bluuebunny/crossref_metadata_2025 huggingface dataset:
Dependence of geosynchronous relativistic electron enhancements on geomagnetic parameters
Authors: Dmitriev A. V. , Chao J. K.
Published: November 2003

Relativistic electron fluxes observed in geosynchronous orbit by GOES‐8 in 1997 to 2000 were considered as a complex function of geomagnetic indices PC, Kp, and Dst, as well as parameters of the magnetosphere size, subsolar Rs, and terminator Rf magnetopause distances. A geosynchronous relativistic electron enhancement (GREE) is determined as daily maximal electron flux exceeding the upper root mean square deviation (RMSD) threshold of about 1500 (cm2s sr)−1. Comparison analysis of the GREE dynamics and geomagnetic conditions on the rising phase of current solar cycle revealed suppression of the relativistic electron enhancements by substantially increased strong geomagnetic activity in the solar maximum. Statistical consideration of a relationship between the GREEs and the geomagnetic parameters showed that the most important parameters controlling the geosynchronous relativistic electron enhancements were 4‐day averaged Kp index, PC index, and magnetopause termination distance Rf, delayed on 3 and 14 hours, respectively. Relatively high averaging time for Kp was explained by the cumulative effect of substorm energy release in a gradual mechanism accelerating the relativistic electrons in the magnetosphere. Very short time delay for PC index was interpreted as intensification of a fast acceleration mechanism producing the GREEs during severe geomagnetic storms. Substantial increase of the PC index (PC > 5) was found to be a sufficient condition for GREE occurrence. The fast response of the geosynchronous relativistic electron fluxes on the magnetosphere compression was explained by drift losses of the energetic electrons at the magnetopause, which approaches the Earth during geomagnetic storms.
Case study of the 15 July 2000 magnetic storm effects on the ionosphere‐driver of the positive ionospheric storm in the winter hemisphere
Authors: Kil Hyosub , Paxton Larry J. , Pi Xiaoqing , Hairston Marc R. , Zhang Yongliang
Published: November 2003

The ionospheric response to the magnetic storm of 15 July 2000 is investigated using the global total electron content (TEC) maps provided by global positioning system and the measurements of ion density, composition, and drift velocity from the Defense Meteorological Satellite Program (DMSP) F13 and F15 spacecraft. The global TEC maps showed clear seasonal effects that can be characterized by a dominance of a negative ionospheric storm (decrease in plasma density) in the summer (northern) hemisphere and the pronounced positive ionospheric storm (increase in plasma density) in the winter (southern) hemisphere. The northern negative storm phase rapidly expanded to the equator at midnight and even penetrated to the opposite hemisphere during the storm main phase. In the southern hemisphere, the negative storm phase began in the morning sector but was confined to narrow latitude and local time sectors owing to strong poleward winds and ion drag on the dayside. The negative storm phases in the opposite hemispheres kept out of phase, lasted for a day, and corotated with Earth. These characteristics show good qualitative similarity with the predictions of global model simulations. The positive storm phase prevailed in the southern low‐middle latitudes and was most pronounced during nighttime. In that region, the quiet time DMSP measurements at 1800 LT, 2100 LT, 0600 LT, and 0900 LT showed low ion density, low O+ proportion, and large downward ion drift velocity compared with those in the northern hemisphere. During storm time the O+ proportion and ion concentration increased to the levels seen in the northern hemisphere while the downward ion drift velocity was much decreased. The excellent temporal and spatial correspondence of the increase in ion concentration with the decrease in downward ion drift velocity indicates that the maintenance of the F layer at high altitudes by the storm‐induced equatorward neutral winds was the main driver of the positive ionospheric storm. The quiet time hemispheric asymmetry was most significant at nighttime, and therefore the positive storm effect appeared most pronounced at nighttime in the winter hemisphere.
Seasonal to interannual ensemble streamflow forecasts for Ceara, Brazil: Applications of a multivariate, semiparametric algorithm
Authors: Souza Filho Francisco Assis , Lall Upmanu
Published: November 2003

A semiparametric approach for forecasting streamflow at multiple gaging locations on a river network conditional on climate precursors is developed. The strategy considers statistical forecasts of annual or seasonal streamflow totals at each of the sites and their disaggregation to monthly or higher resolution flows using a k nearest neighbor resampling approach that maintains space‐time consistency across the sites and subperiods. An application of the approach to forecasting inflows at six reservoirs in the state of Ceara in northeastern Brazil is presented. The climate precursors used are the NINO3 index for the El Niño‐Southern Oscillation and an equatorial Atlantic sea surface temperature index. Forecasts of January through December streamflow are made at three lead times: in January of the same year and in October and July of the preceding year. The skill of the ensemble forecasts generated is evaluated on subsets of the historical data not used for model building. Correlations with the equatorial Atlantic index and with NINO3 translate into useful streamflow forecasts for the next 18 months of reservoir operation and water management.
Adsorption as a methane storage process in natural lake sediment
Authors: Sugimoto A. , Dan J. , Kumai T. , Murase J.
Published: November 2003

Methane stored in a natural lake sediment was investigated. Fresh sediment (8–25 cm in sediment depth) taken from Lake Biwa, Japan, contains 2.6 μmol/g d.s. (dry sediment) of CH4 on average. The sediment retained 0.31 μmol/g d.s. of CH4 even after air drying, which is 12% of the total CH4 in the fresh sediment. The higher the temperature for drying of the sediment, the smaller the amount of CH4 retained. The result of an adsorption experiment indicated that dried and completely degassed lake sediment adsorbs CH4. Clay particles in the sediment are possibly responsible for the adsorption of CH4. Methane observed in the fresh lake sediment was probably produced by bacteria in the past, then adsorbed on the sediment particles. Adsorption is another form of storage of CH4 in lake and ocean sediments, in addition to the well known forms of dissolved, bubble, and hydrate CH4.
Jupiter's main auroral oval observed with HST‐STIS
Authors: Grodent D. , Clarke J. T. , Kim J. , Waite J. H. , Cowley S. W. H.
Published: November 2003

An extended series of FUV images obtained on 7 days during winter 2000–2001, with fixed pointing, yielded highly accurate tracking of emisson features as Jupiter rotated. They provided newly detailed measurements of the degree of corotation of auroral emissions and their variations with changing central meridian longitude. This 2‐month data set provides a statistical average location of the auroral emission and leads to the definition of new “reference ovals.” The overall auroral morphology pattern is shown to be fixed in System‐III longitude and unchanged over a 5‐year period. When arranged in central meridian longitude ranges, the images show a significant contraction of the northern main oval as the central meridian longitude increases from 115 to 255°. The main auroral oval brightness is globally very stable in comparison with its terrestrial counterpart. It is shown to vary with magnetic local time, increasing from noon to dusk and then decreasing again in the magnetic evening. Hectometric emissions observed simultaneously with Galileo and Cassini reveal interplanetary shocks propagating outward from the Sun which may be related to the contraction of the main auroral oval observed in the HST images taken on 14 December 2000. In addition, we find that a brightening and a significant contraction of the main oval observed on 13 January 2001 corresponded to a time of increased solar wind dynamic pressure.
Soot and smoke aerosol may not warm climate
Authors: Penner Joyce E. , Zhang Sophia Y. , Chuang Catherine C.
Published: November 2003

Soot and smoke aerosol contain black carbon, which absorbs solar radiation. These aerosols may reduce the overall negative climate forcing of anthropogenic aerosols by absorbing radiation that might otherwise be scattered back to space. They may also reduce overall cloudiness, an effect termed the “semidirect” effect, which is thought to enhance climate warming. Here, we evaluate the climate forcing associated with black carbon and other aerosols using the concept of “relaxed forcing,” which is the forcing associated with two simulations using fixed sea surface temperatures. The consideration of longwave perturbations associated with the relaxed forcing leads to a diminished or even negative semidirect effect associated with absorbing aerosols rather than an enhanced warming. The overall forcing depends significantly on the altitude of injection of the aerosols because higher‐altitude injections tend to enhance the negative longwave forcing. In addition, high‐altitude injection of absorbing aerosols can increase cloudiness at lower altitudes where temperatures, in general, may decrease.
Phase partitioning and dry deposition of atmospheric nitrogen at the mid‐Atlantic U.S. coast
Authors: Russell Kristina M. , Keene William C. , Maben John R. , Galloway James N. , Moody Jennie L.
Published: November 2003

The deposition of atmospheric nitrogen contributes significantly to total nitrogen (TN) entering U.S. coastal water bodies. Nitrogen inputs via wet deposition are well quantified but dry‐deposition fluxes are uncertain. In this study, dry fluxes of major atmospheric nitrogen species (including gaseous NH3 and HNO3 and particulate NH4+, NO3−, NO2−, and organic nitrogen (ON)) were quantified during a 2‐week summer sampling period at Lewes, Delaware, on the mid‐Atlantic U.S. coast. Results indicate that dry deposition contributed approximately 43% to total atmospheric nitrogen deposition. Under all flow conditions, NH3(g) accounted for the largest fraction of TN dry deposition (averaging 60%); HNO3(g) and NO3− also contributed considerably (averaging 25 and 8%, respectively). During onshore flow, scavenging of HNO3(g) by sea‐salt aerosols shifted the phase partitioning and relative dry fluxes of total NO3 (HNO3(g) + NO3−) toward particulate NO3−. The mass‐weighted deposition velocities for particulate NO3− (associated primarily with sea‐salt size fractions) were similar to those of HNO3(g). Consequently, phase changes did not substantially alter the dry‐deposition fluxes of total NO3. In light of these results, dry‐deposition monitoring programs at coastal locations should (1) quantify NH3(g) deposition; (2) reliably sample supermicron particles (with which most particulate NO3− is associated); and (3) apply deposition models for particulate nitrogen that are consistent with corresponding size distributions.
Range expansion and the possibility of an emerging contact zone between two subspecies of Chiffchaff Phylloscopus collybita ssp.
Authors: Hansson Maria C. , Bensch Staffan , Brännström Omar
Published: November 2003

The Chiffchaff Phylloscopus collybita is represented in Sweden by two different subspecies; the northern well‐established abietinus and the southern recently established collybita which has expanded its range northward during the past two decades. At present, an area approximately 500 km wide separates the two subspecies. In order to document differences between the northern and southern populations we compared morphology, vocalisation, habitat choice, and neutral genetic variation in mitochondrial (mt) DNA and at four microsatellite loci of 30 male Chiffchaffs from each subspecies. Our results show significant differences in several morphological traits and in song. Playback experiments revealed a significant difference in aggressive behaviour depending on which population‐specific song that was played to the birds. Mitochondrial DNA was geographically structured with ∼90% of the birds carrying a mt haplotype matching their sample population. No allelic differences at the microsatellite loci were found between populations. Our data demonstrate a substantial differentiation between the northern and southern populations despite gene flow, clearly separating them into the subspecies abietinus and collybita.
Parental care and social mating system in the Lesser Spotted Woodpecker Dendrocopos minor
Authors: Wiktander Ulf , Olsson Ola , Nilsson Sven G.
Published: November 2003

The sexes’ share in parental care and the social mating system in a marked population of the single‐brooded Lesser Spotted Woodpecker Dendrocopos minor were studied in 17 woodpecker territories in southern Sweden during 10 years. The birds showed a very strong mate fidelity between years; the divorce rate was 3.4%. In monogamous pairs, the male provided more parental care than the female. The male did most of the nest building and all incubation and brooding at night. Daytime incubation and brooding were shared equally by the sexes, and biparental care at these early breeding stages is probably necessary for successful breeding. In 42% of the nests, however, though still alive the female deserted the brood the last week of the nestling period, whereas the male invariably fed until fledging and fully compensated for the absent female. Post‐fledging care could not be quantified, but was likely shared by both parents. Females who ceased feeding at the late nestling stage resumed care after fledging. We argue that the high premium on breeding with the same mate for consecutive years and the overall lower survival of females have shaped this male‐biased organisation of parental care. In the six years with best data, most social matings were monogamous, but 8.5% of the females (N=59) exhibited simultaneous multi‐nest (classical) polyandry and 2.9% of the males (N=68) exhibited multi‐nest polygyny. Polyandrous females raised 39% more young than monogamous pairs. These females invested equal amounts of parental care at all their nests, but their investment at each nest was lower than that of monogamous females. The polyandrously mated males fully compensated for this lower female investment. Polygynous males invested mainly in their primary nest and appeared to be less successful than polyandrous females. Polyandry and polygyny occurred only when the population sex ratio was biased, and due to strong intra‐sexual competition this is likely a prerequisite for polygamous mating in Lesser Spotted Woodpeckers.
Nestling sex ratios in a population of Bluethroats Luscinia svecica inferred from AFLP™ analysis
Authors: Questiau S. , Escaravage N. , Eybert M.‐C. , Taberlet P.
Published: November 2003

We studied the sex ratio of Bluethroat Luscinia svecica broods using AFLPs. Our aim was to test whether there is a bias towards males that could be explained by sexual selection theories, or conversely, a bias towards females that could help explain the female‐biased sex ratio among juveniles observed at a wintering site. The AFLP technique was reliable in sexing the nestlings from even small initial DNA quantities. Given the large number of polymorphic markers that can be obtained for each primer combination, the probability of detecting a W‐chromosome‐linked fragment is reasonably high. As a consequence, this method could be used in other species for sex‐ratio studies and for other genetic purposes. Among 246 nestlings, we found an overall proportion of males of 50.8% at hatching and the sex‐ratio variation using broods as independent units was not significantly different from expectation under a binomial distribution. None of the parental and environmental variables tested changed significantly the deviance to the model. Thus, sex determination in the Bluethroat seems to match the classical Mendelian model of a 1:1 sex ratio and cannot explain the biased sex ratio towards juvenile females found at the wintering site.
Flight altitude of trans‐Sahara migrants in autumn: a comparison of radar observations with predictions from meteorological conditions and water and energy balance models
Authors: Klaassen Marcel , Biebach Herbert
Published: November 2003

Radar observations on the altitude of bird migration and altitudinal profiles of meteorological conditions over the Sahara desert are presented for the autumn migratory period. Migratory birds fly at an average altitude of 1016 m (a.s.l.) during the day and 571 m during the night. Weather data served to calculate flight range using two models: an energy model (EM) and an energy‐and‐water model (EWM). The EM assumes that fuel supply limits flight range whereas the EWM assumes that both fuel and water may limit flight range. Flight ranges estimated with the EM were generally longer than those with the EWM. This indicates that trans‐Sahara migrants might have more problems balancing their water than their energy budget. However, if we assume fuel stores to consist of 70% instead of 100% fat (the remainder consisting of 9% protein and 21% water), predicted flight ranges of the EM and EWM largely overlap. Increased oxygen extraction, reduced flight costs, reduced exhaled air temperature, reduced cutaneous water loss and increased tolerance to water loss are potential physiological adaptations that would improve the water budget in migrants. Both the EM and EWM predict optimal flight altitudes in agreement with radar observations in autumn. Optimal flight altitudes are differently predicted by the EM and EWM for nocturnal spring migration. During spring, the EWM predicts moderately higher and the EM substantially higher flight altitudes than during autumn. EWM predictions are therefore in better agreement with radar observations on flight altitude of migrants over the Negev desert in spring than EM predictions.
Song activity and variability in relation to male quality and female choice in Whitethroats Sylvia communis
Authors: Balsby Thorsten J. S.
Published: November 2003

To investigate whether song variability or activity could be used as a cue to male quality in the Whitethroat Sylvia communis and whether the song influenced female choice, songs from 18 males were recorded and analysed, and their perch song and flight song activity were registered. Song repertoire was measured as Rep1000 (the average number of different elements within sequences of 1000 elements), Max1000 (the maximum number of different elements in a 1000 element sequence) and number of elements per repertoire. Old males had larger Rep1000, Max1000 and number of different elements per song than 1‐yr‐old males. 1‐yr‐old males had higher perch song and flight song activity than old males. A principal component factor analysis on the song variables showed that (1) males with a large principal component factor score on the first component (PCFS1) typically were old males and (2) the PCFS1 was positively related to male wing length. Rep1000 and Max1000 and a low perch and flight song activity contributed to a positive factor score. Males that mated had larger PCFS1 than males that remained unmated, and there was a significant negative correlation between mating date and PCFS1.  The study suggests that song variability potentially could act as a cue to male quality. Females may prefer males with elaborate songs. However, arrival date could account for the mating pattern and it cannot be excluded that other factors, such as territory quality, also could have influenced the observed mating pattern.
Foraging behaviour of Blue Tits Parus caeruleus in a patchy environment under contrasting levels of natural food supply
Authors: Pulido Fernando J. , Díaz Mario
Published: November 2003

We analysed the foraging behaviour of free‐ranging Blue Tits Parus
caeruleus in open holm oak Quercus ilex woodlands of western
Spain during winter. Such woodlands are patchy for foraging tits because
of the scattered distribution of trees and the patterns of abundance of
canopy arthropods within and among trees. Results were compared with
those obtained in spring of the same year, when we found that the
foraging behaviour and spatial distribution of Blue Tits were largely
unaffected by food availability (Pulido and Díaz 1997). Patch
(tree) residence time was highly variable both within and among
individual birds, and it was uncorrelated with either previous travel
time or patch quality. Contrary to a priori expectations, the behaviour of tits did not conform to short‐term energy maximizing rules in winter, in spite of a 2.5‐fold decrease in food supply from spring to winter and a likely 2‐fold increase in bird requirements. Instead, birds tended to fly towards patches that were further away than locally available. Overall, we conclude that energy intake rate was not the fitness‐related currency that birds were trying to maximize while foraging.
Nesting success of understory forest birds in central Panama
Authors: Robinson W. Douglas , Robinson Tara Rodden , Robinson Scott K. , Brawn Jeffrey D.
Published: November 2003

Greater nest predation in tropical than temperate birds has been hypothesized to be a primary selective force generating latitudinal differences in avian life history traits. Few extensive data sets, however, have been available from tropical forests to compare with data from temperate forests. To increase the amount of empirical information available for addressing issues related to the evolution of life history traits of tropical birds, we measured the nesting success of understory birds in lowland forest of central Panama. We found and monitored the fates of 696 nests of 71 species over two breeding seasons. Daily nest predation rates for the ten species for which we obtained the largest samples ranged from 1.6 to 8.3%, equivalent to a loss of 43 to 92% of nests. These values overlapped extensively the range of daily predation rates experienced by ecologically similar species in North America. Proportion of nests fledging young, estimated with the Mayfield method, was significantly lower in tropical (range: 8 to 57%) than temperate (27 to 60%) species. Nesting success in Panama varied among years, however, being greater in 1996 than 1997. In 1996, nesting success was similar to that of species breeding in forest fragments of midwestern North America. When compared with success of nests in large, contiguous forest tracts of North America, however, tropical avian nesting success was consistently lower by approximately 23%. We conclude that nesting success in central Panama may be poor in most breeding seasons, but also may be punctuated by occasional years of relatively exceptional success, a possibility heretofore unappreciated because of a general paucity of data from the tropics. Furthermore, our results indicate substantial variation in levels of nesting success among species, and almost no variation in clutch size. Such large interspecific variation, as well as potentially large annual variation, in nesting success does not support the hypothesis that uniformly low levels of nesting success select for small tropical clutch sizes.
Fat and body condition in migrating Redwings Turdus iliacus
Authors: Redfern Christopher P. F. , Slough Adam E. J. , Dean Ben , Brice Jo L. , Jones Peter Hope
Published: November 2003

During the night of 29–30 October 1995, over 600 Redwings Turdus iliacus died as a result of flying into the lighthouse at Bardsey, Gwynedd, North Wales. These migrating birds were used to investigate fat levels in relation to age, sex, biometrics and pectoral muscle mass. Wing length was the best single linear measure of size and mean wing length of males was 2.5 mm greater than that of females. Body mass of the casualties declined during the night and the mean body mass of birds arriving towards the end of the night was 1.5 g lower than that of the first arrivals. Fat deposits at different body sites were significantly correlated with each other and with body mass, and, by extrapolation, the mass of intra‐abdominal fat remaining would be significant when other fat deposits have been depleted. Fat in the tracheal pit (the claviculo‐coracoid fat body) demonstrated the best correlation with body mass and was linearly correlated with visual fat scores. Fat was also present in the pectoral muscle but did not make a significant contribution to overall body mass. Two‐thirds of the variation in body mass was accounted for by wing length, the mass of claviculo‐coracoid fat and the lean‐dry mass of pectoral muscle. Claviculo‐coracoid fat and lean pectoral‐muscle mass contributed independently to overall body mass. These data support the view that increase in fat in relation to migration is accompanied by an increase in protein or lean muscle mass, but suggest that these are controlled independently.
Post‐fledging recovery and dispersal of ringed Eurasian Sparrowhawks Accipiter nisus
Authors: Newton Ian , Rothery Peter
Published: November 2003

Ring recoveries were used to explore the effect of early experience on the subsequent survival and dispersal of young Sparrowhawks in two areas in south Scotland. Young raised on high grade territories were recovered in greater proportion than young on low grade territories, implying that they had survived better after leaving the nest. Recovery rate tended to decline with increasing elevation of the nesting territory, implying that young from the high‐ground territories survived less well than those from low‐ground territories. Recovery rate showed no relationship with brood‐size or sex composition, or with maternal age (yearling or older).  After the post‐fledging period, dispersal distances were greater in females than in males and showed significant increases with increasing elevation of nesting territory (one area only) and with lateness of laying (or fledging) date. Regardless of laying date, young males from yearling mothers also dispersed further than young from older mothers, and young males from high elevation territories further than those from lower territories. No significant relationships emerged between dispersal distances and grade of natal territory, brood size or sex composition.
Process in the evolution of bird migration and pattern in avian ecogeography
Authors: P. Bell Christopher
Published: November 2003

Current ideas about the evolution of bird migration equate its origin with the first appearance of fully migratory populations, and attribute its evolution to a selective advantage generated by increased breeding success, gained through temporary emigration from resident populations to breed in under‐exploited seasonal areas. I propose an alternative hypothesis in which migration first appears as a temporary directional shift away from the breeding site outside the reproductive period, in response to seasonal variation in the direction and/or severity of environmental gradients. Fully migratory populations then appear through either extinction of sedentary phenotypes, or colonisation of vacant seasonal areas by migrants. Where colonisation occurs, resident ancestral populations can be driven to extinction by competition from migrants which invade their range outside the breeding season, resulting in fully migratory species. An analogous process drives the evolution of migration between high latitudes and the tropics, since extension of breeding range into higher latitudes may drive low latitude populations to extinction, resulting in an overall shift of breeding range. This process can explain reverse latitudinal gradients in avian diversity in the temperate zone, since the breeding ranges of migratory species concentrate in latitudes where they enjoy the highest breeding success. Near absence of forest‐dwelling species among Palaearctic‐African migrants is attributable to the lack of forest in northern Africa for much of the Tertiary, which has precluded selection both for southward extension of migration by west Palaearctic forest species, and northward breeding colonisation by African forest species.
Do male hoots betray parasite loads in Tawny Owls?
Authors: Redpath Stephen M. , Appleby Bridget M. , Petty Steve J.
Published: November 2003

Bird song structure may honestly reveal the health and vigour of individual males to potential mates and competitors. If this is the case then song may reflect the level of parasitic infections in males. We initially examined the relationship between blood parasite infections and the time taken to respond by 22 male Tawny Owls to a broadcast hoot. We then examined the call structure (total length and frequency) in relation to parasite infection, an index of owl condition and an index of food abundance. Owls with higher parasite loads responded more slowly to an intruder, although this relationship was not significant once condition and vole abundance were controlled for. We found no relationship between call length and any of the measured variables. However, the high frequency and the range of frequencies used in calls decreased with increasing parasite load. Thus, there was the potential for individuals to assess male parasite load from the speed of response and the structure of the call. Experimental tests of these relationships are now required.
Patterns of growth and heterochrony in moundbuilders (Megapodiidae) and fowl (Phasianidae)
Authors: Starck J. Matthias , Sutter Ernst
Published: November 2003

Megapode hatchlings are “superprecocial” compared to hatchlings of other Galliformes. In this paper, we examine patterns of growth and inquire about evolutionary processes that led to different degrees of precocity at hatching in Galliformes. The postnatal development of body mass and that of seven morphometric parameters of wing and leg of Brush Turkey Alectura lathami, Peacock Pavo cristatus, Pheasant Phasianus colchicus and Japanese Quail Coturnix japonica was characterized by the ratio of exponential growth rate (EGR) to relative size (ln (W/A); W=size at a given age; A=asymptote) at a given age. From that relationship, we derived developmental trajectories as the slopes of a least squares regression of EGR on relative size. The slopes of the developmental trajectories are indicative of the degree of precocity of development. We found that Brush Turkey, Peacock, and Pheasant follow the same developmental trajectory. However, the Brush Turkey hatches heterochronically delayed on that trajectory and consequently, its hatchlings are superprecocial. The Quail follows a significantly steeper developmental trajectory and hatches with a high degree of embryonic function (EGR). From a comparative phylogenetic analysis we reconstruct the ancestral galliform developmental trajectory and infer that hypermorphosis of Brush Turkey embryos led to the superprecocial hatchlings. The steeper developmental trajectory of Quail is evolutionary derived from ancestral patterns of growth by somatic paedomorphosis. Using a multivariate approach we show that development of different parts of the body is coherent, i.e., that patterns of development of wing and leg do not vary independently of each other. Consequently, selection for changed development of any part of the wing or the leg will cause the other parts to change too.
Sensitivity of comparative analyses to population variation in trait values: clutch size and cavity excavation tendencies
Authors: Mönkkönen Mikko , Martin Thomas E.
Published: November 2003

Importance of within‐species (population) variation in trait values to correlations of traits among species has received very little attention in comparative analyses. We use randomization and bootstrapping techniques to provide a sensitivity analysis of the influence of population variation on correlations between clutch size and propensity to excavate. These traits are predicted to be negatively correlated under the limited breeding opportunities hypothesis, but opposing results have been found by two studies using different population estimates for western Palearctic Paridae. Our analyses support the limited breeding opportunities hypothesis and suggest low sensitivity to within‐species variation in trait values. Yet, a small proportion of population data provide non‐significant results. Checking for the effects of this variation on the postulated association between traits is necessary in comparative studies if one wishes to avoid type I and type II errors.
Lesser Whitethroats under time‐constraint moult more rapidly and grow shorter wing feathers
Authors: Hall K. Susanna S. , Fransson Thord
Published: November 2003

Migrating passerines moulting in the breeding quarters before autumn migration sometimes end up with less time than needed for a normal moult. To deal with this the birds could for example suspend moult or moult faster. In this paper we investigate the effect of an induced time‐constraint on the moult of Lesser Whitethroats Sylvia curruca. The time‐constraint was induced through a shift in light regime large enough to transfer the birds to a date when, under normal conditions, they already should have started moulting. Time‐constrained birds moulted faster and also grew shorter wing feathers, resulting in a shorter wing, compared to control birds. Only one individual responded by interrupting moult and retained a number of inner primaries unmoulted. The observed adjustments of moult, and the higher fuel loads towards the end of moult, are consistent with the ideas that time is an important factor in bird migration, affecting not only migration but also the events preceding it.
The influence of age on reproductive performance in the Brown Thornbill
Authors: Green David J.
Published: November 2003

I examined age effects on reproduction in the Brown Thornbill Acanthiza pusilla in Canberra, Australia. I found that the reproductive performance of both males and females improved with age, although only age‐related improvement in male performance had a significant effect on annual reproductive success. Reproductive success improved with male age as a result of improved performance during two stages of the breeding cycle: first‐year males were less likely to fledge young than those aged two or more, while both first and second‐year males were less successful at raising fledglings to independence than males of three or more. Male performance appears to improve over three years as they gain experience at provisioning nestlings and caring for fledglings without attracting predators, rather than as a direct result of improved foraging skills. In contrast, reproductive success only improved slightly with female age, although females of two or more years initiated their first clutch earlier in the season than one‐year‐old females, and tended to be more likely to re‐nest if a breeding attempt failed. The poor performance of young females appears unlikely to be related to their foraging ability but may be associated with costs imposed by dispersing to a breeding vacancy earlier in the year. Although the reproductive performance of Brown Thornbills improves considerably with age I found no evidence that performance improved as a result of repeated breeding attempts with the same partner.
Intraspecific variation in reproductive physiology and egg quality in the European Starling Sturnus vulgaris
Authors: Christians Julian K. , Williams Tony D.
Published: November 2003

Egg mass shows large intraspecific variation in birds and is repeatable within individuals. The mechanisms underlying this variation are unknown. We hypothesized that measures of egg quality (the mass of yolk protein, yolk lipid, and albumen protein) would be positively correlated with the plasma pools of the yolk precursor vitellogenin, and the masses of the oviduct, metabolic machinery (liver, heart, lungs, kidneys, gizzard, small intestine and pancreas), and endogenous stores of protein and lipid. We tested these predictions in European Starlings Sturnus vulgaris collected at the peak of egg production effort. In contrast to our predictions, both yolk protein and yolk lipid were negatively correlated with plasma vitellogenin levels. Albumen protein was positively related to oviduct mass, but other aspects of body composition failed to explain variation in egg quality. Hence, while we observed correlations between egg composition and peripheral systems (circulating precursor pools and the oviduct), we found no evidence that egg quality is determined by more general processes, i.e., the supply and processing of nutrients.
Female brood desertion increases with number of available mates in the Rock Sparrow
Authors: Pilastro Andrea , Biddau Luca , Marin Guglielmo , Mingozzi Toni
Published: November 2003

We studied the reproductive strategy of a Rock Sparrow Petronia petronia population, breeding in nest boxes in the Western Alps (Italy). Over seven years of study (1991–1997) 19% of the females laid second clutches after successfully fledging the first one. Among these, about 50% deserted the first nest when nestlings were 14.3 d old (range=8–19 d), 3.6 d before fledging (range=1–8 d). In all these cases the primary male mate took over all parental duties and successfully reared the young. Inter‐clutch time of deserting females was 8.1 d shorter than that of non‐deserting double‐brooded females. The breeding success of deserting females was significantly greater than that of both single‐brooded females and double‐brooded females that did not desert their first brood. The fledging success of the second clutches depended on the status of the secondary male: females paired with previously unpaired males had a higher fledging success than those that paired with a polygynous male. The frequency of deserting females varied among years from 0 to 16%, and was significantly and positively correlated with the frequency of males available as mates at the time of desertion. In this study we showed that sequential polyandry with brood desertion is a regularly occurring strategy in the female Rock Sparrow.
Cryptic differentiation and geographic variation in genetic diversity of Hall's Babbler Pomatostomus halli
Authors: Miura Grant I. , Edwards Scott V.
Published: November 2003

Sequence variation was examined in domain I of the mitochondrial control region in three Queensland populations of Hall's Babbler Pomatostomus halli, a geographically restricted, monotypic songbird in eastern Australia. Surprisingly, we found that domain I sequences were strongly differentiated into two major clades differing by 3.29%. These two clades exhibited nearly complete geographic concordance with northern and southern populations, except for two haplotypes which were sampled in the north of the range but were phylogenetically allied to the southern clade. We also found a seven‐fold higher level of genetic diversity in the northern than in the southern populations. Neutrality and molecular clock tests suggested that selection or differences in substitution rates were not responsible for this difference in diversity. However, a maximum likelihood analysis of gene flow between the north and south suggested that the difference in diversity could be due to both greater population size in the north and asymmetric gene flow dominated by south to north dispersal events. A likelihood ratio test rejected a model in which population sizes were equal and rates of gene flow symmetric, and came close to rejecting a model in which only population sizes were constrained to be equal. These results suggest that different population sizes and asymmetric gene flow could be a major source of differences in genetic variation between populations of Hall's Babbler, although ecological and biogeographic causes for these differences are obscure.
Reduced reproductive performance prior to death in the Black‐legged Kittiwake: senescence or terminal illness?
Authors: Coulson J. C. , Fairweather J. A.
Published: November 2003

The breeding of Black‐legged Kittiwakes Rissa tridactyla in their last breeding season has been compared with that of pairs which survived to the next breeding season. The time of laying was not affected but the clutch size, breeding success and productivity were significantly lower and a higher proportion of pairs totally failed to rear any young in pairs where one of the partners died before the next breeding season. When both partners died before the next breeding season, the breeding performance was reduced to a greater extent, suggesting an additive influence. The depressive effect on the last breeding attempt was confirmed by comparing the breeding success of individual females in their ultimate and penultimate breeding attempts. The effect was present in breeding birds of all ages, from first time breeders to the oldest individuals, and so could not be interpreted as an effect of senescence. Most of the adults which died apparently did so several months after breeding, during the winter half of the year when the kittiwake is oceanic. It is suggested that this depressive effect on breeding is the result of terminal illness which caused the birds to lose condition progressively over several weeks or months. It is possible that stress in the form of disease or parasite infections is primarily responsible for the death of many of the individuals. Attention is drawn to the possible confusion between the effect reported here and claims that senescence leads to lower reproductive output in old birds. It is suggested that more critical examinations are needed of claims that senescence directly affects the breeding success of birds.
The effects of elevated testosterone on plumage hue in male House Finches
Authors: Stoehr Andrew M. , Hill Geoffrey E.
Published: November 2003

The majority of studies examining the role of hormones in the proximate mechanisms of plumage coloration in birds have focused on intersexual differences (plumage dichromatism) and on structural‐ or melanin‐based plumage coloration. The relationship between hormones and carotenoid‐based plumage color, and in particular intrasexual plumage color variation, has received little attention. We manipulated testosterone levels of both captive and wild male House Finches to determine whether testosterone influences the expression of male plumage color in this species. We found that in captive male House Finches elevated testosterone delayed molt and resulted in drabber, less red plumage, even when birds were supplemented with dietary carotenoids. Elevated testosterone also resulted in drab plumage color in wild males, and appeared to delay molt in wild birds as well. Wild males implanted with testosterone showed wide variation in expression of plumage coloration. Those implanted early in the year molted plumage similar in color to their pre‐treatment plumage, but those implanted later molted substantially duller plumage, possibly because delayed molt resulting from elevated testosterone caused these males to molt when carotenoid pigments were not available in sufficient amounts. These observations have the potential to explain previously reported relationships between plumage color and behavior in male House Finches, and highlight the importance of considering the proximate mechanisms of plumage coloration in avian sexual selection.
Efficient copulation and the evolutionary loss of the avian intromittent organ
Authors: Briskie James V. , Montgomerie Robert
Published: November 2003

The absence of an intromittent organ (IO) in most species (>97%) of birds is an enigma: birds are the only terrestrial vertebrates in which insemination typically occurs without the use of an IO. In an earlier review, we evaluated six hypotheses to explain the loss of IOs among birds. We found some support for the influence of sperm competition and female choice, but other hypotheses (e.g. avoidance of sexually transmitted disease) could not be tested because of a lack of empirical data. Wesołowski (1999, J. Avian Biol. 30: 483–485) has criticised our female choice and sexually transmitted disease hypotheses as implausible and insufficient to explain the loss of the IO in birds. Instead, he proposes that IOs were lost to minimise the risk of predation (by shortening duration of copulation) and/or to increase the efficiency of sperm transfer. Here we respond to Wesołowski's (1999) criticisms and test his efficient copulation (EC) hypothesis with data on the duration of copulation in 243 species. Contrary to expectations from the EC hypothesis, copulation durations did not differ significantly between species with and without an IO. Thus we can reject the EC hypothesis as an explanation for the loss of IOs in birds.
Study of immunological and virological parameters during thalidomide treatment of SIV‐infected cynomolgus monkeys
Authors: Di Fabio S. , Trabattoni D. , Geraci A. , Ruzzante S. , Panzini G. , Fusi M.L. , Chiarotti F. , Corrias F. , Belli R. , Verani P. , Dalgleish A. , Clerici M. , Titti F.
Published: November 2003

The potential therapeutic utility of thalidomide (Thd), an effective inhibitor of tumor necrosis factor (TNF)‐αin vitro, was
investigated in cynomolgus monkeys (Macaca fascicularis) at 10
months after infection with simian immunodeficiency virus (SIV).
Thd‐treated macaques (n=8) received an oral dose (10 mg) daily for 7
days, followed by a wash‐out period of 5 weeks. A 2nd cycle of treatment
was performed on the same animals at higher doses (20 mg Thd/day) for 14
days. The control monkeys (n=7) received a placebo for the same period of
time. In the present study, we show that Thd, in addition to inhibiting
TNF‐α production after in vitro mitogen stimulation of
peripheral blood mononuclear cells (PBMCs), was able to restore the
proliferative responses to SIV peptides in monkeys that were infected
with SIV. Interestingly, we found that such effects are associated with
an increased expression of CD28 cell surface receptors on CD4+
T‐cells paralleled by a decrease on CD8+ T‐cells. At the same time, significant reduction in either cell‐associated viral load or plasma viral RNA was not observed among the SIV‐infected monkeys during the two treatment cycles, when compared with the placebo group.
Microsatellite DNA variation in Bornean orangutans (Pongo pygmaeus)
Authors: Warren K.S. , Nijmian I.J. , Lenstra J.A. , Swan R.A. , Heriyanto  , Den Boer M.
Published: November 2003

Orangutans (Pongo pygmaeus) on the islands of Borneo and Sumatra are considered two separate subspecies. However, the genetic relationships between isolated populations on Borneo are not clear. This study determined the extent of variation within the Bornean subspecies of orangutan, using microsatellite DNA analysis. Blood samples were collected from 96 individuals of known origin from East, West and Central Kalimantan. Human microsatellite primer pairs located at human map position D2S141, D4S431, D11S925, D16S420 and D17S791 were suitable for use in primates. D4S431 appeared monomorphic for all orangutans. In three cases (D2S141 East and West and D16S420 West), a highly significant excess of homozygous allele frequencies was detected, but with other primer pairs no significant difference in allele frequencies occurred. We conclude that the divergence between the different populations on Borneo is less than the variation within the populations. There was also evidence that inbreeding occurred within the populations.
Use of intrauterine devices (IUDs) for contraception in the common chimpanzee (Pan troglodytes)
Authors: Gould Kenneth G. , Johnson‐Ward Jill
Published: November 2003

The common chimpanzee (Pan troglodytes) is a species
phylogenetically very close to man. It was not many years ago that the
captive population of chimpanzees (P. troglodytes) was considered at risk because of perceived problems with reproductive success. With the potential need for many individuals for research in a variety of areas, particularly in the areas of parasitic and viral infections, an NIH‐funded program was established to promote the breeding of the species. That program, the ‘National Chimpanzee Breeding and Research Program’, was highly successful, so successful, in fact, that there is now a surplus of animals available for current research programs. This situation has prompted the use of intrauterine devices (IUDs) as a method of fertility control. Overall, this method is successful and associated with a failure (of pregnancy) rate similar to that reported in the human. Physical and logistic constraints, however, render the method less than ideal for situations where a pregnancy rate of zero is desired.