First breeding record of the light-mantled sooty albatross (Phoebetria palpebrata) for the maritime Antarctic

The light-mantled sooty albatross is a medium-sized albatross with a circumpolar distribution in the Southern Ocean. The known breeding sites are restricted to Islands in sub-Antarctic latitudes close to the Antarctic convergence between 46° and 53°S. In the austral summer season 2008/2009 we discovered a new breeding colony with at least two confirmed and three probable nests at Fildes Peninsula, King George Island, South Shetland Islands, Antarctica (62°12′S, 59°01′W). The new breeding colony of light-mantled sooty albatross described here represents the southernmost breeding place of any albatross species ever recorded

Unexpected diversity in socially synchronized rhythms of shorebirds

The behavioural rhythms of organisms are thought to be under strong selection, influenced by the rhythmicity of the environment. Such behavioural rhythms are well studied in isolated individuals under laboratory conditions, but free-living individuals have to temporally synchronize their activities with those of others, including potential mates, competitors, prey and predators. Individuals can temporally segregate their daily activities (for example, prey avoiding predators, subordinates avoiding dominants) or synchronize their activities (for example, group foraging, communal defence, pairs reproducing or caring for offspring). The behavioural rhythms that emerge from such social synchronization and the underlying evolutionary and ecological drivers that shape them remain poorly understood. Here we investigate these rhythms in the context of biparental care, a particularly sensitive phase of social synchronization where pair members potentially compromise their individual rhythms. Using data from 729 nests of 91 populations of 32 biparentally incubating shorebird species, where parents synchronize to achieve continuous coverage of developing eggs, we report remarkable within-and between-species diversity in incubation rhythms. Between species, the median length of one parent's incubation bout varied from 1-19 h, whereas period length-the time in which a parent's probability to incubate cycles once between its highest and lowest value-varied from 6-43 h. The length of incubation bouts was unrelated to variables reflecting energetic demands, but species relying on crypsis (the ability to avoid detection by other animals) had longer incubation bouts than those that are readily visible or who actively protect their nest against predators. Rhythms entrainable to the 24-h light-dark cycle were less prevalent at high latitudes and absent in 18 species. Our results indicate that even under similar environmental conditions and despite 24-h environmental cues, social synchronization can generate far more diverse behavioural rhythms than expected from studies of individuals in captivity. The risk of predation, not the risk of starvation, may be a key factor underlying the diversity in these rhythms.</p

Unexpected diversity in socially synchronized rhythms of shorebirds

The behavioural rhythms of organisms are thought to be under strong selection, influenced by the rhythmicity of the environment1, 2, 3, 4. Such behavioural rhythms are well studied in isolated individuals under laboratory conditions1, 5, but free-living individuals have to temporally synchronize their activities with those of others, including potential mates, competitors, prey and predators6, 7, 8, 9, 10. Individuals can temporally segregate their daily activities (for example, prey avoiding predators, subordinates avoiding dominants) or synchronize their activities (for example, group foraging, communal defence, pairs reproducing or caring for offspring)6, 7, 8, 9, 11. The behavioural rhythms that emerge from such social synchronization and the underlying evolutionary and ecological drivers that shape them remain poorly understood5, 6, 7, 9. Here we investigate these rhythms in the context of biparental care, a particularly sensitive phase of social synchronization12 where pair members potentially compromise their individual rhythms. Using data from 729 nests of 91 populations of 32 biparentally incubating shorebird species, where parents synchronize to achieve continuous coverage of developing eggs, we report remarkable within- and between-species diversity in incubation rhythms. Between species, the median length of one parent’s incubation bout varied from 1–19 h, whereas period length—the time in which a parent’s probability to incubate cycles once between its highest and lowest value—varied from 6–43 h. The length of incubation bouts was unrelated to variables reflecting energetic demands, but species relying on crypsis (the ability to avoid detection by other animals) had longer incubation bouts than those that are readily visible or who actively protect their nest against predators. Rhythms entrainable to the 24-h light–dark cycle were less prevalent at high latitudes and absent in 18 species. Our results indicate that even under similar environmental conditions and despite 24-h environmental cues, social synchronization can generate far more diverse behavioural rhythms than expected from studies of individuals in captivity5, 6, 7, 9. The risk of predation, not the risk of starvation, may be a key factor underlying the diversity in these rhythms

Impact of Nesting Mortality on Avian Breeding Phenology: A Case Study on the Red-Backed Shrike (Lanius collurio)

The seasonal timing of avian reproduction is supposed primarily to coincide with favourable feeding conditions. Long-term changes in avian breeding phenology are thus mostly scrutinized in relation to climatic factors and matching of the food supplies, while the role of nesting mortality is largely unexplored. Here we show that higher seasonal mean daily mortality rate leads to a shift in the distribution of breeding times of the successful nests to later dates in an an open-nesting passerine bird, the red-backed shrike Lanius collurio. The effect appeared to be strong enough to enhance or counteract the influence of climatic factors and breeding density on the inter-annual variation in mean hatching dates. Moreover, the seasonal distribution of reproductive output was shifted to larger, or smaller, broods early in the season when the nesting mortality increased, or decreased, respectively, during the season. We suggest that population level changes in timing of breeding caused by a general advancement of spring and of the food supplies might be altered by the seasonality in nesting mortality. Hence, we argue that consideration of nesting mortality is of major importance for understanding long-term trends in avian phenology, particularly in species capable of renesting

Predators and predation rates of skylark <em>Alauda arvensis</em> and woodlark <em>Lullula arborea</em> nests in a semi-natural area in the Netherlands

Predation is a major cause of breeding failure in bird species with open nests. Although many studies have investigated nest predation rates, direct identification of nest predators is sporadic, especially in (semi-)natural habitats. We quantified nest success and identified nest predators in a population of Skylarks Alauda arvensis and Woodlarks Lullula arborea breeding in a protected semi-natural area dominated by heathland and different succession states of grassland on nutrient-poor soil in The Netherlands. We monitored 54 nests by means of continuous video surveillance to determine survival times and predators, and monitored another 44 nests without a camera. Fates of the 58 (40) Skylark (Woodlark) nests were: fledging 41(27), depredation 13 (12), egg desertion 1 (0) and nestling death 3 (1). The overall nest success of all monitored nests (58 (40), Mayfield estimate) was 33% (22%; all mortality factors considered) or 43% (25%; only depredation). Predators of Skylark nests were Red Fox Vulpes vulpes (5), Carrion Crow Corvus corone (1) and European Adder Vipera berus (1). Woodlark nests were depredated by Carrion Crow (2), Eurasian Jay Garrulus glandadus (1) and Red Fox (1). Results suggest that the main nest predators might differ between the two co-occurring lark species; Skylark nests located in more open sites were preyed upon mainly by Red Fox, while the main predators of Woodlark nests, located generally closer to trees, are corvids.</p

Predators and predation rates of skylark Alauda arvensis and woodlark Lullula arborea nests in a semi-natural area in the Netherlands

Predation is a major cause of breeding failure in bird species with open nests. Although many studies have investigated nest predation rates, direct identification of nest predators is sporadic, especially in (semi-)natural habitats. We quantified nest success and identified nest predators in a population of Skylarks Alauda arvensis and Woodlarks Lullula arborea breeding in a protected semi-natural area dominated by heathland and different succession states of grassland on nutrient-poor soil in The Netherlands. We monitored 54 nests by means of continuous video surveillance to determine survival times and predators, and monitored another 44 nests without a camera. Fates of the 58 (40) Skylark (Woodlark) nests were: fledging 41(27), depredation 13 (12), egg desertion 1 (0) and nestling death 3 (1). The overall nest success of all monitored nests (58 (40), Mayfield estimate) was 33% (22%; all mortality factors considered) or 43% (25%; only depredation). Predators of Skylark nests were Red Fox Vulpes vulpes (5), Carrion Crow Corvus corone (1) and European Adder Vipera berus (1). Woodlark nests were depredated by Carrion Crow (2), Eurasian Jay Garrulus glandadus (1) and Red Fox (1). Results suggest that the main nest predators might differ between the two co-occurring lark species; Skylark nests located in more open sites were preyed upon mainly by Red Fox, while the main predators of Woodlark nests, located generally closer to trees, are corvids