| 1. |
- Adler, Sven
(författare)
-
Body mass change and diet switch tracked by stable isotopes indicate time spent at a stopover site during autumn migration in dunlins Calidris alpina alpina
- 2016
-
Ingår i: Journal of Avian Biology. - : Wiley. - 0908-8857 .- 1600-048X. ; 47, s. 806-814
-
Tidskriftsartikel (refereegranskat)abstract
- Birds may change their diet and foraging habitat during or after migration. Dunlins Calidris alpina alpina breed in the tundra of northern Europe and Russia where they feed exclusively on terrestrial prey. However, up to 80% of the flyway population uses the Wadden Sea as their first important staging site on the way to wintering grounds, feeding exclusively on marine prey. Adult birds migrate earlier than immatures and tend to fly non-stop, whereas immatures may stage for at least a few days en route, mainly in the Baltic region. There they mostly feed on brackish water prey showing similar isotopic values compared to terrestrial prey. When they arrive in the Wadden Sea, dunlin body reserves are depleted and lower than those of individuals that have already staged for several days. We hypothesized that lighter individuals should retain a strong terrestrial isotopic blood signature, while heavier ones should show a stronger marine signature. We found a significant positive correlation between scaled mass index and carbon (delta C-13) and nitrogen (delta N-15) stable isotopes, reflecting the switch from terrestrial to marine prey during migration. A mixing model revealed differences in isotopic values between heavy and light adults and immatures, respectively, in relation to the isotopic prey signatures. Adults showed stronger marine signals compared with immatures, emphasizing the different modes of migration (i.e. a later departure in immatures) as well as the known spatial segregation of age classes in the Wadden Sea, i.e. adults use tidal flats distant from the shore while immatures use coastal areas influenced by terrestrial carbon sources. The results of this study demonstrate the value of scaled mass index in migratory birds as an indicator of time elapsed after diet switching following migration. Furthermore, this study extents the existing knowledge on the timing of dunlin migration by using an isotopic approach.
|
|
| 2. |
- Barani-Beiranvand, Hossein, et al.
(författare)
-
Phylogeny of penduline tits inferred from mitochondrial and microsatellite genotyping
- 2017
-
Ingår i: Journal of Avian Biology. - : WILEY. - 0908-8857 .- 1600-048X. ; 48:7, s. 932-940
-
Tidskriftsartikel (refereegranskat)abstract
- Penduline tits (Remiz spp.) are renowned for their diverse mating and parenting strategies, and are a well-studied system by behavioural ecologists. However, the phylogenetic relationships and species delimitations within this genus are poorly understood. Here, we investigate phylogenetic relationships within the genus Remiz by examining the genetic variation in the mitochondrial cytochrome-b gene of 64 individuals and in ten autosomal microsatellite markers from 44 individuals. The taxon sampling includes individuals from all currently recognized species (R. pendulinus, R. macronyx, R. coronatus, and R. consobrinus) and most subspecies in the Palearctic region. We showed that R. coronatus and R. consobrinus are genetically well differentiated and constitute independent evolutionary lineages, separated from each other and from R. pendulinus/macronyx. However, we found no evidence for significant differentiation among R. pendulinus/macronyx individuals in mtDNA haplotypes and only marginal differences between R. pendulinus and R. macronyx in microsatellite markers. Hence, based on present data our recommendation is to treat R. pendulinus and R. macronyx as conspecific and R. coronatus and R. consobrinus as separate species.
|
|
| 3. |
- Briedis, Martins, et al.
(författare)
-
Breeding latitude leads to different temporal but not spatial organization of the annual cycle in a long-distance migrant
- 2016
-
Ingår i: Journal of Avian Biology. - : Wiley. - 0908-8857 .- 1600-048X. ; 47:6, s. 743-748
-
Tidskriftsartikel (refereegranskat)abstract
- The temporal and spatial organization of the annual cycle according to local conditions is of crucial importance for individuals' fitness. Moreover, which sites and when particular sites are used can have profound consequences especially for migratory animals, because the two factors shape interactions within and between populations, as well as between animal and the environment. Here, we compare spatial and temporal patterns of two latitudinally separated breeding populations of a trans-Equatorial passerine migrant, the collared flycatcher Ficedula albicollis, throughout the annual cycle. We found that migration routes and non-breeding residency areas of the two populations largely overlapped. Due to climatic constraints, however, the onset of breeding in the northern population was approximately two weeks later than that of the southern population. We demonstrate that this temporal offset between the populations carries-over from breeding to the entire annual cycle. The northern population was consistently later in timing of all subsequent annual events - autumn migration, non-breeding residence period, spring migration and the following breeding. Such year-round spatiotemporal patterns suggest that annual schedules are endogenously controlled with breeding latitude as the decisive element pre-determining the timing of annual events in our study populations.
|
|
| 4. |
- Cauchard, Laure, et al.
(författare)
-
The relationship between plumage colouration, problem-solving and learning performance in great tits Parus major
- 2017
-
Ingår i: Journal of Avian Biology. - : Wiley. - 0908-8857 .- 1600-048X. ; 48:9, s. 1246-1253
-
Tidskriftsartikel (refereegranskat)abstract
- Recent studies suggest that individuals with better problem-solving and/or learning performance have greater reproductive success, and that individuals may thus benefit from choosing mates based on these performances. However, directly assessing these performances in candidate mates could be difficult. Instead, the use of indirect cues related to problem-solving and/or learning performance, such as condition-dependent phenotypic traits, might be favored. We investigated whether problem-solving and learning performance on a novel non-foraging task correlated with sexually selected plumage colouration in a natural population of great tits Parus major. We found that males successful in solving the task had darker blue-black crowns than non-solvers, and that males solving the task more rapidly over multiple attempts (i.e. learners) exhibited blue-black crowns with higher UV chroma and shorter-wavelength hues than non-learners. In contrast, we found no link between behavioural performance on the task and the yellow breast colouration in either sex. Our findings suggest that blue-black crown colouration could serve as a signal of problem-solving and learning performance in wild great tit males. Further research remains necessary to determine whether different sexually selected traits are used to signal cognitive performance for mate choice, either directly (i.e. cognitive performance influencing individual's health and ornamentation through diet for example) or indirectly (i.e. due to a correlation with a third factor such as individual quality or condition).
|
|
| 5. |
|
|
| 6. |
- Fletcher, Kevin, et al.
(författare)
-
Importance of infection of haemosporidia blood parasites during different life history stages for long-term reproductive fitness of collared flycatchers
- 2019
-
Ingår i: Journal of Avian Biology. - : John Wiley & Sons. - 0908-8857 .- 1600-048X. ; 50:8
-
Tidskriftsartikel (refereegranskat)abstract
- The interaction between birds and haemosporidia blood parasites is a well-used system in the study of parasite biology. However, where, when and how parasites are transmitted is often unclear and defining parasite transmission dynamics is essential because of how they influence parasite-mediated costs to the host. In this study, we used cross-sectional and longitudinal data taken from a collared flycatcher Ficedula albicollis population to investigate the temporal dynamics of haemosporidia parasite infection and parasite-mediated costs to host fitness. We investigated host-parasite interactions starting at the nestling stage of the bird's life-cycle and then followed their progress over three breeding attempts to quantify their fitness - measured as the number of offspring they produced that recruited back into the breeding population. We found that the majority of haemosporidia blood parasite infections occurred within the first year of life and that the most common parasite lineages that infected the breeding population also infected juvenile birds in the natal environment. Moreover, our findings suggest that collared flycatcher nestlings in poorer condition could be at a higher risk of haemosporidia blood parasite infection. In this study, only female and not male bird fitness was adversely affected by parasite infection and the cost of infection on female fitness depended on the timing of transmission. In conclusion, our study indicates that in collared flycatchers, early-life is potentially important for many of the interactions with haemosporidia parasite lineages, and evidence of parasite-mediated costs to fitness suggest that these parasites may have influenced the host population dynamics.
|
|
| 7. |
- Fourcade, Yoan
(författare)
-
Evaluating interspecific niche overlaps in environmental and geographic spaces to assess the value of umbrella species
- 2017
-
Ingår i: Journal of Avian Biology. - : Wiley. - 0908-8857 .- 1600-048X. ; 48, s. 1563-1574
-
Tidskriftsartikel (refereegranskat)abstract
- The concept of umbrella species assumes that concentrating resources on the protection of a single species contributes to the conservation of a suite of species and ecological processes belonging to the same ecosystem. The environmental requirements and geographical distribution of the umbrella species should thus overlap those of the group of targeted species. In western France, the conservation of several large grassland floodplains relies on agri-environmental schemes targeting one single bird species, the corncrake Crex crex. It is considered as an umbrella species but no real assessment of its effectiveness has been carried out so far. We used a two-step methodology to assess the potential of the corncrake to act as an umbrella species by estimating niche overlap in the environmental and geographic space between the main ground-nesting species of the bird community in these grasslands, including the corncrake and four passerines. The five species showed substantial differences in their ecological niches so that their distributions did not perfectly overlap. Overlaps in predicted distributions between pairs of species depended on the threshold used to convert suitability to binary maps. Moreover, the number of species that could be protected by a candidate umbrella species was affected by the overlap criterion of success. Although the corncrake may be used as an umbrella species, it would be outperformed by several passerine species. Our study highlights the potential of using niche overlap to select umbrella species. It also reveals the importance of analysing the sensitivity of outputs when changing thresholds and overlap criteria.
|
|
| 8. |
|
|
| 9. |
- Gómez‐blanco, David, et al.
(författare)
-
Beak morphology predicts apparent survival of crossbills: due to selective survival or selective dispersal?
- 2019
-
Ingår i: Journal of Avian Biology. - : Wiley. - 0908-8857 .- 1600-048X. ; 50:12
-
Tidskriftsartikel (refereegranskat)abstract
- Dozens of morphologically differentiated populations, subspecies and species of cross- bills (genus Loxia) exist. It has been suggested that this divergence is due to variation in the conifer cones that each population specialises upon, requiring a specific beak size to efficiently separate the cone scales. If so, apparent survival should depend on beak size. To test this hypothesis, we undertook multievent capture–recapture modelling for 6844 individuals monitored during 27 years in a Pyrenean common crossbill L. curvirostra population in a forest of mountain pine Pinus uncinata. Apparent survival was indeed related to beak width, resulting in stabilizing selection around an optimum that was close to the observed mean beak width, indicating that local crossbill beak morphology is adapted to the conifer they feed upon. Both natural selection (selective mortality) and selective emigration of maladapted individuals may explain our find- ings. As is often the case in capture–recapture analyses but rarely recognised, we could not formally decompose apparent survival into selective mortality versus selective per- manent emigration. Nonetheless, there are several indications that selective permanent emigration should not be fully excluded. First, natural selection by itself would have to be unusually strong compared to other empirical estimates to create the observed pat- tern of apparent survival. Second, the observed mean beak width was a bit lower than the estimated optimum beak width. This can be explained by immigration of crossbills with smaller beaks originating from southern populations, which may subsequently have left the study area permanently in response to low food intake. This is in line with a detected transient effect in the data, yet apparently little influx from crossbills from northern Europe. When permanent emigration is phenotypically selective this will have ecological and evolutionary consequences, so this possibility deserves more attention in general.
|
|
| 10. |
- Hedenström, Anders, et al.
(författare)
-
Wind tunnel as a tool in bird migration research
- 2017
-
Ingår i: Journal of Avian Biology. - : Wiley. - 1600-048X .- 0908-8857. ; 48:1, s. 37-48
-
Tidskriftsartikel (refereegranskat)abstract
- Wind tunnels, in which birds fly against an artificially generated air flow, have since long been used to evaluate aerodynamic properties of steady bird flight. A new generation of wind tunnels has also allowed the many processes associated with migratory flights to be studied in captivity. We review how wind tunnel studies of aerodynamics and migratory performance together have helped advancing our understanding of bird migration. Current migration theory is based on the power-speed relationship of flight as well as flight range equations, both of which can be evaluated using birds flying in wind tunnels. In addition, and depending on wind tunnel properties, performance during gliding and climbing flight, and effects of air pressure, humidity and turbulence on bird flight has been measured. Long-distance migrant species have been flown repeatedly for up to 16 h non-stop, allowing detailed studies of the energy expenditure, fuel composition, protein turnover, water balance, immunocompetence and stress associated with sustained migratory flights. In addition, wind tunnels allow the fuelling periods between migratory flights to be studied from new angles. We end our review by suggesting several important topics for future wind tunnel studies, ranging from on of the key questions remaining, the efficiency at which chemical power in converted to mechanical power, to new useful avenues, such as improving and calibrating the techniques used for tracking of individual birds in the wild.
|
|
