (birds without territories). According to the ‘interference' hypothesis, the frequency of intrusion...
Body size strongly influences fitness, with larger individuals benefiting in terms of both greater productivity and survivorship; for reverse sexual size dimorphic (RSD) species, this relationship may be more complex. We examined the selection pressures acting on body size in male and female Merlins Falco columbarius to assess whether larger or smaller individuals of this RSD species were favoured...
Key demographic parameters often show substantial annual variation that can have important consequences for rates of population growth. Since 2011 we have conducted annual estimates of the productivity of Icelandic Black‐tailed Godwits Limosa limosa islandica over a large part of their breeding range. During this period, a volcanic eruption resulted in extensive dust deposition across the region....
Respiratory cryptosporidiosis was first diagnosed in Red Grouse Lagopus lagopus scotica, the UK subspecies of Willow Ptarmigan, in 2010. In the next 3 years, respiratory infection by Cryptosporidium baileyi had manifested itself in Grouse on half the moors in northern England and 80% of moors in the North Pennine Hills. In this first account of the impact of respiratory cryptosporidiosis on the population...
Two hypotheses have been proposed to link population regulation to density‐dependent changes in demographical parameters: the habitat heterogeneity hypothesis (HHH) states that, as population density rises, an increasing proportion of individuals are forced to occupy low‐quality territories, which provokes a decline in average per‐capita survival and/or productivity although some individuals show...
Density‐dependence effects acting on fecundity can be explained by two competing hypotheses. The individual adjustment hypothesis (IAH) states that, as population density increases, interference among individuals negatively affects their breeding performance. The second hypothesis, the habitat heterogeneity hypothesis (HHH), proposes that, as more individuals occupy the space available, lower quality...
Many hirundine (swallows and martins) species are declining throughout their ranges. The Common House Martin Delichon urbicum is a migratory hirundine that breeds throughout Europe but has shown recent declines in some parts of the UK, particularly in the south. We conducted a large‐scale citizen science survey to assess how the breeding performance of House Martins, measured by the number of attempted...
Old World vultures are experiencing dramatic population declines and now are among the species most threatened with extinction. Understanding the environmental variables that can influence the reproductive indexes of vulture populations can facilitate both habitat and species management. The aim of this study was to identify which environmental variables primarily affect the breeding successes of...
The European population of Eurasian Curlew Numenius arquata arquata, a near‐threatened wader subspecies, has undergone pronounced population declines over the past 30 years. To assess the demography and viability of its global population, we surveyed studies quantifying demographic rates (productivity and survival) and complemented this review with new estimates of survival probability at the flyway...
Recent insect abundance declines may have affected populations of insectivorous bird species but evidence for this is limited. Here, we use spatially overlapping 29‐year time‐series of aerial insect biomass and Barn Swallow Hirundo rustica numbers and breeding success from southern England to model the association between changes in invertebrate prey abundance, Swallow productivity and population...
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