Outermost Tail Feathers Research Articles

Fine morphology of experimental tail streamers and flight manoeuvrability in the house martinDelichon urbica

Summary 1. Recent studies suggest that long tail streamers (narrow outermost tail feathers) of the barn swallow Hirundo rustica , Linnaeus have initially evolved purely via natural selection for enhanced manoeuvrability. According to an alternative view, streamers have evolved initially solely via sexual selection for costly signalling, and their slender profile is merely an adaptation reducing the aerodynamic cost of a long tail ornament. 2. In order to distinguish between these alternative hypotheses we performed a standardized flightmaze experiment, in which we imitated the initial elongation of outermost tail feathers in a streamer-less hirundine, the house martin Delichon urbica , Linnaeus, contrasting the effects on flight manoeuvrability from adding either a broad or a narrow piece of feather. 3. ‘Narrow-feathered’ house martins (which had initial tail streamers modelled on a natural streamer of the barn swallow) manoeuvred better than ‘broad-feathered’ house martins (which had the natural shape of tips of experimentally elongated outermost tail feathers left unchanged), independent of elongation of the feather. 4. A small elongation of outermost tail feathers did not significantly improve manoeuvrability either in the case of ‘narrow-feathered’ or ‘broad-feathered’ birds. 5. These results suggest that it is the slender shape, but not elongation of streamers that is important for manoeuvrability, and thus streamer elongation is better explained by the sexual-selection than the improved-manoeuvrability hypothesis. We discuss hypothetical scenarios for evolution of hirundine tail streamers.

The Anna's hummingbird chirps with its tail: a new mechanism of sonation in birds

A diverse array of birds apparently make mechanical sounds (called sonations) with their feathers. Few studies have established that these sounds are non-vocal, and the mechanics of how these sounds are produced remains poorly studied. The loud, high-frequency chirp emitted by a male Anna's hummingbird (Calypte anna) during his display dive is a debated example. Production of the sound was originally attributed to the tail, but a more recent study argued that the sound is vocal. Here, we use high-speed video of diving birds, experimental manipulations on wild birds and laboratory experiments on individual feathers to show that the dive sound is made by tail feathers. High-speed video shows that fluttering of the trailing vane of the outermost tail feathers produces the sound. The mechanism is not a whistle, and we propose a flag model to explain the feather's fluttering and accompanying sound. The flag hypothesis predicts that subtle changes in feather shape will tune the frequency of sound produced by feathers. Many kinds of birds are reported to create aerodynamic sounds with their wings or tail, and this model may explain a wide diversity of non-vocal sounds produced by birds.

Assemblage and population-level consequences of forest fragmentation on bilateral asymmetry in tropical montane birds

Habitat fragmentation has the potential to influence the development and thus the phenotype of organisms. The asymmetry of bilateral traits may be indicative of the extent to which developmental stability is compromised by the stressful conditions underlying fragmentation. Using an assemblage- and population-level approach, we explored asymmetry differences in tarsus and outermost tail feathers of birds inhabiting fragmented landscapes in the tropical Andes of Colombia. More than 2500 individuals of 185 species were mist-netted at nine forest sites representing continuous forest (> 1000 ha), medium- (70–110 ha), and small-sized (8–20 ha) fragments. Feathers showed true fluctuating asymmetry (FA), whereas tarsus presented a mixture of FA and directional asymmetry. Overall, asymmetry was lowest in continuous forest, and highest in small and medium fragments. These patterns remained unchanged when directionality and differences in species composition, abundance, and foraging tactics were considered. The population-level analyses showed a general trend of increased asymmetry variation in fragments, yet the responses were not always in the same direction. Increased asymmetry may represent an outcome of processes that contribute to the persistence of species in changing environments, and to the generation of phenotypic innovation, which suggests individual adjustments of development to deal with stress. This calls into question the deliberated application of FA as a biomonitoring tool for conservation. © 2007 The Linnean Society of London, Biological Journal of the Linnean Society, 2007, 92, 119–133. ADDITIONAL KEYWORDS: Andes – Colombia – developmental stability – directional asymmetry – feathers – fluctuating asymmetry – Neotropical birds – tarsus.

Evaluation of the usefulness of bird feathers as a non-destructive biomonitoring tool for organic pollutants: A comparative and meta-analytical approach

In this study, we investigated whether bird feathers can be used as a non-destructive biomonitor for organic pollutants. We analysed the outermost tail feathers of 8 terrestrial and aquatic bird species from Belgium (8 species, n = 108) for polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs) and organochlorine pesticides (OCPs). Every compound class could be quantified in one single tail feather of the birds under study (sum PCBs ranging from 5.5 to 510 ng/g feather, sum PBDEs from 0.33 to 53 ng/g feather, sum DDTs from 1.5 to 730 ng/g feather), except for PBDEs in feathers of the common moorhen ( Gallinula chloropus). Further, we calculated Pearson correlations between concentrations of organic pollutants in feathers and concentrations in corresponding muscle or liver tissue from the birds. Correlations were found significant in half of the cases of the terrestrial species, but were found not significant for the aquatic species, with the exception of a significant correlation of sum PCBs in the common moorhen. Only for the common buzzard ( Buteo buteo) ( n = 43) all correlations were found significant (0.32 < r < 0.77). In order to cope for low statistical power, we performed a meta-analysis on all bird species together. This led to significant correlations between levels in feathers and corresponding levels in muscle or liver for all terrestrial birds ( p < 0.05 in all cases, effect size 0.59 ( p, p′-DDE) to 0.71 (Σ PCB) for levels in feather and muscle). When correlations were recalculated excluding the birds that had died due to starvation, correlation coefficients for the terrestrial birds were found even higher (effect size up to 0.83 (Σ PCB)). These results have important implications for non-destructive and retrospective biomonitoring. Although our results suggest that exact concentrations in the body cannot be predicted using feathers, bird feathers can give a good estimate of contamination levels in a population and as such are a potential non-destructive biomonitoring tool for organic pollutants. Outermost tail feathers and muscle tissue were also examined for nitrogen (δ 15N) and carbon (δ 13C) stable isotope content in the different bird species. However, δ 15N/δ 13C signatures in feather or muscle were not significantly correlated with the corresponding levels of organic pollutants in these tissues. Various confounding factors (such as habitat, condition, age, sex) may have masked a relationship between δ 15N values and organic pollutant levels in the birds under study.

Do melanin-based tail patterns predict individual quality and sex in Lesser Grey Shrikes Lanius minor?

In many bird species, males display colourful, usually carotenoid or structurally based plumage ornaments. On the other hand, there are many bird species and entire avian genera that are achromatic, i.e. with predominantly white, grey and black plumage colours. Achromatic plumage is a typical feature in many shrikes for example. In this study, we examine the importance of an achromatic plumage pattern, namely, the black tail spots on the two outermost tail feathers (T6 and T5) of Lesser Grey Shrikes (LGS) for sex discrimination and as an indicator of individual quality. Our results suggest that the black tail patterns, especially spots on T5, are important for sex discrimination, but only in combination with other melanin-based or morphological features. The presence of black tail spots on T5 is also an indicator of male age. However, there is no indication that presence, size and asymmetry of these black spots are indicators of individual quality of both sexes in the terms of breeding performances.

Lead concentrations in feathers and blood of common blackbirds (Turdus merula) and in earthworms inhabiting unpolluted and moderately polluted urban areas

Despite the dramatic decrease of atmospheric lead (Pb) concentrations in urban areas of most industrialised countries, we hypothesised that urban common blackbirds (Turdus merula) may still be contaminated by Pb concentrations of toxicological concern due to transfer from soil through the food chain. We sampled blackbirds and earthworms, one of their main preys, in Besançon, a middle-size city of Eastern France (where atmospheric Pb concentrations decreased from 0.5 microg/m(3) in 1987 to nearly 0 in 2002) and in a rural reference site. Lead concentrations were determined in the tissues of the different functional groups of earthworms (anecic, epigeous and endogeous) and in blood, washed and unwashed outermost tail feathers and breast feathers of blackbirds. Fresh masses and an index of individual body condition were measured in the two blackbird populations as biomarkers of possible toxic effects. Lead concentrations in earthworms did not differ among functional groups but were significantly higher in urban individuals than in rural ones. Concentrations in outermost tail feathers, breast feathers and blood were significantly higher in urban blackbirds (7.75+/-4.50, 3.15+/-1.77 and 0.15+/-0.09 microg/g, respectively) than in rural individuals. In urban blackbirds, concentrations in washed and unwashed outermost tail feathers allowed estimating the external contamination (probably due to deposition of dusts and/or to excretion of the uropygial gland) at 37% of the total Pb concentration of the unwashed feathers. Remaining 63% should be linked to food chain transfer of persistent Pb from urban soils. Among the 23 sampled blackbirds, 4 of them (3 in the urban site and 1 in the rural site) exhibited blood Pb concentrations higher than the benchmark value (0.20 microg/g) related to subclinical and physiological effects in birds. Variations in body condition index were not correlated to Pb concentrations in blackbird tissues. Present results suggest that Pb may still be of environmental concern for blackbirds in urban areas because of the persistence of Pb in soils and its transfer through the food chain.

Interval between clutches, fitness, and climate change

Timing of optimal reproduction can be affected by the presence of multiple broods, with multi-brooded species breeding earlier (and later) than the optimal timing of breeding as compared with single-brooded species that only need to optimize the timing of a single brood. Approximately two-thirds of barn swallows Hirundo rustica produce 2 broods per year, and I tested whether the constraints on timing of reproduction were affected by climate change because climatic amelioration would allow both an earlier start and a later termination of reproduction. The duration of the interval between first and second clutches and the variance in the duration increased during 1971--2005 when temperature during spring, but not summer, increased rapidly. Interclutch interval was shorter when mean date of breeding was late and also among late-breeding individuals during individual years. When clutch size and brood size of the first clutch were large, interval until the second brood increased. Pairs with a long interval produced more fledglings than pairs with a short interval. Pairs with first broods with strong mean T-cell--mediated immune responses took shorter time to start their second clutch, whereas mean body mass or tarsus length of first broods were not significantly related to interclutch interval. Interclutch interval increased with the size of a secondary sexual character, the length of the outermost tail feathers of adult male barn swallows, but not with tail length of females, or with size of several other phenotypic characters in either sex. These findings are consistent with the hypothesis that the duration of the interclutch interval is determined by a combination of environmental conditions, reproductive effort, and sexual selection. Copyright 2007.

Experimental tail elongation in male Barn SwallowsHirundo rusticareduces provisioning of young, but only in second broods

At the beginning of the breeding season, the outermost tail feathers of 31 male Barn SwallowsHirundo rusticawere either shortened by 20 mm, elongated by 20 mm or left unmanipulated. In first broods, the number of feeding bouts (per nestling per hour) by males and females did not differ significantly among experimental groups. However, in second broods, males with elongated tails fed their nestlings less often than males with shortened or unmanipulated tails. Male tail elongation may have been detrimental to flight, making capture of insects more difficult. Females paired to long‐tailed males did not compensate for this reduction in feeding by males and their nestlings received less food. Neither feeding rates nor brood size differed significantly between first and second broods. Variation in abundance of large insects at different times of the day (high around noon and low in the morning and afternoon) matched variation in feeding rates, supporting the importance of large insects in the Barn Swallow diet. Different feeding rate patterns in first and second broods by males with elongated tails could have at least three explanations: (1) such males were able to adjust their parental effort to some extent, temporarily compensating for an imposed handicap; (2) they were more sensitive than males in the other experimental groups to late season food shortage (a decrease in numbers of large insects, the main Barn Swallow prey, was observed as the season progressed); and (3) they were more sensitive than males in the other experimental groups to the deterioration in their physical condition after first broods.

Sexing Common Snipe (Gallinago gallinago) in the Field - is there any Simple Method?

Sexing Common Snipe (Gallinago gallinago) in the Field - is there any Simple Method? There are a few methods used for sex determination in the Common Snipe. However, all proposed methods are based on data obtained from dead birds. The most important feature is the total length of the outermost tail feather. The performed analysis showed that the vane length was strongly correlated with the total length of this feather. It allowed to predict this measurement having only the vane length. Because the measurement procedure influences the vane length, new ranges of vane length typical for each sex are proposed. However, the analysis of the vane length distribution suggested that there were no two homogenous groups that would represent the two sexes. This supports the prediction that the total feather length should be used rather cautiously as a simple sex trait in the Common Snipe. Also the second trait based on the tail feather colour resulted in overestimation of the proportion of females.

Male tail streamer length predicts fertilization success in the North American barn swallow (Hirundo rustica erythrogaster)

In socially monogamous species, extra-pair paternity has the potential to increase the variance in male reproductive success, thereby affecting the opportunity for sexual selection on male extravagant ornamentation. In the European barn swallow (Hirundo rustica rustica), the tail streamer length is a sexually selected male ornament and an honest indicator of viability. The North American barn swallow (Hirundo rustica erythrogaster) also shows sexual dimorphism in tail streamer length, but whether this trait holds the same signalling function in this subspecies is a controversial issue, and the available literature is presently scarce. Here, we present data on paternity in the North American barn swallow, including a complete sampling of extra-pair sires in four colonies. We analysed how extra-pair paternity affected the variance in male fertilization success and examined whether male tail streamer (i.e. the outermost tail feather) length correlated with fertilization success (n=86 males). Extra-pair paternity constituted 31% of all offspring and significantly increased the variance in male fertilization success. The number of offspring sired by extra-pair males accounted for almost half of the total variance in male fertilization success. Males with naturally long tail streamers had a higher fertilization success than males with shorter tail streamers, and this pattern was mainly caused by a higher extra-pair success for males with long tail streamers. Males with long tail streamers also paired with early breeding females in prime body condition. These results are consistent with the idea that there is directional sexual selection on male tail streamer length, possibly mediated through male extra-pair mating success or the timing of breeding onset.

Experimental tail shortening in Barn Swallows (Hirundo rustica) affects haematocrit

Summary Recent studies in Scotland suggest that the outermost tail feathers of Barn Swallows (Hirundo rustica Linnaeus) may be around 10–12 mm longer than the aerodynamic optimum, with sexual selection for long tails accounting for this extra length. To test this hypothesis, we shortened the outermost tail feathers in male and female Barn Swallows in southern Spain by cutting 1, 11 or 21 mm from the tips of the feathers, and checked for change in haematocrit 1 month later. Haematocrit levels were high when birds arrived at the breeding grounds due to an intense effort for flight during migration, but these levels decreased during the breeding season. We predicted that this decrease would be more pronounced when tail length was closer to the aerodynamic optimum (tails shortened by 11 mm), and less pronounced as tail length was displaced from that optimum (tails shortened by 1 or 21 mm). Contrary to expectations, we found that the smaller the experimental reduction in tail length, the more pronounced the decrease in haematocrit. Barn Swallows with little parental effort and originally long tail feathers experienced a more pronounced decrease in haematocrit than individuals with strong parental effort and originally short tail feathers, respectively, although only in the group of birds with tails shortened by 21 mm. These results do not support the hypothesis that outermost tail feathers in Barn Swallows have been elongated because of sexual selection, at least in the population studied, but are consistent with tail length being at an aerodynamic optimum, or very close to it. Differences in tail length among populations might help to understand the disagreement with previous studies.

Effects of heavy metal exposure on the condition and health of adult great tits ( Parus major)

We examined the possible effects of heavy metal exposure on the quality and health of adult great tits ( Parus major) at four study sites along a pollution gradient near a non-ferrous smelter in Belgium. Tarsus length, wing length, body mass and condition of great tits were compared with respect to study site, age (first-year and older great tits), sex and season (birds caught in winter and during breeding). Tarsus length did not differ significantly among study sites. The wing length of great tits was larger at the study site furthest from the smelter, especially for older great tits. The length of the outermost tail feathers, however, did not differ significantly among study sites. We found no signs of loss of body mass or condition towards the pollution source. The body mass and condition was lowest for female great tits at the site furthest from the smelter, especially during winter. Haematocrit values did not differ significantly among sites. Overall, we found no clear significant effects of heavy metal pollution on morphological measurements and health parameters of great tits.

Adaptive fault bar distribution in a long-distance migratory, aerial forager passerine?

Fault bars are translucent bands produced by stressful events during feather formation. They weaken feathers and increase their probability of breakage, and thus could compromise bird fitness by lowering flight performance. It has been recently suggested (‘fault bar allocation hypothesis’) that birds could have evolved adaptive mechanisms for reducing fault bar load on the feathers with the highest function during flight. We tested this hypothesis by studying first-year individuals of the long-distance migratory, aerial forager barn swallow Hirundo rustica . We predicted that fault bars should be less abundant on the outermost wing and tail feathers, but more frequent on the tail than on the outermost wing feathers. Accordingly, we found that fault bars occurred more often in tertials than in primaries or secondaries. Tail feathers had fewer fault bars than tertials, but more than primaries. Within the tail, the distribution pattern of fault bars was W-shaped, with the highest fault bar load occurring on the streamers and on the two central feathers. Because streamers are the most important tail feathers for flight performance, this finding seems to contradict the ‘fault bar allocation hypothesis’. However, flight performance is much less sensitive to changes in the shape of the tail than of the wings, which could explain why evolutionary forces have not counteracted the increase of fault bars associated with feather elongation during the recent evolution of streamers in the tail of hirundines. © 2005 The Linnean Society of London, Biological Journal of the Linnean Society , 2005, 85 , 455‐461.

Frequency and consequences of feather holes in Barn SwallowsHirundo rustica

The relationship between feather quality, estimated through the prevalence and intensity of feather holes, and the breeding performance and survival of the Barn SwallowHirundo rusticawas studied over a 5‐year period. In addition, we present some indirect data on the role of chewing lice in producing the feather holes. The balanced distribution of feather holes (high prevalence, low aggregation) corresponds with the pattern of distribution of lice on colonial birds, and in the Barn Swallow. Feather holes were significantly and positively associated with the arrival dates of the birds, as both males and females with an increased number of feather holes started laying later. Females that survived the winter had significantly fewer holes than non‐surviving females, whereas there was no difference in feather hole number between surviving and non‐surviving males. Given that there was no association between the number of feather holes and body condition indices, except for the tail length of male Barn Swallows, we suggest that the negative effect of feather holes on the fitness of the birds is mainly apparent during periods of intensive locomotor activity, such as migration. Alternatively, if feather holes are an indicator of quality, those birds with a high intensity of feather holes may have been of poor quality. These birds may have been less able to cope with the environmental conditions, resulting in the lower survival and later arrival of the birds to the breeding grounds. The negative relationship between the length of the outermost tail feathers of males and the incidence of feather holes suggests that the tail is a condition‐dependent secondary sexual characteristic.

Protandry, sexual selection and climate change

AbstractProtandry refers to the earlier appearance of males before females at sites of reproduction. Sexual selection has been hypothesized to give rise to sex differences in benefits and costs of early arrival, thereby selecting for earlier appearance by the sex subject to more intense sexual selection. If sexual selection is more intense, there is a greater premium on early arrival among individuals of the chosen sex because of direct selection for earlier arrival. This hypothesis leads to the prediction that changes in the costs and benefits of early arrival related to changes in environmental conditions should particularly affect the sex that arrives first and hence the degree of protandry. I tested this hypothesis using the Barn SwallowHirundo rustica. During 1971–2003, the degree of protandry increased significantly in a Danish population because males advanced arrival date while females did not. This earlier arrival by males compared with females was correlated with a significant increase by over 1.2 standard deviations in the length of the outermost tail feathers of males, a secondary sexual character, suggesting direct selection on both protandry and the secondary sexual character. Environmental conditions during spring migration in Northern Africa, as reflected by the normalized difference vegetation index, have deteriorated since 1984, resulting in increased mortality among males during spring migration, but not among females, and this deterioration of climatic conditions was positively correlated with an increasing degree of protandry. Likewise, an increase in April temperatures at the breeding grounds during recent decades is positively correlated with increased protandry, apparently because males can arrive earlier without increasing the fitness cost of early arrival. Local population size did not predict changes in arrival date. These findings suggest that rapid changes in climate can cause a change in degree of protandry and secondary sexual characters.

Rapid evolutionary change in a secondary sexual character linked to climatic change

The ability of organisms to respond evolutionarily to rapid climatic change is poorly known. Secondary sexual characters show the potential for rapid evolutionary change, as evidenced by strong divergence among species and high evolvability. Here we show that the length of the outermost tail feathers of males of the socially monogamous barn swallow Hirundo rustica, feathers that provide a mating advantage to males, has increased by more than 1 standard deviation during the period from 1984 to 2003. Barn swallows from the Danish population studied here migrate through the Iberian Peninsula to South Africa in fall, and return along the same route in spring. Environmental conditions on the spring staging grounds in Algeria, as indexed by the Normalized Difference Vegetation Index, predicted tail length and change in tail length across generations. However, conditions in the winter quarters and at the breeding grounds did not predict change in tail length. Environmental conditions in Algeria in spring showed a temporal deterioration during the study period, associated with a reduction in annual survival rate of male barn swallows. Phenotypic plasticity in tail length of males, estimated as the increase in tail length from the age of 1 to 2 years, decreased during the course of the study. Estimates of directional selection differentials for male tail length with respect to mating success, breeding date, fecundity, survival and total selection showed temporal variation, with the intensity of breeding date selection, survival selection and total selection declining during the study. Response to selection as estimated from the product of heritability and total selection was very similar to the observed temporal change in tail length. These findings provide evidence of rapid micro-evolutionary change in a secondary sexual character during a very short time period, which is associated with a rapid change in environmental conditions.

The importance of exogenous contamination on heavy metal levels in bird feathers. A field experiment with free-living great tits, Parus major

Feathers have been used extensively as non-destructive biomonitors for heavy metal pollution. Birds excrete heavy metals into growing feathers during moult. After feather formation, the feathers become isolated from the rest of the body, suggesting that the feathers contain information of circulating heavy metal concentrations in the blood at the time of their development. However, heavy metal levels may change due to exogenous contamination, resulting in higher concentrations in feathers that are exposed most to exogenous conditions. We studied the effect of exogenous contamination in free-living adult great tits (Parus major) by measuring--within the same individual--the concentrations of twelve heavy metals (Ag, Al, As, Cd, Co, Cu, Fe, Hg, Mn, Pb, Tl and Zn) in three outermost tail feathers that were exposed to exogenous contamination for different periods of time. In particular, for each individual heavy metal levels in the removed left outermost tail feather were compared with levels in the regrown left and the right outermost tail feather, that were both removed 40 days after removal of the original left feather. This study revealed that, with the exception of mercury, the concentration of all heavy metals was significantly different among the three outermost tail feathers. Our results suggest that concentrations of most heavy metals build up with increasing age of the feather, indicating that exogenous contamination may be an important source of heavy metals in feathers. However, we found no significant differences in Hg concentrations and we found only small differences in Zn concentrations among tail feathers. Consequently, the concentrations of zinc and mercury in feathers are probably primarily due to endogenous deposition.

Extrapair paternity in relation to sexual ornamentation, arrival date, and condition in a migratory bird

We tested the novel hypothesis that arrival date in migratory birds represents a reliable indicator of male quality that can be used by females as a cue in extrapair mating decisions. Secondary sexual characters are often condition-dependent, and competition for early arrival leads to condition-dependent migration. Hence, both secondary sexual characters and arrival date are predicted to be condition-dependent indicators of male phenotypic quality. We studied the relationship between expression of a secondary sexual character, arrival date, and condition, respectively, and extrapair paternity in a Spanish population of barn swallows, Hirundo rustica. By using microsatellite markers to determine paternity, we showed that 17.8% of all offspring (N = 674) and 32.4% of all broods (N = 170) were due to extrapair paternity. Quasi-parasitism (in which the male nest owner fathered the offspring, but the eggs were laid by another female) occurred in 2.6% of all nestlings and 2.9% of all broods. Individuals were consistent in the frequency of extrapair paternity among first, second, and third broods. Males with long outermost tail feathers, arriving early and in prime body condition, had little extrapair paternity in their nests. This was also the case when controlling for the confounding effects of male age. Partial correlation analysis was used to investigate the direct and indirect effects of tail length, arrival date, and body condition on extrapair paternity. Body condition accounted for most of the variance in extrapair paternity, whereas tail length and arrival date accounted for a smaller proportion of the variance. Body condition was strongly correlated with tail length and arrival date. However, because females cannot directly assess condition or arrival date (males arrive before females), females may obtain an indirect measure of condition and migration ability from tail length and other phenotypic traits of males. This suggests that extrapair paternity depends on the effects of condition, through its indirect effects on arrival date, tail length, and other variables.

Variation of heavy metals within and among feathers of birds of prey: effects of molt and external contamination

In this study we examined the effect of external contamination on the heavy metal (Ag, Al, As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb and Zn) concentration in feathers. We compared the heavy metal content among the 10 primary wing feathers of sparrowhawks ( Accipiter nisus), little owls ( Athene nocta) and barn owls ( Tyto alba) and the variation within the outermost tail feather of sparrowhawks and tawny owls ( Strix aluco). The concentration of Hg was significantly higher in feathers molted first, suggesting that levels in feathers reflect levels in the blood during formation. For some other elements (Al, Co, Ni, Pb, Zn) on the other hand, there are strong indications that external contamination may have an important impact on the levels detected in the feathers. This should be taken into account in future monitoring studies.

A new species of parasitic mites of the genus Syringophiloidus Kethley 1970 (Acari: Syringophilidae) from the barn swallow Hirundo rustica Linnaeus, 1758.

A new quill mite species Syringophiloidus hirundinis (Acari: Syringophilidae) is described from the Barn Swallow Hirundo rustica. The species Syringophiloidus hirundinis had a prevalence of 17.1% in the two outermost tail feathers (N = 208 adult Barn Swallows) during the breeding season of the Barn Swallow host. Intensity of infestation was 9.7 adult mites per pair of infested tail feathers. The sex ratio was highly biased towards females, with only 7.5% of all individuals being males (20:3).