African departure rather than migration speed determines variation in spring arrival in pied flycatchers

Properly timed spring migration enhances reproduction and survival. Climate change requires organisms to respond to changes such as advanced spring phenology. Pied flycatchers Ficedula hypoleuca have become a model species to study such phenological adaptations of long-distance migratory songbirds to climate change, but data on individuals' time schedules outside the breeding season are still lacking. Using light-level geolocators, we studied variation in migration schedules across the year in a pied flycatcher population in the Netherlands, which sheds light on the ability for individual adjustments in spring arrival timing to track environmental changes at their breeding grounds. We show that variation in arrival dates to breeding sites in 2014 was caused by variation in departure date from sub-Saharan Africa and not by environmental conditions encountered en route. Spring migration duration was short for all individuals, on average 2 weeks. Males migrated ahead of females in spring, while migration schedules in autumn were flexibly adjusted according to breeding duties. Individuals were therefore not consistently early or late throughout the year. In fast migrants like our Dutch pied flycatchers, advancement of arrival to climate change likely requires changes in spring departure dates. Adaptation for earlier arrival may be slowed down by harsh circumstances in winter, or years with high costs associated with early migration

Repeatability in spring arrival dates in Pied Flycatchers varies among years and sexes

Timing of arrival in long-distance migration could have fitness consequences: arrival too early impairs survival chances, whereas arrival too late reduces current reproductive success. Evolution thus may have favoured a phenotype that arrived at the optimal time. However, individuals within populations of long-distance migrant species arrive over a considerable time span, and often show consistency in whether they are early or late. This repeatability in arrival varies between studies, and we hypothesise it to be affected by conditions encountered en route or in winter. Here we report on the spring arrival dates of Pied Flycatchers Ficedula hypoleuca to their Dutch breeding sites during eight consecutive years. Our field estimates of arrival were highly accurate, as validated by geolocator data on 13 individuals. Years differed in mean arrival dates. Within years and sexes, arrival date generally spanned more than two weeks. First-year individuals arrived on average 4-5 days later than older individuals. Using repeated arrival dates of more than 500 individuals we show that (1) the overall arrival repeatabilities were similar for females and males, (2) arrival repeatabilities varied temporally, with individuals in consecutive years having sometimes moderate (R = 0.2) and sometimes rather high (>0.40) repeatabilities, and (3) individual females arrived later in their first than in their second year. In females, repeatabilities of arrival and laying dates were similar. We hypothesize that individual flycatchers have a high individual consistency in their spring migration departure date from the wintering grounds. However, previous studies suggest the expression of this individual schedule to be affected by environmental circumstances at the wintering grounds or by what is encountered en route, determining whether this variation is still present at arrival on the breeding grounds. Sexes seemed to differ in this respect, as year-to-year variation in repeatabilities of timing was explained by individual consistency in females, but not in males. We discuss the relevance of the observed variation for the potential for an evolutionary response when environments change

Weak Effects of Geolocators on Small Birds: A Meta-analysis Controlled for Phylogeny and Publication Bias

Currently, the deployment of tracking devices is one of the most frequently used approaches to study movement ecology of birds. Recent miniaturization of light-level geolocators enabled studying small bird species whose migratory patterns were widely unknown. However, geolocators may reduce vital rates in tagged birds and may bias obtained movement data. There is a need for a thorough assessment of the potential tag effects on small birds, as previous meta-analyses did not evaluate unpublished data and impact of multiple life-history traits, focused mainly on large species and the number of published studies tagging small birds has increased substantially. We quantitatively reviewed 549 records extracted from 74 published and 48 unpublished studies on over 7,800 tagged and 17,800 control individuals to examine the effects of geolocator tagging on small bird species (body mass <100 g). We calculated the effect of tagging on apparent survival, condition, phenology and breeding performance and identified the most important predictors of the magnitude of effect sizes. Even though the effects were not statistically significant in phylogenetically controlled models, we found a weak negative impact of geolocators on apparent survival. The negative effect on apparent survival was stronger with increasing relative load of the device and with geolocators attached using elastic harnesses. Moreover, tagging effects were stronger in smaller species. In conclusion, we found a weak effect on apparent survival of tagged birds and managed to pinpoint key aspects and drivers of tagging effects. We provide recommendations for establishing matched control group for proper effect size assessment in future studies and outline various aspects of tagging that need further investigation. Finally, our results encourage further use of geolocators on small bird species but the ethical aspects and scientific benefits should always be considered.Grantova Agentura Ceske Republiky 13-06451SInstitut Polaire Francais Paul Emile Victor IPEV-1036Institutional Research Plan RVO: 68081766Leverhulme Trust RPG-2013288Russian Foundation for Basic Research Arctic-18-05-60261Russian Science Foundation 17-14-0114

New genetic loci link adipose and insulin biology to body fat distribution.

Body fat distribution is a heritable trait and a well-established predictor of adverse metabolic outcomes, independent of overall adiposity. To increase our understanding of the genetic basis of body fat distribution and its molecular links to cardiometabolic traits, here we conduct genome-wide association meta-analyses of traits related to waist and hip circumferences in up to 224,459 individuals. We identify 49 loci (33 new) associated with waist-to-hip ratio adjusted for body mass index (BMI), and an additional 19 loci newly associated with related waist and hip circumference measures (P < 5 × 10(-8)). In total, 20 of the 49 waist-to-hip ratio adjusted for BMI loci show significant sexual dimorphism, 19 of which display a stronger effect in women. The identified loci were enriched for genes expressed in adipose tissue and for putative regulatory elements in adipocytes. Pathway analyses implicated adipogenesis, angiogenesis, transcriptional regulation and insulin resistance as processes affecting fat distribution, providing insight into potential pathophysiological mechanisms

Alternate non-stop migration strategies of pied flycatchers to cross the Sahara desert

Each year more than two billion songbirds cross the Sahara, but how they perform this formidable task is largely unknown. Using geolocation tracks from 27 pied flycatchers, a nocturnally migrating passerine, we show that most birds made diurnal flights in both autumn and spring. These diurnal flights were estimated to be part of non-stop flights of mostly 40-60 h. In spring, birds flew across the Sahara, while autumn migration probably circumpassed part of the desert, through a long oversea flight. Our data contradict claims that passerines cross the Sahara by intermittent flight and daytime resting. The frequent occurrence of long non-stop flights to cross the desert shows migrants' physiological abilities and poses the question why this would not be the general migration strategy to cross the Sahara

Data from: African departure rather than migration speed determines variation in spring arrival in pied flycatchers

Properly timed spring migration enhances reproduction and survival. Climate change requires organisms to respond to changes such as advanced spring phenology. Pied flycatchers Ficedula hypoleuca have become a model species to study such phenological adaptations of long-distance migratory songbirds to climate change, but data on individuals’ time schedules outside the breeding season are still lacking. Using light-level geolocators, we studied variation in migration schedules across the year in a pied flycatcher population in the Netherlands, which sheds light on the ability for individual adjustments in spring arrival timing to track environmental changes at their breeding grounds. We show that variation in arrival dates to breeding sites in 2014 was caused by variation in departure date from sub-Saharan Africa and not by environmental conditions encountered en route. Spring migration duration was short for all individuals, on average 2 weeks. Males migrated ahead of females in spring, while migration schedules in autumn were flexibly adjusted according to breeding duties. Individuals were therefore not consistently early or late throughout the year. In fast migrants like our Dutch pied flycatchers, advancement of arrival to climate change likely requires changes in spring departure dates. Adaptation for earlier arrival may be slowed down by harsh circumstances in winter, or years with high costs associated with early migration

survival_experimental

A dataset with pied flycatcher chicks born in 2009-2011 within the delayed hatching experiment (as control or delay) in relation to their treatment, body weight and 'survival'

transitions

Contains raw data on sunset and sunrise times (so called 'transitions') used to estimate longitude, movement and stationary periods. The file shows data of 27 solar geolocator-loggers deployed on pied flycatchers, Ficedula hypoleuca, in Drenthe The Netherlands (Longitude: 6.378, Latitude: 52.820) in 2013, using Intigeo-W50 made by Migrate Technology Ltd logger. Data was processed using the program BASTrack