bluuebunny/crossref_metadata_2025 huggingface dataset:
Altitudinal distribution and habitat preferences of forest birds on Halmahera and Buru, Indonesia: implications for conservation of Moluccan avifaunas
Authors: POULSEN MICHAEL K. , LAMBERT FRANK R.
Published: April 2008

The BOU Indonesia Expedition, with BirdLife International, carried out surveys on the Moluccan Islands of Buru and Halmahera in 1994‐96 as part of a process of protected area identification. Data on resident forest birds were collected during ten‐minute sampling periods at points along altitudinal gradients, in primary and modified forests and in rainforests on different geology. While all species ever reported from Halmahera have been recorded down to near sea level, many of the forest birds of Buru, including a number of restricted‐range and endemic species, are largely confined to montane forest, and only common above 800–900 m altitude. The existence of a distinct montane bird community on Buru, but not on Halmahera, is attributed to the relatively large, continuous area of forest at high altitude on this island. Forest on Halmahera at such altitudes is limited and fragmented. While most species survive in modified forests, some were significantly rarer in this habitat and may depend on adjacent areas of primary forest. Mangroves supported impoverished forest bird communities, typically of more adaptable species. On Halmahera, rainforest on ultrabasic rock appears to be impoverished when compared with rainforest on other rock formations, in particular supporting very low numbers of two species of threatened parrot. Implications for conservation concern lowland forests on Halmahera. Despite the surveys, a number of species of conservation concern that occur on Halmahera and Buru still remain largely unknown.
Daily accumulation of body reserves under increased predation risk in captive Greenfinches Carduelis chloris
Authors: LILLIENDAHL KRISTJAN
Published: April 2008

The effect of increased perceived risk of predation on the trajectory describing the daily gain in body mass of captive Greenfinches Carduelis chloris was tested. Theoretically, increased risk of predation is expected to shift the gain in body mass towards the latter part of the day and reduce body mass. The perceived risk of predation was increased with a stuffed flying hawk three times per day. Following each presentation of the predator, foraging stopped and the birds lost mass. When feeding resumed, the birds compensated for the mass loss by increasing the rate of body mass gain, in line with theoretical predictions. In the presence of the predator, the daily accumulation of body reserves was lower compared with risk‐free situations. However, on the days following presentation of the hawk, when the birds were presumably aware of an increased risk of predation, Greenfinches did not exhibit the predicted change in reserve accumulation, but rather maintained their usual pattern of body mass gain.
Fly or die: the role of fat stores in the growth and development of Grey‐headed Albatross Diomedea chrysostoma chicks
Authors: REID KEITH , PRINCE PETER A. , CROXALL JOHN P.
Published: April 2008

Chicks of albatrosses, like other Procellariiformes, become independent at a mass similar to their parents but during growth attain a peak mass some 30% or more greater, before losing mass prior to fledging. The current views are that this high peak mass represents chicks storing fat reserves as an energy sink, or as an insurance against periodic food scarcity, or as a Consequence of natural stochastic variation in provisioning rate. We analysed growth and body composition of Grey‐headed Albatross Diomedea chrysostoma chicks at Bird Island, South Georgia in 1984 and 1986, two years of very different food availability. In 1984 when overall breeding success was only 28% (the lowest in 20 years and less than halt that in 1986), chicks were significantly smaller in terms of peak mass (by 37%), primary length (by 25%), liver, lung, heart and kidney size (by 18–34%) and fat (by 75–80%) but not significantly different in terms of skeletal (tarsus, culmen, ulna, sternum) or muscle (pectoral, leg) size. Despite these differences, there were some important similarities in the patterns of growth in both years. Up to the attainment of peak mass, most of the growth of organs and of skeletal structures was completed and little fat was deposited. In the remaining part of the chick‐rearing period, feather growth and acquisition of fat stores were undertaken. Thus Grey‐headed Albatross chicks begin to acquire substantial fat stores only during the later part of the development period; this is contrary to the predictions of any of the existing hypotheses concerning provisioning patterns and the role of fat stores in Procellariiformes. We propose that the deposition of fat in the later stages of chick growth is an adaptation to: (a) ensure against energy demands and/or nutritional stress affecting the quality of flight feathers (many of which are not renewed for up to three years after fledging); and (b) provide an energy reserve for chicks to use in the critical period immediately after independence.
Hunting mode and success of African PeregrinesFalco peregrinus minor,does nesting habitat quality affect foraging efficiency?
Authors: JENKINSz ANDREW R.
Published: April 2008

Peregrine FalconFalco peregrmushunting behaviour was studied at nest‐sites in three areas of South Africa over eight years. In Africa, resident Peregrines are mostly restricted to high cliffs, possibly because these structures provide optimal conditions for hunting. This hypothesis is examined in terms of the influence of nest‐site quality, particularly cliff height, on foraging efficiency. Foraging mode varied considerably between sites, and males foraged more actively than females but there was little variation in the design of hunts between sexes, seasons or study areas. Individually, Peregrines spent 30–50% of the day on or near the nest cliff. On average, about 0.5 hunts were recorded per hour of observation. Foraging mode was not correlated with cliff height or elevation above the surrounding terrain, but Peregrine pairs occupying higher cliffs achieved greater hunting success rates. Most hunts were initiated from elevated perches on the nest cliff, and perch hunts were more successful than strikes made from the air. Success was highest in strikes at doves and small passerines, and over habitats with moderate cover. The height difference between Peregrine and prey at the start of a hunt positively and significantly affected hunting success. Overall, Peregrines were relatively sedentary and made extensive use of the nesting habitat as a foraging area. High nest cliffs contributed to foraging success by providing perch‐hunting falcons with an effective height advantage over their prey.
Effects of supplemental food on intra‐and inter‐specific behaviour of the Varied TitParus varius
Authors: KUBOTA HARUO , NAKAMURA MASAHIKO
Published: April 2008

Varied TitsParus variuslived in flocks containing a pair, or a pair with one or two unpaired birds. To test whether the sociality of Varied Tits or their participation in mixed‐species flocks is sensitive to additional food (sunflower seeds), we compared the following parameters between fed and unfed periods at the individual level: population size, degree of site fidelity, mono‐specific flock size and the stability of its membership, home‐range size and distribution, attendance rate with mixed‐species flocks, and flock size. Neither the size of the mono‐specific flock nor its membership was affected by food supply. Whether food was added or not, individuals exhibited a strong site fidelity resulting in stable population size. Supplemental feeding had no effect on home‐range size or distribution. In the presence of extra food, Varied Tits were observed in mono‐specific flocks but rarely in mixed‐species flocks. However, when we stopped feeding, they shifted to mixed‐species flocking. After adding food, mixed‐species flocks were significantly smaller than in the control samples. Varied Tits were more likely to join mixed‐species flocks as temperatures dropped and wind speed increased. These results suggest that intra‐specific sociality of Varied Tits is relatively insensitive to food supply, but they easily shift to mixed‐species flocking in relation to food and weather conditions. We conclude that Varied Tits participate in mixed‐species flocks to obtain short‐term benefits e.g. increased foraging efficiency but they also obtain long‐term benefits from stability of pair bonds and strong site fidelity, which did not respond to supplemental food.
Nectar consumption of warblers after long‐distance flights during spring migration
Authors: SCHWILCH REGINE , MANTOVANI ROSITA , SPINA FERNANDO , JENNI LUKAS
Published: April 2008

The consumption of nectar by European passerines has been reported only occasionally. In this study we investigated the occurrence and significance of nectar consumption of small passerine birds on spring migration after crossing the Mediterranean Sea. On Ventotene Island in the Tyrrhenian Sea, four migrating species of Sylvia warblers [Garden Warbler S. borin, Subalpine Warbler S. cantillans, Whitethroat S. communis, Blackcap S. atricapilld) regularly foraged on the two most common flowering species at that time of year, Brassica fruticulosa (Cruciferae) and giant fennel Ferula communis (Umbelliferae), while other species visited flowers only occasionally or not at all. Feeding behaviour, pollen traces on the head, and the examination of pollen and sugar remains in droppings indicated that nectar was the main target of the Sylvia warblers, rather than pollen or insects on the flowers. This was confirmed by food choice experiments indicating a clear preference by Garden Warblers and Whitethroats for nectar from artificial flowers over mealworms. Although conclusive experiments are not available, we hypothesize that nectar might be a diet easy to obtain and to absorb for birds after a long‐distance flight in which they have incurred a depletion of energy stores and a reduction of the digestive tract.
Significance of the White Sea as a stopover for Bewick's Swans Cygnus columbianus bewickii in spring
Authors: NOLET BART A. , ANDREEV VALERY A. , CLAUSEN PREBEN , POOT MARTIN J. M. , WESSEL ERIK G. J.
Published: April 2008

We searched for a major stopover site of Bewick's Swans Cygnus columbianus bewickii in the White Sea following the suggestion that one should exist on the stretch between Estonia and the breeding grounds (1750 km). We discovered 733 Swans in Dvina Bay during a late aerial survey in spring 1993. Subsequently, ground‐based research was carried out in May 1994, 1995 and 1996 in the Dry Sea, a tidal, shallow bay with fresh to brackish water just north of the Dvina Delta. The total number of passing Bewick's Swans was estimated at 10974 (1994), 9593 (1995) and 17 972 (1996) (32–60% of the flyway population). Estimated peak numbers staging were 1500–2000 (9 May 1994), 4937 (17 May 1995) and 4457 (24 May 1996) (> 5–16% of the flyway population). The Swans foraged almost exclusively on submerged water plants apart from some supplemental feeding on emerged food plants around high tide. Stoneworts Chara spp. were an important food in the late spring of 1996, because they grew in places where bog streams quickly melted the ice. At this latitude (65d̀N) food alternatives to the submerged macrophytes are rare in spring, but we cannot rule out the possibility that the Swans forage on grass rhizomes on inundated pastures. One bird tracked by satellite staged 15 days in Dvina Bay, of which four days were spent in the Dry Sea, in accordance with other indications that the Dry Sea is part of a larger stopover site within Dvina Bay. Recent evidence shows that the Swans largely skip the White Sea during autumn migration. However, in spring the birds probably need this stopover to be able to carry reserves to the breeding grounds. At present, the preservation of the submerged vegetation in Dvina Bay seems to be crucial to the conservation of this Bewick's Swan population.
Seasonal variation in reproductive measures of tropical Roseate Terns Sterna dougallih previously undescribed breeding patterns in a seabird
Authors: RAMOS JAIME A.
Published: April 2008

Seasonal variation in egg‐laying, egg size, hatching success, hatchling mass, fledging success and chick growth of Roseate Terms Sterna dougallii breeding on Aride Island (Seychelles), Indian Ocean, were studied in 1997 and 1998. I investigated to what extent two patterns, common in a range of species, were followed by tropical Roseate Terns: (a) seasonal decrease in clutch size, egg size and breeding success and (b) an increase in breeding success with increasing egg weight. In 1997 (a poor year), the earliest nesting birds laid significantly smaller eggs, and chicks were lighter at hatching than those of peak nesting birds. The mean clutch size, of 1.04 eggs, showed no seasonal variation and no ‘b’‐eggs hatched. In 1998 (a good year) the earliest nesting birds laid eggs of similar size and their chicks were of similar weight to those of peak nesting birds. Mean clutch size, of 1.25 eggs, increased significantly through the season and about 60% of the ‘b’‐eggs hatched. In 1997, hatching success was 57% whereas in 1998 it was 80%. In both years, breeding success declined significantly through the season. The fact that the earliest breeding birds laid smaller eggs in a poor year and smaller clutches in a good year is in marked contrast to a range of other species, and to temperate‐nesting Roseate Terns. Egg volume explained about half of the variance in hatchling mass in both years, but only 15% of the variation in linear growth rate. Hatching date was the only variable with a significant effect on fledging success. Roseate Terns on Aride seemed to sacrifice egg size and clutch size for earliness of laying. Presumably it is a strategy of older birds to lay as early as possible and may be regarded as a response of tropical Roseate Terns to breeding under relatively poor, and seasonally declining, food conditions.
Autumn migration of raptors on Java, Indonesia: composition, direction and behaviour
Authors: NIJMAN VINCENT
Published: April 2008

The migration of four northern migrant raptors (Oriental Honey‐buzzard Pernis ptilorhyncus, Chinese Sparrowhawk Accipiter soloensis,Japanese Sparrowhawk A. gularis and Common Buzzard Buteo buteo) was studied in the Dieng mountains, Central Java, Indonesia during September‐October 1998. Populations migrating through Central Java originate from northern Asia and most likely have passed over the Thai‐Malay peninsula and Sumatra before reaching West and Central Java. An unknown proportion continues on to Bali and/or the Lesser Sunda Islands. In all, 68 groups totalling 885 individuals were counted passing by. Ninety‐five percent of individuals identified were accipiters, two‐thirds of which could be identified to the species level. Passage was directed from WSW‐SW to E‐ESE, following the alignment of volcanoes on the island. The number of groups was highest during late morning; single individuals were observed significantly more often during the early morning and large (> 25 individuals) groups during the afternoon. Single individuals and small (five or fewer individuals) groups spent significantly less time in the area than large groups. The forests of the Dieng mountains are also used as an overnight stopover and hunting site. Differences in the proportion of the two species of Accipiter identified at Javan and Bali study sites suggests an additional migration route to the one following the Javan mountains. This may follow the eastern edge of the Sunda Shelf. The Dieng mountains qualify as a globally Important Bird Area (IBA) on the grounds of the raptor congregations, as well as because of the presence of globally threatened and restricted range species.
Annual survival rates of adult Red‐necked Nightjars Caprimulgus ruficollis
Authors: FORERO MANUELA G. , TELLA JOSE L. , ORO DANIEL
Published: April 2008

Nothing is known about the survival rates of Nightjars. Here we estimate annual survival rates of adult Red‐necked Nightjars Caprimulgus ruficollisin and around the Donana National Park, southwest Spain. During the period 1989‐95, 557 adults were marked and 19.7% of them were recaptured at least once in subsequent years. Capture‐recapture models were built to estimate separately survival and recapture probabilities. The final selected model showed that probabilities of recapture differed between years (0.06‐0.30) but not between sexes, and were independent of recapture effort. Survival was dependent on the interaction between sex and rainfall, this effect being negative for females and positive for males. However, it is not clear why rainfall influences the survival of males and females differentially due to the lack of accurate information on other life history traits. Average adult survival for the whole period was 0.74 for males (95% CI: 0.63‐0.82) and 0.64 for females (95% CI: 0.56‐0.72).
Density‐dependent habitat selection of corridors in a fragmented landscape
Authors: FERNANDEZ‐JURICIC ESTEBAN
Published: April 2008

This paper assesses the occurrence of density‐dependent habitat selection in an urban fragmented landscape, composed of forest fragments (urban parks) connected by corridors (wooded streets), to test the hypothesis that as population density increased in the parks their suitability decreased and individuals entered alternative habitats, such as wooded streets. Density variation of six species was studied during two consecutive breeding seasons. Vegetation structure in wooded streets was significantly less complex than in urban parks, supporting the view that wooded streets were less suitable for breeding birds. Five species (Coal Tit Parus ater, Spotless Starling Sturnus unicolor, Serin Serinus serinus, Black‐billed Magpie Pica pica and Woodpigeon Columba palumbus) showed density‐ dependent habitat occupation of wooded streets, while the Common Blackbird Turdus merula did not. As park suitability decreased with rising densities, wooded streets became a profitable alternative in terms of foraging, breeding, or for moving between parks. However, the relationships varied both between and within species in different years. Such differences could have been caused by variable rates of human disturbance, renewal of resources and predation risks in wooded streets. More detailed studies are required to determine how birds perceive and regulate their population dynamics in fragments and associated corridors, particularly for species targeted for management.
Effects of age, cohort and individual on breeding performance in the Lapwing Vanellus vanellus
Authors: PARISH DAVID M. B. , THOMPSON PATRICK S. , COULSON JOHN C.
Published: April 2008

The breeding performance of individually colour‐ringed Lapwings Vanellus vanellus was studied on marginal grassland in Upper Teesdale, County Durham (UK), from 1992 to 1995. Contrary to many studies of birds, female age had only a minor effect on breeding performance: yearling females produced eggs on average 5% smaller than those of adults. In contrast, the average productivity of male Lapwings was estimated to increase by around 40% between one and two years of age, and by a further 10% between two and three years of age. This was because of a 40% increase in the proportion of males that bred between one and two years of age, and of an increase in mating success with age coupled with a higher breeding success for polygynous males. The likelihood of breeding for male Lapwings was affected by year of hatching. More than half of those males that hatched in 1990, and which were present in both 1993 and 1994, did not breed. It was suggested that this was due to environmental effects experienced by these males as chicks, resulting in reduced success in securing a breeding territory later in life. Individual female Lapwings showed a high degree of consistency between years in both laying date and egg size, and those that raised up to two young in 1993 raised approximately the same number in 1994. However, females producing more than two young in 1993 raised significantly fewer in 1994, perhaps suggesting a cost of reproduction.
Taxonomic status of the Namibian Violet Woodhoopoe Phoeniculus damarensis as determined by mitochondrial DNA
Authors: COOPER MARK I. , CUNNINGHAM MICHAEL , CHERRY MICHAEL I.
Published: April 2008

The Violet Woodhoopoe Phoeniculus damarensis damarensis is considered a threatened subspecies and one of ten bird taxa endemic to Namibia and southwestern Angola. This species is distinguished from the more common and widespread Green Woodhoopoe P. purpureus by a variable plumage trait, resulting in uncertainty as to the distribution and degree of overlap between these taxa. Mitochondrial sequences from the cytochrome oxidase I (COI) gene show minimal divergence among Namibian woodhoopoes (0.15%, including P. d. damarensis and P. p. angolensis), and low divergence between Namibian birds and South African (1.06%, P. p. purpureus) or Kenyan (2.30%, P. p. marwitzi) Green Woodhoopoes. Sequences from Namibian woodhoopoes are phylogenetically nested within P. purpureus, rendering this species paraphyletic at mitochondrial DNA. Genetic divergences among Violet and Green Woodhoopoes fall within the range of intraspecific values recorded for avian mitochondrial protein coding genes, and are substantially less than most interspecific values. Comparisons with the related Scimitarbill Rhinopomastus cyanomelas suggest that the low divergences among Green and Violet Woodhoopoes are not an artefact of slow evolutionary rates in Phoeniculidae. We suggest that in the absence of evidence for evolutionary independence or a clear phenotypic diagnosis, the Violet Woodhoopoe should be synonymized with the Green Woodhoopoe. It is the status of this taxon that should be considered in formulating priorities for avian conservation in Namibia.
Comparative breeding ecology and hybridization of Eastern and Western Marsh Harriers Circus spilonotus and C. aeruginosusin the Baikal region of Eastern Siberia
Authors: FEFELOV IGOR V.
Published: April 2008

New information on the breeding ecology and inter‐breeding of Western Circus aeruginosus and Eastern C. spilonotus Marsh Harriers in the Baikal region of Eastern Siberia is presented. Hybridization is relatively common (one of the parents was not ‘pure’ C. spilonotus in six out of 28 nesting cases) in the Irkutsk area, where nests of a mixed pair were found with chicks in 1999 and 2000. Eastern Marsh Harriers are more similar to Western in size, biology and coloration of young birds, but to the Australasian C. approximans in their displays and mating system, and intermediate between C. aeruginosus and C. approximans in the plumage coloration of females. The systematic status (species' or ‘subspecies’) of the Western and Eastern Marsh Harriers depends on the systematic approach taken, and existing data seem to be inadequate to resolve this. The Siberian Mongolian zone of contact of these marsh harriers is unique as other marsh harriers of the world are allopatric. More research on ecology, behaviour and molecular systematics is necessary to resolve the situation.
Spatial patterns of range contraction in British breeding birds
Authors: DONALD PAUL F. , GREENWOOD JEREMY J.D.
Published: April 2008

We use ornithological atlas data to assess evidence for the existence of a number of spatial patterns of range contraction in British breeding birds. For 18 of the 25 species which suffered the greatest range contractions between 1968 and 1991, there wais a greater likelihood of local extinction in areas where the species was initially less widespread, so ranges tended to contract towards their cores. However there was evidence for a number of other patterns, with some species having a greater likelihood of local extinction in the centres of their ranges and others suffering random local extinctions throughout their range. The different spatial patterns identified were largely independent of the overall range contraction suffered by each species nationally. We suggest that range contractions in British birds can generally be explained better by a general decline in habitat quality or other factors than by contagious anthropogenic effects, as might be expected in a country with a long history of human environmental modification.
Low flock coherence in mild winters leads to a lack of subordination costs in Bridled Titmouse foraging groups
Authors: CHRISTMAN BETH J.
Published: April 2008

Titmouse winter social behaviour has previously been studied in regions with severe winter weather. This paper reports on a study of the non‐breeding behaviour of the Bridled Titmouse Parus wollweberi in Southeastern Arizona. Bridled Titmice in larger foraging groups spent a greater proportion of their time in locations that were more exposed to predators but also more profitable in terms of prey capture rate. Flock coherence was low, with flock mates usually foraging in separate trees. Dominant and subordinate group members did not differ in their use of dangerous foraging sites. These results indicate that Bridled Titmice make an adaptive trade‐off in the use of foraging locations, using more profitable sites when predation risk is decreased through larger group size. Additionally, subordination appears to be less costly than in other tits studied previously. The warmer temperatures and longer days of this study, compared with similar studies, are likely to have strongly influenced the flock dynamics of the Bridled Titmouse.
How well do predation rates on artificial nests estimate predation on natural passerine nests?
Authors: WEIDINGER KAREL
Published: April 2008

Daily survival rates (DSR) of three nest types were compared among three passerine species in woodland habitats of the Czech Republic in 1998‐99. The species were: Yellowhammer (YH) Emberiza citrinella, Blackcap (BC) Sylvia atricapilla, Song Thrush (ST) Turdus philomelos. The nest types were: AA, artificial nests with artificial plastic eggs, both mimicking the real models (total n= 432); NA, natural nests left in their original position and baited with artificial plastic eggs (n= 706); and NN, active natural nests observed during the egg stage (n= 596). Rodents were dominant predators of the near‐ground YH nests while predation by corvids slightly prevailed in the shrub nests of BC and ST. There was no consistent relationship between nest type (AA vs. NA) and type of predator. Effects of nest type (AA vs. NA or AA vs. NN, respectively), species, date and study plot on DSR were examined by fitting logistic regression models. Marginally significant (< P < 0.05) differences were found between AA and NA nests in both years. Due to the interaction with date in 1998, the model predicted lower/higher DSR for AA nests before/after about 25 May respectively. In 1999 the DSR of AA nests was consistently higher (difference: 0.011; 95% CI: 0.001 to 0.021). Marginally significant differences between AA and NN nests were found only in 1998: the DSR of AA nests was consistently lower (‐0.014, 95% CI: ‐0.027 to ‐0.001). Comparisons of mean DSR within each species‐year sample showed that the differences between nest types were of both directions and varied from almost zero to 0.02 (ST, BC; ns) or 0.04 (YH; P < 0.05). Although the experimental nests accurately reflected the mean values as well as seasonal trends and interspecific differences in DSR of the real nests in some subsets of data, the pattern was not consistent across species and between years. This study suggests that artificial nests could not be used to assess survival of natural nests without careful validation of the experimental results.
Sex roles, parental effort and offspring desertion in the monogamous Eurasian Curlew Numenius arquata
Authors: CURRIE DAVE , VALKAMA JARI , BERG ÅKE , BOSCHERT MARTIN , NORRDAHL KAI , HÄNNINEN MIKKO , KORPIMÄKI ERKKI , PÖYRI VILLE , HEMMINKI OSSI
Published: April 2008

The reasons for female desertion of offspring and the evolution of predominantly male care among monogamous bird species are not clearly understood. We studied parental effort during the incubation and chick rearing periods in the Eurasian Curlew Numenius arquata in western Finland, and compared timing of brood desertion with other populations in Europe. Males and females contributed equally to incubation and showed no differences in the intensity of mobbing behaviour towards a potential nest predator (stuffed crow) shortly after hatching. However, females deserted their offspring approximately halfway through the brooding period (c. 16 d after hatching), while males remained with chicks until independence (c. 35 d). Females with late‐laid clutches deserted their offspring sooner after hatching than those with clutches produced earlier in the season. Curlew females deserted younger chicks in northeast Europe, where laying dates were later, breeding seasons shorter and migration distances were longer, than in western and central Europe. We suggest that the most likely reasons for offspring desertion by females may be associated with increased female survivorship and maintenance of pairbond between years.
Habitat selection in a recovering Osprey Pandion haliaetus population
Authors: LOHMUS ASKO
Published: April 2008

Sequential habitat occupation and productivity of Ospreys Pandion haliaetus were studied in the recovering Estonian population from 1985 to 1999. During this period, the number of known nests increased from five to 32. Nest‐sites closer to the foraging grounds and with more lakes nearby were occupied first and had the highest productivity. Through a reduction in the quality of sites available, the average productivity of Ospreys decreased as their numbers rose, consistent with despotic distribution models. The sites occupied first during the recolonization were also those that had been the last to be abandoned during the population's decline prior to 1980. However, newcomers preferred sites near established pairs. Therefore, conspecific attraction explained some stochasticity left unexplained by deterministic resource models.
Survival analysis of Little PenguinEudyptula minorchicks on Motuara Island, New Zealand
Authors: RENNER MARTIN , DAVIS LLOYD S.
Published: April 2008

Chick survival of Little PenguinsEudyptula minorwas studied on predator‐free Motuara Island, Cook Strait, New Zealand (41d̀05'S, 174d̀15'E), in 1995 and 1996. We used the Kaplan‐Meier estimator and robust Cox regression to estimate chick survival rate (pL se) at 0.325 pL 0.044, leading to an estimated survival from laying to fledging of 0.13 or a reproductive output of 0.26 chicks per pair and breeding attempt. Starvation posed the greatest mortality risk, followed by unknown factors and rain. Risk of death due to rain was restricted to the guard stage, whereas starvation occurred throughout the nesting period, though with a peak in the early guard stage. Significant seasonal differences in survival rate were detected in both years, but with reversed trends, survival decreasing with the season in 1995 and increasing in 1996. Failure of adults to relieve their partner on the nest after chicks hatched accounted for 16% mortality or 34% of all chick deaths. Differences in chick survival rate between nest types were significant in 1995, a year with high rainfall, but not in 1996. Nests in the base of hollow trees had the highest chick survival rate. Of chicks in open nests ‐ a nest type that is unusual for this species ‐ 5.4% fledged. Our results suggest that on Motuara Island good breeding sites are scarce and that the food supply has been poor during the years of this study.
New specimens of the Middle Eocene fossil mousebird Selmes absurdipes Peters 1999
Authors: MAYR GERALD
Published: April 2008

Described here are an excellently preserved new specimen of the Middle Eocene mousebird Selmes absurdipes from the type locality Messel (Hessen, Germany) and first records of this species from the Geiseltal (Sachsen‐Anhalt, Germany). These specimens allow the recognition of several previously unknown osteological features, and thus more detailed comparisons with other fossil and recent Coliiformes. Selmes absurdipes, which previously has been known only from a single poorly preserved skeleton, most closely resembles the Lower Eocene species Chascacocolius oscitans in its overall morphology. The species shares a derived character with each of the two coliiform families, the extinct Sandcoleidae and the Coliidae, and at present it cannot be assigned to either of these families with certainty.
The timing and duration of moult in adult Starlings Sturnus vulgaris in east‐central England
Authors: ROTHERY PETER , WYLLIE IAN , NEWTON IAN , DAWSON ALISTAIR , OSBORN DAN
Published: April 2008

The timing and duration of primary moult were estimated for wild adult Starlings Sturnus vulgaris near Monks Wood in 1977‐78, and for captive birds in 1999. The model of Underhill and Zucchini (1988) was modified to allow for a non‐linear increase in the moult score, based on scores of captive birds. For wild birds, estimates of moult duration in 1977 and 1978 were 100 days and 98 days, with mean and standard deviation in start dates of 6 June and 7.3 days in 1977, and 2 June and 9.7 days in 1978. For captive birds, moult duration was 85 days, with mean and standard deviation of 31 May and 4.1 days. Differences between these estimates and those reported for other wild and captive Starling populations are discussed.
Recognition of individual European Nightjars Caprimulgus europaeus from their song
Authors: REBBECK M. , CORRICK R. , EAGLESTONE B. , STAINTON C.
Published: April 2008

The European Nightjar is a difficult bird to observe, being mainly nocturnal but also highly mobile, often travelling several kilometres at night to feed. Despite a recent reprieve in the UK, there is international concern about its status. A non‐intrusive monitoring method using vocal individuality therefore has considerable potential. The churring song commonly supposed to mark a territory was recorded from two principal localities in North Yorkshire. A computer program was developed to measure the pulse rates and phrase lengths of the churr and these variables were subjected to discriminant analysis. The pulse rates alone were able to classify 95% of individuals and this improved to 98.5% when the phrase lengths were included. The individual characteristics have been used to suggest movements within a season and the return of one individual to the same territory in three successive years.
Seeing without being seen: a removal experiment with mixed flocks of Willow and Crested Tits Parus montanus and cristatus
Authors: KRAMS INDRIK IS
Published: April 2008

This paper tests the hypothesis that foraging site selection reflects a trade‐off between the various needs for concealment from predators, to find food, and for the individual to maintain some view of its surroundings. After removal of Crested Tits Parus cristatus (the dominant species in mixed flocks), Willow Tits P. montanus did not decrease their foraging heights as expected but remained in the most exposed parts of young pines. In contrast, after removal of Willow Tits, Crested Tits increased their foraging height from the sheltered lower canopy to sites previously occupied by Willow Tits. When flock size was reduced, the birds maintained the same high levels of vigilance without concealing themselves in dense vegetation. I suggest that flock members may benefit from foraging in sites that afford good anti‐predator vigilance.
Impaired nitroglycerin biotransformation in patients with chronic heart failure
Authors: Petersson Magnus , Rundqvist Bengt , Bennett Brian M. , Adams Michael A. , Friberg Peter
Published: April 2008

Objective:  Patients with chronic heart failure (CHF) often require higher doses of nitroglycerin (glyceryl trinitrate, GTN) than patients with normal cardiac function to achieve a given haemodynamic goal. Two pathways leading to biotransformation of GTN have been characterized; a high‐affinity pathway operative in nanomolar concentration ranges yielding predominantly 1,2‐glyceryl dinitrate (1,2‐GDN), and a low‐affinity pathway operative at higher, micromolar concentrations of GTN associated with a greater proportion of 1,3‐GDN formation. We tested the hypothesis that, at a given GTN‐induced blood pressure reduction, the CHF group would present with: (i) higher concentrations of GTN; and (ii) decreased ratios of 1,2‐GDN/GTN and 1,2‐GDN/1,3‐GDN compared with healthy subjects (HS).

Methods:  Twelve patients with CHF (left ventricular ejection fraction 20 ± 5%, NYHA III) and nine HS were investigated during a right cardiac catheterization. GTN was titrated intravenously until mean arterial blood pressure (MAP) was reduced by 15%.

Results:  At arterial GTN concentrations of 27·2 [10·0–57·8] nmol l−1 in CHF and 2·8 [2·5–3·5] nmol l−1 in HS [median (quartile range), P<0·05 between groups], MAP and mean capillary wedge pressures were reduced similarly in both groups (approx. 15% and 65%, respectively, P = NS between groups). The ratios of 1,2‐GDN/GTN and 1,2‐GDN/1,3‐GDN were lower in CHF (0·86 [0·28–1·58] and 5·8 [5·6–6·3]) compared with HS [1·91 (1·54–2·23) and 7·6 (7·2–10·2), P<0·05], with a negative correlation between the 1,2‐GDN/1,3‐GDN ratio and the arterial GTN concentrations in the CHF patients (R = −0·8, P<0·05).

Conclusion:  Patients with CHF have attenuated GTN responsiveness and decreased relative formation of 1,2‐GDN in comparison with HS, indicating an altered biotransformation of GTN.
Effect of Relining Method on Dimensional Accuracy of Posterior Palatal Seal. An In Vitro Study
Authors: Kim Yeongjeong , Michalakis Konstantinos X. , Hirayama Hiroshi
Published: April 2008

Purpose: The posterior palatal seal contributes to the retention of the complete denture. Distortion of this area can occur during reline procedures. The purpose of this study was to evaluate the dimensional accuracy of various denture relining methods and materials on the maxillary posterior palatal seal area.

Materials and Methods: A stainless steel cast was constructed from a maxillary edentulous cast. Fifty identical complete dentures were fabricated on 50 definitive casts made from the original metal cast. Five relining methods and materials were evaluated during this study, in regards to posterior palatal seal distortion: (I) laboratory conventional heat‐polymerizing method (Lucitone), (II) laboratory heat/pressure‐polymerizing method (SR‐Ivocap), (III) laboratory autopolymerizing method (Perm), (IV) chairside autopolymerizing method (Tokuso Rebase), and (V) chairside light‐polymerizing method (Astron). The dimensional changes of the posterior palatal seal areas were determined by placing a low‐viscosity silicone impression material between the metal cast and the tissue surface of the relined dentures. The silicone thickness was measured at five predetermined points, under a measuring microscope. Statistical analysis was performed using descriptive statistics, one‐way analysis of variance, and Student‐Newman‐Keuls tests (α= 0.05).

Results: The gap at the posterior palatal seal area ranged from 68.76 to 331.55 μm, when measured at the five predetermined points. Group IV exhibited the smallest mean gap (137.62 μm) and Group I revealed the largest mean discrepancy (192.35 μm). The different relining methods and materials presented statistically significant differences (p < 0.0001).

Conclusion: The chairside autopolymerizing method exhibited smaller gap recordings than the rest of the tested complete denture relining methods.
Mechanical Behavior and Failure Analysis of Prosthetic Retaining Screws after Long‐term Use In Vivo. Part 3: Preload and Tensile Fracture Load Testing
Authors: Al Jabbari Youssef S. , Fournelle Raymond , Ziebert Gerald , Toth Jeffrey , Iacopino Anthony M.
Published: April 2008

Purpose: The aim of this study was to determine the preload and tensile fracture load values of prosthetic retaining screws after long‐term use in vivo compared to unused screws (controls). Additionally, the investigation addressed whether the preload and fracture load values of prosthetic retaining screws reported by the manufacturer become altered after long‐term use in vivo.

Materials and Methods: For preload testing, 10 new screws (controls) from Nobel Biocare (NB) and 73 used retaining screws [58 from NB and 15 from Sterngold (SG)] were subjected to preload testing. For tensile testing, eight controls from NB and 58 used retaining screws (46 from NB and 12 from SG) were subjected to tensile testing. Used screws for both tests were in service for 18–120 months. A custom load frame, load cell, and torque wrench setup were used for preload testing. All 83 prosthetic screws were torqued once to 10 Ncm, and the produced preload value was recorded (N) using an X–Y plotter. Tensile testing was performed on a universal testing machine and the resulting tensile fracture load value was recorded (N). Preload and tensile fracture load values were analyzed with 2‐way ANOVA and Tukey post‐hoc tests.

Results: There was a significant difference between preload values for screws from NB and screws from SG (p < 0.001). The preload values for gold alloy screws from NB decreased as the number of years in service increased. There was a significant difference between tensile fracture values for the three groups (gold alloy screws from NB and SG and palladium alloy screws from NB) at p < 0.001. The tensile fracture values for gold alloy screws from NB and SG decreased as the number of years in service increased.

Conclusions: In fixed detachable hybrid prostheses, perhaps as a result of galling, the intended preload values of prosthetic retaining screws may decrease with increased in‐service time. The reduction of the fracture load value may be related to the increase of in‐service time; however, the actual determination of this relationship is not possible from this study alone.
Mechanical Behavior and Failure Analysis of Prosthetic Retaining Screws after Long‐term Use in vivo. Part 4: Failure Analysis of 10 Fractured Retaining Screws Retrieved from Three Patients
Authors: Al Jabbari Youssef S. , Fournelle Raymond , Ziebert Gerald , Toth Jeffrey , Iacopino Anthony M.
Published: April 2008

Purpose: The aim of this study was to perform a failure analysis on fractured prosthetic retaining screws after long‐term use in vivo. Additionally, the study addresses the commonly asked question regarding whether complex repeated functional occlusal forces initiate fatigue‐type cracks in prosthetic retaining screws.

Materials and Methods: Ten fractured prosthetic retaining screws retrieved from three patients treated with fixed detachable hybrid prostheses were subjected to a failure analysis. In patients 1 and 2, the middle three retaining screws of the prostheses were found fractured at retrieval time after they had been in service for 20 and 19 months, respectively. In patient 3, the middle three and one of the posterior retaining screws were found to be fractured at retrieval after they had been in service for 18 months. Low power stereomicroscopy and high‐power scanning electron microscopy (SEM) were performed to analyze the fractured surfaces of the retaining screws examining fatigue cracks in greater detail.

Results: Typical fatigue failure characterized by ratchet mark formation was revealed by light microscopy and SEM for all examined screws. Using low magnification light microscopy, ratchet marks were visible on the fracture surfaces of only two screws. SEM examination revealed all three classical stages of fatigue failure, and it was possible to see the ratchet marks on the fracture surfaces of all specimens, indicating a fatigue zone. The final catastrophic overload fracture appeared fibrous, indicating ductile fracture. The final overload ductile fracture surfaces showed equiaxed dimples, suggesting tensile overload in all examined screws except in two specimens that showed an elongated dimple pattern indicating shear/tearing overload forces.

Conclusions: Fracture of prosthetic retaining screws in hybrid prostheses occurs mainly through a typical fatigue mode involving mostly the middle anterior three screws. Fatigue cracks can grow in more than one prosthetic retaining screw, leading to fracture before the patient or clinician determines that any problem exists.
Proximodistal Alignment of the Canine Patella: Radiographic Evaluation and Association with Medial and Lateral Patellar Luxation
Authors: MOSTAFA AYMAN A. , GRIFFON DOMINIQUE J. , THOMAS MICHAEL W. , CONSTABLE PETER D.
Published: April 2008

Objectives—To evaluate the contribution of proximodistal alignment of the patella to patellar luxation, and to evaluate the structures contributing to proximodistal alignment of the patella relative to the femoral trochlea.

Study Design—Retrospective study using a convenience sample.

Animals—Medium to giant breed dogs (n=106).

Methods—Medical records and stifle radiographs of 106 dogs were reviewed. Radiographic measurements evaluated the proximodistal alignment of the patella with respect to the femoral trochlea, distal aspect of the femur, and proximal aspect of the tibia. Measurements were compared between dogs with clinically normal stifles (controls; n=51 dogs, 66 stifles), and dogs with a clinical diagnosis of medial patellar luxation (MPL, n=46 dogs, 65 stifles) or lateral patellar luxation (LPL, n=9 dogs, 11 stifles) using ANOVA.

Results—In dogs with MPL, the ratio of patellar ligament length (PLL) to patellar length (PL) was increased, as was the ratio of the distance from the proximal aspect of the patella to the femoral condyle (A) to PL (P<.0001). Dogs with LPL had a decreased A:PL (P=.003) and an increased ratio of the proximal tibial length (PTL) to distal tibial width (DTW;P=.009).

Conclusions—MPL is associated with a relatively long patellar ligament and patella alta in medium to giant breed dogs. LPL is associated with a relatively long proximal tibia and patella baja. Values for PLL:PL>2.06 and A:PL>2.03 are suggestive of the presence of patella alta, whereas a value for A:PL<1.92 is suggestive of patella baja.

Clinical Relevance—Measurements of both PLL:PL and A:PL are recommended in dogs with patellar luxation, and surgical correction should be considered in those with abnormal values.
Computed Tomographic Features of Incomplete Ossification of the Canine Humeral Condyle
Authors: CARRERA INES , HAMMOND GAWAIN J. C. , SULLIVAN MARTIN
Published: April 2008

Objectives— To describe computed tomographic (CT) features of canine elbows with incomplete ossification of the humeral condyle (IOHC) and investigate co‐existing incongruence in the elbow joint.

Study Design— Case control study.

Animals— Dogs with IOHC (n=20; 38 elbows) and 25 normal elbows.

Methods— Elbows with IOHC and normal elbows were assessed by CT. Standardized dorsal and sagittal reconstructions were created at 3 levels using image analysis software to obtain single measurements of the humero‐radial and humero‐ulnar joint spaces. On dorsal plane reconstructions, joint space measurements were obtained at the center point of the humero‐radial and humero‐ulnar articulations. Joint incongruity was defined as the difference between the humero‐radial and the humero‐ulnar joint spaces.

Results— Nineteen dogs (95%), all Spaniel breeds, had either bilateral IOHC demonstrable as a saw‐toothed intercondylar complete or incomplete hypoattenuating defect with hyperattenuating margins, or IOHC with contralateral humeral condylar fracture (HCF). Joint incongruity values for IOHC were compared with those of normal elbows. Significant differences were noted at the levels of the medial coronoid apex (P<.0001) and base (P<.004) indicative of humero‐ulnar incongruence. Evidence of medial coronoid disease in 10 elbows (26%) and degenerative joint disease in 30 elbows (79%) was also found.

Conclusions— Presence of elbow incongruence may be an underlying factor in failure of ossification centers to fuse leading to IOHC.

Clinical Relevance— IOHC is clearly defined by CT, and it should be considered in larger Spaniel breeds, with a chronic forelimb lameness or HCF.