bluuebunny/crossref_metadata_2025_split huggingface dataset:
Response to experimental photoperiods by a migratory bunting, Emberiza melanocephala
Authors: Kumar Vinod , Tewary P. D. 
Published: April 2008

Little is known about the effects of photoperiod on avian migrants that visit southeast Asia. In this paper, we report experiments performed on an emberizid finch, the Black‐headed Bunting Emberiza melanocephala, to investigate its photoperiodic responses under artificial photoperiods, and continuous light and darkness.Two series of experiments were performed with the photosensitive male birds. In the first series, different groups were exposed to seven different artificial photoperiods: 3L/21D, 6L/18D, 8L./16D, 11L/13D, 12L/12D, 15L/9D and 20L/4D, for 30 days. They were weighed and laparotomized at the beginning and end of the experiments. The birds responded to 12L/12D, 15L/9D and 20L/4D, but not to 3L/21D, 6L/18D, 8L/16D and 11L/13D. In the second series, photosensitive birds were placed under continuous light (LL) and dark (DD) conditions for 130 and 90 days. Periodic observations indicated that testicular growth and fattening followed by involution and fat‐depletion had resulted in birds under LL, indicating the onset of photorefractoriness, while DD had no effect either on gonads or fattening in the buntings.Our results demonstrate that light stimulation is a prerequisite to reproductive and metabolic activities (pre‐migratory and migratory changes, fattening and weight gain) in the Black‐headed Bunting, which has a photoperiodic threshold to these events at between 11 and 12 h daily photoperiods.
Breeding displays of the African Spoonbill Platalea alba
Authors: Kahl M. P. 
Published: April 2008

Breeding colonies of the African Spoonbill Platalea alba were studied in Kenya and South Africa during 1980. In Kenya nesting was in trees and in South Africa in reedbeds; the nesting area in both colonies was shared with other species of waterbirds.During the breeding season, adult African Spoonbills acquire a more immaculate plumage and brighter soft‐part coloration. Sexes are distinguishable by the larger size and more robust proportions of males.Males are more sedentary and aggressive during pair formation, and females are more mobile and submissive. The general pattern of pair formation is described, with a variety of ritualized courtship displays acting to bring and keep the sexes together.Comfort movements, vocalizations, and 14 distinct ritualized social displays are described and illustrated for the African Spoonbill. Some similarities and possible homologies with displays of other ciconiiform birds are mentioned. This paper represents the first part of a continuing study of the comparative ethology of the five species of spoonbills of the world.
The timing of breeding and wing‐moult of four African Sturnidae
Authors: Craig Adrian 
Published: April 2008

Wing‐moult of the Cape Glossy Starling, Red‐winged Starling, Pale‐winged Starling and Pied Starling was examined primarily from specimens in southern African museums. Breeding data were obtained from nest record cards.The Cape Glossy Starling breeds from October to March, with the moult period from December to May. There is no evidence of moult‐breeding overlap in individual birds. The Red‐winged Starling breeds from September to March, while the moult takes place between November and April, overlapping with the second broods. The Pale‐winged Starling breeds from October to April and moults between November and May. The Pied Starling moults between November and April, while breeding varies regionally, occurring concurrently with moulting in some areas.
A new species of sunbird from Tanzania
Authors: Jensen Flemming P. 
Published: April 2008

During August 1981 a ten‐day visit was paid to Mwanihana Forest Reserve, a rain forest on the eastern scarp of Uzungwa Mountains, eastern Tanzania. Stuart et al. (1981) and Stuart & Jensen (1981) have documented a number of notable range extensions of forest birds from this area, which, until recently, was unexplored by ornithologists. Jensen & Stuart (in press) described four new subspecies of birds and Homewood & Rodgers (in press) described a new subspecies of the Crested Mangabey Cercocebus galeritus from the same locality. Both the physiognomy of the rainforest and the composition of the avifauna suggest strong affinities between Mwanihana Forest, and the forested scarps of other basement block mountains in eastern Tanzania, most notably the Mgurus and the Ulugurus (Stuart, et al. 1981).On 2 August 1981, while carrying out a mist‐netting study in the forest at 1000 m, a male specimen was caught of a very distinct and hitherto undescribed sunbird. On a subsequent visit in September 1981, Miss T. A. van der Willigen, S. N. Stuart and Dr K. M. Howell secured a female specimen of this new species to be described as:
On the maintenance and origin of alternative strategies in the Ruff Philomachus pugnax
Authors: Rhijn JOHAN G. van 
Published: April 2008

This paper has tried to answer the question of how the independent and the satellite strategy of the Ruff originated and has been maintained during evolution. It is not intended as a report of a piece of completed research but gives a number of tentative, but testable hypotheses.Data are presented that independent males and satellites are equally successful in copulating, provided that almost all copulations occur on leks, and independent males and satellites spend an equal proportion of their time on leks. The extent that males with the different strategies are attached to leks is analysed. Within the group of independent males, considerable differences exist: a resident male is strongly attached to only one particular lek and a marginal male seems to sample many leks. A satellite male behaves intermediately: he is attached to a limited number of leks. The mechanism for the maintenance of both strategies could not be explained by competition for resources (copulations). Contests between independent males and satellites are asymmetric, the satellite being the weaker contestant. The mechanism seems to be due to enlarging the accessibility of the resource by cooperation between both strategies.The ideas on the origin of the system are based mainly on the behaviour of females. There is no relation between the distribution of leks and the size of a female's foraging area, except that most leks are situated along the migration route. It further seems that the number of copulating females in the Netherlands is larger than the number of males on leks, but the number of breeding females is much lower. It is suggested that many females copulate on migration, which is related to extreme breeding conditions in the north of the range. Apart from a change in the sex ratio from south to north, a change in the proportion of satellites is also predicted. The origin of the system is ascribed to the incompatibility between favourable food conditions for chicks and further possibilities for inter‐male competition on leks in the same area. The satellite strategy is considered as being derived from a non‐competitive strategy accompanying females on migration. In the phase of cooperation between resident and satellite males, individual recognition became important. This could be the factor underlying the evolution of white plumages in satellites and the extreme plumage diversity in independent males.
Variation in numbers, territoriality and flock size of a Goldcrest Regulus regulus population in winter
Authors: Hogstad Olav 
Published: April 2008

A Goldcrest Regulus regulus population living in a spruce‐dominated forest near Oslo (c.60°N), in southern Norway, was studied during the winters (November‐March) from 1966–67 to 1971–72. A significant reduction in population size occurred between November and March, the recorded values varying from 76 to 96%, with a mean reduction for all six winters studied of 86%. This winter decline in numbers was significantly correlated with both precipitation (i.e., snowfall) and ambient temperature, but not with bird density. Spiders were the predominant prey items of the Goldcrests, and it is suggested that the birds experience food shortages that affect their survival rate. Although not statistically significant, a mean change in the ratio of males:females from 2:1 in October‐November to 10:1 in December—February was observed, suggesting that a greater mortality of females than males occurs during the winter.Partly based on data for colour‐banded birds, it is suggested that the Goldcrests form social flocks, which move around as individual units within territories of about 9 ha (7.5 12 ha, n= 5) in extent. The mean flock size decreased significantly from 4.57 (n= 157) birds in November‐December to 2.82 (n = 74) birds in January‐February, probably because of the reductions in the size of the local population during the winter. The mean flock size in November‐December varied inversely with the ambient temperature (r= ‐0.92).
Double nesting of the Red‐legged Partridge Alectoris rufa
Authors: Green R. E. 
Published: April 2008

Some Red‐legged Partridge females lay two clutches in separate nests, one immediately after the other, which are incubated separately by the male and female of the pair. Pairs remained together during the laying of both clutches so that there were delays between the end of laving and incubation at the first nests. Incubation of the two nests began at approximately the same time but discrepancies of up to ten days occurred. Males incubated first clutches and females usually the second, but probably the first if the second was destroyed during laying. The proportion of surviving eggs which hatched was similar in first and second clutches but declined if the delay between laying and hatching was exceptionally long.Yearling females began laying late and few seemed to attempt two clutches compared with older females of which 60–80% showed the double nesting habit. A model predicting reproductive success for both sexes in relation to the rate of nest predation during laying, suggested that attempting two clutches rather than one would be disadvantageous at high predation rates. Females would produce more young if their mates incubated their first clutch immediately it was complete rather than accompanying them during the laying of the second. However, males may benefit by this delay, even though it exposes the nest to predators for a longer time, because they are able to guard their mate and prevent other males from mating with her and fertilizing eggs of her second clutch.
Laying date, clutch size and egg size of the Mallard Anas platyrhynchos and Tufted Duck Aythya fuligula
Authors: HILL D.A. 
Published: April 2008

The effect of spring temperature on first egg date, laying period and last clutch date was studied in the Mallard and Tufted Duck. Seasonal clutch size and egg size trends were also examined. In years When Mallard laid early, Tufted Duck also did so. The first Mallard clutch was started earlier and laying period was longer in years with a high mean February temperature. The last clutch was started later in years with a high mean June temperature. In Tufted Duck the laying period increased and the last clutch was started later in years with high mean April temperatures.Mean hatching date of Mallard clutches was later in years when the date of peak chironomid emergence was late.In both species, clutch size declined through the season. Egg volume was not related to clutch size in either species, but egg volume in the Tufted Duck declined through the season. No difference in Tufted Duck egg size existed between sites, but the significance of egg size on duckling survival is discussed. Genetic factors related to individual consistency in egg size in Mallard may have obscured egg volume trends during the season because of renesting.
Patterns of variation in size of Boat‐tailed Grackle Quiscalus major eggs
Authors: Bancroft G. Thomas 
Published: April 2008

Boat‐tailed Grackle Quiscalus major eggs averaged 8.09 g wet weight. Mean egg weight represented 8 05 % of female body weight. Based on egg weight, Grackle eggs have a shorter incubation period than the general passerine pattern.Egg weight varied significantly with sequence of laying and between clutches in both two‐egg and three‐egg clutches. Last laid eggs weighed less than first laid eggs. The mean weight of the first two eggs laid in three‐egg clutches did not differ from the mean egg weight of two‐egg clutches. The average clutch of two and three eggs weighed 16.33 g and 24.16 g, respectively.Mean egg weight varied between study colonies and with season. Grackles at East Lake laid eggs that weighed less than grackles at either Alligator Lake or North Lake. Eggs laid during March averaged less than eggs laid later in the season. The locality variation reflects the different timing of nesting between sites rather than food abundance. As nutrient provisioning increases with an increase in egg weight, the seasonal change in egg weight probably reflects improved feeding conditions for the female. This suggests that selection favours beginning laying before reserves of the female are sufficient to lay the largest egg possible.The size of the young at hatching was correlated with egg size. Newly hate had young averaged 79.6% of fresh egg weight. Egg weight did not determine the probability of hatching or starvation of the young. Females do not appear to adjust egg size facultatively depending on the sex of the young. Eggs producing males and females did not vary significantly in weight, whether comparisons were made within or between clutches.
Mechanisms of song differentiation in introduced populations of Chaffinches Fringilla coelebs in New Zealand
Authors: Jenkins Peter F. , Baker Allan J. 
Published: April 2008

Chaffinches Fringilla coelebs were introduced to New Zealand from Great Britain over 100 years ago, and since then their songs have diverged from British ones in both syllable structure and basic organization of syllable sequences. The New Zealand populations seem to be unique in that their songs have undergone differentiation of trill segments by progressive elaboration of syllable morphology and hp ascending and descending changes of pitch. Published sonagrams of British song types have significantly more trill phrases and significantly fewer syllables in the end phrase than do Yew Zealand ones. Many New Zealand song types have much elaborated end phrases and concomitantly simpler trill segments, with songs quite commonly having only one trill phrase. This reversal of complexity between the trill and end phrase in New Zealand seems to have been derived by progressive reduction of the ultimate trill phrase to one syllable, and by recombination of end phrase syllables from different song types into one compound end phrase. The significance of the increased complexity in the end phrases of many song types may relate to the sound transmission properties of dense pine forests in New Zealand, in which Chaffinches are ubiquitous. Elaborate end phrases degrade much less from reverberation in pine forests because individual syllables have more dispersed temporal patterning.Recombination of syllables to form new song types is a major mechanism of song differentiation in New Zealand. Although whole song copying is the predominant mode of replication, very few song types in a locality sample are composed of a unique set of syllables. Rather, song types in an area are interconnected by different combinations of shared syllables, suggesting that the incorporation of some local syllables in a bird's repertoire is sufficient to signal its status as a member of a neighbourhood and also allows the evolution of broadcast complexity.
Recent Ornithological Publications:Books
Authors: Champ BOOKS:Stanley 
Published: April 2008

BOOKS:Abs, M. (ed.) 1983. Physiology and behaviour of the pigeon. Pp. 360; numerous figures and tables. LondonBOOKS:Angus, S. (ed.). 1983. Sutherland birds. A guide to the status and ecology of birds in Sutherland DistrictBOOKS:Cooper, J. (ed.). 1981. Proceedings of the symposium on birds of the sea and shore, 1979. Pp. vi + 474. Cape Town: African Seabird GroupBOOKS:Cramp, S. & Simmons, K. E. L. (eds.). 1983. Handbook of the birds of Europe, the Middle East and North Africa: the birds of the western Palearctic. Vol. 3, Waders to GullsBOOKS:Glutz Von Blotzheim, U. N. & Bauer, K. M. (eds.). 1982. Handbuch der Vogel MitteleuropasBOOKS:Farner, D. S., King, J. R. & Parkes, K. C. 1982. Avian biologyBOOKS:Flint, P. R. & Stewart, P. F. 1983. The birds of CyprusBOOKS:Foiger, H. 1982. KolibrisBOOKS:Mobbs, A. J. 1982. Hummingbirds. Pp. xi+192; 32 colour photographs, 56 black‐and‐white photographs. Hindhead, Surrey: Saiga Publishing Co. LtdBOOKS:Freethy, R. 1982. How birds work — a guide to bird biologyBOOKS:Glutz Von Blotzheim, U. N. & Bauer, K. M. (eds.) 1982. Haridbuch der Vogel MitteleuropasBOOKS:Grant, G. S. 1982. Avian incubation: egg temperature, nest humidity, and behavioral thermoregulation in a hot environment. Ornithological Monographs No. 30BOOKS:Jonsson, L. 1982. Birds of the Mediterranean and Alps. Pp. 160; numerous colour plates and distribution maps.BOOKS:Kalchreuter, H. 1983. The woodcock. See review of Spano, S. 1982.BOOKS:Köing, C. 1983. Auf Darwins Spuren, Oekologische Betrachtungen im Lande des Kondors.BOOKS:Meanley, B. 1982. Waterfowl of the Chesapeake Bay Country. Pp. 210; 104 black‐and‐white photographs and text figures, 8 tables. Centreville, MarylandBOOKS:Siobbs, A. J. 1982. Hummingbirds. See Review of FolgerBOOKS:O'donald, P. 1983. The Arctic Skua: a study of the ecology and evolution of a seabird. Pp. 324; 27 figures, 91 tables. CambridgeBOOKS:Remmert, H. 1980. Arctic animal ecology.BOOKS:Spano, S. 1982. II punto sulla beccacciaBOOKS:Kalchreuter, H. 1983. The woodcock. Pp. 127; line drawings, tables and figures. Mainz: Verlag Dieter HoffmanBOOKS:Sultana, J. and Gauci, C. 1982. A new guide to the birds of MaltaBOOKS:Thibault, J.‐C. 1983. Les oiseaux de la CorseBOOKS:Thomas, K. 1983. Man and the natural world. Changing attitudes in England
Moult of the giant petrels Macronectes halli and M. giganteus at South Georgia
Authors: Hunter S. 
Published: April 2008

Moult scores were collected from colour‐ringed individuals of known reproductive status of the two species of giant petrel, Macronectes halli and M. giganteus, at Bird Island, South Georgia between 1978–81.Both species showed a substantial overlap between breeding and wing‐moult, unlike most other Southern Ocean seabirds. Males started moult before females and both sexes of M. giganteus moulted at an earlier stage of the breeding cycle than M. halli, which breeds six weeks earlier than its congener.Changes in moult rate during the breeding season are documented for both species, with Id. halli showing a rapid increase as the chick nears fledging. Male M. giganteus show a notably different pattern to the other three species‐sex groups, starting moult much earlier (at egg‐laying), with greater individual synchrony and usually suspending primary moult throughout the main chick growth period, whereas only two male M. halli and no females of either species suspended moult. Differences in pattern, timing and rate of moult are interpreted in terms of availability of food resources and the competing energy demands of other activities, especially chick‐rearing.Completion of primary moult could not be observed in the field but was estimated using data frcsm non‐breeding birds and failed breeders; the latter started a rapid moult almost immediately they failed. In both sexes of both species moult is probably concluded at least by early winter.The general pattern of moult in giant petrels at Bird Island is contrasted with that of other populations and species of Southern Ocean seabirds. It is suggested that the unusually extensive overlap between breeding and moult in giant petrels is a consequence of the very abundant and easily available summer food supplies (especially carrion) and the much diminished winter resources, favouring a completion of moult by the beginning of the winter.
Behaviour of young Ringed Plovers Charadrius hiaticula and its relationship to growth and survival to reproductive age
Authors: Pienkowski Michael W. 
Published: April 2008

The behaviour, growth and survival of Ringed Plover chicks were studied in 1974 at Mestersvig, northeast Greenland, and from 1973 to 1976 at Lindisfarne, northeast England. Post‐fledging survival, dispersal and recruitment were also investigated for the Lindisfarne population.Growth rates were similar in both study areas, and to those reported from other sites. A diurnal rhythm in feeding activity was more evident in the Arctic than at temperate latitudes, despite continuous daylight in the former area. This was correlated with low nocturnal temperatures and prey availability. It is concluded that food supply did not limit growth or chick survival in either study area. Brooding decreased progressively during the pre‐fledging period; the relationship of brooding period to age, environmental conditions and area was investigated. The adaptations of feeding and brooding behaviour for arctic and temperate breeding Ringed Plovers are discussed.Survival from hatching to fledging varied between 40% and 60% in different areas and years, and at least 59% of birds survived from fledging to about one year old. Minimum survival from one to two years old was only 57%. but year‐to‐year survival of older birds was higher, that of breeding adults being at least so?;. Most birds returned to the breeding area and attempted to breed when one year old. The extent of dispersal from Lindisfarne and the wintering areas of the Lindisfarne‐breeding birds are investigated.
The annual cycle of the Toc‐toc Foudia sechellarum on Cousin Island, Seychelles
Authors: BROOKE M. DE L. 
Published: April 2008

The Seychelles Fody or Toc‐toc shows a fairly well‐defined annual cycle. A full pre‐nuptial moult, lasting 90–100 days, occurs from February to May at the end of the wet season. During this period males enter eclipse plumage and there is little breeding. In most years there is a peak of breeding during the dry southeast monsoon from May to September. The subsequent period of post‐fledging parental care is lengthy, up to four months. I suggest that this cycle, which minimizes variation in adult energy requirements through the year, may be particularly advantageous to a generalist feeder like the Toc‐toc.Annual adult mortality is not higher than 17–21%, a figure which agrees reasonably with observed juvenile recruitment of 15–16%. The Cousin population of this globally scarce species is estimated at 1300.
The breeding ecology and diet of the Hobby Falco subbuteo in southern England
Authors: PARR S. J. 
Published: April 2008

Brecding densities, nest spacing, breeding habitat, productivity and diet are compared for Hobbies Falco subbuteo in the New Forest (heathland and largely coniferous woodland), river valley farmland and largely cultivated chalk downland. Regular spacing of nests was characteristic of the three areas. The New Forest had the highest density and lowest mean nearest neighbour distance for nests. Nest areas tended to be traditional. A high proportion of clutches were laid in disused nests of Carrion Crows Corvus corone which favoured the crowns of Scots pine Pinus sylvestris. Except on downland, the availability of such sites is unlikely to provide a constraint on Hobby distribution. In the New Forest, woodland clearings and valley mires were a feature of nest territories. There was no evidence of a habitat‐related difference in fledging success.Division of labour between sexes is marked. The male is responsible for provisioning the female throughout most of the breeding season as well as the young. During the incubation period many woodland passerines were taken but when feeding nestlings Hobbies tended to specialize on Swallows Hirundo rustica, House Martins Delichon urbica and, where they had access to more urban areas, Swifts Apus apus. By breeding relatively late, Hobbies take advantage of the availability of the juveniles of such prey on which to feed their young. Large insects supplemented the diet before egg‐laying and when the Hedged young were learning to hunt.