bluuebunny/crossref_metadata_2025 huggingface dataset:
The breeding biology of the Dalmatian Pelican Pelecanus crispus
Authors: CRIVELLI A. J. , HATZILACOU D. , CATSADORAKIS G.
Published: April 2008

The breeding biology of the Dalmatian Pelican Pelecanus crispus, a vulnerable bird species in the Palaearctic, has been studied for 7 years at Lake Mikri Prespa, a continental wetland and Tsoukalio lagoon, a coastal wetland within the Amvrakikos Gulf. The two colonies showed stability, with fluctuations in the number of breeding attempts each year varying by about 30% over a period of 7 years. The date of arrival at the breeding sites and the date of laying of the first egg varied between mid‐February and mid‐March. The egglaying period (including renesting) varied between 18 and 114 days between years. The annual average clutch size varied between 1.60 and 1.94 eggs per nest. The incubation period averaged 31.4 ± 1.4 days. The overall hatching success varied from 36% to 70%. Egg losses were mainly due to nest abandonment, infertile eggs and eggs rolled from the nests. The Dalmatian Pelican chicks took 11–12 weeks to fledge. Nestling mortality was very low in contrast to other species of pelican. Such a low nestling mortality explains why the breeding success each year is largely explained by the hatching success.
Nectar sugar preferences and absorption in a generalist African frugivore, the Cape White‐eye Zosterops pallidus
Authors: FRANKE ELKE , JACKSON SUE , NICOLSON SUE
Published: April 2008

Sugar preferences and absorption efficiencies were investigated in the Cape White‐eye Zosterops pallidus, a generalist frugivore. Unlike the mainly American frugivorous passerines previously studied, Cape White‐eyes preferred 20% (weight: weight) solutions of sucrose to glucose or fructose, and apparently possess high sucrase activity because absorption efficiencies for all three sugars were close to 100%. Cape White‐eyes rejected 20% solutions containing a fourth nectar sugar, xylose, recently found in the nectar of Protea and Faurea (Proteaceae). Absorption efficiencies for xylose averaged 61%, but we do not know whether this sugar is utilized by the birds. Cape White‐eyes thus resemble specialized southern African nectarivores (Nectariniidae, Promeropidae) in their responses to nectar sugars.
Brood reduction and begging behaviour in the Swift Apus apus; no evidence that large nestlings restrict parental choice
Authors: LOTEM ARNON
Published: April 2008

Brood reduction in birds is generally viewed as an adaptive process by which parents can maximize reproductive success in the face of an unpredictable environment. However, brood reduction may not be adaptive for the parents if the reduction is instead caused by large nestlings that block the nest entrance, thereby restricting parental choice. To determine the degree of difficulty faced by the parents in obtaining access to their smallest nestlings, a simple experiment was conducted in the Swift Apus apus. By inserting a human hand blindly into Swift nesting holes, nestlings were stimulated to beg and to grasp the approaching fingers. The results show that the smallest nestlings in the nest were the first to encounter the approaching fingers. Small nestlings were also just as likely to be found with at least some food in their crops as were medium and large nestlings, but gained mass at a significantly slower rate. I suggest that parent Swifts can easily access small nestlings, but prefer either to allocate more food to larger nestlings or to allow sibling competition in order to facilitate brood reduction.
Breeding season diet of the Goshawk Accipiter gentilis in Wales
Authors: TOYNE E. P.
Published: April 2008

Information on the diet of the Goshawk Accipiter gentilis during the breeding season was collected in Wales during 1991–1993. Diet consisted mainly of birds (87%) and mammals (13%). Forty‐five prey species were collected, ten of which were important in numerical or biomass terms: Feral Pigeon Columba livia, Woodpigeon Columba palumbus, Crow/Rook Corvus coronet Corvus frugilegus, Magpie Pica pica, Jay Garrulus glandarius, Mistle Thrush Turdus viscivorus, Song Thrush Turdus philomelos, Blackbird Turdus merula, Grey Squirrel Sciurus carolinensis and Rabbit Oryctolagus cuniculus. Pigeon biomass was important throughout the breeding season and was more important in the diet of nesting Goshawks on higher ground (>250 m). On lower ground, corvids, mammals and pigeons were the main contributors to the Goshawk diet. Rabbits were more frequently taken at lower nesting territories, and thrushes occurred at all altitudes. Mammals, particularly Grey Squirrel, were found in higher numbers in the diet of Goshawks nesting in small woods (<1000 ha) compared with the diet of Goshawks nesting in two large forests (c. 3500 ha and c. 6100 ha). Goshawks preyed upon juvenile Woodpigeons, corvids and thrushes, and switched from young thrushes to young corvids as the latter became available. Predation peaks on young birds corresponded with the presence of nestling Goshawks in late May to early July. Predation of juvenile prey led to a decrease in mean prey item mass (April‐May, 437 g; July, 376 g). No evidence was found to suggest that sexual size dimorphism in Goshawks resulted in partitioning of prey captured during the breeding season. Differences found were probably due to local abundance and vulnerability of prey species rather than specific selection by the two sexes.
Migratory restlessness in the Yellow‐faced Honeyeater Lichenostomus chrysops(Meliphagidae), an Australian diurnal migrant
Authors: MUNRO URSULA , MUNRO JOHN A.
Published: April 2008

The Yellow‐faced Honeyeater Lichenostomus chrysops is a diurnal migrant which covers short to moderate distances in eastern Australia. Recordings of locomotor activity of nine wild‐caught Yellow‐faced Honeyeaters kept under a simulated natural photoperiod in the laboratory over a period of 13 months showed that these birds exhibit a distinct seasonal pattern in hopping activity. Two major seasonal peaks of enhanced activity were observed. The first occurred during the time of autumn migration in March to July, while a second peak from September to December coincided roughly with spring migration. Daily activity patterns of Yellow‐faced Honeyeaters showed two major peaks. The first peak ranged from the early morning hours to approximately early afternoon, while a second smaller peak was observed in the late afternoon. During their migratory periods in spring and autumn, the morning as well as the afternoon peaks were considerably higher than in months when Yellow‐faced Honeyeaters do not migrate.
Coevolution in an Amazonian hummingbird‐plant community
Authors: COTTON PETER A.
Published: April 2008

Relationships between hummingbirds and their food plants are often considered to have arisen through coevolution. However, while it is certainly the case that hummingbirds and plants are coevolved, it is not always clear to what extent coevolution has shaped community structure and the morphology of the birds and plants. Here I examine the hummingbird‐plant community of a lowland Amazonian rainforest in southeastern Colombia and test hypotheses concerning coevolution and community structure. To determine the strength of interrelationships and the degree to which character displacement has occurred, the distributions of three floral traits (flowering phenology, nectar production and corolla length) and two hummingbird traits (culmen length and foraging ecology) have been statistically tested against random null models. Although the hummingbird‐plant community at Matamatá is diverse and is highly likely to have a long shared evolutionary history, there is little evidence for pairwise coevolution. Instead, the community appears to have evolved through diffuse coevolution, resulting in guilds of hummingbirds and plants.
Effects of winter and early spring grazing by Wigeon Anas penelope on their food supply
Authors: MAYHEW PETER , HOUSTON DAVID
Published: April 2008

Wigeon Anas penelope selectively grazed small patches of grassland near water. Their grazing activity affected the vegetation on which they fed, resulting in a 52% increase in leaf production over the winter and, at the end of winter, 4.75% higher protein levels compared with plants which were ungrazed. These responses of the plants were caused by defoliation, which stimulated growth, and not a fertiliser effect from the birds' droppings. We suggest that repeated feeding on the same areas is a deliberate strategy used by Wigeon which causes an improvement in their dietary quality in late winter and early spring.
Estimation of parrot and hornbill densities using a point count distance sampling method
Authors: MARSDEN STUART J.
Published: April 2008

The suitability of point count distance methods for estimating densities of tropical parrots and hornbills was assessed during surveys in Indonesia. The methods will perform well, so long as the following are considered. (1) Enough bird records must be accumulated to model species' detection curves precisely. For some species, around 2000 point counts may be needed and, in very rare species, the method may not be appropriate. Pooling data across habitats, species or years may increase precision in cases of small sample size. (2) Point counts are likely to be less biased than line transects because bird detection rates close to the recorder may be higher and there may be less chance of double‐counting birds. Distances greater than 400 m between census points are unnecessary. (3) Count periods lasting ten minutes may be needed to ensure that most birds close to the recorder are detected. Controlled flushing of concealed birds after the main count period may also be appropriate. (4) The best time of day for census is the period when bird detectability is high but bird mobility low. For many large avian frugivores, this corresponds to the period between one hour after dawn and 10.30 h. (5) Records of flying birds must be excluded from density calculations. In the species studied, between 2% and 20% should be added to density estimates to compensate for the exclusion of flying birds.
Genetic and morphological variation in Dunlin Calidris alpina breeding in the Palearctic tundra
Authors: WENNERBERG LIV , HOLMGREN NOÉL M.A. , JÖNSSON PAUL‐ERIC , SCHANTZ TORBJÖRN VON
Published: April 2008

The extensive overlap in morphological characters between populations of Dunlin Calidris alpina imposes problems of determining the origin of migrating and wintering birds. The morphology of the birds also varies between the sexes, and the sex of a Dunlin may often be difficult to determine. To clarify if mitochondrial DNA can be used to identify which breeding areas migrating Dunlin come from, we investigated the occurrence of different mtDNA haplotypes in Dunlin from eight breeding areas on the Russian and Siberian tundra. Four haplotypes were found and at most sites more than one haplotype occurred. The European haplotype predominated in the area west of the Taymyr Peninsula, the Siberian haplotype in central Siberia (from the Taymyr Peninsula to the Lopatka Peninsula) and the Beringian haplotype in eastern Siberia. One individual of an Alaskan haplotype, not detected previously among breeding birds outside North America, was found on Wrangel Island. The sex of each bird was identified genetically and the morphology of males and females was analysed separately. Birds with the European haplotype were generally smaller than birds with the Beringian or Alaskan haplotypes. Birds possessing the Siberian haplotype showed intermediate values in most cases. After compensating for differences between sites, males with the Siberian haplotype had significantly longer bills than males having the European haplotype. Multiple regressions indicate that mitochondrial DNA analysis improves models estimating the breeding origin of migrating Dunlin.
Variation in the nocturnal flight behaviour of migratory birds along the northwest coast of the Mediterranean Sea
Authors: FORTIN DANIEL , LIECHTI FELIX , BRUDERER BRUNO
Published: April 2008

The Mediterranean Sea is one of the largest obstacles that has to be crossed by Palearctic birds migrating from Europe to Africa; it thus offers a good opportunity to study variations in migratory behaviour of birds facing a major ecological barrier. Using a passive infrared device, the flight directions of nocturnal migrants were determined and flight altitudes estimated at ten sites along the French and Spanish coast of the Mediterranean Sea in September and October 1995. The variation of migratory intensity, flight direction and altitude in the course of the night was examined. The highest density of migration was recorded within the first hour after sunset, followed by relatively high densities over the next several hours, and a progressive decrease in the last third of the night. In spite of broad variation in the course of the coastline relative to the basic directions of migration and specific reactions of the migrants to the local conditions, a decrease in seaward migration corresponding to an increase in landward migration from the first to the second half of the night was a general feature at nearly all sites. The results suggest a shift in the motivation of the birds depending on the time of arrival in a coastal area, leading to an adjustment in the flight behaviour of nocturnal migrants.
The Golden‐spectacled Warbler: a complex of sibling species, including a previously undescribed species
Authors: Alström Per , Olsson Urban
Published: April 2008

The Golden‐spectacled Warbler, usually treated as a single species, Seicercus burkii, is widely distributed in mountains of southern Asia. We argue that it should be treated as five different species, one of which is described here for the first time. Two species occur in sympatry in the Himalayas. The other three species are found in eastern Asia, where all three are sympatric in China, and two of these breed sympatrically also in Vietnam. In Burma and adjacent parts of India, one of the Himalayan species is sympatric with one of the east Asian species. We describe differences in morphology, vocalizations, altitudinal distribution and habitat between these five species, as well as results from playback tests, which show that all sympatric taxa differ and appear to be reproductively isolated from each other.
First nest description, breeding, ranging and foraging behaviour of the Short‐legged Ground‐Roller Brachypteracias leptosomus in Madagascar
Authors: Thorstrom Russell , Lind Johan
Published: April 2008

The secretive, endemic Short‐legged Ground‐Roller Brachypteracias leptosomus was studied from October 1996 to February 1997 on the Masoala Peninsula, northeast Madagascar. Several vocalizations were associated with contact, courtship feeding and food solicitation. One study pair ranged within an area of 19.1 ha and spent 90% of their time together. They used small trees for foraging and resting, and durations of perch time averaged 9.8 min. Of the 229 identified prey items recorded, 88% were invertebrates and 12% vertebrates. The first described nests for this species were observed in December 1996 and January 1997. The first nest was in a natural tree cavity 18.1 m above the ground in a 133‐cm diameter‐at‐breast height (dbh) Weinmannia sp., and it contained at least one egg. This nest failed on 1 January 1997 when a swarm of Honey Bees Apis mellifera took over the cavity. On 7 January, the pair began excavating another nest 22 m above the ground in a 174‐cm dbh Canarium madagascarense, in the root mass and decayed material of epiphytes and below a 1 ‐m diameter forked branch. Incubation lasted between 22–26 days and the nestling period was 30 days. One young fledged in March 1997.
Within‐pair testosterone covariation and reproductive output in Greylag Geese Anser anser
Authors: Hirschenhauser Katharina , Mostl Erich , Kotrschal Kurt
Published: April 2008

In monogamous animals, reproductive success may vary considerably among pairs. To study this variation, we focussed on reproductive events and the circannual hormonal co‐ordination within pairs during the reproductive cycle. Testosterone was chosen as covariable for both sexes because of its mediator function between behaviour and physiology. In a flock of free‐living Greylag GeeseAnser anser, individual faecal samples were collected weekly from 23 pairs over a complete annual cycle. From the faeces, equivalents of testosterone, oestrogen and other steroid hormones were analysed by enzyme immunoassay. In contrast to correlations between male and female testosterone, no correlations were found between oestrogen‐oestrogen or oestrogen‐testosterone. Therefore, only testosterone (T) is considered here. Sex‐specific differences in T were in amplitude rather than in the annual timing of maxima and minima. However, the annual timing varied to some degree between individuals within sexes. Therefore, we examined the degree of annual testosterone correlation (TC) within pairs. Pairs that nested had significantly higher TC over the year than pairs that did not. The higher the within‐pair TC, the larger the clutches and the heavier the eggs. Also, TC in the year investigated was positively and significantly correlated with the pairs' long‐term reproductive output. No correlation was found between TC and the duration of the pair‐bond, individual age, or age difference from pair partner. We suggest that TC is a measure of behavioural synchrony and, therefore, pair‐bond quality. We consider whether within‐pair TC results from mate choice.
Geographic variation of the storing behaviour in the Coal tit Parus ater: role of winter residency and environmental conditions
Authors: Brotons Lluís , Haftorn Svein
Published: April 2008

Foraging and hoarding behaviour of the Coal Tit Parus ater were studied in two widely separated populations, in the Pyrenees and in Norway. The two populations differed in their degree of winter residence and environmental pressures. Location of foraging and hoarding sites were described in the Pyrenees during winter, and during autumn in Norway where no hoarding takes place during winter. Significant differences in the hoarding behaviour of Coal Tits between these areas were observed. In the Pyrenees, birds hoarded on inner and lower parts of the trees, using trunks and thick branches as caching sites, which are the substrates most heavily used in conditions of winter environmental stress. In Norway, birds hoarded items on outer and higher parts of the trees, mainly among needled twigs, which were the substrates used in normal foraging. Animal food was hoarded more frequently by the Norwegian population. Our results show that hoarding behaviour varies among populations and suggest that the differences recorded may be related to differences in competitive pressures and the prevailing environmental conditions. Furthermore, the absence of a safe long‐term hoarding niche in the Norwegian population, due to interspecific competition, would make a strong sedentary habit difficult, offering a functional explanation for the differences observed in the degree of winter residence between Norwegian and Pyrenean Coal Tits.
Seasonal changes in habitat use by Houbara Bustards Chlamydotis [undulata] macqueenii in northern Saudi Arabia
Authors: Heezik Yolanda Van , Seddon Philip J.
Published: April 2008

Habitat preferences by Houbara Bustards Chlamydotis [undulata] macqueenii in Harrat al‐Harrah reserve, in northern Saudi Arabia were determined from sightings of birds in all seasons over three years. Vegetation and crawling invertebrate abundance were sampled in each habitat. Houbara Bustards showed seasonally changing habitat preferences that appeared to be influenced primarily by vegetation phenology, abundance and cover. More densely vegetated areas (10–17% cover) were preferred. Seasonal and inter‐habitat variations in invertebrate numbers were not reflected in differential habitat use by Houbara Bustards. The highest selection ratio for a single habitat (dry lakes) occurred in summer, coinciding with the fruiting of Shafallah Capparis spinosa. Selectivity of habitats was least in spring, when green vegetation was most widespread. Changes in Houbara Bustard habitat preferences in response to marked seasonal changes in habitats brought about by well‐defined patterns of rainfall indicate that studies of habitat selection should consider the entire annual cycle. The importance of vegetative cover and the sensitivity of Houbara Bustards to human disturbance suggest that reserves set aside for Houbara Bustards should be extensive, diverse and largely free of livestock, human occupation and its associated disturbances.
Ranging behaviour and foraging habitats of breeding Sparrowhawks Accipiter nisus in a continuous forested area in Norway
Authors: Selås Vidar , Rafoss Trond
Published: April 2008

The ranging behaviour and foraging habitats of Sparrowhawks Accipiter nisus were studied in a continuous forest area in southern Norway by use of radiotelemetry in 1995 and 1996. The mean size of the home ranges was 9.2 km2 for males (sd ± 3.7, n= 6) and 12.3 km2 for females (sd ± 6.4, n= 6), but the difference was not significant. Females ranged farther away from nests (mean 1824 m) than did males (mean 1240 m). None of the Sparrowhawks were located outside forest habitats. For the three pairs where both mates were radiotracked in 1996, habitat use did not differ between the sexes. Habitat composition in the home ranges differed from that of the study area. The most important difference was a higher proportion of medium‐aged forest and a lower proportion of old forest in home ranges than in the study area. The selection for medium‐aged forests was probably a response to high food supply and good hunting opportunities. Mixed regeneration and old forests were used more than clear‐fell areas, which were seldom used. Mixed regeneration was also used more than coniferous replanting. The large home ranges in this study compared with those in studies in Great Britain is probably due to lower land productivity and associated lower densities of prey species in the present study. The study indicates that the Sparrowhawk benefits from modern forestry, which has created an increased proportion of medium‐aged stands in the forest landscape.
Age‐dependent prospecting and recruitment to a breeding colony of Short‐tailed Shearwaters Puffinus tenuirostris
Authors: Bradley J.S. , Gunn B.M. , Skira I.J. , Meathrel C.E. , Wooller R.D.
Published: April 2008

In a small colony of Short‐tailed ShearwatersPuffinus tenuirostris, monitored annually since 1947, many of the young ringed as nestlings returned to their natal colony for one or more years before breeding for the first time. These ‘prospectors’ were first recorded at 4.1 ± 0.1 (range 2–7) years old; they started breeding at 7.0 ± 0.2 (4–14) years old. Overall, 31% of all prospectors bred on their natal island with no significant annual variation in this proportion. However, 8% of all natal recruits started breeding without having been recorded prospecting and bred first when significantly younger (5.6 ± 0.4 years old) than those first recorded prospecting. Shearwaters which subsequently bred at their natal colony started prospecting when significantly older (4.3 ± 0.1) than those that did not breed at their natal colony (4.0 ± 0.1 years). Non‐natal recruits spent significantly less time prospecting (1.0 ± 0.1 years) than prospectors born on the island (1.9 ± 0.1 years). The shearwaters appeared to become progressively more faithful to the colony during their prospecting period.
Relative importance off environmental variables in determining the growth off nestling Tree Swallows Tachycineta bicolor
Authors: Mccarty John P. , Winkler David W.
Published: April 2008

Unpredictable, short‐term changes in environmental conditions associated with weather patterns have severe impacts on the reproductive success of Tree Swallows Tachycineta bicolor, as well as other aerial insectivores. We examined the effects of day‐to‐day environmental variation on the growth of nestling Tree Swallows. Using path analysis, we compared the relative importance of changes in food availability, ambient temperature and wind speed on changes in mass and feather length over four years at our study site near Ithaca, New York. Changes in environmental conditions explained a significant amount of the variation in nestling growth, with daily high temperature having the greatest influence for nestlings younger than five days. Both food supply and temperature had significant direct effects on growth of nestlings older than nine days, with temperature also having a significant indirect effect through its influence on food availability. For both young and old chicks, mass gains were smaller for chicks hatched later in the season. Environmental conditions also explained a significant amount of the linear growth of the ninth primary feather in one of two years, with food supply showing the most consistent positive effect. Environmental conditions several days prior to the measurements significantly influenced feather growth, indicating that the effects of adverse conditions are spread out over several days of feather growth, but this effect was not seen for change in mass.
Consequences of a female‐biased sex‐ratio in a socially monogamous bird: female‐female pairs in the Roseate Tern Sterna dougallii
Authors: Nisbet Ian C.T. , Hatch Jeremy J.
Published: April 2008

In the socially monogamous gulls and terns, female‐biased sex ratios are sometimes revealed by the occurrence of ‘supernormal clutches’, which are usually attended by female‐female pairs or other multi‐female associations. We studied these phenomena in the endangered Roseate TernSterna dougalliiat Bird Island, USA, from 1970 to 1995. DNA‐techniques were used to sex breeding adults in 1992–94.

Supernormal clutches (with three or four eggs) have comprised 1–7% of all Roseate Tern clutches at Bird Island since at least 1970, probably increasing in frequency since 1980. Supernormal clutches were spatially clustered; most were laid late in the peak period of nesting during each season. More than 80% of supernormal clutches and at least 7% of normal clutches were attended by multi‐female associations; most of these were female‐female pairs, with a few trios (male + two females, or three females) and one quartet (four females). More than half of the multi‐female associations attended normal clutches. Some female‐female pairs were maintained for up to five years. The age‐distribution of females mated to females did not differ significantly from that of females mated to males. Females mated together usually laid eggs synchronously (±2 days). Such females laid fewer eggs than females mated to males (means 1.20 versus 1.73), and had lower fertility and hatching success (about 46% versus 98%); they were less successful in raising young from eggs that did hatch (means 58% versus 73%), but this difference was not significant. Their overall breeding success was much lower (about 0.34 fledglings per female versus 1.35). The sex‐ratio of breeders was about 127 females to 100 males; about 20% of breeding females did not have male mates. Female Roseate Terns that do not obtain male mates appear to be of low phenotypic ‘quality’ ‐ based on late laying, small clutches and small eggs. Our data support the hypothesis that such females have a higher fitness if they mate with each other and raise a few young than if they do not breed at all.
Attendance off breeders and prospectors reflects the quality off colonies in the Kittiwake Rissa tridactyla
Authors: Cadiou Bernard
Published: April 2008

Attendance of breeders and prospectors (prebreeders, failed breeders and non‐breeding adults) was studied from the time of hatching to the end of the breeding season in parts of two neighbouring Kittiwake Rissa tridactyla colonies in Brittany (France). Many clutches in one subcolony had been predated by a Carrion Crow Corvus corone, leading to a lower breeding success. Attendance of breeders and prospecting activity were greater in the more successful colony, and the number of breeding pairs increased in the following year in this colony only. Local reproductive success and social behaviour contributed to the attraction exerted by a colony. The demographic trend was explained by a performance‐based conspecific attraction mechanism, acting through the effect of local reproductive success on recruitment, non‐breeding and fidelity. Study of breeding success and prospecting activity allowed both evaluation of the quality of a colony and prediction of local demographic trends for the following year.
Effectiveness of nest defence in the Acadian Flycatcher Empidonax virescens
Authors: OLENDORF ROBERT , ROBINSON SCOTT K.
Published: April 2008

We used presentations of models to determine the effectiveness of nest defence in the Acadian Flycatcher Empidonax virescens against a nest predator (Blue Jay Cyanocitta cristata) and a brood parasite (Brown‐headed Cowbird Molothrus ater). Principal components analysis (PCA) of four component variables of nest defence (call rate, swoop rate, closest approach and number of adults) generated a measure of overall nest defence (aggression). We determined effectiveness of defence by looking for correlations between measures of defence and measures of nest success (nest predation and brood parasitism). We also determined whether nest defence increased with clutch size, nestling age and time in the breeding season. Defence against model Brown‐headed Cowbirds did not correlate with levels of parasitism, clutch size, age of young or time of breeding. There was, however, a strong, but insignificant, trend for nests with high levels of all measures of defence to suffer less from brood parasitism. Aggression, vocalization rate, closest approach and number of adults defending against models of predatory Blue Jays correlated positively with nesting success during the egg stage but not the nestling stage of the nesting cycle. Aggression, vocalization rate, closest approach correlated with clutch size and age of the brood. These results suggest that nest defence can effectively deter nest predators, but may be less effective against brood parasites. Different behavioural components of nest defence may work at different stages of the nest cycle and against different nest predators. The components of nest defence that correlated with nest success also correlated with clutch value, a result consistent with hypotheses on the evolution of nest defence.
Mate fidelity in Cory's Shearwater Calonectris diomedea on Selvagem Grande
Authors: MOUGIN JEAN‐LOUIS , JOUANIN CHRISTIAN , ROUX FRANCIS
Published: April 2008

In the Cory's Shearwater Calonectris diomedis boreadis breeding on Selvagem Grande (30d̀ 09'N, 15d̀52'W), mate fidelity averaged 71.4%. Two‐thirds of the changes were the result of the absence of the former mate and one‐third only, carried out in its presence, were true divorces. The rate of divorce and the rate of replacement of an absent former mate had increased since the beginning of the 1980s. Among young and inexperienced birds, the rate of divorce decreased with the increase of age and experience before becoming stable. Breeding failure during the previous year increased the probability of divorce. Temporary non‐breeding increased both the rate of divorce and the rate of replacement of an absent former mate.
Phylogenetic relationships within the turacos (Musophagidae)
Authors: VERON GÉRALDINE , WINNEY BRUCE J.
Published: April 2008

Cytochrome b sequences were used to investigate both the systematic position of the Musophagidae and the species relationships within the family. Phylogenetic analyses (neighbour‐joining, maximum likelihood and maximum parsimony) supported the hypothesis that the Musophagidae are more closely related to the cuckoos, parrots and the Hoatzin than the gamebirds. Within the family, three major clades are evident that correspond to the three subfamilies generally recognized. The ‘grey turacos’ and the turacin‐bearing turacos form two separate monophyletic groups. Corythaixoides leucogaster appears to be basal within the subfamily Criniferinae (the ‘grey turacos’). This analysis yields a hypothesis for the controversy surrounding the position of Gallirex porphyreolophus and Tauraco johnstoni, which appear to be closely related and basal to the other turacin‐bearing turacos. The Musophaga species are placed within the Tauraco clade and appear to be specialized forms of typical turacos. The superspecies persa forms a monophyletic group, within which T. hartlaubi falls. This is an association that has not been suggested previously.
Measurement of plumage badges: an evaluation of methods used in the Great Tit Parus major
Authors: FIGUEROLA JORDI , SENAR JUAN C.
Published: April 2008

There is an increasing interest in the variation in plumage coloration and a number of theories have been proposed to explain its evolution (Butcher & Rohwer 1989, Savalli 1995). Birds haye been considered to signal through plumage their dominance status, ability to evade predators, parasite resistance or for example their parental care abilities (reviewed in Butcher & Rohwer 1989, Anderson 1994, Savalli 1995, Johnstone 1997). However, the measuremcnt of plumage badges and its accuracy have received little attention (Savalli 1995). In the case of the Great Tit Parus major, for instance, several studies have analysed the importance of the breast stripe size as an indicator of dominance status in winter flocks (Jarvi & Bakken 1984, Piiysa 1988, Lemel 1989, Wilson 1992) and its importance in mate choice (Norris 1990, 1993), but the badgc has been estimated using very different indices, even in studies performed by the same authors (Norris 1990, 1993). We compare the performance of differvnt indices in estimating Great Tit stripe size, by comparing them with badge surface area obtained from image analysis of digital photographs. We propose that digital photography provides a reliable and inexpensive method to measure plumage badges in birds and we demonstrate its performance in the Great Tit.
The diets of Malaysian swiftlets
Authors: LOURIE SARA A. , TOMPKINS DANIEL M.
Published: April 2008

Four species of swiftlet (Aves: Apodidae), two of which produce ‘edible nests’, occur sympatrically in Malaysia. Food boluses were analysed to investigate (1) diet differences and resource partitioning among the four species and (2) the influence of habitat on the diet of the Glossy Swiftlet Collocalia esculenta. Hymenoptera and diptera were the most abundant prey in all diets. Black‐nest Swiftlets Aerodramus maximus were extremely selective; 89% of the items taken were hymenoptera, of which 97% were flying ants. White‐nest Swiftlets A. fuciphagus and Mossy‐nest Swiftlets A. salanganus took more than twice as many prey items as either of the other species. Their diets were taxonomically diverse and differed only in the average prey size taken, Mossy‐nest Swiftlets taking the larger prey. Glossy Swiftlets took a higher proportion of coleoptera than did the other species. For the habitat comparisons, diptera were the main constituents of the Glossy Swiftlet diet in an urban habitat (71% of total prey items), whereas hymenoptera predominated in forest habitat (42% of total prey items). The results suggest that diet separation occurs among the four species of Malaysian swiftlet, in relation to both species and habitat. The implications of potentially habitat‐driven dietary changes are discussed for the edible‐nest swiftlets.
Strategies of passerine migration across the Mediterranean Sea and the Sahara Desert: a radar study
Authors: BIEBACH HERBERT , BIEBACH IRIS , FRIEDRICH WOLFGANG , HEINE GEORG , PARTECKE JESKO , SCHMIDL DIETER
Published: April 2008

Radar observations of the diurnal timing of bird migration in the Sahara Desert are presented for autumn migration. Study sites were on a transect along the north‐south migratory direction. Three groups of birds migrating either during day, evening or night in the northern part of the Western desert in Egypt were identified. The maximum of day and night groups occurred later the further south the study sites were. Based on the distance between sites and the timing of peak migration, birds were flying at an estimated ground speed of about 20 m/s. The maximum of the evening group was at about 21:00 h at all sites. The three groups were classified according to three different strategies of migration across the Mediterranean Sea and the Sahara Desert: (1) the day group of birds performed a non‐stop flight across the sea and at least the northern part of the desert; [2] the night group performed an intermittent migratory strategy with stopover at the coast of Egypt to continue migration the next evening; (3) the evening group birds were also intermittent migratory fliers, but they stopped somewhere in the desert after a continuous flight across the sea and part of the desert. About 20% of all migrants are involved in non‐stop migration and 80% in intermittent migration with stopover at the coast (70%) or with stopover in the desert (10%). It is argued that any species of small passerine has the option to use any of the three strategies.
Winter spacing and non‐breeding social system of the Coal Tit Parus ater in a subalpine forest
Authors: BROTONS LLUÍS
Published: April 2008

In the genus Parus, non‐breeding social territoriality has often been attributed to the presence of food hoarding which, by increasing the value of an area, is thought to favour the existence of exclusive territories. To test this, it is necessary to analyse the social structure of hoarding populations inhabiting different environments. I studied Coal Tit spacing patterns and winter social systems in a colour‐ringed hoarding population inhabiting a mountain coniferous forest in the Pyrenees. Using data on home range, range overlap and social coherence, the social system was found to be based on adult birds that had previously bred together and which occupied relatively small home ranges. Large home ranges of resident juveniles overlapped extensively with each other and with those of adults. However, resident juveniles were resighted much closer to their ringing place than was expected at random, suggesting restricted floater ranges. Associations, composed mainly of juveniles, seemed to be rather large and loose, with little coherence. No territorial defence by any group of birds was detected during the study. Therefore, the social organization described for the present Coal Tit population is similar to the loose, non‐territorial basic flock system of non‐hoarding species. Resident social patterns seemed to be linked primarily to the availability of breeding resources, probably leading to the high site fidelity of adults and the floater life of resident juveniles. On the other hand, short‐term survival chances may attract transients to a rich food supply and thus affect flocking strategies of birds. High availability of resources allowing a high population density seems to be the main proximate factor influencing the spacing patterns described.
Rediscovery of Grallaria alleni (Formicariidae) with notes on its range, song and identification
Authors: KRABBE NIELS , COOPMANS PAUL
Published: April 2008

In 1992 the Moustached Antpitta Grallaria alleni was feared extinct. We present the first records of the species from Ecuador, discuss new data on the unique subspecies G. a. andaquiensis as well as its taxonomic position, describe the previously unknown vocalizations of this species and compare the latter with those of several congeners.
Influence of adult breeding experience on growth and provisioning of Wandering Albatross Diomedea exulans chicks at South Georgia
Authors: BERROW SIMON D. , HUMPIDGE RICHARD , CROXALL JOHN P.
Published: April 2008

For most seabirds, reproductive performance improves with age; in albatrosses this is thought not to be so (experience being acquired before starting breeding) but only one study (of chick growth in a single season at one site) has specifically addressed this. We compared the provisioning performance and growth rates of chicks of Wandering Albatrosses Diomedea exulans breeding for the first (IN), second and third (LE) and fourth or more times (EE) on Bird Island, South Georgia in the austral winters of 1996 and 1997. Eggs from EE adults were significantly heavier than the other two categories and these chicks had a greater mass and longer wings up to 160 days of age and longer culmen and tarsus up to 115 days old. However chicks from all categories fledged at the same average mass, size and age. No significant differences between categories in feeding frequency or meal size were detected but experienced adults made shorter long foraging trips and spent more time at the nest than less experienced birds. Adults that remained at the nest gave chicks smaller meals than those that left immediately after feeding the chick. Although provision of smaller but more frequent meals by experienced adults promotes more rapid chick growth, the resulting differences do not persist into the late chick‐rearing period. Our results were very similar to those from Iles Crozet in the Indian Ocean, supporting the hypothesis that when Wandering Albatrosses start to breed they are fully competent foragers but that it takes a while, during early chick‐rearing, for birds breeding for the first time to adapt to the additional demands of provisioning a chick.
Breeding behaviour of the Bearded Vulture Gypaetus barbatus: minimal sexual differences in parental activities
Authors: MARGALIDA ANTONI , BERTRAN JOAN
Published: April 2008

Monogamous biparental care is expected to occur when opportunities for extra‐pair copulations are rare, and both parents are required to raise the chick. Bearded Vultures Gypaetus barbatus fulfill these conditions. Contributions by male and female Bearded Vulture to nest building, nest defence, incubation, nest attendance and chick feeding were studied over five years in eight pairs from the Pyrenees [Catalonia, northeast Spain). Overall, the sexes show equal investment, although the degree of parental effort developed differs depending on the specific activities. During pre‐laying, males were significantly more active than females in supplying material to the nest and in territorial defence behaviour, which increased (in both sexes) as the season advanced. Incubation was shared equally both by day and by night. During chick‐rearing, the nest was attended by both sexes and the presence of both parents at the nest decreased in parallel with the growth of the chick. Activities related to chick feeding were also equally divided. These results are discussed in the context of female selection of mates and the particular ecology of this species.
Common Cuckoo Cuculus canorus and host behaviour at Reed Warbler Acrocephalus scirpaceus nests
Authors: MOKSNES ARNE , RØSKAFT EIVIN , HAGEN LISE GREGER , HONZA MARCEL , MØRK CECILIE , OLSEN PER H.
Published: April 2008

This study is based on continuous video recordings made at 53 Reed Warbler Acrocephalus scirpaceus nests each day during the laying period. Egg‐laying by the Common Cuckoo Cuculus canorus was recorded in 14 (26.4%) of these nests. By analysing the activity of the host birds around and at the nest, we found that this is probably not the only cue used by the Common Cuckoo when locating suitable nests to parasitize. Furthermore, in most cases there was no significant difference between the length of time the host birds spent at the nest in the morning and afternoon, thus providing little support for the hypothesis that the Common Cuckoo lays in the afternoon because it is less likely to be seen by the nest owners then. Parasitized Reed Warblers rejected the Common Cuckoo egg more frequently when they observed the parasite at their nests. However, contrary to what should be expected, most Common Cuckoos laid their eggs in the presence of the host(s), and in general their egg‐laying behaviour (for example duration of stay at the nest) was less secretive than described earlier. When partially depredating host clutches, Cuckoos showed the same behavioural pattern at parasitized and unparasitized nests, indicating that the latter may act as a potential reserve for egg‐laying.
Capercaillie Tetrao urogallus in Scotland ‐ demography of a declining population
Authors: MOSS ROBERT , PICOZZI NICHOLAS , SUMMERS RON W. , BAINES DAVID
Published: April 2008

Capercaillie Tetrao urogallus numbers declined in Scottish forests between 1992 and 1997, although the rate (mean 16% per year, 95% CL 1–30%) differed among forests. Hens declined more quickly than cocks despite the sex ratio in chicks favouring females. A probable explanation is that adult cocks lived longer. Juvenile survival was less than adult survival, largely because juveniles were more likely to die from hitting fences. Although poor reproduction was probably the main cause of the decline, this might not have occurred had fence strikes been substantially fewer.
Breeding biology and breeding success of the Lesser Grey Shrike Lanius minor in a stable and dense population
Authors: KRISTIN ANTON , HOI HERBERT , VALERA FRANCISCO , HOI CHRISTINE
Published: April 2008

The Lesser Grey Shrike Lanius minor is highly endangered throughout Europe, having declined markedly in abundance and range. Long‐term changes in climate and agricultural practices have been identified as the main reasons for its decline. To determine which factors influence short‐term changes in breeding success, we examined several aspects of its breeding biology. Our investigation revealed that our study area bears a large and stable population of this species. In 1996 and 1997, we recorded 84 and 77 breeding pairs in an area of 20 km2, with an average of 4.20 and 3.85 pairs/km2 respectively. Data on breeding density, clutch size and fledging success from 1989 to 1997 (excluding 1992) indicate a stable breeding population with a constant high breeding success. Reproductive success declined through the season, mainly through seasonal variation in clutch size rather than chick mortality. However, breeding success was generally high (69% and 79% of the nests produced chicks], with low hatching failure and few nest losses. The main cause of breeding failure was nest predation (at least 50% of nest losses), mainly by magpies (at least 66% of depredated nests). Although in this population the Lesser Grey Shrike tends to aggregate in clusters, breeding density had no obvious effect on breeding success and nest predation.
Food provision to nestlings in the Hoopoe Upupa epops: implications for the conservation of a small endangered population in the Swiss Alps
Authors: FOURNIER JÉRÔME , ARLETTAZ RAPHAËL
Published: April 2008

In an attempt to recognize the possible ecological causes of the decline of a population of Hoopoes Upupa epops in the Swiss Alps, we collected data on resource exploitation. The prey provisioned to nestlings by parents was investigated at four breeding sites using photographs (n = 4353, 80% of which enabled prey identification). Molecrickets Gryllotalpa gryllotalpa and Lepidoptera (larvae and pupae) were dominant in nestling diet (93% frequency; 97% biomass). Although Molecrickets were provisioned less frequently (26%) than Lepidoptera (67%), they represented 68% of the total biomass (vs 29% for Lepidoptera). There was an overall negative relationship between the proportion of Molecricket biomass in the diet and the parents' feeding rate, whereas a comparison between broods showed that a higher provisioning activity did not lead to an increase in the biomass supplied to the chicks. A diet based on Molecrickets therefore appears to be energetically advantageous. As Molecrickets are a traditional prey of Hoopoes in central Europe, this might be relevant to other populations. In the study area, Molecrickets occur only on the intensively cultivated plain, whereas the majority of Hoopoe pairs nest at various altitudes on the foothills adjacent to the plain as the latter provides at present almost no suitable nesting sites. Hoopoes breeding higher up on the foothills seem to experience greater provisioning costs and have, on average, lower breeding success. Providing nest sites on the plain is the main conservation measure proposed for the local Hoopoe population. Further attention should also be paid to Molecrickets as these may be crucial for Hoopoes.