Collared Flycatcher Ficedula Albicollis Research Articles

Sexual selection resulting from extrapair paternity in collared flycatchers

Extrapair paternity has been suggested to represent a potentially important source of sexual selection on male secondary sexual characters, particularly in birds with predominantly socially monogamous mating systems. However, relatively few studies have demonstrated sexual selection within single species by this mechanism, and there have been few attempts to assess the importance of extrapair paternity in relation to other mechanisms of sexual selection. We report estimates of sexual selection gradients on male secondary sexual plumage characters resulting from extrapair paternity in the collared flycatcherFicedula albicollis, and compare the importance of this form of sexual selection with that resulting from variation in mate fecundity. Microsatellite genotyping revealed that 15% of nestlings, distributed nonrandomly among 33% of broods (N=79), were the result of extrapair copulations. Multivariate selection analyses revealed significant positive directional sexual selection on two uncorrelated secondary sexual characters in males (forehead and wing patch size) when fledgling number was used as the measure of fitness. When number of offspring recruiting to the breeding population was used as the measure of male fitness, selection on these traits appeared to be directional and stabilizing, respectively. Pairwise comparisons of cuckolded and cuckolding males revealed that males that sired young through extrapair copulations had wider forehead patches, and were paired to females that bred earlier, than the males that they cuckolded. Path analysis was used to partition selection on these traits into pathways via mate fecundity and sperm competition, and suggested that the sperm competition pathway accounted for between 64 and 90% of the total sexual selection via the two paths. The selection revealed in these analyses is relatively weak in comparison with many other measures of selection in natural populations. We offer some explanations for the relatively weak selection detected.

Density dependence in resource exploitation: empirical test of Levins’ metapopulation model

Levins’ model of metapopulation dynamics is modified to incorporate variable degrees of density dependence in the per capita exploitation of resource patches. We demonstrate a simple means of testing for this density dependence in a sample of metapopulations, each at its equilibrium balance of local colonization to extinction. The fraction of habitable unoccupied patches equilibrates to a constant number under the null model of density independent colonization, and to a constant proportion under strong density dependence. We compare the null model to two density dependent alternatives, using data on exploitation of nest boxes by collared flycatchers Ficedula albicollis. The analysis shows how predicted trends in the equilibrium unoccupied fraction are similar for both spatial interference and net immigration. This needs to be recognized, since the null hypothesis of a constant unused resource applies also to the dynamics of consumable resources, where it is expressed in a constant stock of uneaten prey at the dynamic equilibrium of predators to prey.

Spring migratory routes of eight trans‐Saharan passerines through the central and western Mediterranean; results from a network of insular and coastal ringing sites

Detailed information on spring migration routes of songbirds across the Mediterranean is still scanty. Results are presented here from a study on the occurrence of eight Palaearctic‐African migrants across the western and central Mediterranean based on ringing data collected during the Progetto Piccole Isole, a co‐ordinated project based on standardized mist netting at 21 islands and coastal stations. The species were Melodious Warbler Hippolais polyglotta, Icterine Warbler Hippolais icterina,Bonelli's Warbler Phylloscopus bonelli, Wood Warbler Phylloscopus sibilatrix, Pied Flycatcher Ficedula hypoleuca, Collared Flycatcher Ficedula albicollis, Red‐backed Shrike Lanius collurio and Woodchat Shrike Lanius senator. Their capture frequencies were expressed as the frequency of each species relative to the total number of migrants ringed at each station in order to correct for differences in capture effort between stations. For most species, the detailed, quantitative results confirmed the scanty information available so far, whereas in the case of Melodious Warbler and Bonelli's Warbler, evidence of undescribed and unexpected migration routes was found. These results suggest that standardized mist netting provides an important method for studying the migratory routes of small birds, in particular for those species which are not frequently ringed in their breeding and wintering grounds.

Are Rooster Crows Honest Signals of Fighting Ability?

1995. Correlation between some body components and visible fat index in the Willow Warbler Phylloscopus trochilus (L.). Ornis Svecica 5:75-79. METCALFE, N. B., AND S. E. URE. 1995. Diurnal variation in flight performance and hence potential predation risk in small birds. Proceedings of the Royal Society of London Series B 261:395-400. M0LLER, A. P. 1994. Phenotype-dependent arrival time and its consequences in a migratory bird. Behavioral Ecology and Sociobiology 35:115122. OJANEN, M. 1984. The relation between spring migration and onset of breeding in the Pied Flycatcher Ficedula hypoleuca in northern Finland. Annales Zoologici Fennici 21:205-208. PENNYCUICK, C. J. 1989. Bird flight performance: A practical calculation manual. Oxford University Press, Oxford. PETTERSSON, J., AND D. HASSELQUIST. 1985. Fat deposition and migration capacity of Robins Erithacus rubecula and Goldcrest Regulus regulus at Ottenby, Sweden. Ringing and Migration 6:6676. PIERSMA, T., AND A. LINDSTROM. 1997. Rapid reversible changes in organ size as a component of adaptive behavior. Trends in Ecology and Evolution 12:134-138. ROWE, L., D. LUDWIG, AND D. SCHLUTER. 1994. Time, condition, and the seasonal decline of avian clutch size. American Naturalist 143:698-722. SANDBERG, R. 1996. Fat reserves of migrating passerines at arrival on the breeding grounds in Swedish Lapland. Ibis 138:514-524. SANDBERG, R., AND F. MOORE. 1996. Fat stores and arrival on the breeding grounds: Reproductive consequences for passerine migrants. Oikos 77: 577-581. SVENSSON, L. 1992. Identification guide to European passerines, 2nd ed. Published by author, Stockholm, Sweden. WEATHERS, W. W., AND K. A. SULLIVAN. 1989. Juvenile foraging proficiency, parental effort, and avian reproductive success. Ecological Monographs 59:223-246. WIGGINS, D. A., T. PART, AND L. GUSTAFSSON. 1994. Seasonal decline in Collared Flycatcher Ficedula albicollis reproductive success: An experimental approach. Oikos 70:359-364. WILLIAMSON, K., AND A. BUTTERFIELD. 1954. The spring migration of the Willow Warbler in 1952. British Birds 47:175-197. WITTER, M. S., AND I. C. CUTTHILL. 1993. The ecological costs of avian fat storage. Philosophical Transactions of the Royal Society of London Series B 340:73-92.

The effect of body condition on the cost of reproduction in female Collared Flycatchers Ficedula albicollis

Survival of females in relation to their body condition was investigated in the Collared Flycatcher Ficedula albicollis on Gotland, Sweden. The brood size was manipulated by enlarging or reducing the number of nestlings by one or two chicks. We found a positive relationship between experimental treatment and the condition of the female in the year of the experiment. Among females which disappeared (had apparently died) between years, the relationship was negative but not significant. When the effect of brood manipulation on the probability of survival was analysed separately for females in poor and good body condition, a negative relationship between experimental treatment and probability of survival among females in poor condition was found. This result indicates the existence of a cost of reproduction in terms of survival in low quality females. There was no effect of brood manipulation on the survival of females in good body condition. Our analyses suggest that individuals have different costs of reproduction, depending on their conditional state.

Antagonistic natural selection revealed by molecular sex identification of nestling collared flycatchers

Natural selection may act in different directions during different life‐history stages, or in different directions on different classes of individuals. Antagonistic selection of this kind may be an important mechanism by which additive genetic variation for quantitative traits is maintained, and can prevent populations or species reaching local adaptive peaks. This paper reports the results of a study of viability selection on morphological traits of nestling collared flycatchers Ficedula albicollis. Analyses performed without knowledge of the sex of nestlings suggested that no selection was occurring on these traits. However, using molecular sex identification with the avian CHD gene, it is shown that selection acts in different directions on male and female body size from fledging to breeding, apparently favouring relatively small males and large females. The results suggest that differential selection on male and female nestlings may contribute to purely phenotypic sexual size dimorphism in this species. These findings highlight the potential of newly developed molecular sexing techniques to reveal the consequences of an individual's gender for many aspects of its life history in taxa where gender cannot be determined on the basis of external appearance.

Experimentally increased badge size increases male competition and reduces male parental care in the collared flycatcher

Experimental enlargement of sexually selected traits that are energetically cheap to produce is expected to reveal costs resulting from increased risk of predation or social competition. Given a trade–off between sexually selected traits and life history traits such costs may be expected to affect not only the males themselves but also their offspring. In this study I manipulated the size of the forehead patch, a sexually selected trait that functions as a badge of status in male collared flycatchers Ficedula albicollis ). First, I found that a male9s likelihood to establish a breeding territory with respect to his original badge size was affected by the treatment such that old males (older than or equal to two years) with relatively small original badges enjoyed an increased likelihood of establishing a breeding territory while young males (yearlings) suffered a reduced likelihood of establishment when their badges were enlarged as compared to unchanged. Second, young males with enlarged badges that were able to establish a territory fed their nestlings less in relation to their females compared to the control males. However, the females adjusted their parental effort to such an extent that no significant differences were observed in total feeding rate nor in reproductive success between the two groups of males. These results suggest that experimentally enlarged badge size in the collared flycatcher may result in increased male competition and that males have to trade their effort spent in male contest against their parental effort.

EXPRESSION OF GENETIC VARIATION IN BODY SIZE OF THE COLLARED FLYCATCHER UNDER DIFFERENT ENVIRONMENTAL CONDITIONS.

Heritability of body size in two experimentally created environments, representing good and poor feeding conditions, respectively, was estimated using cross-fostered collared flycatcher Ficedula albicollis nestlings. Young raised under poor feeding conditions attained smaller body size (tarsus length) than their full-sibs raised under good feeding conditions. Parent-offspring regressions revealed lower heritability (h2 ) of body size under poor than under good feeding conditions. Hence, as the same set of parents were used in the estimation of h2 in both environments, this suggests environment-dependent change in additive genetic component of variance (VA ), or that the genetic correlation between parental and poor offspring environment was less than that between parental and good offspring environment. However, full-sib analyses failed to find evidence for genotype-environment interactions, although the power of these tests might have been low. Full-sib heritabilities in both environments tended to be higher than estimates from parent-offspring regressions, indicating that prehatching or early posthatching common environment/maternal effects might have inflated full-sib estimates of VA . The effect of sibling competition on estimates of VA was probably small as the nestling size-hierarchy at day 2 posthatch was not generally correlated with size-hierarchy at fledging. Furthermore, there was no correlation between maternal body condition during the incubation and final size of offspring, indicating that direct maternal effects related to nutritional status were small. A review of earlier quantitative genetic studies of body size variation in birds revealed that in eight of nine cases, heritability of body size was lower in poor than in good environmental conditions. The main implication of this relationship will be a decreased evolutionary response to selection under poor environmental conditions. On the other hand, this will retard the loss of genetic variation by reducing the accuracy of selection and might help explain the moderate to high heritabilities of body-size traits under good environmental conditions.

Glycosylated haemoglobin: a new measure of condition in birds

The influence of condition on time of breeding and reproductive success has been discussed since Darwin first suggested a relation in 1871. We used a novel method to investigate the influence of condition on the timing of breeding and reproductive success by measuring a relatively inert physiological parameter-the amount of glycosylated haemoglobin-in blood samples taken from the collared flycatcher Ficedula albicollis. The percentage of glycosylated haemoglobin (%HbG) was assumed to be proportional to the average blood glucose level, during the 3-5 weeks before the blood sampling. The%HbG was influenced neither by sex nor age. Date of arrival at the breeding ground was negatively correlated with%HbG so that early-arriving birds had significantly higher%HbG than those arriving later. Clutch size, corrected for the effect of laying date, correlated positively with%HbG in females, as did the number of fledged young, corrected for the effect of laying date, for both sexes. We found no correlation between body mass and the%HbG. We suggest that prebreeding condition influences the timing of breeding and subsequent reproductive performance and that%HbG can be used as an indicator of prebreeding-condition in migrating birds.

Does breeding experience explain increased reproductive success with age? An experiment

Accumulation of breeding experience is often assumed to explain enhanced reproductive performance with age. This hypothesis is usually tested by comparing reproductive performance of individuals of the same age but having different amounts of previous breeding experience, thus using natural variation in the age of first breeding. However, individual quality may confound such a comparison, since age of first breeding is likely to covary with individual quality. I delayed experimentally the age of first breeding in female collared flycatchers Ficedula albicollis, and found that: (i) individual quality differences were likely to cause the observed higher reproductive success of unmanipulated experienced as compared with inexperienced two-year-old females; and (ii) breeding experience had no or very little effect on reproductive performance as compared with the effects of reproductive costs. A review of previous tests of the breeding experience hypothesis in birds reveals no consistent trends, although some studies suggest that breeding experience may improve reproductive performance. However, several of these studies also suggest that high-quality individuals start to breed at a younger age. Hence, at present there is no unequivocal evidence that breeding experience explains the enhanced reproductive performance with age. It is more likely that other age-related improvements in competence (e.g. foraging, nest site selection) and increased reproductive effort with age are responsible for this change.

Sexual Dimorphism and Breeding Success in Tree Swallows and Collared Flycatchers

The common pattern of small differences in body size between the sexes of many bird species has been related to a number of ecological factors, including functional differences in niche utilization (Selander 1966, Wallace 1974, Hogstad 1978), sexual differences in nest defense requirements (e.g., Wiklund and Stigh 1983, Safina 1984), and to differential migration strategies (Ketterson and Nolan 1983). While a number of these studies assume that a small degree of sexual dimorphism in body size leads to differential flight performance (see Andersson and Norberg 1981), the possible consequences of such differences have rarely been investigated empirically. Gosler (1987a, 1987b) suggested that sexual differences in the bill length of Great Tits (Parus major) may enhance the ability of pair members to aquire food, through decreased intrapair competition. This same argument has been made for the evolution of reversed sexual size dimorphism in raptors (Newton 1979), typically in reference to differences in wing size/shape and flight performance. This argument rests on the premise that pair members that differ in body size/shape are able to exploit a wider range of prey items. Gosler's (1987a, 1987b) studies of Great Tits provided such evidence and also drew a direct link between the degree of within-pair sexual dimorphism and breeding success. However, more recent work by Matthysen et al. (1991) found no such link among Blue (P. caeruleus) and Great Tits in Belgium. Previous studies have demonstrated significant effects of small differences in wing length and shape on the foraging behavior of several species of birds (e.g., Andersson and Norberg 1981, Lifjeld and Slagsvold 1988). In this paper, we assess the relationship between reproductive success and intra-pair differences in wing length. This study differs from previous efforts by focusing on an aerial insectivore, the Tree Swallow (Tachycineta bicolor), and on a species that feeds by gleaning and flycatching, the Collared Flycatcher (Ficedula albicollis).

BACK FROM AFRICA: WHO'S RUNNING AHEAD? ASPECTS OF DIFFERENTIAL MIGRATION OF SEX AND AGE CLASSES IN PALEARCTIC-AFRICAN SPRING MIGRANTS

Summary Spina F., Massi A., Montemaggiori A. 1994. Back from Africa: who's running ahead? Differential migration of sex and age classes in Palearctic-African spring migrants. Ostrich 65:139-150. The differential migration of sex and age classes in 16 species of Palearctic-African migrants during their northward spring journey through the Central Mediterranean has been investigated from a large data set collected on 4 Italian islands during the “Progetto Piccole Isole”. Species investigated were: Euro Nightjar Caprimulgus europaeus, Barn Swallow Hirundo rustica, Yellow Wagtail Motacill flava. Common Redstart Phoenicurus phoenicurus, Whinchat Saxicola rubetra, Northern Wheatear Oenanthe oenanthe, Black-eared Wheatear O. hispanica, Subalpine Warbler Sylvia cantillans, Whitethroat S. communis, Blackcap S. atricapilla, Collared Flycatcher Ficedula albicollis, Pied Flycatcher F. hypoleuca. Golden Oriole Oriolus oriolus, Red-backed Shrike Lanius collurio, Woodchat Shrike L. senator, Ortolan Bunting Emberiza hort...

Selection on Fledging Mass in the Collared Flycatcher and the Great Tit

The selection on residual mass (relative to body size) at fledging was investigated in the Collared Flycatcher Ficedula albicollis and the Great Tit Parus major. Directional selection for high fledging mass was evident in 6 of 7 yr in Collared Flycatchers but only in 1 of 5 yr in Great Tits. Three different methods of demonstrating and testing stabiilizing selection are compared. Stabilizing selection on relative mass occurred in both species, but the frequency with which this was established depended on which method was used. None of the methods seemed to be universally reliable, and the problem of defining and testing stabilizing selection is discussed. In Collared Flycatchers mass seemed to be most important for juvenile survival. Also in Great Tits mass was important, but in addition other traits (e.g., hatching date) strongly influenced juvenile survival in this species. This possible difference between the two species is suggested to relate to differences in their territory establishment.

Acceleration of senescence in the collared flycatcher Ficedula albicollis by reproductive costs

SENESCENCE is the innate deterioration of an organism that leads to a decline in its fitness components such as fecundity and survival expectations with advancing age1,2. Williams3 proposed that the evolution of senescence could be understood in terms of age-specific pleiotropic gene action, where a mutation increases fitness early in life at the expense of reducing it later on. The basic idea, first proposed by Medawar1, is that mutations acting early in life are more sensitive to selection than those acting later, as the early effects would be expressed in more individuals than would the late effects. A cost of reproduction, where an increase in reproductive rate reduces future survival or fecundity, could be the kind of pleiotropic gene action that generates senescence2,3. Evidence exists for such costs in animals and plants4–8, but their role in the evolution of senescence is so far not clear2. Most empirical work has been with fruit-flies in laboratory studies, where selection experiments indicate negative genetic correlations between early and late fitness components9–12. But it is not certain how applicable the results of such studies are to natural populations. Here we report that the clutch size of older individuals in the collared flycatcher Ficedula albicollis is affected by their reproductive effort early in life. This provides empirical support for Williams's idea that costly reproduction accelerates senescence for fertility in a vertebrate species under natural conditions.

Natal Dispersal in the Collared Flycatcher: Possible Causes and Reproductive Consequences

Possible causes and reproductive consequences of natal dispersal in both sexes of the Collared Flycatcher Ficedula albicollis were investigated using data from a longterm population study on the island of Gotland in the Baltic. Females moved further than males. Of several factors related to natal conditions, only natal brood size was significantly related to dispersal distance, females from small broods moving further than those from large broods. No association between population density and natal dispersal was found. Increased natal dispersal distance was associated with low reproductive success among females and low survival rate among males. For both females and males this association was only significant among birds hatched late in the season. Natal dispersal distance of resident species has been found to show positive, negative, or no correlation with population density and time of birth. I suggest that the use of simple correlations, which fail to detect other relationships than monotonically increasing or decreasing ones, may be one explanation for this inconsistency. It is suggested that prior knowledge of a breeding area may tend to raise the quality of sites chosen and that short-dispersers therefore are more successful than long-dispersers. This may be an important advantage of philopatry.

The costs of reproduction in the collared flycatcher Ficedula albicollis

There has been considerable interest in testing Lack's1 hypothesis that the most frequent clutch size should be the one which yields the highest number of viable offspring. Many tests, however, have shown that the clutch size that produces the most fledglings is actually larger than the most frequent size2,3. This discrepancy has been accounted for by suggesting that high fecundity may result in a reduction in fledgling survival1, juvenile survival4, adult survival5,6, subsequent fecundity7 or the fecundity of the offspring8 or, alternatively, that there is a relationship between parent quality or territory quality and brood size9. We evaluate three different methods of determining these costs and conclude that experimental manipulations provide the only reliable means of determining the costs. The collared flycatcher, Ficedula albicollis, on the island of Gotland forms an isolated population with a remarkably high site fidelity of both adults and young such that the lifetime reproductive success can be assessed with an accuracy rarely possible under natural conditions. Experimental modifications of the actual clutch size showed that the main costs of an enlarged clutch were that the juveniles were less likely to survive, that the subsequent fecundity of the parents was reduced and the offspring had a lower fecundity. Adult survival was unaffected by clutch size.

Inter‐ and intraspecific competition for nest holes in a population of the Collared Flycatcher Ficedula albicollis

Field experiments with nest boxes show that nest holes are a limiting factor on the local population size of the Collared Flycatcher Ficedula albicollis. When this limiting resource occurs with different types that are quality related there is intraspecific competition among males for the best nest boxes, with bigger males being the better competitors. Population dynamics of Great Tit Parus major and Blue Tit P. caeruleus when compared with Collared Flycatchers suggests that there is strong interspecific Competition for available nest holes. This is also shown by removal experiments.

Geographic Variation in Secondary Sexual Plumage Colour Characteristics of the Male Pied Flycatcher

The plumage colour of the head and back of the male Pied Flycatcher Ficedula hypoleuca varies from a female-like brown to pure black, and the mean colour of a population varies geographically, with lighter coloured populations found in Central Europe and darker populations in Fennoscandia. In dark populations the blacker males are significantly larger than the brown males, while in light populations there is no significant size dimorphism between brown and black males. Brown males probably survive better than black males, irrespective of the population they belong to, because they have a higher return rate. The tendency of light populations to have higher rates of polygyny among the males than dark populations is insignificant. Two different hypotheses are proposed to explain the adaptive significance of this geographical variation in plumage colouration: (1) The predation rate varies geographically and affects colouration; this is unlikely, however. (2) The overlap in Central Europe with a sympatric species, the Collared Flycatcher Ficedula albicollis has led to selection for lighter colour of the Pied Flycatcher populations there. This seems to provide a reliable explanation, but the present results did not indicate which of the three sub-hypotheses (a) Female choice of the right species, (b) Fighting Ability, or (c) Interspecific Female Mimicry provides the best explanation for this variation. These alternatives need to be further investigated.