12 research outputs found
Effects of forest management practices in clearings on breeding performance of the Red-backed Shrike (Lanius collurio)
The structure and quality of breeding habitats play an essential role for breeding success of individuals and thus, the viability of populations. Knowledge on habitat requirements can guide management practises to ensure optimal conditions for breeding. In this study, we investigate the effect of different habitat features and forest management strategies on the breeding performance of Red-backed Shrikes (Lanius collurio) breeding in Gribskov forest, Denmark. We found that the availability of available perches for hunting is the main predictor having a positive effect on number of breeding pairs and fledglings. It was also positively associated with the number of years that the clearing has been occupied by breeding pairs. Furthermore, clearings with grazing animals contained breeding pairs for more years than clearings without grazing, suggesting improved foraging conditions in clearings with low vegetation. Our results provide direct applications for forestry management for improving the conservation status of this species
Remarkably similar migration patterns between different red-backed shrike populations suggest that migration rather than breeding area phenology determines the annual cycle
The regular fluctuation of resources across the Globe guides movements of migratory animals. To ensure sufficient reproductive output and maintain viable population sizes, migratory animals should match arrival at breeding areas with local peaks in resource availability. It is generally assumed that breeding phenology dictates the timing of the annual cycle, but this is poorly studied. Here, we use light-level geolocator tracking data to compare the annual spatiotemporal migration patterns of a long-distance migratory songbird, the red-backed shrike, Lanius collurio, breeding at widely different latitudes within Europe. We find that populations use remarkably similar migration routes and are highly synchronized in time. Additional tracks from populations breeding at the edges of the European range support these similar migration patterns. When comparing timing of breeding and vegetation phenology, as a measure of resource availability across populations, we find that arrival and timing of breeding corresponds to the peak in vegetation greenness at northern latitudes. At lower latitudes birds arrive simultaneously with the more northerly breeding populations, but after the local greenness peak, suggesting that breeding area phenology does not determine the migratory schedule. Rather, timing of migration in red-backed shrikes may be constrained by events in other parts of the annual cycle.</p
First description of the egg with other notes on the biology of Loveridge\u27s sunbird Nectarinia loveridgei
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Migration of red-backed shrikes from the Iberian Peninsula: optimal or sub-optimal detour?
The current Northern Hemisphere migration systems are believed to have arisen since the last glaciation. In many cases, birds do not migrate strait from breeding to non-breeding areas but fly via a detour. All western European populations of red-backed shrikes Lanius collurio are assumed to reach their southern African wintering grounds detouring via southeast Europe. Based on theoretical considerations under an optimality framework this detour is apparently optimal. Here, we use individual geolocator data on red-backed shrikes breeding in Spain to show that these birds do indeed detour via southeast Europe en route to southern Africa where they join other European populations of red-backed shrikes and return via a similar route in spring. Disregarding potential wind assistance, the routes taken for the tracked birds in autumn were not optimal compared to crossing the barrier directly. For spring migration the situation was quite different with the detour apparently being optimal. However, when considering potential wind assistance estimated total air distances during autumn migration were overall similar and the barrier crossing shorter along the observed routes. We conclude that considering the potential benefit of wind assistance makes the route via southeast Europe likely to be less risky in autumn. However, it cannot be ruled out that other factors, such as following a historical colonisation route could still be important
Detecting flying insects using car nets and DNA metabarcoding
Monitoring insects across space and time is challenging, due to their vast taxonomic and functional diversity. This study demonstrates how nets mounted on rooftops of cars (car nets) and DNA metabarcoding can be applied to sample flying insect richness and diversity across large spatial scales within a limited time period. During June 2018, 365 car net samples were collected by 151 volunteers during two daily time intervals on 218 routes in Denmark. Insect bulk samples were processed with a DNA metabarcoding protocol to estimate taxonomic composition, and the results were compared to known flying insect richness and occurrence data. Insect and hoverfly richness and diversity were assessed across biogeographic regions and dominant land cover types. We detected 15 out of 19 flying insect orders present in Denmark, with high proportions of especially Diptera compared to Danish estimates, and lower insect richness and diversity in urbanised areas. We found 319 species not known for Denmark and 174 species assessed in the Danish Red List. Our results indicate that the methodology can assess the flying insect fauna at large spatial scales to a wide extent, but may be, like other methods, biased towards certain insect orders.Statistical analyses were carried out in RStudio on the original samples (size sorted samples were merged prior to analysis). Scripts can be found here: https://github.com/CecSve/InsectMobile_CarNet. The data in this Dryad repository are the data used in script 02.
Funding provided by: Aage V. Jensens FondeCrossref Funder Registry ID: http://dx.doi.org/10.13039/501100002721Award Number:Flying insects were collected with car nets during June 2018 in Denmark. Citizen scientists drove back and forth on 5 km routes and the insects were shipped to the Natural History Museum of Denmark in 96% EtOH. The insects were size sorted in two size fractions prior to DNA extraction with a non-destructive DNA lysis buffer and further processing with a DNA metabarcoding protocol. The full laboratory protocol for the research project 'InsectMobile' can be accessed here: https://dx.doi.org/10.17504/protocols.io.bmunk6ve. Only the output of fwh primer pair is used in this study
Transanal Versus Transabdominal Minimally Invasive (Completion) Proctectomy With Ileal Pouch-anal Anastomosis in Ulcerative Colitis A Comparative Study
Objective: This study aims to compare surgical outcome of transanal ileal pouch-anal anastomosis (ta-IPAA) with transabdominal minimal invasive approach in ulcerative colitis (UC), using the comprehensive complication index (CCI). Background: Recent evolutions in rectal cancer surgery led to transanal dissection of the rectum resulting in a better exposure of the distal rectum and presumed better outcome. The same approach was introduced for patients with UC, resulting in decreased invasiveness. Methods: All patients, undergoing minimally invasive restorative proctocolectomy in 1, 2, or 3 stages between January 2011 and September 2016 in 3 referral centers were included. Only patients who underwent either multiport, single port, single port with 1 additional port, hand-assisted, or robotic (R) laparoscopy were included in the analysis. CCI, registered during 90 days after pouch construction, was compared between the transanal and the transabdominal approach. Results: Ninety-seven patients (male: 52%) with ta-IPAA were compared to 119 (male: 53%) with transabdominal IPAA. Ninety-nine (46%) patients had a defunctioning ileostomy at time of pouch construction. A 2-step model showed that the odds for postoperative morbidity were 0.52 times lower in the ta-IPAA group (95% confidence interval [0.29; 0.92] P = 0.026). In patients with morbidity, mean CCI of the transanal approach was 2.23 points lower than the transabdominal approach (95% confidence interval: [-6.64-3.36] P = 0.13), which was not significant. Conclusions: Ta-IPAA for UC is a safe procedure, resulting in fewer patients with morbidity, but comparable CCI when morbidity is present. Overall, ta-IPAA led to lower CCI score
Temporal trends of mercury differ across three northern white-tailed eagle (Haliaeetus albicilla) subpopulations
Desert crossing strategies of migrant songbirds vary between and within species
Each year, billions of songbirds cross large ecological barriers during their migration. Understanding how they perform this incredible task is crucial to predict how global change may threaten the safety of such journeys. Earlier studies based on radar suggested that most songbirds cross deserts in intermittent flights at high altitude, stopping in the desert during the day, while recent tracking with light loggers suggested diurnal prolongation of nocturnal flights and common non-stop flights for some species. We analyzed light intensity and temperature data obtained from geolocation loggers deployed on 130 individuals of ten migratory songbird species, and show that a large variety of strategies for crossing deserts exists between, but also sometimes within species. Diurnal stopover in the desert is a common strategy in autumn, while most species prolonged some nocturnal flights into the day. Nonstop flights over the desert occurred more frequently in spring than in autumn, and more frequently in foliage gleaners. Temperature recordings suggest that songbirds crossed deserts with flight bouts performed at various altitudes according to species and season, along a gradient ranging from low above ground in autumn to probably >2000 m above ground level, and possibly at higher altitude in spring. High-altitude flights are therefore not the general rule for crossing deserts in migrant songbirds. We conclude that a diversity of migration strategies exists for desert crossing among songbirds, with variations between but also within species.Peer reviewe