bluuebunny/crossref_metadata_2025_split huggingface dataset:
THE SELECTION OF TITS PARUS SPP. BY SPARROWHAWKS ACCIPITER NISUS
Authors: GEER TIMOTHY A. 
Published: April 2008

SummarySelection of the Wytham Wood population of tits by Sparrowhawks during the tit post‐fledging period was studied over three years. Within three weeks of the median date of tit fledging, juvenile Blue Tits were selected more frequently than juvenile Great Tits but thereafter juvenile Great Tits were selected more frequently; it is suggested that the former was due to greater vulnerability of Blue Tits in the two to three weeks after fledging, and the latter due to changes in availability due to immigration/emigration of juvenile tits. When juvenile tits killed by hawks were compared on the basis of brood and physical characteristics with their cohorts in the entire population and in those surviving to the following year, only one factor, fledging date, was found to have affected selection by hawks. It is believed that this was because hawks selected late fledged young still in family parties in preference to early fledged young which had already become independent of their parents and were foraging in the better cover of the forest canopy. When adults killed by hawks were compared with all adults available for selection on the basis of species, sex, timing of nesting and whether or not they had been born in the wood, the only selection trend found was that male Great Tits were taken more often than females due, possibly, to greater risk of exposure for males while foraging or during territorial behaviour. When compared with availability, juveniles were selected more frequently than adults in only one year, possibly a result of yearly differences in the number of prey available per hawk, the rate of non‐predator related juvenile mortality or unknown hawk hunting strategies. The overall finding of relative non‐selectivity by hawks was attributed to the surprise factor associated with the hunting methods used by Sparrowhawks in woodland.
Palaearctic migrants in the central Sudan
Authors: Hogg P. , Dare P. J. , Rintoul J. V. 
Published: April 2008

A brief account is given of the topography and climate of the Sudan and a more detailed survey is made of the vegetation and habitats afforded to wintering Palaearctic migrants in the Sahel and Soudan savannah zones in the central Sudan. Climatic conditions during the migration seasons are mentioned and the utilization of habitats by wintering migrants is broadly surveyed.The status of 196 Palaearctic migrant species is treated briefly. The basic observational data are tabulated to summarize observed patterns of migration in terms of date, relative abundance and region (for which purpose the central Sudan is divided into four from west to east). Hitherto unpublished field notes of the authors and their collaborators are used, together with dated observations (including specimens collected) of earlier authors, to provide the fullest data on each species.Moreau's (1967) paradox is discussed as it relates to the Sahel and Soudan savannah zones in the central Sudan, together with the degree of competition with resident African species in those zones. Some disparities between the spring and autumn abundance and d. istribution of Palaearctic migrants are discussed in relation to 40 species ana some tentative views are advanced on the possible reasons for such disparities. Evidence is adduced which points to Lanius minor and Coraczus garrulus (and possibly Circus pygargus, partially at least) having loop migrations, south through the Sudan and north through Arabia, and Falco wespertinus south through the Sudan and north through West Africa. An explanation is offered for the greater volume of water birds observed migrating down‐Nile in spring compared with their volume up‐Nile in autumn, and for the reversed situation observed in the region west of the Nile for these same species.Shelduck Tadorna tadorna is included in the Sudan list for the first time.
Turnover and dispersal in a Peregrine Falco peregrinus population
Authors: Mearns R. , Newton I. 
Published: April 2008

In south Scotland, most Peregrines returned to the same territories to breed in successive years, though a few females changed territory from one year to the next.Annual mortality among breeding birds was at most 9% among females (or 11% in both sexes combined). There may have been considerable annual variation, however, and excluding one exceptional year out of five reduced the estimate for females to 7%. These estimates are maxima, but are still considerably lower than those obtained from ring recoveries of dead birds reported by members of the public.Among trapped birds, four males first bred at age two years, one at three and another at four or five; two females first bred at one year, 13 at two years old and one at three. Five other females which were seen to be in first‐year plumage but were not trapped, also laid eggs, and 12 other such paired females held territory but did not lay. Only one paired male held territory in first‐year plumage.In their movements between natal and breeding territories, some females moved further than males, with median distances of 83 and 58 km respectively. In addition, of birds trapped breeding in the study area, a greater proportion of the males than of the females had been born locally, despite an equal sex ratio among fledglings; this was also consistent with a greater dispersal of females. In general, Peregrines made much longer movements in their first year of life than subsequently. Movements were in any direction.
Moult of Malayan Barn Owls Tyto alba
Authors: Lenton Graham M. 
Published: April 2008

Moult in Malayan Barn Owls Tyto alba was studied in two pairs of wild collected captive birds and from feathers taken from nest sites throughout peninsular Malaysia.Post‐juvenile captive birds moulted nearly to completion prior to first breeding, beginning with P6 at a mean age of 301.5 days. This contrasted with the only other study of moult in captive Barn Ow‐Is in Germany when moult began at an age of 400 days, and then continued for a protracted period of two years separated by a suspension of moult during the normal breeding season.The complex sequence of moult in primaries and secondaries both in the Malayan and German birds was similar.Moult among adult Malayan birds in the wild showed a broad and somebyhat irregular seasonal trend With lower incidence during peak breeding periods.
Maternal nutrition, egg quality and breeding success of Scottish Ptarmigan Lagopus mutus
Authors: Moss R. , Watson A. 
Published: April 2008

Samples of Ptarmigan eggs were hatched in captivity. They had been taken from ground adjacent to study areas where the wild birds' breeding success by early August, and their food plants, were measured.Almost all deaths of chicks in captivity occurred within a few days of hatching and examination postmortem showed no specific cause. The proportion of chicks which died in captivity before 15 days of age varied markedly between years and study areas. These variations occurred in parallel with variations in breeding success in the wild populations from which the eggs had been taken. It was concluded that the survival of chicks both in captivity and in the wild was determined in part before the eggs hatched.Variations in breeding success from year to year were correlated with the number of days that the food plants had been growing before the hens finished laying. Breeding success in the wild and chick survival in captivity were better for a ‘rich’ area overlying some base‐rich rocks than for a ‘poor’ one overlying granite and with less blaeberry. It was inferred that, as in Red Grouse, maternal nutrition affected breeding success through the quality of the eggs.
Successive nest building and polygyny of Fan‐tailed Warblers Cisticola juncidis
Authors: Ueda Keisuke 
Published: April 2008

The polygynous mating system of the Fan‐tailed Warbler Cisticola juqcidis was investigated between 1978 and 1981. The male warbler builds many nests unaided; however, he has no more than one active vacant nest for courting at any time. Nest building lasted from April until August. After completing the outer fabric of a nest, the male advertised it and led a female to the nest site by a unique invitation flight. On average a male built 6.5 nests during one breeding season and three of them were accepted by females. The most successful male completed 18 nests, and mated with 11 females. Out of a total of 111 males which established a territory, 30 had no mate, 14 were monogamous, and the rest were polygynous. About 50 to 70% males were polygynous over the four years. The sex ratio varied from 1.41:1 to 2.17:1 (females: male) in the breeding population. It was partly caused by the presence of ‘floating males’. After the completion of the outer fabric of the nest, the male warbler did not take any further role in nesting and caring for young.The polygynous mating system of the Fan‐tailed Warbler is characterized by successive nest building. Its extreme development results from the long breeding period and the male having no role in parental care.
Slow continuous wing‐moult of Zebra Finches Poephila guttata from southeast Australia
Authors: ZANN RICHARD 
Published: April 2008

Moult of the remiges was studied over eight years in a population of Zebra Finches from southeast Australia. In first‐year birds the first primary was lost at mean age of 80 days in both sexes; moult took 204 days to complete in males and 223 in females. Birds hatched in autumn postponed the start of their primary moult until spring. Primaries were replaced slowly in a rigid, non‐overlapping, ascending order from #1 to #9 but the secondaries did not display a rigid sequence.Adult Zebra Finches moulted remiges throughout the year. Primary moult was initiated in any month. Primary moult had a mean duration of 229 days for males and 240 days for females. Primaries moulted in continuous waves: the interval between successive moults in males was –16 days and +6 days in females. Limited food, low temperatures and breeding slowed, but did not stop, wing‐moult. Birds caring for eggs and young actively replaced remiges.The pattern of wing‐moult displayed here by Zebra Finches is exceptional for passerines and may be related to the opportunistic breeding strategy necessary in an arid, unpredictable environment. Its presence in the Victorian birds may be non‐adaptive.
Phylogenetic relationships of turacos (Musophagidae; Cuculiformes) based on comparative chromosome banding analysis
Authors: TUINEN P. VAN , VALENTINE M. 
Published: April 2008

Cladistic analysis of chromosome banding patterns in nine species of turacos (Musophagidae; Cuculiformes) revealed the existence of two clades, one comprised of species of the genera Tauraco, Gallirex (=Tauraco) and Musophaga, and another of species of Corythaixoides. The results are consistent with the allocation of the former to a subfamily Tauracinae and the allocation of the latter to the subfamily Criniferinae which also includes Crinifer. Comparative C‐banding suggests that the putatively polytypic Tauraco corythaix is occupied by more than one species; more such studies in this group may resolve other questionable cases of conspecificity. Comparison of our results to studies of Cuculidae suggest that they do not share with musophagids two major derived fissions that set musophagids apart from other avian orders. Detailed comparison of ancestral karyotypes from several groups (Galliformes, Cuculidae, Musophagidae and Opisthocomidae) may help to resolve their still unresolved phylogenetic relationships.Our results confirm previous studies showing karyotypic uniformity within avian orders. The uniformity suggests a negligible role for chromosome rearrangement in speciation in this group, since several indisputably distinct species do not differ karyotypically in any significant fashion. Intraspecific uniformity is punctuated by the presence in Livingstone's turaco Tauraco corythaix livingstonii of inversion heteromorphism, the class of rearrangement encountered most frequently in other avian species.
Factors determining the laying date of the Waved Albatross Diomedea irrorata
Authors: RECHTEN C. 
Published: April 2008

The Waved Albatross laying period is between mid‐April and the end of June. This paper investigates the factors determining when, during this period, a female lays. It is shown that birds breeding for the first time lay relatively late. For older birds, the laying date depends on date and outcome of the previous year's attempt: females that bred successfully in the previous year lay slightly later than in that year, while birds that failed lay earlier. A corresponding difference exists in the dates of arrival at the breeding grounds of successful and failed males. It is argued that one calendar year is not quite sufficient for pairs that have reared a chick successfully to regain breeding condition, while failed breeders can choose the laying date more freely.Under catastrophic El Niño weather conditions in 1983, all albatrosses arrived late at the breeding grounds, but still the birds that had failed in 1982 were clearly earlier than those that had reared a chick.
Seasonal variations in feeding range and flock structure of the Rook Corvus frugilegus in eastern Ireland
Authors: MACDONALD R. A. , WHELAN J. 
Published: April 2008

The feeding range and flock structure of Rooks showed temporal variations caused mainly by the dispersion of food and reproductive behaviour.Feeding range was restricted in spring, autumn and early winter when food availability was high and Rooks were reproductively active. A large feeding range occurred in late summer and late winter, when food availability was either generally low or locally distributed and when Rooks were reproductively inactive. The occurrence of flocks common to several rookeries mirrored variations in feeding range; mixed rookery flocks were more common in late summer and late winter. Similarly, the size of the rookery (as measured by the number of nests) was related to feeding range only when Rooks were reproductively inactive and at such times larger rookeries had greater feeding ranges.Flock structure showed similar seasonal variations; small widely spaced flocks predominated in summer, autumn, early winter and spring, whereas large dense flocks occurred in late winter. Diurnal variations in flock structure occurred within any one season. Both seasonal and diurnal variations in flock structure may be determined by the dispersion of the prey and the feeding strategy used to obtain it, reproductive behaviour and the risk of predation.
Reproduction and survival of polygynous and monogamous Blue Tit Parus caeruleus
Authors: DHONDT ANDRÉ A. 
Published: April 2008

In a seven‐year study of Blue Tits in optimal habitat near Antwerp, Belgium, 45 polygynous broods involving 22 males out of 667 successful first broods were found. In another 43 nests no male was found, although a major effort was made to trap all adults. The estimated proportion of polygynous males is 3.4%, if only confirmed cases are considered, but 10.8% if all possible cases are included. One male was paired simultaneously to three females.Primary females (laying earliest in a triangle) were as successful as monogamous ones. Secondary (laying later in a triangle) and deserted females (nests in which no male was trapped), although still quite successful, raised fewer young and in one plot had a lower probability of recruiting offspring.Both in males and females, the frequency of polygyny was independent of age. Adult survival did not differ between monogamous and polygynous males. Among females no effect of pairing status on survival was found in one plot, but in a second plot monogamous females survived better than others. It is concluded that in any study of Blue Tits in optimal habitat one could expect to find polygyny.
A quantitative analysis of habitat preferences of Woodcock Scolopax rusticola in the breeding season
Authors: HIRONS GRAHAM , JOHNSON T. H. 
Published: April 2008

In Britain, prior to breeding, Woodcock Scolopax rusticola switch from feeding on pastures by night to feeding in woodland by day. Their major food is earthworms (Lumbricidae). In April and May 1985, vegetation structure and composition and soil parameters including earthworm numbers (30 habitat variables) were recorded for quadrats containing 50 feeding locations of six radio‐tagged birds, seven nests and 50 random locations in Whitwell Wood, northeast Derbyshire.Significantly different mean values between feeding and random sites were found for 11 habitat variables. Feeding sites were in younger stands, with a higher percentage ground cover of dog's mercury Mercurialisperennis and consistently high values for pH. Earthworm biomass was on average 82% greater than in random plots. Areas of beech Fagus sylvaticus were avoided. A discriminant function based on six habitat variables correctly classified 85‐5% of the feeding and random sites; 70% of the feeding locations were correctly classified by a jack‐knife procedure. The important factors determining where feeding occurs are probably safety from avian predators and high availability of earthworms.Discriminant analysis of the habitats used for feeding by solitary birds, broods and for nesting produced significant functions which correctly classified 84% of sites. Nests were in areas with a high percentage cover of brambles Rubus spp. and more open ground vegetation. Broods and solitary birds used similar areas characterized by denser ground vegetation than nest sites.The results of this study indicate that both habitat structure and food availability influence the distribution of Woodcock in the breeding season.
Breeding site fidelity and natal philopatry in the Redshank Tringa totanus
Authors: THOMPSON PATRICK S. , HALE W.G. 
Published: April 2008

This paper presents the results of a study carried out on breeding Redshank in the Ribble Marshes, Lancashire, England.Redshank tend to return to the same breeding area year after year. There was no detectable sex bias in return rates. Experienced birds were more site faithful than inexperienced birds, with previously successful birds exhibiting the highest degree of breeding site fidelity. Older, more experienced birds were more successful at hatching eggs than inexperienced birds.Breeding dispersal was the same both within and between years. Faithful pairs and males nesting with a new mate dispersed significantly shorter distances than females nesting with a new partner. Dispersal distances in female Redshank were affected by breeding success: unsuccessful females, nesting with a new mate, dispersed significantly farther than successful females. A pair's breeding success influenced the following year's mate fidelity. However, other factors such as overwintering survival and date of return may also have influenced mate fidelity.Redshank were highly faithful to their natal area; a high proportion of birds that survived post‐fledging mortality returned to breed in their area of birth. No sex bias in natal dispersal was detected. Approximately 50% of Redshank breed in their first year of life.
Nesting biology and mating system in an alpine population of Temminck's Stint Calidris temminckii
Authors: BREIEHAGEN TORGRIM 
Published: April 2008

A colour‐marked population of Temminck's Stint Calidris temminckii was studied in an alpine area of southern Norway over 3 years. Birds arrived from late May until late June, and egg‐laying occurred over approximately 1 month. Each year, one to three males out of about 15–17 males still displayed after the last recorded clutch‐completion date.There were six documented cases of double‐clutching. Inter‐clutch intervals varied (range 2–8‐9‐1 days), longer intervals probably being caused by weather‐induced food shortage. A successively bigamous mating pattern was recorded in both sexes. A polygynously (bigamously) mated male invariably incubated its first mate's clutch. Females consistently changed mates between layings of successive clutches, the last one incubated by themselves.An excess of nesting females was found, particularly in parts of the study area where nesting started late. This appears to have been caused mainly by a considerable annual immigration of late‐arriving females, having probably laid their first clutch(es) elsewhere, in nesting habitats that were available earlier. I suggest that male availability is relatively unimportant compared with other factors governing female movements between layings of successive clutches; females may increase their reproductive success, either by achieving a longer egg‐laying season (i.e. by moving from nesting habitats/areas available early in the season to those available later) or by being capable of utilizing favourable feeding habitats/conditions in different areas.
A preliminary assessment of the quantities of Shetland sandeels taken by seabirds, seals, predatory fish and the industrial fishery in 1981–83
Authors: FURNESS R. W. 
Published: April 2008

Shetland holds a very high concentration of seabirds that feed to a large extent on sandeels Ammodytes marinus. The available data allow an assessment of the quantity of sandeels consumed by seabirds each year 1981–83, and sensitivity analysis suggests that this figure is accurate to about ±30%. Only very approximate estimates of sandeel consumption by seals and by predatory fish can be made.From 1981 to 1983 the Shetland fishery catch averaged 45,000 tonnes of sandeels, with an estimated natural consumption of 47,000 tonnes by seabirds (predominantly Guillemots Uria aalge and Fulmars Fulmarus glacialis). Based on sensible guesses and the little data available, consumption may have been about 25,000 tonnes by predatory fish and 9,000 tonnes by seals. The figures suggest that natural mortality of the Shetland sandeel stock in 1981–83 was considerably in excess of the figure used in VPA stock assessments. Further information is required for key variables in order to permit better estimates of sandeel stock dynamics. In particular, we need better data on numbers and diets of seals in Shetland, numbers and diets of predatory fish, diets and foraging distributions of Fulmars, especially out with the chick‐rearing period. In future, sandeel biomass assessments for Shetland should incorporate estimates of predation by seabirds as this is clearly an important part of total mortality for the stock.
Effects of food variability on growth rates, fledging sizes and reproductive success in the Yellow‐eyed Penguin Megadyptes antipodes
Authors: HEEZIK YOLANDA VAN , DAVIS LLOYD 
Published: April 2008

Effects of a change of diet on growth rates and fledging sizes of Yellow‐eyed Penguins Megadyptes antipodes were examined at two breeding areas on South Island, New Zealand, during two breeding seasons. An adverse change in diet was observed in the second season. Evidence for this included depressed growth rates of weight, differential growth of weight and most morphometric parameters between one‐ and two‐chick nests in the second season, lower fledging weights, lower adult body weights, delayed moult, higher chick mortality and higher adult mortality during moult. The change in diet is suggested as being from one including oil‐rich prey species, to one of oil‐poor species.Growth rates of first‐ and second‐hatched chicks, and of survivors and non‐survivors within a brood were not significantly different in either season, and growth rates of two‐chick broods were only slightly slower than one‐chick broods for some parameters in the second season. This, and synchronous hatching of chicks, equal egg‐size and lack of sibling competition during feeding sessions, suggests that brood reduction is not an option available to Yellow‐eyed Penguins, and that food supply may not be a limiting factor in the majority of breeding seasons.Few changes in growth rates of morphometric parameters at either breeding area, and similar absolute sizes at fledging, indicate that slowing of growth rates of morphometric parameters only occurs when feeding conditions are so bad as to result in mortality and that, although fledging periods may be longer, patterns of development remain essentially unchanged.