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1.
Potentially, pathogenic bacteria are one of the main infective agents against which a battery of chemical and physical barriers has evolved in animals. Among these are the secretions by the exocrine uropygial gland in birds. The antimicrobial properties of uropygial secretions may prevent colonization and growth of microorganisms on feathers, skin and eggshells. However, uropygial gland secretions also favour the proliferation of feather mites that feed on secretions and microorganisms living on feathers that would otherwise reach eggshells during incubation if not consumed by feather mites. Therefore, at the interspecific level, uropygial gland size (as an index of volume of uropygial secretion) should be positively related to eggshell bacterial load (i.e. the risk of egg infection), whereas eggshell bacterial loads may be negatively related to abundance of feather mites eating bacteria. Here, we explore these previously untested predictions in a comparative framework using information on eggshell bacterial loads, uropygial gland size, diversity and abundance of feather mites and hatching success of 22 species of birds. The size of the uropygial gland was positively related to eggshell bacterial loads (mesophilic bacteria and Enterobacteriaceae), and bird species with higher diversity and abundance of feather mites harboured lower bacterial density on their eggshells (Enterococcus and Staphylococcus), in accordance with the hypothesis. Importantly, eggshell bacterial loads of mesophilic bacteria, Enterococcus and Enterobacteriaceae were negatively associated with hatching success, allowing us to interpret these interspecific relationships in a functional scenario, where both uropygial glands and mutualistic feather mites independently reduce the negative effects of pathogenic bacteria on avian fitness.  相似文献   

2.
    
We investigated the mechanical properties (Young's modulus, bending stiffness, barb separation forces) of the tenth primary of the wings, of the alulae and of the middle tail feathers of Falco peregrinus. For comparison, we also investigated the corresponding feathers in pigeons (Columba livia), kestrels (Falco tinnunculus), and sparrowhawks (Accipiter nisus). In all four species, the Young's moduli of the feathers ranged from 5.9 to 8.4 GPa. The feather shafts of F. peregrinus had the largest cross‐sections and the highest specific bending stiffness. When normalized with respect to body mass, the specific bending stiffness of primary number 10 was highest in F. tinnunculus, while that of the alula was highest in A. nisus. In comparison, the specific bending stiffness, measured at the base of the tail feathers and in dorso‐ventral bending direction, was much higher in F. peregrinus than in the other three species. This seems to correlate with the flight styles of the birds: F. tinnunculus hovers and its primaries might therefore withstand large mechanical forces. A. nisus has often to change its flight directions during hunting and perhaps needs its alulae for this maneuvers, and in F. peregrinus, the base of the tail feathers might need a high stiffness during breaking after diving. J. Morphol. 276:33–46, 2015. © 2014 Wiley Periodicals, Inc.  相似文献   

3.
1.  The relationship between the composition of communities of micro-organisms and their hosts remains poorly understood. We conducted extensive field studies of feather-degrading bacteria, other cultivable bacteria, and fungi on the plumage of a migratory bird, the barn swallow Hirundo rustica Linnaeus, to understand the association between micro-organisms, host sociality and host antimicrobial defences, as reflected by the size of the uropygial gland.
2.  The abundance of feather-degrading bacteria, but not other cultivable bacteria or fungi, decreased with increasing size of the uropygial gland.
3.  Females had more feather-degrading bacteria than males.
4.  Barn swallows living in larger colonies had more feather-degrading bacteria than less social conspecifics.
5.  These findings suggest that the uropygial gland plays a specific role in regulating the abundance of feather-degrading bacteria that furthermore depends on the social environment of the host.  相似文献   

4.
    
Wing and tail morphology strongly affect flight performance which may consequently decline during feather moult due to the creation of feather gaps in the flight‐surface. Hence, the size and shape of moult‐related gaps may directly affect flight capacity. Here, I examined the divergent rectrix moult sequence compared to the more common distal moult sequence. In the divergent moult, the focus of rectrix moult is shifted from the tail centre (R1; rectrices numbered distally from mid‐tail outward) to another rectrix (R2 or R3), and then rectrices are moulted bidirectionally, towards the tail centre and outwards. The result of this moult sequence is the splitting of the tail gap into multiple smaller gaps. Using a large moult database including 5669 individuals of 47 Western Palaearctic passerine species, I found evidence of divergent moult sequence for only seven species. Using comparative and experimental approaches, I found that the divergent rectrix sequence is correlated with higher moult speed and lower aerodynamic cost. Furthermore, the divergent rectrix sequence is more common among adults than juveniles. This work focused on the feather moult sequence – a seldom studied aspect of the avian life‐history. I propose that moult‐related aerodynamic costs may be an important evolutionary factor not only in moult speed, but also in moult sequence.  相似文献   

5.
    
Current avian migration patterns in temperate regions have been developed during the glacial retreat and subsequent colonization of the ice‐free areas during the Holocene. This process resulted in a geographic gradient of greater seasonality as latitude increased that favoured migration‐related morphological and physiological (co)adaptations. Most evidence of avian morphological adaptations to migration comes from the analysis of variation in the length and shape of the wings, but the existence of intra‐feather structural adjustments has been greatly overlooked despite their potential to be under natural selection. To shed some light on this question, we used data from European robins Erithacus rubecula overwintering in Campo de Gibraltar (Southern Iberia), where sedentary robins coexist during winter with conspecifics showing a broad range of breeding origins and, hence, migration distances. We explicitly explored how wing length and shape, as well as several functional (bending stiffness), developmental (feather growth rate) and structural (size and complexity of feather components) characteristics of flight feathers, varied in relation to migration distance, which was estimated from the hydrogen stable isotope ratios of the summer‐produced tail feathers. Our results revealed that migration distance not only favoured longer and more concave wings, but also promoted primaries with a thicker dorsoventral rachis and shorter barb lengths, which, in turn, conferred more bending stiffness to these feathers. We suggest that these intra‐feather structural adjustments could be an additional, largely unnoticed, adaptation within the avian migratory syndrome that might have the potential to evolve relatively quickly to facilitate the occupation of seasonal environments.  相似文献   

6.
    
We present the first report of complete overlap of breeding and moult in a shorebird. In southeastern Australia, Hooded Plovers Thinornis rubricollis spend their entire lives on oceanic beaches, where they exhibit biparental care. Population moult encompassed the 6‐month breeding season. Moult timing was estimated using the Underhill–Zucchini method for Type 2 data with a power transformation to accommodate sexual differences in rates of moult progression in the early and late stages of moult. Average moult durations were long in females (170.3 ± 14.2 days), and even longer in males (210.3 ± 13.5 days). Breeding status was known for most birds in our samples, and many active breeders (especially males) were also growing primaries. Females delayed the onset of primary moult but were able to increase the speed of moult and continue breeding, completing moult at about the same time as males. The mechanism by which this was achieved appeared to be flexibility in moult sequence. All moult formulae fell on one of two linked moult sequences, one faster than the other. The slower sequence had fewer feathers growing concurrently and also had formulae indicating suspended moults. Switching between sequences via common formulae is possible at many points during the moult cycle, and three of 12 recaptures were confirmed to have switched sequences in the same moult season. Hooded Plovers thus have a prolonged primary moult with the flexibility to change their rate of moult; this may facilitate high levels of replacement clutches that are associated with passive nest defence and low reproductive success.  相似文献   

7.
    
Non‐breeding Cackling Branta hutchinsii, Ross's Anser rossii and Lesser Snow Geese Anser caerulescens caerulescens captured during remigial moult on Baffin Island in 2015 showed no loss of body mass with moult stage, and individual variation in mass was largely explained by sex and measures of body size (tarsus length). Exceptional conditions in 2015 resulted in almost no reproductive effort or success in that year, so captured geese of all three species were likely to have been non‐breeding individuals that initiated moult early, whereas there were almost no failed or successful breeders, which would normally moult later. This suggests that in a non‐breeding year (i.e. in the absence of competition from large numbers of goslings), locally moulting geese can obtain sufficient exogenous energy to meet their needs during the flightless wing moult period without losing body mass. This also is consistent with the hypothesis that in other species of geese, accumulation of fat stores prior to, and depletion of such stores during, wing moult is adaptive and likely to be a feature of individual plasticity to meet particular needs, such as undertaking moult migration to remote sites where precise foraging and predation conditions cannot be anticipated, or where competition from more dominant individuals may restrict their access to a reliable food supply.  相似文献   

8.
The fatty acid and alcohol composition of the uropygial gland wax from four species of birds of the order Laro-limicolae was investigated. Compounds were identified by GLC-MS and the major components were found to be mono-, di and tri-methyl-branched fatty acids and n-, mono- and di-methyl-substituted alcohols. The wax patterns of the three species of the family Scolopacidae (Tringa totanus L., Calidris canutus L., Calidris alpina L.) were shown to be closely related and different from that of the oystercatcher (Haematopus ostralegus L.) by the occurrence of trimethyl-substituted fatty acids and dimethyl-substituted alcohols. In contrast to the species of Scolopacidae, the substituents in the monomethyl-branched alcohols of the oystercatcher are exclusively located in postions near the aliphatic end of the molecule. There are some relationships in uropygial gland wax composition between the Scolopacidae and the Alicae and Laridae.

Résumé

Die Zusammensetzung der Bürzelwachsbestandteile von vier Vertretern der Larolimicolae wurde mit Hilfe der GLC-MS-Kombination bestimmt. Hauptbestandteile sind mono-, di- und tri-methyl-verzvveigte Fettsäuren sowie n-, Mono- und Di-methyl-alkanole. Die Bürzelwachsmuster dieser Arten aus der Familie Scolopacidea (Tringa totanus L., Calidris canutus L., Calidris alpina L.) sind untereinander sehr ähnlich, unterscheiden sich jedoch von dem des Austernfischers (Haematopus ostralegus L.) durch das Auftreten von trimethylsubstituierten Fettsäuren und dimethyl-substituierten Alkoholen. Im Gegensatz zu den ScolopacidaeArten liegt die Methylverzweigung der Methylalkanole beim Austernfischer ausschlieβlich im aliphatischen Molekülende. Es existieren chemotaxonomische Beziehungen der Familie Scolopacidae zu den Alcidae und Laridae.  相似文献   

9.
10.
    
To increase fitness, a wide range of vertebrates preferentially mate with partners that are dissimilar at the major histocompatibility complex (MHC) or that have high MHC diversity. Although MHC often can be assessed through olfactory cues, the mechanism by which MHC genes influence odour remains largely unclear. MHC class IIB molecules, which enable recognition and elimination of extracellular bacteria, have been suggested to influence odour indirectly by shaping odour‐producing microbiota, i.e. bacterial communities. However, there is little evidence of the predicted covariation between an animal's MHC genotype and its bacterial communities in scent‐producing body surfaces. Here, using high‐throughput sequencing, we tested the covariation between MHC class IIB genotypes and feather microbiota in the blue petrel (Halobaena caerulea), a seabird with highly developed olfaction that has been suggested to rely on oduor cues during an MHC‐based mate choice. First, we show that individuals with similar MHC class IIB profiles also have similar bacterial assemblages in their feathers. Then, we show that individuals with high MHC diversity have less diverse feather microbiota and also a reduced abundance of a bacterium of the genus Arsenophonus, a genus in which some species are symbionts of avian ectoparasites. Our results, showing that feather microbiota covary with MHC, are consistent with the hypothesis that individual MHC genotype may shape the semiochemical‐producing microbiota in birds.  相似文献   

11.
    
As DNA sequencing technology continues to rapidly improve, studies investigating the microbial communities of host organisms (i.e., microbiota) are becoming not only more popular but also more financially accessible. Across many taxa, microbiomes can have important impacts on organismal health and fitness. To evaluate the microbial community composition of a particular microbiome, microbial DNA must be successfully extracted. Fecal samples are often easy to collect and are a good source of gut microbial DNA. Additionally, interest in the avian preen gland microbiome is rapidly growing, due to the importance of preen oil for many aspects of avian life. Microbial DNA extractions from avian fecal and preen oil samples present multiple challenges, however. Here, we describe a modified PrepMan Ultra Sample Preparation Reagent microbial DNA extraction method that is less expensive than other commonly used methodologies and is highly effective for both fecal and preen oil samples collected from a broad range of avian species. We expect our method will facilitate microbial DNA extractions from multiple avian microbiome reservoirs, which have previously proved difficult and expensive. Our method therefore increases the feasibility of future studies of avian host microbiomes.  相似文献   

12.
The uropygial gland waxes of Aegithalos, Certhia, Leiothrix, Mesia, Panurus, Paradoxornis, Regulus, Remiz and Siva are monoester waxes composed of 2-; 2,x-; 2,x,y-; and 2,x,y,z-methyl-branched acids and unbranched as well as monomethyl-branched alcohols. Dimethylbranched alcohols occur in traces. All waxes are very similar. Chemotaxonomically all birds investigated are closely related and well separated from the family Paridae (tits).  相似文献   

13.
The presence of multiple distinct ornamental traits in the same species is frequently explained by context‐specificity and different information content. However, the expression of multiple ornaments is often correlated, and such traits may therefore function as a single, integrated signal. Delayed use of an integrated signal relative to production requires temporal stability in integration, which has seldom been examined. We used autumn and spring reflectance data from the breast, breast stripe, and crown of great tits (Parus major) to assess the stability and mating implications of colour signal integration, as well as the repeatability of any integrated colour trait and its correlation with condition during moult. We found high levels of stability between seasons, years, sexes, and ages in the correlation patterns of colour measures across the three plumage areas. The first principal component colour axis described joint variation of ultraviolet (UV) reflectance on the crown and the breast stripe, thereby representing an among‐trait UV chroma axis. However, only breast yellow chroma showed condition‐dependence, whereas temporally consistent and significant assortative mating was restricted to crown UV chroma. Our results therefore do not support the idea that the overall UV chroma of the breast stripe and the crown is special in condition‐dependence and repeatability, or that it plays a specific role in mutual sexual selection as an integrated signal. The results show that stable association between display traits is an existing phenomenon. They also indicate that, even in the presence of correlated traits, functional trait integration among these requires further scrutiny. © 2014 The Linnean Society of London, Biological Journal of the Linnean Society, 2014, 114 , 92–108.  相似文献   

14.
    
Andrea Gehrold 《Ibis》2014,156(4):850-863
The choice of the moulting habitat is of paramount importance for wing‐moulting waterbirds that have to cope with a flightless period of several weeks. However, some species might have more restricted habitat requirements during moult than others, for example due to a highly specialized feeding ecology. The moult‐related habitat use of five species (Gadwall Anas strepera, Red‐crested Pochard Netta rufina, Common Pochard Aythya ferina, Tufted Duck Aythya fuligula, Coot Fulica atra) was compared at a European inland moulting site that offered a variety of water bodies characterized by different levels of nutrient concentration, water depth, shoreline vegetation density and disturbance. To determine location‐ and species‐specific densities, birds were regularly counted throughout the moulting seasons of 2010 and 2011. In 2011, additional data on Gadwalls were used to assess differences in requirements between the flightless phase of moult and the periods before and after. Furthermore, habitat choice of 38 tagged Gadwalls was compared among two to four successive years. During the moulting season, all species showed clear preferences for specific levels of nutrient content, suggesting an active choice of suitable food sources in both food specialists and generalists. Species showing the strongest attachment to shallow water (Gadwall and Coot) were most sensitive to human disturbance and increasing water depths, and species averse to diving (Gadwall) used ponds with dense shore vegetation while flightless. For Gadwalls, habitat conditions rather than nutrient supply became increasingly important during the flightless phase. Average return rates of 59 and 54% were recorded for male and female Gadwalls, respectively, and the repeated use of familiar locations could be demonstrated in the majority of returning birds (65%). Familiarity with the habitat apparently plays an important role and may enable individuals to compensate for suboptimal conditions at the moulting site.  相似文献   

15.
The uropygial gland wax from rails contains ester waxes, triester waxes and triglycerides. The ester waxes are composed of mainly methyl-substituted fatty acids with predominantly n-alkanols. Methyl-branched alcohols are only found in minor amounts. The occurrence of 2,6,10- and 4,8,12-trimethyl-substituted acids can be used as chemotaxonomie markers. The triester waxes contain n-fatty acids, n-alkanols and alkyl-hydroxymalonic acids.  相似文献   

16.
    
Culex pipiens, the endemic mosquito vector of West Nile virus in eastern North America, is responsible for maintenance of the virus in avian reservoir hosts, the most important of which appears to be the American robin. One reason for the greater involvement of robins is believed to be the feeding preference of Cx. pipiens, however, the basis of this preference is not understood. We tested the hypothesis that the species‐specific chemical profile of avian uropygial gland secretions are used by Cx. pipiens as cues to locate birds and, therefore, may contribute to the observed feeding preferences. We used gas chromatography‐mass spectrometry to identify the semi‐volatile components of the uropygial gland secretions of American robins and two other common reservoir host species, the house sparrow and European starling. We found that the chemical composition of the robin secretions was different from those of the sparrows and starlings. Through behavioral choice trials conducted in a dual‐port olfactometer, we also found that Cx. pipiens did not prefer the secretions of robins over the other two species. Surprisingly, however, we found that Cx pipiens were more often attracted to live starlings over robins and to the secretions of starlings over those of robins.  相似文献   

17.
    
ADRIAN SURMACKI 《Ibis》2008,150(2):335-341
The plumage coloration of wild birds often changes during the breeding season. One of the possible reasons for this is that sunlight, and particularly ultraviolet (UV) wavelengths, degrades the pigments responsible for plumage coloration. It has been suggested that birds may apply preen wax to feathers to protect feathers from bleaching. This hypothesis is tested by exposing carotenoid-based breast feathers of Great Tits to ambient light, light filtered to exclude UV and darkness. Preen waxes were experimentally removed from feather samples and the effect of light on coloration of treatment and control feathers compared. Ambient light had an effect on feather colour but preen wax did not. Feathers exposed to sun gradually became less saturated and hues shifted towards shorter wavelengths. This was not apparent in control feathers kept in darkness. Feathers exposed to full-spectra sunlight faded more than those that were kept in light with UV wavelengths removed. There was a decrease in brightness of feathers in both experimental and control groups, which was assumed to be an effect of dirt accumulation. This experiment confirmed earlier suspicions regarding the detrimental effects of UV irradiation on carotenoid-based coloration of avian feathers but failed to show any protective function of preen waxes. The possible consequences of these mechanisms of colour change for birds with regard to mating strategies are discussed.  相似文献   

18.
    
DAVID R. WELLS 《Ibis》2011,153(2):429-432
Female Calyptomena broadbills have 10 large primaries, whereas adult males have nine. At or before the main post‐juvenile moult, males abort what appears to be juvenile P5. This creation of row space is accompanied by a shortening of the wing tip, a development (together with tail shortening) that, as in some Neotropical suboscines, may relate to performance of exaggerated displays. Calyptomena has been linked taxonomically with Afrotropical Smithornis, the one genus of broadbills with proven display‐related modification of flight‐feathers.  相似文献   

19.
    
Seabird moult is poorly understood because most species undergo moult at sea during the non-breeding season. We scored moult of wings, tail and body feathers on 102 Mediterranean Cory's Shearwaters Calonectris diomedea diomedea accidentally caught by longliners throughout the year. Primary renewal was found to be simple and descendant from the most proximal (P1) to the most distal (P10) feather. Secondaries showed a more complex moulting pattern, with three different asynchronous foci: the first starting on the innermost secondaries (S21), the second on the middle secondaries (S5) and the latest on the outermost secondaries (S1). Rectrix moult started at a later stage and was simple and descendant from the most proximal feather (R1) expanding distally. Although a few body feathers can be moulted from prelaying to hatching, moult of ventral and dorsal feathers clearly intensified during chick rearing. Different moulting sequences and uncoupled phenology between primary and secondary renewal suggest that flight efficiency is a strong constraint factor in the evolution of moulting strategies. Moreover, moult of Cory's Shearwaters was synchronous between wings and largely asynchronous between tail halves, with no more than one rectrix moulted at once. This result is probably related to the differential sensitivity of wings and the tail on flight performance, ultimately derived from different aerodynamic functions. Finally, Cory's Shearwater females renewed feathers earlier and faster than males, which may be related to the lower chick attendance of females.  相似文献   

20.
    
The evolution of migratory strategies in birds is likely to have been influenced by ecological as well as socio-sexual factors in both wintering and breeding areas. In this comparative study, we analysed timing of spring passage of 38 long-distance migratory bird species that winter south of the Sahara desert and breed in Europe, in relation to wintering and breeding latitudes, moult strategy, nesting site (open vs. cavity), and sexual dimorphism in size and coloration, which may reflect intensity of sexual selection. We employed a large data set consisting of more than 190 000 individuals ringed during spring migration in the Mediterranean Sea. We found that the species that migrated earlier were those wintering farther north, nesting in cavities and showing the largest degree of sexual size dimorphism (SSD). However, sexual dichromatism was not related to migration date. Among passerine species, moulting wing-feathers in Africa delayed migration. We found no support for the energetic constraint hypothesis, which proposes that early arrival selects for large male size, since early arriving species were not larger than late arriving ones. Thus, the observed associations suggest that variation in migration schedules at the interspecific level may have evolved in relation to ecological factors and SSD, possibly reflecting the intensity of mating competition.  © 2005 The Linnean Society of London, Biological Journal of the Linnean Society , 2005, 85 , 199–210.  相似文献   

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