Within- and between-year variation in the presence of individually marked Ruff <i>Calidris pugnax</i> at a stopover site during northward migration

Ruffs Calidris pugnax migrate from wintering areas in West-Africa and Europe tobreeding grounds in northern Eurasia, using stopover sites along the way. At onesuch stopover site in southwest Friesland (53°N, The Netherlands), we studiedvariation in the timing of individual stopover based on 6474 Ruffs colour-ringedin 2004–2012. 43% of males and 22% of females were recorded in the studyarea in March–May the years following marking. Minimal stopover duration ofreturning individuals showed substantial within-year heterogeneity. We distinguishedtwo classes: (1) ‘transient’ individuals were observed only on a singleday in the study area within a season (51% of observed males and 79% offemales), and (2) ‘staging’ individuals were observed on multiple days. Weobserved two seasonal peaks in the presence of transient Ruffs, typically coincidingwith the peak of arrival and departure of staging birds. Males known towinter in Europe were more likely to be observed in the study area and arrivedearlier than males of unknown winter origin (3.1 days and 3.7 days earlier fortransient and staging males, respectively), but departure was unrelated to winterorigin. Staging and transient females arrived later than males. Between-yearrepeatability of individual behaviour was low, and individuals did not significantlyadvance their arrival date over the course of years, in contrast with a pattern ofshifting arrival dates at the population level. The observation that a large proportionof Ruffs visit southwest Friesland for only a short stop suggests that manyindividuals rely on other sites for moulting and refuelling during spring migration.Resightings of marked individuals elsewhere in western Europe indicated thatthese sites are largely located between 51° and 54°N. Thus, during springmigration, Ruffs marked in southwest Friesland displayed high between- andwithin-individual variation in minimal stopover duration

Ruffs in rough times

De Kemphaan, Philomachus pugnax, een steltloper die in het binnenland van Eurasie broedt en in West Afrika overwintert is sterk in aantal afgenomen. Op basis van een lange termijn ring-terugvangprogramma in een belangrijke voorjaars pleisterplaats in de Noord-Nederlandse graslanden, wilden we inzicht verkrijgen in de mechanismen die de aantalsafname veroorzaakten. Noorwaarts trekkende Kemphanen die in Nederland pleisteren namen af van 20000 in eind 1990 tot 5000 in 2008, waarna hun aantal stabiliseerde. De restpopulatie is heterogeen. De meeste kemphanen overwinteren in draslanden ten zuiden van de Sahara en gebruiken gedurende de trek naar het noorden waarschijnlijk landbouwgrond en rijstvelden, zij vliegen niet linea recta terug. Voor de kleine populatie mannen die in Europa overwintert is Nederland ook een belangrijke pleisterplaats. Lagere jaarlijkse overleving van de meest aan Nederland trouwe vrouwelijke pleisteraars suggereren selectieve sterfte van vrouwen, mogelijk door kwetsbaarheid voor de jacht in Afrika en veranderende landbouwpraktijken langs hun trekweg. De intensivering van het graslandbeheer heeft repercussies voor de opvetsnelheid van Kemphanen in alle fasen van hun trek. Lokaal hebben we een verschuiving van de fourageergebieden van de Kemphanen vastgesteld richting nieuw gecreëerd binnenlands drasland. We toonden aan dat Kemphanen daar graag voedselzoeken, en dat ze gedurende de dag visuele stimuli gebruiken om regenwormen in de bovenste laag van de bodem te detecteren. Regenwormen, maar ook insecten bepalen waarschijnlijk in belangrijke mate de haalbare opvetsnelheid voor de Kemphaan. Daarom is duurzaam beheer van land en water cruciaal voor de bescherming van de Kemphaan en andere binnenlandse trekkende steltlopers

Using multistate recapture modelling to assess age-specific bottlenecks in breeding success: a case study in the greater flamingo Phoenicopterus roseus.

9 pagesInternational audienceBird reproductive performance often increases with age or experience as a result of improved foraging skills, increased reproductive effort, improved coordination between partners, or a selection process. However, it remains unclear whether age and/or experience affect equally the successive steps of the breeding process, from egg laying to incubation and chick rearing. Using data from a long-term study of the Camargue (southern France) population of the greater flamingo Phoenicopterus roseus, we studied the influence of age on step-specific breeding performances during a single breeding season. We used, for the first time, multistate recapture models to evaluate the effect of age on breeding attendance (as a surrogate for breeding success) during incubation, early chick rearing and late chick rearing. Our results show a significant positive influence of age on breeding attendance, but only during the incubation period. Older parents had a higher probability than younger ones of completing incubation, whereas after the chick had hatched, the influence of parental age on breeding attendance was no longer significant. Although a high rate of nest desertion by younger flamingos during the middle of the incubation period coincided with a period of heavy rainfall, including rainfall level as a covariate did not improve the fit of the models. We discuss our results in relation to the evolution of life-history strategies in long-lived bird species and the influence of environmental instability

Female migration phenology and climate conditions explain juvenile Red Knot (Calidris canutus rufa) counts during fall migration

The management of avian populations at risk requires accurate estimates of vital rates across age and sex classes to effectively identify the most vulnerable demographic and support conservation actions. In the endangered Red Knot (Calidris canutus rufa), there are relatively few reliable estimates of reproductive success because they breed in such low densities across such a large and relatively inaccessible area in Arctic Canada. The purpose of this study is to test whether a migratory time lag between adult male and female knots during post-breeding southbound migration could be a reliable index of reproductive success for this species. If so, we expected to find a positive relationship between a time lag in male migration and the number or proportion of juveniles present at the same fall migration site. To test this hypothesis, we analyzed 13 years of capture-mark-recapture and census data from an important staging area during southbound migration. We found a strong and consistent age and sex-specific chronology; median passage dates for females were approximately 2 weeks earlier than males, with juveniles following 1 month later than adults of both sexes. For most years, there was a significant time lag of up to 27 days between females and males. However, we found no evidence to support that this time lag explained variation in the number of juveniles at the stopover site each year. Instead, we found that the timing of female migration along with an index of environmental conditions on the breeding grounds and during migration best described the proportion of juveniles present during migration. Overall, our results cast doubt on the reliability of the male migratory time lag as an indicator of breeding success

Microsatellites genotypes

Microsatellites genotypes of 891 individual house sparrows (Passer domesticus) at 10 loci. Details of genotype matrix see ReadMe file