Whitethroat Research Articles

The importance of arable habitat for farmland birds in grassland landscapes

Summary Over the last 25 years, populations of seed‐eating birds have declined severely over most of western Europe. Local extinctions have occurred in grassland‐dominated areas in western Britain, which may be influenced by loss in habitat diversity and a decline in the amount of arable cultivation. We used the large‐scale British Breeding Bird Survey of 1998 to investigate the importance of arable habitat within grassland landscapes for 11 common seed‐eating birds and four similar sized insectivores. Generalized linear models were used to model the number of birds recorded in agricultural habitat within survey squares as a function of the amount of arable habitat present. Numbers of grey partridge Perdix perdix, skylark Alauda arvensis, tree sparrow Passer montanus, corn Miliaria calandra and reed buntings Emberiza schoeniclus, yellowhammer Emberiza citrinella and whitethroat Sylvia communis increased with the amount of arable habitat present in a survey square; the numbers of house sparrow Passer domesticus, four finch species, dunnock Prunella modularis, robin Erithacus rubecula and blackcap Sylvia atricapilla did not. The positive association between numbers of some species and arable habitat within 1‐km squares was strongest where arable habitat was rare in the surrounding area, and weakest or even reversed when arable habitat was common. These results demonstrate the scale‐dependence of bird–habitat associations in agricultural landscapes, only demonstrable where data are available at fine grain over large geographical areas. These results support the hypothesis that range contractions (i.e. local extinctions) of some granivorous species have occurred because of contraction in arable cultivation. The loss of arable habitat where it is scarce may be causing declines in some areas, even though intensification of arable management is thought to be the main cause of declines elsewhere. Agri‐environment schemes may need to vary between regions, for example to encourage arable cultivation in pastoral areas.

Cultural ecology of Whitethroat ( Sylvia communis) habitat management by farmers: winter in farmland trees and shrubs in Senegambia

The presence of Whitethroats and their potential invertebrate prey in farmland trees and shrubs was investigated. The management of this vegetation by farmers, and their motivation for that management, was explored using participatory techniques. Whitethroats were associated with Guiera senegalensis, the shrub species which supports most caterpillars and spiders. Farmers reported declines in trees and shrubs since the 1950s, loss of fallow areas, declines in soil fertility and crop yields, and increases in the use of fire for clearing fields. Trees are valued by people for their cultural and medicinal uses and some species used by Whitethroats and other birds have potential for restoring soil fertility, although this was not recognised by farmers. More sustainable use of savanna farmland could have both agronomic and wider conservation benefits, and the provision of information that accommodates farmers’ cultural and economic incentives could benefit both farmers and wildlife.

Cultural ecology of Whitethroat ( Sylvia communis) habitat management by farmers: Field-boundary vegetation in lowland England

Field-boundary structure, its use by territorial Whitethroats, and its management by farmers were investigated in southern Wiltshire using a combination of fieldwork and a questionnaire survey. Whitethroats favour wide herbaceous field boundary strips and low hedges. Long-term cultural and short-term economic interests combine to influence farmers’ management decisions. Only farmers with game and conservation interests claimed to adopt field-boundary management that would benefit Whitethroats, but across all farms, intended and actual herbaceous strips were too narrow, and their management too imprecise, for Whitethroats and other wildlife. Agricultural advisors and magazines were the main influences on farmers’ management decisions. Improving habitat for Whitethroats could have both agronomic and wider conservation benefits, and the provision of information that accommodates farmers’ cultural and economic incentives could benefit both farmers and wildlife.

Wing moult in relation to autumn migration in adult Common Whitethroats Sylvia communis communis

Most long‐distance passerine migrants in Sweden moult on breeding grounds before leaving on autumn migration to winter quarters. However, birds laying second or replacement clutches, or just breeding late, have too little time for a normal moult on the breeding grounds. When time is limited the birds may respond by making various adjustments to the moult, for example by moulting more quickly or by suspending the moult. In this study, the relationship between the performance of post‐nuptial remex moult in Common Whitethroats breeding on Gotland, southeast Sweden, and autumn migration departure was investigated. The majority (77%) of the birds had interrupted moult in either the primaries or secondaries. Interruption of moult was more common among birds with a later onset date, as was asymmetry in moult between wings. The interruption of moult led to a significant time gain and moult completion was, consequently, more synchronized than moult onset. The results from this study indicate, in accordance with other data, that an early start of autumn migration is important. An early start may be crucial to facilitate the crossing of the Sahara Desert once the dry season has begun.

Indexing European bird population trends using results of national monitoring schemes: a trial of a new method

Many European countries have annual breeding bird monitoring schemes based on nationwide samples; most are in northern and western Europe. We have developed a method to produce yearly population indices of bird species across countries by combining the results of existing national schemes. The method takes into account the differences in population sizes per country, as well as the differences in field methods, and the numbers of sites and years covered by the national schemes. In order to test the method, we collected raw data from a number of countries and applied an index method to produce scheme results per country. Data were collected for five farmland species (Lapwing Vanellus vanellus, Linnet Carduelis cannabina, Skylark Alauda arvensis, Whitethroat Sylvia communis and Yellowhammer Emberiza citrinella), from seven countries (UK, Netherlands, Denmark, Germany, Finland, Latvia and Estonia) for a 20-year period (1978–97). The trial demonstrated that it was possible to combine national indices to provide supra-national yearly totals and their standard errors; the results were similar to those produced when the raw data were used. Thus, yearly European indices can be produced by exchanging only limited amounts of information, that is the national yearly indices of each species or, preferably, the yearly population numbers and their standard errors. At a European scale, the populations of the five species selected have changed considerably. In western Europe (UK, Netherlands, Denmark and former West Germany combined), Linnet, Skylark and Yellowhammer have declined and Whitethroat has increased. Most changes occurred during the first ten-year period (1978–88). The changes in eastern Europe (the remaining countries) were less clear, in part because the statistical power of the national schemes is as yet limited.

Whitethroat Sylvia communis and Yellowhammer Emberiza citrinella nesting success and breeding distribution in relation to field boundary vegetation

Field boundary characteristics influencing territory establishment and nesting success of Whitethroats and Yellowhammers on farmland in Leicestershire were investigated. Hedge height had a negative influence on the presence of breeding Whitethroats. The abundance of herbaceous vegetation in field boundaries had a positive influence on both species. The relationship was strongest for Whitethroats which nested almost exclusively in herbaceous vegetation. Nesting success of Whitethroats was higher than that of Yellowhammers. Yellowhammer nests in hedges were more susceptible to predation than those in herbaceous vegetation. Maintaining low hedges and establishing uncut 2-m strips of perennial herbaceous vegetation in field boundaries would contribute to the conservation of Whitethroats and Yellowhammers on farmland.

Distributions of birds in lowland agricultural landscapes of England and Wales: How distinctive are bird communities of hedgerows and woodland?

Within agricultural landscapes many species of birds depend on hedgerows and woodland, but few studies have examined their relative importance as habitats for breeding birds. Breeding bird communities in hedgerows and woodland in lowland England and Wales were compared in terms of species richness and similarity of species composition. The preference of individual species for hedgerows and woodland was also assessed. The data were drawn from 33 farmland and 35 woodland Common Birds Census plots for 3 years: 1990, 1993 and 1996. Woodland plots were significantly richer in species than farmland plots. Species number on farmland plots increased linearly with the cover of farm woodland and non-linearly with density of total hedgerow. Species number increased with density of non-roadside hedgerows, but not with density of roadside hedgerows. Although the farmland and woodland plots supported distinctive bird communities, there was considerable overlap between them in species composition. The similarity between the species composition on individual farms and that theoretically possible for woodland increased significantly with the cover of farm woodland, hedgerow density and the total amount of woody habitat present within the farmland plot. Canonical correspondence analysis and preference indices indicated that seven species could be regarded as hedgerow specialists: Dunnock Prunella modularis, Whitethroat Sylvia communis, Lesser Whitethroat S. curruca, Linnet Carduelis cannabina, Goldfinch C. carduelis, Greenfinch C. chloris and Yellowhammer Emberiza citrinella. Species showing clear preferences for woodland were: Tawny Owl Strix aluco, Marsh Tit Parus palustris, Coal Tit P. ater, Goldcrest Regulus regulus, Spotted Flycatcher Muscicapa striata, Treecreeper Certhia familiaris, Nuthatch Sitta europaea, Great Spotted Woodpecker Dendrocopos major, Chiffchaff Phylloscopus collybita and Blackcap Sylvia atricapilla. The habitat needs of the hedgerow specialists show considerable variation and do not always coincide with the hedgerow structures that support the greatest numbers of bird species and highest densities of birds. Management strategies that maintain a diversity of hedgerow structures are, therefore, desirable. Hedgerow and woodland bird communities are essentially complementary and habitat creation initiatives in lowland agricultural landscapes should not be excessively weighted towards one habitat or the other.

COMPARATIVE FUEL USE OF MIGRATING PASSERINES: EFFECTS OF FAT STORES, MIGRATION DISTANCE, AND DIET

Abstract Lipids are the dominant fuel source during migratory flight, but the factors controlling the relative importance of lipid, protein, and carbohydrate to flight metabolism remain unclear. I tested the nonexclusive hypotheses that diet, migration distance, or endogenous lipid reserves mediate variation in the fuels birds catabolize during migration. Blood plasma metabolite concentrations were significantly different among species, and indicated clear differences in protein and lipid utilization among three turdid chat and five sylviid warbler species caught during spring migration in the Negev Desert, Israel. Fruit-eating species (omnivores) catabolized less protein and more lipid during migration than insectivores. Metabolite concentrations of omnivorous Blackcaps (Sylvia atricapilla), Garden Warblers (S. borin), and Lesser Whitethroats (S. curruca) were consistent with low rates of proteolysis (low uric acid), and high rates of lipolysis (high free-fatty acid and β-hydroxybutyrate). On the other h...

SEED DISPERSER EFFECTIVENESS: THE QUANTITY COMPONENT AND PATTERNS OF SEED RAIN FORPRUNUS MAHALEB

In this paper we analyze the seed dispersal stage of the Prunus mahaleb-frugivorous bird inter- action from fruit removal through seed delivery within the context of disperser effectiveness. The effectiveness of a frugivorous species as a seed disperser is the contribution it makes to plant fitness. Effectiveness depends on the quantity of seed dispersed (''quantity component'') and the quality of dispersal provided each seed (''quality component''). For the main frugivores, we studied abundance, visitation rate, and feeding behavior, the major variables influencing the quantity component of effectiveness, and the postforaging microhabitat use and resultant seed shadows, which set the stage for postdispersal factors that will influence the quality component of effectiveness. Legitimate seed dispersers (SD) swallowed fruits whole and defecated or regurgitated intact seeds; pulp consumers (PC) pecked fruits to obtain pulp and dropped seeds to the ground, but some species occasionally dispersed seeds (PCSD species). Overall numbers of fruits removed (i.e., handled) by avian frugivores were similar in the two study years; however, the estimated percentage of seeds dispersed differed significantly, with lower relative dispersal success in the year with greater relative abundance of PC species. Similar numbers of seeds were dispersed in the two years despite nearly a fourfold difference in number of fruits produced. Fruit crop size explained .80% variance in the number of seeds dispersed per tree. A total of 38 species of birds were recorded during censuses, with frugivores representing 68.8% of them; the relative representation of SD, PC, and PCSD species was 42.2%, 17.2%, and 9.4%, respectively. Individual trees showed extensive variation in visitation rates, ranging from 0.3 to 41.6 visits/10 h in any year. The main visitors were the SD species Phoenicurus ochruros (10.8 visits/10 h), Turdus viscivorus (9.2 visits/10 h), Erithacus rubecula(3.5 visits/10 h), and Sylvia communis(2.6 visits/10 h); and the PC species Fringilla coelebs (16.7 visits/10 h) and Parus ater (4.7 visits/10 h). Species with large quantity components of effectiveness typically had either high visit or high feeding rates, combined with high probability of dispersing a handled seed. Variation among species in fruit-handling behavior, however, was the main factor influencing variation in the quantity component. Visit rate in turn was influenced largely by local abundance. No single frugivore trait, however, can adequately estimate the quantity component of disperser effectiveness. A ''gulper''/''masher'' dichotomy helps explain differences in fruit handling among major frugivore types and shows many correlates with other aspects of frugivore activity that ultimately influence the quantity component. Most species showed marked preferences for microhabitats with plant cover, especially P. mahaleb,midheight shrubs, and Pinus (86.1% of the departure flights) and avoided open microhabitats. Most flights were over short distances (77.5% to perches located within 30 m). Among the main frugivores, 40.3% of the exit flights were to perches .15 m away from the feeding tree, but only 18.5% of these flights were to perches .15 m from any P. mahaleb. Covered microhabitats received significantly more seeds (39.3 6 5.0 seeds dispersed/m 2 , 1988 (mean 6 1 SE); 31.7 6 5.9 seeds dispersed/m 2 , 1989) than open microhabitats (2.8 6 0.7 seeds dispersed/m 2 , 1988; 1.8 6 0.4 seeds dispersed/m 2 , 1989). The potential contribution of each bird species to the seed rain in each microhabitat was estimated from the number of visits recorded, the mean number of seeds dispersed per visit, and the proportion of exit flights to each microhabitat. Microhabitats differed strongly in the proportions of seeds delivered by the main frugivores, and bird species also differed in the proportions of seeds delivered to a given microhabitat. The seed rain to covered microhabitats was delivered by a more heterogeneous assortment of species than the seed rain to open sites. The resulting seed shadow was a complex result of the interaction between movement patterns of a suite of bird species differing both in the quantity of seed dispersed and microhabitat preferences and in the landscape distribution of these microhabitat patches. This seed shadow was extremely nonrandom due both to a strong overall preference by most of the birds for the relatively scarce covered microhabitats and to species-specific preferences for particular types of covered microhabitats. Different microhabitat types not only received variable amounts of dispersed seed, but also differed in the number and identity of disperser species contributing to that seed rain.

A quantitative comparison of neck-collar and faecal analysis to determine passerine nestling diet

Two commonly used methods for diet determination, neck-collars (ligatures) and faecal analysis, were compared. Samples were collected from the chicks of three nidicolous species: Dunnock Prunella modularis, Yellowhammer Emberzia citrinella and Whitethroat Sylvia communis. As determined by the two methods, significant differences in diet composition were found for Dunnock and Whitethroat. For faecal samples compared with neck-collar samples, more Coleoptera and fewer Collembola were identified in Dunnock and more Coleoptera and Diptera in Whitethroat. For invertebrate diversity, analysis of faecal samples identified significantly more invertebrate groups in the diet for Whitethroat, while for Dunnock, neck-collars contained the greater diversity. No differences were detected between the two sampling methods for Yellowhammer in respect of either invertebrate groups or diversity. The relative value of these two methods is discussed.

Body mass of six long-distance migrant passerine species along the autumn migration route

We analysed body mass and moult data of six passerine species along their autumn migration route from northern Europe to North Africa and derived hypothetical models of the organisation of their migration in terms of fuel store accumulation. We analysed data of 46,541 first-year birds from 34 trapping sites, sampled in a network of collaborating European and African ringing stations. After accounting for effects of time of day and size, there were marked differences between the six species examined in the change of body mass along the migration route and in the timing of moult. Garden Warblers (Sylvia borin) and Pied Flycatchers (Ficedula hypoleuca) underwent their postjuvenile moult prior to migration and increased their average body mass along the migration route. Sedge Warblers (Acrocephalus schoenobaenus) also increased body mass towards the south, but started the migration bout without further refuelling well before the Sahara and moulted mainly in the wintering grounds. Reed Warblers (Acrocephalus scirpaceus) and Whitethroats (Sylvia communis) migrated while still moulting and did not increase average body mass towards south. They accumulated the energy needed to fly over the Sahara just before it. Spotted Flycatchers (Muscicapa striata) behaved in the same way, but contrary to Reed Warblers and Whitethroats they did not accumulate much fat stores in North Africa, which might urge them to stop and fuel up regularly in the Sahara. In the course of the season average body mass of all species increased slightly, which enabled them to migrate faster. In general, average body mass of first-year birds in northern and central Europe during the migration period was comparable to that of adults during breeding.

Influence of landscape and land‐use on the distribution of breeding birds in farmland in eastern England

AbstractThe relationships between landscape, land‐use and the number of territories of eight species of birds, most with declining populations, were studied over 3 years in an area of largely arable agriculture in eastern England. Two species, skylark Alauda arvensis and yellow wagtail Motacilla flava, established territories within crops. More than half of skylark territories were in autumn‐sown cereals, but densities were higher in set‐aside and spring‐sown crops, while a conservation grassland cut for hay in late July held the highest density. Skylarks did not switch territories in winter cereals for other crops as the breeding season progressed. Weak preferences were found for spring‐sown crops and weak avoidance of autumn‐sown crops (i.e. there were fewer territories than expected from the area under autumn‐sown crops). Skylarks showed preferences for set‐aside and conservation grassland but other grassland was avoided. Skylark numbers were negatively associated with hedgerow length within tetrads. Most yellow wagtails nested in spring‐sown crops, especially potatoes, for which there was a strong preference; most territories were in the largest fields. More than 75% of territories of turtle dove Streptopelia turtur were associated with residential areas, scrub and woodland, with hedges used much less often than expected from their occurrence. Grass was a strongly preferred land‐use. Linnets Carduelis cannabina were mainly located in small areas of scrub and there was an association with winter oil‐seed rape. Common whitethroats Sylvia communis showed preferences for hedges, especially for tall hedges, though many territories were situated in field boundaries with only scattered shrubs. Lesser whitethroats S. curruca preferred only tall hedges. Both species had more territories adjacent to grass than expected, with common whitethroat also showing a preference for winter oil‐seed rape. Yellowhammers Emberiza citrinella declined over the 3 years of the study. Territories were strongly associated with tall hedges, but preferences for crops were weak. The small number of reed bunting E. schoeniclus territories were almost all by water, with a preference for adjacent grass. Possible mechanisms for reversing the downward trends of bird populations on farmland are discussed.

Song activity and variability in relation to male quality and female choice in Whitethroats Sylvia communis

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.

Migration strategies of sylviid warblers: chance patterns or community dynamics?

The effects of community dynamics in birds on the optimisation of their migratory strategies is a neglected area. For three years, we captured migrating warblers on autumn passage at a coastal site in western Britain. We used canonical correspondence analysis (CCA) to assess spatio‐temporal patterns of occurrence, and principal components analysis (PCA) to assess morphological variation. We calculated Euclidean distance in ordination and morphological space to assess separation between species pairs, and used Monte‐Carlo simulations to assess the probability of pattern occurring by chance. Ordination revealed five species‐groups separated by habitat type and time of passage. Reed Warbler Acrocephalus scirpaceus and Sedge Warbler A. schoenobaenus (Group 1) occurred in wet habitats and peaked simultaneously. In drier habitats with scrub, a first wave of Blackcap Sylvia atricapilla (Group 2) significantly preceded Grasshopper Warbler Locustella naevia, Willow Warbler Phylloscopus trochilus, Whitethroat Sylvia communis and Lesser Whitethroat Sylvia curruca (Group 3), which in all but one case (Lesser Whitethroat) significantly preceded Garden Warbler Sylvia borin (Group 4); peak numbers of Chiffchaffs Phylloscopus collybita and a second wave of Blackcaps (Group 5) occurred later still. Age effects were found only in Acrocephalus, with adults peaking before juveniles. For seven out of eight pairings within genera, separation in time of passage increased significantly in species that were morphologically similar. The only exception was Blackcap and Lesser Whitethroat which differed substantially in both passage time and morphology. Monte‐Carlo simulations showed that chance was unlikely to be responsible for ordination patterns, nor for inter‐specific variation in passage time and its relationship with species morphology. These data provide annually consistent evidence that migrating sylviid warblers are separated ecologically by habitat use, time of passage and morphology: we cannot refute the hypothesis that community dynamics have influenced niche use and autumn migratory strategy. We call for further tests of the ‘migrant interaction’ hypothesis in other geographical locations and taxa, particularly where migrants are allopatric and interact ecologically only on migration.

THE FUNCTION OF SONG IN WHITETHROATS SYLVIA COMMUNIS

ABSTRACTTo test the mate attraction hypothesis and the territory defence (establishment) hypothesis in the Whitethroat Sylvia communis, I studied the pattern of vocal activity in the different phases of the breeding cycle in 1995 and 1996. Furthermore the response of unmated and mated males to playback was studied in 1997. The low “perch song” activity and “flight song” activity of mated males compared to unmated males suggest that song was used in mate attraction. The perch and flight song activity in the morning tended to increase during the season but only significantly in 1996. The perch song was also used in territorial defence as suggested by unmated males responding to the playback with increased song activity. The diving song was apparently used in courtship of the female, since most diving songs were directed towards females. In mated males the dscharp-call was the most frequent vocal behaviour and mated males primarily used this call in response to playback. The more discreet vocal behaviour of mated males suggests that males use a silent strategy.

Habitat selection by Whitethroats Sylvia communis during spring passage in the Sahel zone of northern Nigeria

Minimum densities of Whitethroats Sylvia communis were estimated from 409 point counts at five sites in the Sahel zone of northern Nigeria during March–April 1995. Higher densities occurred in woodland than on farmland, open rangeland or semi-desert. Within woodland Whitethroats were seen more frequently in Balanites aegyptiaca than would be expected from its relative availability. Balanites aegyptiaca had the densest canopy and highest density of invertebrates, suggesting that the preference of Whitethroats for this tree may be because it offers the best protection from predators, heat and/or the best foraging opportunities. The presence or absence of Whitethroats within a point was, however, best predicted by high tree species diversity rather than foliage volume, canopy volume or tree density (though all of these factors were correlated). It seems likely, therefore, that diverse, relatively undegraded Sahelian woodland is a preferred habitat for Whitethroats during the spring migration period.

Coming Between the "Black Beast" and the White Virgin: The Pressures of Liminality in Thomas Dixon

girl uttered a cry, long, tremulous, heart-rending, piteous. A single tiger-spring, and the claws of the sank into the soft white throat and she was still. --Thomas Dixon, Clansman I have three daughters, but, so help me God, I would rather find either one of them killed by a tiger or a bear and gather up the bones and bury them, conscious that she died in the purity of her maidenhood, than to have her crawl to me and tell me the horrid story that she had been robbed of the jewel of her maidenhood by a fiend. --Senator Benjamin Tillman South Carolina Senator Benjamin Tillman defended lynching in this extraordinary speech, made in 1906 on the Senate floor. Tillman justified the maiming and hanging of the male body by evoking another besieged body--that of the white woman. Just as the lynched body is replaced by the white woman's body, her body, too, undergoes displacements: Tillman rhetorically dismembers her, substituting scattered bones for her whole, enfleshed, penetrable body. Senator didn't bother to make clear whether the robbing of her maidenhood is the work of rape or consensual sex, probably because he could not admit the latter possibility. Nonetheless, his glossing over this information is vital. Whether rape victim or sex partner, better that she die than become, like the black fiend, a crawling animal. In response to his daughter's miscegenation, the white father in Tillman's fantasy suffers a parallel degradation: The young girl thus blighted and brutalized drags herself to her father and tells him what has happened .... Our brains reel under this staggering blow and hot blood surges to the heart ... we revert to the original savage.(1) In making this speech, Senator Tillman was, according to Eric Sundquist, taking a page directly from Dixon.: Certainly the Senator eerily echoed a character who crops up repeatedly in Thomas Dixon: the filicidal white father, professing an urge to murder his daughter in order to save her from violation. Tillman evoked in his speech first and central model of miscegenation: the black beast attacking the white virgin who cannot fend him off. only adequate response for Dixon and Tillman to such merging of and white bodies is to break the bodies involved. man's must be castrated and lynched, the white woman's killed, by the black beast, by herself, or symbolically executed in the imagination of her father, who would rather find her dead than in bed. imperative to separate the two bodies plays out in the way the man's body gets separated from itself, his testicles severed, and the way Tillman imagines his daughter's bones scattered on the ground. At the beginning of the twentieth century, Thomas Dixon Jr. was a popular and influential writer, as evidenced by the echoing of his rhetoric in the speeches of the nation's political leaders. To Sundquist, Tillman's speech indicates two things: the degree of popularity, and the reason for it. Dixon's great popularity.., depended upon a leering, propagandistic portrait of the rapist.(3) Today, Dixon is known mostly through his connection to the D. W. Griffith movie Birth of a Nation (1915), based on two of earliest novels, Leopard's Spots (1902) and Clansman (1905).(4) Of course, Birth of a Nation has its technical brilliance to justify its continued life despite its racist content. Unlike Griffith, Dixon does not have artistry to secure him a place in history. Not only was he a racist, he was a bad writer. Given this deadly combination, it seems sensible to consign Dixon to a well-deserved obscurity. At best, Dixon seems a cultural footnote, a popular writer who articulated the racism and separatism that surged at the turn of the century. It was a wave that Dixon both helped generate and rode, and that ultimately left him beached, an antiquated racist unable to adjust to new literary tastes in the 1920s and 1930s, an anachronism. …

Patterns of Migratory Fuelling in Whitethroats Sylvia communis in Relation to Departure

Whitethroats at a coastal autumn stopover site were supplied with mealworms ad libitum and their fuel accumulation rates were recorded by repeated weighings by means of a remote-controlled balance. This study focuses on two questions: (1) How does the daily fuelling rate change in relation to departure? (2) Is the decision to depart affected by weather conditions? The fuelling rates were not constant during the fuelling period. A decreasing fuelling rate close to the departure was evident in both first-year and adult birds and as many as a fourth of the birds did not gain any body mass on the last day before departure. Among possible explanations for the observed pattern are mass-dependent costs, adverse weather conditions as well as physiological changes in preparation for the flight. The decision to depart was not affected by local weather conditions (wind and cloudiness) and some individuals departed under head wind and overcast conditions. The frequency of strong head winds was, however, low during the period of departure. Weather data do not support the hypothesis that individuals that did not gain any body mass on the last day did so as a result of their departures being delayed as a consequence of adverse weather.

A feeding experiment on migratory fuelling in whitethroats,Sylvia communis

The influence of food abundance on whitethroats' behaviour when preparing for autumn migration was investigated in a feeding experiment on the island of Gotland in the Baltic. Whitethroats attracted to a feeding site during post-juvenile moult attained a stable body mass 1.4g higher than birds in natural conditions. This fuel load is well below the maximum that whitethroats could deposit. After maintaining stable body mass during moult, the whitethroats started to gain mass and thereafter soon departed on migration. This shift was due to the birds increasing their gross food intake by about 70%. Both the average rate of fuel deposition (about 7% of lean body mass per day) and the average departure fuel load (over 50% of lean body mass) were much higher for birds at the feeding site than for birds in natural conditions. No correlation between rate of fuel deposition and departure fuel load was found at the feeding place. Larger departure fuel loads in late individuals suggest that departure decisions are affected by temporal cues. Comparisons with models of time-minimization during migration show that the lack of correlation between rate of fuel load and departure load contradicts the predictions in one model. In another model, where a finite distance is included, the relationship between rate of fuel deposition and departure fuel load is predicted to be step-wise. This means that within certain ranges of rate of fuel deposition the departure fuel load should not change, which is consistent with the result found in this study.

The effects of prey size on diet differentiation of seven passerine species at two spring stopover sites

Prey size was evaluated for seven passerine trans‐Saharan migrant species at two spring stopover sites in Sardinia, Italy. The species considered were Pied Flycatcher Ficedula hypoleuca, Spotted Flycatcher Muscicapa striata, Redstart Phoenicurus phoenicurus, Garden Warbler Sylvia borin, Whitethroat Sylvia communis, Willow Warbler Phylloscopus trochilus and Wood Warbler Phylloscopus sibilatrix. The analysis was made for three prominent prey types: beetles (Coleoptera), ants (Hymenoptera: Formicidae) and “flying prey” (wasps and bees [Hymenoptera, excluding ants] and flies, Diptera, pooled), The prey size distribution in the diets of some species was very similar to that caught in our insect traps, showing that our estimates of availability are, at least partially, relevant. On the whole, diets deviated from food available in a species consistent way. The size distributions of “flying prey” differed between the two sites but were almost constant in the birds' diets. In contrast, size distributions of available beetles and ants at the sites were similar but were different in the birds' diets. Different feeding behaviour of the birds, in terms of physiological constraints during migratory stopovers, is discussed. Paired species comparisons show that the diets of most species differ significantly in the distribution of the size classes of at least some prey types. The conclusions drawn from the comparisons of the size distributions of all prey items collected from a bird species in one season are very similar to the conclusions drawn from comparisons based on the presence/absence of a size class per faecal sample. We compared the similarities of diet with and without using information on prey size. With the exception of the Pied Flycatcher and the Redstart at one of the study sites, size information did not add to diet segregation. Certain size classes within prey types tended to be common in the diet of these migrant passerines. However, specialization on certain size classes within broad taxonomic categories was not evident.