bluuebunny/crossref_metadata_2025 huggingface dataset:
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.
The life cycle of the Upland Goose Chloëphaga picta in the Falkland Islands
Authors: Summers Ronald W.
Published: April 2008

Upland Geese Chloëphaga picta were studied between 1977 and 1980, primarily around Darwin, East Falkland, in order to describe their breeding biology, moulting and adult survival. The population of breeding birds in a valley reached a peak from mid‐September to late November when nesting took place. The average territory length was 240 m in five valleys. Breeding adults generally returned to breed in the same territory each year and with the same mate. Nests were on the ground, usually amongst whitegrass Cortaderiapilosa. The mean clutch size was 6‐1, brood size was 5‐1 and fledged family 3–9. Incubation took 30 days and the fledgling period was about 70 days. Most broods were raised in the nesting territory. Growth of goslings is described. The breeding success between laying and fledging was 0–34 (in 1977) and 0–29(in 1978), giving an annual production of 21 and 1–8 young per breeding pair. Fledglings remained in family parties through the autumn and winter and were evicted by their parents in early spring. Some siblings stayed together for short periods and then joined other non‐breeders. Females started pairing at ten months of age and most were paired at 17–18 months. Some bred for the first time at 23 months. Males started pairing at about 20 months of age. Flightless moult (shedding) took place at ponds or in sheltered inlets of the sea, in flocks of up to several hundred birds. Flightless birds were found between 14 November and 11 February, though 50% were flightless between 26 November and 2 January. Individuals were flightless for 36 days. First‐year birds were more synchronized in shedding than adults. The percentage of first‐year males (in the male component) varied from 16‐5 to 45‐9% in shedding flocks, and significantly more males were present in some flocks. The flocks were composed of first‐year and second‐year birds too young to breed and failed breeders. The percentage of a shedding population which returned to the same site in successive years was 25‐3 and 15‐1% at two localities. The moult of other feather tracts is described. The annual survival rate of breeding adults was 82%. A model of the population dynamics is presented. The current level of culling to control the goose population is less than the number which must die each year to maintain a stable population.
Ecological segregation of woodcreepers (Dendrocolaptidae) in the state of Rio de Janeiro, Brasil
Authors: Brooke M. de L.
Published: April 2008

The 48 Neotropical woodcreepers feed in a variety of ways, such as among Mauritia palm fronds (e.g., Cinnamon‐throated Woodcreeper Dendrexetastes rufigula), as obligate ant followers (e.g., White‐chinned Woodcreeper Dendrocincla merula) or by probing the ground (e.g., Scimitar‐billed Woodcreeper Drymornis bridgesii). However the typical foraging method of a member of this group, which lacks obvious ecological counterparts in the rainforests of South‐East Asia and Africa (Pearson 1977, G. H. Orians, pers. comm.), is to glean bark‐living arthropods while ascending a tree trunk, rather in the manner of a Certhia treecreeper. The bird then crosses, often by a descending glide, to begin the ascent of another trunk. Determinants of a species' preferred feeding station are thus likely to include height Above ground and trunk diameter, both of which are readily measured, and bark characteristics. The woodcreepers are therefore potentially admirable (and hitherto unused) subjects for quantitative studies of niche overlap. I report here on the overlap of the woodcreepers of the rainforests of South‐East Brasil.
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.
Song and plumage effects on aggressive display by the European Robin Erithacus rubecula
Authors: Chantrey David F. , Workman Lance
Published: April 2008

The response was observed of territory‐holding male European Robins ETithacus rubecula to red— and brown‐breasted model Robins which were presented either simultaneously with tape‐recorded Robin song, or with no song. Robins displayed and sang at the silent red‐breasted model, but sang and displayed much more at the models that were presented with song. It is suggested that, while the red breast is one important feature of Robins eliciting aggressive behaviour, song is also important. The relationship of these findings to studies of stimulus features eliciting behaviour in other species is discussed.
The social behaviour of the Pin‐tailed Whydah Vidua macroura in northern Ghana
Authors: Shaw Philip
Published: April 2008

This paper describes the pattern of territory usage by male Pin‐tailed Whydahs Vidua macroura, and the display postures used by territorial males, intruding males and visiting females are described. Each territory holder used one or two favoured display sites at which he was visited by, and displayed towards females in groups of one to eight. The frequency of display flights and song output reflected the diurnal pattern of visits by females. Each female was courted by up to six males, but the number of copulations observed was too few to indicate the type of mating system used. The operative sex ratio was estimated at 1:6 (females to territory holders), and the results of a removal experiment suggested that a proportion of males was prevented from breeding.
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.
The population dynamics of the Eider Duck Somateria mollissima and evidence of extensive non‐breeding by adult ducks
Authors: COULSON J. C.
Published: April 2008

The dynamics of an Eider Duck population have been investigated over 25 years, using census and capture‐mark‐recapture methods. During the study the population increased two and a half fold, with two periods of major increases in numbers, giving a stepped growth pattern. Mean clutch size showed considerable annual variation, the extremes being 5.40 and 3.78 eggs. The variation in clutch size was greater than that recorded in the Netherlands. Adult female Eiders had a high annual survival rate, averaging 0.895, and varying between 0.75 and 1.00 in individual years. The survival rate decreased markedly in the old ducks. There was no indication of any change in the survival rate during the study. Recruitment of ducks to the breeding group was irregular, with most years showing little recruitment and a few years high recruitment. However, recruitment, associated with good duckling survival, appears to have been the main factor associated with increase in the population. In many years, an appreciable proportion of the surviving ducks, which had already bred in a previous year, failed to nest. The extent of non‐breeding increased during the study and in one year, 1973, this reached 65%. Lower clutch size and adult survival were associated with years of high non‐breeding. The ‘red‐tides’ in 1968 and 1975 appeared to have little effect on the Eider. It is suggested that the Eider missed breeding in years in which its survival was potentially poor, in order to maximize its reproductive output during its life span. This is supported by the smaller clutch size laid by those females which nest in years when many females fail to breed. It is suggested that young ducks may also miss breeding in the year after first nesting but this is not associated with the non‐breeding in older ducks, although it may he related to body condition. It is suggested that non‐breeding by adults of long‐lived birds may be widespread. This has important implications in survey work based on nest counts.
Reactions of some adult passerines to Bornbus pennsylvanicus and its mimic, Mallota bautias
Authors: Evans David L.
Published: April 2008

Adult Blue Jays, Brown Thrashers, Northern Catbirds, American Robins, and Song Sparrows were offered fresh frozen and thawed Bombus pennsylcanicus and its mimic, Mallota bautias, simultaneously with Tenebrio rnolitor pupae. Mealworm T. rnolitor larvae were offered separately in pairs as controls. Most of the birds refused the model and mimic, but all of the Blue Jays and some of the Brown Thrashers had specialized feeding techniques to deal with the aposematic insects. These techniques and other feeding behaviours are described in detail. Beak wiping appeared to be a displacement behaviour in Song Sparrows and American Robins. Predator — prey relationships are discussed briefly.
Breeding biology of the Mangrove Swallow Tachycineta albilinea and the Grey‐breasted Martin Progne chalybea at Barro Colorado Island, Panama
Authors: Dyrcz Andrzej
Published: April 2008

Information on the breeding biology of Neotropical swallows is scarce (Bent 1942, Ricklefs 1971, Ridgely 1976). The aim of this study was to determine some details of breeding biology of Neotropical swallows for comparison with temperate zone species.
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. London

BOOKS:Angus, S. (ed.). 1983. Sutherland birds. A guide to the status and ecology of birds in Sutherland District

BOOKS:Cooper, J. (ed.). 1981. Proceedings of the symposium on birds of the sea and shore, 1979. Pp. vi + 474. Cape Town: African Seabird Group

BOOKS: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 Gulls

BOOKS:Glutz Von Blotzheim, U. N. & Bauer, K. M. (eds.). 1982. Handbuch der Vogel Mitteleuropas

BOOKS:Farner, D. S., King, J. R. & Parkes, K. C. 1982. Avian biology

BOOKS:Flint, P. R. & Stewart, P. F. 1983. The birds of Cyprus

BOOKS:Foiger, H. 1982. Kolibris

BOOKS:Mobbs, A. J. 1982. Hummingbirds. Pp. xi+192; 32 colour photographs, 56 black‐and‐white photographs. Hindhead, Surrey: Saiga Publishing Co. Ltd

BOOKS:Freethy, R. 1982. How birds work — a guide to bird biology

BOOKS:Glutz Von Blotzheim, U. N. & Bauer, K. M. (eds.) 1982. Haridbuch der Vogel Mitteleuropas

BOOKS:Grant, G. S. 1982. Avian incubation: egg temperature, nest humidity, and behavioral thermoregulation in a hot environment. Ornithological Monographs No. 30

BOOKS: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, Maryland

BOOKS:Siobbs, A. J. 1982. Hummingbirds. See Review of Folger

BOOKS:O'donald, P. 1983. The Arctic Skua: a study of the ecology and evolution of a seabird. Pp. 324; 27 figures, 91 tables. Cambridge

BOOKS:Remmert, H. 1980. Arctic animal ecology.

BOOKS:Spano, S. 1982. II punto sulla beccaccia

BOOKS:Kalchreuter, H. 1983. The woodcock. Pp. 127; line drawings, tables and figures. Mainz: Verlag Dieter Hoffman

BOOKS:Sultana, J. and Gauci, C. 1982. A new guide to the birds of Malta

BOOKS:Thibault, J.‐C. 1983. Les oiseaux de la Corse

BOOKS: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.
Social influences on foraging behaviour of the Red‐cheeked Cordon Bleu Uraeginthus bengalus Estrildidae
Authors: Hamed Dawi Musa , Evans S. M.
Published: April 2008

Red‐cheeked Cordon Bleus U. bengalus forage on bare patches of ground for fallen grass seeds and termites in particular home ranges. Foraging is confined to shaded areas in the middle parts of the day but birds exploit places exposed to the full sun in the early mornings and late afternoons. They mostly occur in pairs but often aggregate to form temporary foraging groups. Although birds in groups spend less time vigilant than those foraging alone, they react sooner than them to approaching danger. Birds foraging in pairs peck more rapidly than those in other situations and it is suggested that one advantage of forming permanent pair bonds is that paired birds forage more efficiently than unpaired ones in preparation for the coming breeding season. Flight calls, contact calls and alarm calls are given in specific behavioural contexts. Birds make contact calls when they become separated from their mates and evidently use them to re‐locate one another. It is shown experimentally that members of pairs can recognize one another's contact calls.
Lekking in birds: choice, competition and reproductive constraints
Authors: Avery Mark I.
Published: April 2008

This paper discusses the importance of female choice and intrasexual competition in lek species. The importance of phenotypic differences between individuals is stressed. Reproductive constraints limit the possible behavioural strategies that can be used by males and females. I suggest that it is difficult to understand reproductive behaviour without a knowledge of these reproductive constraints.
Breeding of the Trindade Petrel Pterodroma arminjoniana on Round Island, Mauritius
Authors: GARDNER ANDREW S. , DUCK CALLAN D. , GREIG SUSAN
Published: April 2008

Round Island (19°51'S, 57°47'E), an uninhabited volcanic islet lying 14 miles NNE of the Mauritian mainland, provides locally important breeding grounds for four species of seabirds; the Trindade Petrel Pterodroma arminjoniana, the Wedge‐tailed Shearwater Puffinus pacificus, the Red‐tailed Tropic Bird Phaethon rubricauda and the White‐tailed Tropic Bird Phaethon lepturus. The landing conditions on the island are notoriously difficult and prior to 1975, visits by naturalists had been limited to short stays, a few days at the most. Accounts of the natural history of the island have been made by Vinson (1965), Bullock (1977) and Bullock & North (1984). This paper gives the results of studies on the breeding biology of the Trindade Petrel during two visits to Round Island from 27 July to 2 September 1978, and from 30 July to 18 August 1982.
A new swallow from the Red Sea
Authors: FRY C. H. , SMITH D. A.
Published: April 2008

A single specimen (Fig. 1), found dead on an islet off Port Sudan in spring 1984 is described as a distinctive new allospecies of African Cliff Swallow Hirundo spilodera.
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.
The colonization, ecology and breeding of the Pied Stonechat Saxicola caprata at Port Moresby, Papua New Guinea
Authors: BELL H. L. , SWAINSON G. W.
Published: April 2008

Data are presented on the colonization, ecology and breeding of the Pied Stonechat Saxicola caprata at Port Moresby, Papua New Guinea. The species apparently colonized the area in the 1950s and its habitat requirements seem correlated with the works of European settlement. Pairs appear to occupy a home range year‐round and defend it for the greater part of the year. Breeding details are given, including nest site, participation of sexes, clutch size, incubation, breeding success and plumage of fledglings. The large clutch size, double‐brooding, breeding with increased day‐length, circumscribed breeding season and preference for cooler climates suggest that the species is a fairly recent colonizer from continental Asia. Reasons are advanced for the discontinuous range of this wide‐spread species.
The influence of food on time budgets and timing of breeding of the Dunnock Prunella modularis
Authors: DAVIES N. B. , LUNDBERG A.
Published: April 2008

In two years, we provided some female Dunnocks with extra food from January through to July. In one year fed females bred ten days earlier than controls and in another year they bred 22 days earlier, but in neither year did they lay larger clutches. Matched comparisons of the same females on the same territories, who had food in one year but not in the other, showed the same effects. Within both feeder and control females, the earliest breeders were those which had spent more time perching in late winter. Perching time may be a good measure of the time an individual has available above that needed for self maintenance. Therefore females who spent more time perching may have been those first able to cross the threshold of extra time needed for the start of breeding activities.
How do male Robins Erithacus rubecula discover that their chicks have hatched?
Authors: HARPER D. G. C.
Published: April 2008

Nice & Nice (1932) raised the question of how male birds of those species in which only the females incubate, discover that their young have hatched. However, there are very few data available with which to provide an answer. In a review of his own observations on American passerines and scattered references in the literature, Skutch (1953) could find no evidence that females deliberately attract the attention of their mates to the nest after hatching has occurred. He concluded that males usually discover their nestlings without any assistance and that their promptness in doing so depends upon the frequency with which they have visited the nest during incubation. Since there were no species for which Skutch (1953) had more than two records of the events leading up to a male feeding his young for the first time, these conclusions were based almost entirely upon interspecific comparisons. In this note I present some limited data on the variation in the speed with which male European Robins Erithacus rubecula discover that their young have hatched.
Diet dimorphism‘ within an Oystercatcher Haematopus ostralegus population– adaptive significance and effects on recent distribution dynamics
Authors: SAFRIEL URIEL N.
Published: April 2008

Of the 50 or so Oystercatcher pairs breeding on Skokholm in 1965 and 1966, 15% bred near the shore and 85% bred inland; 28% fed their young on limpets, and 72% on terrestrial arthropods and earthworms. ‘Terrestrial‐feeders’ were three times more successful than limpet‐feeders in fledging young, irrespective of variation in initial brood size and of hatching date but depending on differential losses to gull predation. This is because parents' vigilance is relatively low in limpet‐feeders' territories, and limpet‐fed young are on average undernourished and hence behave relatively carelessly. Since the 1930s the population of shore‐breeding gulls has increased considerably on Skokholm. A certain increase of the Oystercatcher population during this period seems to have been associated with a shift inland, until the island became saturated at the late 40s. It is proposed that the increase in shore‐breeding gulls has triggered a genetically based behavioural change in Oystercatchers, which has been responsible for the shift to inland habitats and to terrestrial food, which promotes a population increase. This interpretation for events on Skokholm may be applicable for the general trend of habitat shift and population increase of other British populations.
The diet of breeding Dippers Cinclus cinclus and their nestlings in the catchment of the River Wye, mid‐Wales: a preliminary study by faecal analysis
Authors: ORMEROD S. J.
Published: April 2008

A preliminary study by faecal analysis into the diet of seven pairs of breeding Dippers and their nestlings was undertaken in the catchment of the River Wye in spring 1983. Macro‐invertebrate items in faeces could be identified to family and quantified on the basis of mouthparts whilst the macro‐invertebrate prey available to each pair of Dippers was assessed quantitatively by riffle‐sampling.

In terms of numerical abundance, ephemeropteran nymphs, particularly Baetidae, and trichopteran larvae, particularly Hydropsychidae, were more important to adults and nestlings, respectively. When prey weights were taken into account, trichopteran larvae were the most important macro‐invertebrate group to both, but especially to nestlings.

Some macro‐invertebrate groups were selected in proportion to their abundance in the environment although indices of electivity indicated that prey selection for adults and nestlings, respectively, was negatively and positively correlated with prey weight. Significant changes in diet were also apparent with nestling age: smaller items, such as ephemeropteran nymphs, were eaten by younger nestlings whilst larger items, such as trichopteran larvae, became more frequent up to Day 15 after hatching.
Patterns of drinking behaviour of some Australian estrildine finches
Authors: EVANS S. M. , COLLINS J. A. , EVANS ROSALIND , MILLER SARAH
Published: April 2008

Descriptions are given of patterns of drinking behaviour in seven estrildine finches, all of which are common in the Kimberley, northern Australia. Those species which foraged in areas adjacent to waterholes, N. ruficauda, P. acuticauda, P. bichenovii, P. personata and T. guttata, drank at them throughout most daylight hours but C. gouldiae and L. pectoralis, which foraged at greater distances, normally visited them only once in the early morning. Drinking birds are at high risk of predation and probably gain anti‐predator advantages by aggregating in mixed‐species groups while drinking. This is due, at least in part, to inter‐specific facilitation of behaviour. Individuals interrupt the act of drinking periodically to scan their surroundings.
Versatility and continuity in the songs of thrushes Turdus spp.
Authors: INCE S. A. , SLATER P. J. B.
Published: April 2008

A relationship between continuity and versatility was proposed by Hartshorne as a general feature of song organization in birds and argued to be linked to the avoidance of habituation (the monotony threshold principle). Thrushes of the genus Turdus vary greatly in song repertoire size, from the Redwing with a single song phrase to the Song Thrush which normally possesses well over 100 (Table 1), so that this group is well suited to looking for such a relationship. Recordings of 14 Turdus species were used to do so. Species in which successive songs do differ were indeed found to sing with shorter intervals between songs, though no equivalent relationship was found at the level of individual sound elements. There was a suggestion that species might fall into two contrasting groups without intermediates, one with continuous and highly varied songs and the other with discrete and simple songs. It is suggested that the relationship between continuity and versatility is a real phemomenon but that it is unlikely to be explained in the way that Hartshorne proposed. More likely is the hypothesis that continuous and varied songs have evolved primarily as mate attractants through sexual selection, while the principal role of discrete and simple songs is in communication between males.
Wing shape variation of Finnish and Central European Willow Warblers Phylloscopus trochilus and Chiffchaffs P. collybita
Authors: TlAINEN JUHA , HANSKI ILPO K.
Published: April 2008

Wing shape variation of European Willow Warblers Phylloscopus trochilus and Chiffchaffs P. collybita was studied using indices calculated from wing formulae. Our data were from free‐living local populations of P. t. acredula and P. c. abietinus from southern Finland, and P. t. trochilus and P. c. collybita from southwestern Germany.

There were no significant shape differences between the subspecies of the Willow Warbler in which sexual dimorphism was pronounced. The subspecies of the Chiffchaff were significantly different while the sexes were not. There were also significant differences between adult and immature individuals in the autumn. The intrapopulation variation must be considered in attempts to recognize different subspecies or populations in data on birds caught during migration.

In the Willow Warbler at least, the difference between age‐groups was larger in males than in females. If the change in wing formula due to the complete pre‐nuptial moult is similar in both sexes, juvenile males intermediate between adult females and adult males suffer disproportionately high mortality. It was earlier suggested that sexual selection increases body size in Willow Warbler males, but the present results imply additional selection pressures for increasing sexual dimorphism.
Dominance and anti‐predator behaviour of Great Tits Parus major: a field study
Authors: LAET JENNY F. DE
Published: April 2008

During the winter of 1981–82 the hierarchical system of free‐living Great Tits Parus major that visited a feeder supplied with sunflower seeds was studied in relation to the appearance of a predator. Without a predator, dominant birds were more successful in feeding and had to wait less before feeding. A significant negative correlation was found between dominance and the sequence of initial arrival.

After a Sparrowhawk Accipiter nisus had flown over the feeder, a correlation was found between the birds' dominance and the sequence of their return to the feeder. This field study supports the results of an analogous investigation on anti‐predator behaviour and dominance in captive Blue Tits P. caeruleus.
Observations on behaviour and foraging of the Ibisbill Ibidorhyncha struthersii in Nepal
Authors: PIERCE RAYMOND J.
Published: April 2008

In March and April 1984, I studied the territorial, courtship and foraging behaviour of Ibisbills Ibidorhyncha struthersii, mainly on Langtang Khola in Nepal. On their river‐bed breeding grounds, Ibisbills were territorial, rival birds meeting on shingle banks and performing prolonged circling displays. Aquatic invertebrates, especially stoneflies, mayflies and caddisflies, were the main prey, but fish and riparian invertebrates were taken also. When the water temperature was below 5oC, invertebrates were inactive and hidden beneath submerged stones, where the birds probed for them. When the water temperature was above 5oC, many invertebrates drifted in the water and Ibisbills switched to pecking at them from preferred feeding stations. Riparian foraging involved probing beneath stones on shingle banks and probing into soil. Foraging responses to changes in prey behaviour were similar to those of the Black Stilt Himantopus novaezealandiae on New Zealand river‐beds.
Post‐fledging survival of Sparrowhawks Accipiter nisus in relation to mass, brood size and brood composition at fledging
Authors: NEWTON I. , MOSS D.
Published: April 2008

Using ring recoveries, the post‐fledging survival of Sparrowhawks was examined in relation to the growth rates and fledging masses of young and in relation to the size and sex composition of broods, which contained up to six young. On most aspects, no significant relationships were found: light young survived as well as heavy ones, both in the population as a whole and in individual broods; and young in large broods survived as well as young in small broods. This was attributed to relative food abundance in the post‐fledging dependency period and to the fact that most food‐related mortality among young occurs at an earlier stage in the breeding cycle. However, males in all‐male broods and females in all‐female broods survived slightly better after fledging than others of their sex in two‐sex broods. The reason is unknown.