Search birdRS Box

Search birdRS blog posts

Browse the Blog Posts

Or scan through the blog archive below for items of interest as only the latest post is shown below, thanks.

Tuesday, 8 September 2015

Journal of Ornithology October 2015; Volume 156, Issue 4

Journal of Ornithology

Journal of Ornithology

Volume 156, Issue 4, October 2015



Avian genomics: fledging into the wild!
Robert H. S. Kraus, Michael Wink 


Next generation sequencing (NGS) technologies provide great resources to study bird evolution and avian functional genomics. They also allow for the identification of suitable high-resolution markers for detailed analyses of the phylogeography of a species or the connectivity of migrating birds between breeding and wintering populations. This review discusses the application of DNA markers for the study of systematics and phylogeny, but also population genetics and phylogeography. Emphasis in this review is on the new methodology of NGS and its use to study avian genomics. The recent publication of the first phylogenomic tree of birds based on genome data of 48 bird taxa from 34 orders is presented in more detail.

Review of documented beak and feather disease virus cases in wild Cape parrots in South Africa during the last 20 years
Colleen T. Downs, Mark Brown, Lorinda Hart, Craig T. Symes 

Worldwide, there is concern about the increased prevalence of infectious diseases and their effects on biodiversity. Increasing changes in the environment, particularly changes in climatic conditions as a consequence of anthropogenic-induced climate change, are some of the factors driving this increased disease prevalence. Vertebrate taxa that appear to be most affected by these diseases are amphibians and birds, though this may be a consequence of research effort. Beak and feather disease virus (BFDV) affecting psittacine bird species is the disease of concern here. Data on BFDV incidence in wild, endangered Cape parrots (Poicephalus robustus) were collected opportunistically from 1992 to 2014. Data show that the disease is prevalent naturally in the wild during extreme climatic events, including drought. This stresses the birds, which may result in the expression of pathological symptoms. Juveniles in particular appear to succumb during times of drought. This has conservation implications with the impacts of extreme climatic events associated with anthropogenic-induced climate change.


Reassessment of the size of the Scopoli’s Shearwater population at its main breeding site resulted in a tenfold increase: implications for the species conservation
Pierre Defos du Rau, Karen Bourgeois, Mathieu Thévenet… 

Scopoli’s Shearwater (Calonectris diomedea) is a Procellariiform endemic to the Mediterranean Basin which is considered to be vulnerable in Europe due to recent local declines and its susceptibility to both marine and terrestrial threats. In the 1970s–1980s, its population size was estimated at 57,000–76,000 breeding pairs throughout the Mediterranean Basin, with the largest colony, estimated at 15,000–25,000 pairs, found on Zembra Island, Tunisia. The objectives of our study were to re-estimate the size of the breeding population on Zembra Island, to reassess the global population size of the species, and to analyse the implications of these findings on status and conservation of this species in the Mediterranean. Using distance sampling, we estimated the Zembra breeding population to be 141,780 pairs (95 % confidence interval 113,720–176,750 pairs). A review of the most recent data on populations of this species throughout the Mediterranean Basin led us to estimate its new global population size at 141,000–223,000 breeding pairs. Using the demographic invariant and potential biological removal approaches, we estimated the maximum number of adults which could be killed annually by all non-natural causes without causing a population decline to be 8800 (range 7700–9700) individuals, of which could be 3700 breeders. Although these results are less alarming in the context of species conservation than previously thought, uncertainties associated with global population size, trends and major threats still raise questions on the future of this species. More generally, we show how a monitoring strategy for a bird supposed to be relatively well known overall can be potentially misleading due to biases in survey design. The reduction of such biases would therefore appear to be an unavoidable prerequisite in cryptic species monitoring before any reliable inference on the conservation status of the species can be drawn.

Artificial lights and seabirds: is light pollution a threat for the threatened Balearic petrels?
Airam Rodríguez, David García, Beneharo Rodríguez…

Petrels are among the most threatened group of birds. On top of facing predation by introduced mammals and incidental bycatch, these seabirds have to deal with an emerging threat, light pollution, which is increasing globally. Fledglings are disoriented and attracted to artificial lights in their maiden night flights from their nests to the sea. Once grounded, they are exposed to multiple threats leading to high mortality. We report on numbers of three petrel species (Balearic shearwater Puffinus mauretanicus, Scopoli’s shearwater Calonectris diomedea, and European storm-petrel Hydrobates pelagicus) rescued on the Balearic Islands, Mediterranean Sea, in the period 1999–2013. We assessed the proportion of grounded fledglings in the population and colonies impact based on radiance levels measured from a nocturnal satellite image. We also calculated the radius of light pollution impact. At least 304 fledgling birds were found stranded due to attraction to artificial lights, fatally affecting 8.5 % of them. The proportion of grounded fledglings ranged between 0.13 and 0.56 % of the fledglings produced annually. The body mass of Balearic and Scopoli’s shearwater fledglings decreased with rescue date. Light-induced mortality increased during the fledging period for Scopoli’s shearwaters. Birds were rescued at a mean distance of 4833 m from the nearest colony, and between 30 and 47 % of colonies were exposed to light-polluted areas. Although impact seems to be low for all species, urban development and, consequently, the increase in light pollution in the proximity of the colonies should be taken into account to reduce as much as possible this emerging source of mortality.

Black Sparrowhawk brooding behaviour in relation to chick age and weather variation in the recently colonised Cape Peninsula, South Africa
Jakob Katzenberger, Gareth Tate, Ann Koeslag, Arjun Amar 

Understanding the effects climate change may have on animal populations relies on establishing which environmental conditions shape their behaviour and subsequent reproductive output, fitness or survival. South Africa has seen significant warming trends and changes in precipitation over the last few decades; however, the ways in which these trends are likely to influence animal populations are still relatively poorly understood. The Black Sparrowhawk (Accipiter melanoleucus) has expanded its range in South Africa and recently colonised the Cape Peninsula in the Western Cape, a region that experiences a Mediterranean climate. In this study, we examined the brooding behaviour of this species, a vital trait for reproductive success, in the Cape Peninsula breeding population. We examined the influence of chick age as well as temperature, rainfall and wind speed on parental brooding. Additionally, the effect of prey provisioning on brooding was investigated. In our analyses, we used data on brooding from nest cameras together with weather data collected at a fine temporal scale (1 h). The variable with the strongest influence on parental brooding was chick age. This variable showed a non-linear relationship. Initially chicks were brooded >50 % of the time; however after 3 weeks brooding declined rapidly. The proportion of time spent brooding increased with decreasing temperatures, while rainfall and wind speed showed a positive correlation with the amount of brooding. Our model predicted that in common winter conditions of the Western Cape (15 °C, 10 km/h wind speed, 1 mm/h rainfall) A. melanoleucus breeding pairs spent nearly 100 % of their time brooding young chicks (7 days old) to protect them from detrimental weather. Our results highlight measurable effects of weather patterns on avian behaviour at a key stage of the life cycle. Changes in weather conditions predicted for this region will likely further benefit this range-expanding species.

Refugial role of urbanized areas and colonization potential for declining Crested Lark (Galerida cristata) populations in the Czech Republic, Central Europe
Petra Šímová, Karel Šťastný, Miroslav Šálek 

Urban environment is only rarely considered an exclusive refuge for rapidly declining bird species. Crested Lark (Galerida cristata) is a species in Central Europe whose synanthropization began in the second half of the twentieth century due to dramatic changes in agriculture and landscape structure. We analyze how changes in these distribution patterns mirror landscape structures and demonstrate colonization potential from adjacent refuges. We used the Czech Breeding Bird Atlas data from two periods, 1985–1989 and 2001–2003, to model distribution change patterns for Crested Larks in two parts of the country, Bohemia and Moravia. Mapping quadrats comprised the sampling units, and binomial species presence or absence was used to model the change patterns using generalized linear models while considering landscape structure, demographic data and dominant habitat attributes as predictors. Despite similar attributes of landscape structures in Bohemia and Moravia, Crested Larks clearly differed in their extinction patterns. Within isolated Bohemia, the remnant subpopulations were restricted to early successional stands around commercial areas in urban zones. In Moravia, only altitude appeared related to the species’ disappearance. Moravia is connected at the south to the Pannonian Plain with stable or increasing Crested Lark populations, which we consider responsible for the significantly higher number of newly occupied quadrats in Moravia. Our results indicate the more isolated Bohemian population is more prone to extinction than is the Moravian population with its greater colonization potential. The study notes a rare example of urban zones serving as refuges for a bird species demanding early successional stands.

Long-term trends, total numbers and species richness of increasing waterbird populations at sites on the edge of their winter range: cold-weather refuge sites are more important than protected sites
Zuzana Musilová, Petr Musil, Jan Zouhar, Dušan Romportl 

Recent climate changes are most likely the major determining factor for the increasing importance of Central Europe for wintering waterbirds, given that most of the region is located on the edge of these species’ wintering ranges. A few recent large-scale studies have demonstrated changes in species distribution at the flyway level, but detailed studies at the site level are still scarce. Using mid-January wintering waterbird counts from 532 sites taken over a 48-year period (1966–2013), we have assessed the role of ‘cold-weather refuges’, i.e. sites where the selective pressures of winter harshness are reduced (e.g. sites with ample sources of running water, urban areas, warmer sites, sites with a relatively higher proportion of wetlands), and a site’s protection status on species richness, total numbers and trends at the site level. We found prevailing increasing trends in total numbers and species richness at the site level, which are in line with the area’s increasing importance as wintering grounds. However, some sites have likely been affected by density-dependent regulation as mean total numbers per site have not increased since the 1990s. Density dependence may also be a reflection of an increasing number of sites with running water in traditionally cold areas. Factors affecting trends in species richness at the site level are however less predictable. We demonstrate the great importance of cold-weather refuges, where running water has an effect on total numbers, species richness and trend affect total numbers, warmer areas and higher proportions of wetlands in the surroundings affect total numbers and species richness and urban areas affect total numbers. However, we found that legislative safeguards for sites, such as the establishment of Nature Reserves and Special Protection Areas, have no significant effects. Our findings therefore suggest that the effect of temperature and presence of cold-weather refuges (as defined here) are more relevant to this observed increasing trend of wintering waterbirds on the edge of wintering ranges than a reduction in human developmental pressures.

Latitudinal differences in life-history traits and parental care in northern and southern temperate zone House Wrens
Paulo E. Llambías, Mariana E. Carro, Gustavo J. Fernández 

South temperate songbirds differ from north temperate species in life-history traits, having greater adult survival, smaller clutch size, longer developmental periods and extended parental care. Due to its broad distribution, the House Wren, Troglodytes aedon, is an excellent model to evaluate selective pressures that may influence the maintenance of present clutch size. Here we report data on life-history traits and parental care of socially monogamous House Wrens from a north temperate and a south temperate population. Southern House Wrens exhibited smaller clutch sizes and longer developmental periods than Northern House Wrens; however, we did not find significant differences in adult survival probability between populations, contrary to a critical prediction of the cost of reproduction hypothesis. Our data did not support the hypothesis that smaller clutches are the consequence of greater food limitation in the south. Southern wrens have greater adult body mass but smaller territories; southern nestlings reached a greater proportion of adult body mass 6–7 days before fledgling, and provisioning rates to the nest per nestling were greater in the south. We did not find support for the hypothesis that reduced clutch size is a consequence of limited parental activity at the nest as southern wrens did not reduce parental care during the incubation and nestling stage. Our data better supports the offspring quality hypothesis; southern wrens invest more per nestling than northern wrens as provisioning rates per nestling were significantly higher and developmental periods longer in the south. Published results from Tropical House Wrens suggest that neither food limitation nor nest predation can explain reduced clutches in Central America. We suggest that south temperate and tropical wrens may differ in parental investment strategies as tropical wrens seem to invest even less per nestling than north temperate wrens.

Migration strategies revealed by satellite tracking among descendants of a population of European white stork (Ciconia ciconia) reintroduced to Belgium
Jill M. Shephard, Sam Rycken, Osama Almalik, Kris Struyf… 

Migration in the European white stork (Ciconia ciconia) has historically described a predictable annual cycle. The white stork is extensively distributed across continental Europe, which diverges to eastern and western wintering flyways. Within the western European population, some ring recovery and anecdotal information suggests that birds are giving up their traditional wintering grounds in the Sahel and are remaining in alternative sites in the Iberian Peninsula. Here we report on long-term satellite tracking of juvenile and adult stork collected between 2000 and 2011, whose natal site is in Belgium in the northern range of the western migration path. We identified three distinct migration patterns, two of which diverged from traditional expectations. Juvenile birds showed unique migration profiles both individually across migration cycles and when compared to one another, whereas adults showed consistent migrations but failed to migrate to Africa in any of the years surveyed. Stopover and wintering locations within Iberia were strongly associated with refuse sites or modified agricultural land. Overall, non-traditional migration movements appeared to be most strongly linked to artificial food sources rather than alternate drivers such as climate or habitat.

Wanderer of the deepest seas: migratory behaviour and distribution of the highly pelagic Bulwer’s petrel
Maria P. Dias, Maria Alho, José P. Granadeiro, Paulo Catry 

Small-sized nocturnal Procellariiformes are abundant predators in oceanic areas worldwide and are thought to play an important role in many marine food webs as consumers of superabundant mesopelagic prey. However, the spatial ecology and foraging behaviour of the great majority of these species remain largely unknown. We studied the non-breeding distribution and at-sea activity of a migratory small-sized Procellariiform, the Bulwer’s petrels Bulweria bulwerii, from the Selvagem Island colony (subtropical Northeast Atlantic). We found that soon after breeding Bulwer’s petrels migrate towards deep (mean depth of 4416 m), open oceanic waters of the tropical Atlantic, spending the winter far from shelf and shelf-break areas, on regions avoided by most other avian migrants in the Atlantic. When at sea, Bulwer’s petrels spent more time flying during the night (>90 %, all year round) than any other seabird studied so far. This nighttime activity was not influenced by the lunar cycle, suggesting that this highly specialised nocturnal seabird is probably very well adapted to locating and capturing prey even in very dark conditions. The results from the present study may have important implications for the identification of important bird areas in the marine realm, whose boundaries have been delineated so far mostly on the basis of the distribution and behaviour of better studied medium- to large-sized seabirds.

GPS tracking of Red Kites (Milvus milvus) reveals fledgling number is negatively correlated with home range size
Thomas Pfeiffer, Bernd-Ulrich Meyburg 

To date, reliable studies on the spatial area use and home range size of the Red Kite (Milvus milvus) during the breeding season are lacking. Between 2007 and 2014, 43 adult individuals were fitted with GPS transmitters in Germany. The home range sizes of 27 males, which successfully reared 47 broods, ranged between 4.8 and 507.1 km2 based on the 95 % kernel utilization distribution. The median during the nestling and post-fledging dependent periods was 63.6 km2. The home ranges of 12 females, with a total of 21 successful broods, ranged between 1.1 and 307.3 km2. Within a single breeding season, there were considerable differences among home range sizes. There was also considerable variation in the home range size of adults during the course of a season. Across years, the median home range size of all males ranged between 21 and 186 km2, depending on prey availability. For individual males at the same nest site, the home range size varied up to a factor of 28 across years. Kites with very large home ranges had only one fledgling, which indicates that resources were scarce. Individuals with more nestlings had intermediate-sized to small home ranges. The relationship between the number of fledged young and home range size was modelled using a cumulative logit model. Fifty-six, 37, and 26 % of male kite fixes were beyond a 1, 1.5, and 2 km radius around the nest, respectively. Birds with very small or very large home ranges differed considerably from these average figures. Adults sometimes travel very long distances to visit distant grasslands during and shortly after mowing (up to more than 34 km) from the nest, due to the increased likelihood of prey availability at these sites. In conclusion, home rage size serves as a useful indicator of Red Kite habitat quality, which may provide key conservation information at the wider ecosystem level.

Evidence that dorsally mounted satellite transmitters affect migration chronology of Northern Pintails
Jerry W. Hupp, Sergei Kharitonov, Noriyuki M. Yamaguchi… 

We compared migration movements and chronology between Northern Pintails (Anas acuta) marked with dorsally mounted satellite transmitters and pintails marked only with tarsus rings. During weekly intervals of spring and autumn migration between their wintering area in Japan and nesting areas in Russia, the mean distance that ringed pintails had migrated was up to 1000 km farther than the mean distance radiomarked pintails migrated. Radiomarked pintails were detected at spring migration sites on average 9.9 days (90 % CI 8.0, 11.8) later than ringed pintails that were recovered within 50 km. Although ringed and radiomarked pintails departed from Japan on similar dates, the disparity in detection of radiomarked versus ringed pintails at shared sites increased 7.7 days (90 % CI 5.2, 10.2) for each 1000 km increase in distance from Japan. Thus, pintails marked with satellite transmitters arrived at nesting areas that were 2500 km from Japan on average 19 days later than ringed birds. Radiomarked pintails were detected at autumn migration stopovers on average 13.1 days (90 % CI 9.8, 16.4) later than ringed birds that were recovered within 50 km. We hypothesize that dorsal attachment of 12–20 g satellite transmitters to Northern Pintails increased the energetic cost of flight, which resulted in more rapid depletion of energetic reserves and shortened the distance pintails could fly without refueling. Radiomarked pintails may have used more stopovers or spent longer periods at stopovers. causing their migration schedule to diverge from ringed pintails. We urge further evaluation of the effects of dorsally mounted transmitters on migration chronology of waterfowl.

Pattern of non-breeding movements by Stone-curlews Burhinus oedicnemus breeding in Northern Italy
Dimitri Giunchi, Chiara Caccamo, Alessia Mori, James W. Fox… 

The identification of year-round geographical ranges and the quantification of the degree of migratory connectivity are fundamental to the successful conservation of migratory bird populations. The Stone-curlew Burhinus oedicnemus is a species of conservation concern in Europe, but its ecology and behaviour are relatively poorly investigated. In particular, its migratory behaviour and the locations of the wintering ranges of most European populations are not known in detail because of a lack of specific studies and the scarcity of ringing recoveries. This study aimed to identify the wintering areas of a Stone-curlew population breeding in the Taro River Regional Park (Parma, northern Italy) by integrating the information obtained from ringing recoveries (n = 2), geolocators (n = 7), and GPS data loggers (n = 2). Furthermore, we compared two approaches to inferring the location of an assumed stationary bird using geolocator data. The different sources were quite coherent, indicating that tagged Stone-curlews did not leave the Mediterranean basin throughout the year and passed the winter in Sardinia or in Tunisia. The recorded wintering sites coincided with areas where breeding (and possibly resident) populations are reported, further emphasising the importance of these areas for the conservation of the species throughout the annual cycle. To our knowledge, our study represents the first thorough analysis performed to uncover the movements of a Mediterranean population of Stone-curlews. Furthermore, it proves the great potential of the tracking devices used in this work to provide information on the migration and non-breeding sites of elusive species, for which the application of mark–recapture/re-sighting techniques is hindered by profound limitations.

Habitat selection and movements of Piping Plover broods suggest a tradeoff between breeding stages
Mark T. Wiltermuth, Michael J. Anteau, Mark H. Sherfy… 

In precocial birds, adults select breeding areas using cues associated with habitat characteristics that are favorable for nesting success and chick survival, but there may be tradeoffs in habitat selection between these breeding stages. Here we describe habitat selection and intra-territory movements of 53 Piping Plover (Charadrius melodus) broods (320 observations) during the 2007–2008 breeding seasons on mainland- and island-shoreline habitats at Lake Sakakawea, North Dakota, USA. We used remotely sensed habitat characteristics to separately examine habitat selection and movements at two spatiotemporal scales to account for potential confounding effects of nest-site selection on brood-rearing habitat used. The scales used were (1) the entire brood-rearing period within available brood-rearing areas and (2) 2-day observation intervals within age-specific discrete habitat selection choice sets. Analyses at both scales indicated that broods selected areas which were non-vegetated, moderately level, and nearer to the shoreline. Rate of brood movement increased with age up to 5 days, then stabilized; broods that hatched >50 m away from the shoreline moved toward the shoreline. Brood movements were greater when they were in vegetated areas, when the brood-rearing area was of greater topographic complexity, and when broods aged 6–25 days were further away from the shoreline. Using inferences from our results and those of previously published work, we postulate how a potential tradeoff in habitat selection between nesting and brood-rearing can contribute to an ecological trap in a novel habitat. This work, in the context of published works, suggests that plover breeding habitat is a complex of both nesting and brood-rearing habitats and provides a basis for making remotely sensed abundance estimates of suitable breeding habitat for Piping Plovers.

Responses to the black locust (Robinia pseudoacacia) invasion differ between habitat specialists and generalists in central European forest birds
Jan Hanzelka, Jiří Reif 

Biological invasions are among the most important threats to global biodiversity. However, bird species differ in their ability to resist the invasions, and it is thus important to investigate which species’ traits account for their sensitivity to the invasions’ consequences. Here we focused on predictors of such sensitivity by using central European birds in oak forests invaded by the exotic black locust (Robinia pseudoacacia). We performed a detailed mapping of bird occurrence on plots located in the native oak stands and the invaded stands, respectively, controlling for stands’ age. Using multivariate analysis, we quantified bird species’ reliance on the native versus invaded forest stands. In the next step, we tested the hypotheses explaining species’ position along this gradient. We predicted that the species more closely associated with the invaded forest stands will be (1) habitat generalists and (2) species with fast life history strategies. The phylogenetic generalized least squares analysis showed that only the first prediction was supported. Moreover, species’ habitat specialization significantly affected differences in species’ abundance between the invaded and native forests: habitat generalists were more abundant in the black locust stands than in the oak stands, which was not the case of habitat specialists. Our study implies that the spread of invasive plants may contribute to the frequently reported replacement of specialist species by habitat generalists in local bird communities.

Phylogenetic placement of the critically endangered Townsend’s Shearwater (Puffinus auricularis auricularis): evidence for its conspecific status with Newell’s Shearwater (Puffinus a. newelli) and a mismatch between genetic and phenotypic differentiation
Juan E. Martínez-Gómez, Noemí Matías-Ferrer… 

Townsend’s Shearwater (Puffinus auricularis auricularis) is a highly threatened bird and currently breeds on Socorro and Clarión Islands, México. This subspecies has minor differences in plumage patterns when compared to Newell’s Shearwater of Hawaii (USA) (Puffinus auricularis newelli). These two forms are recognized as subspecies by the American Ornithologist’s Union. However, some authors consider them as distinct species based on subtle plumage differences and different breeding chronologies. We used Bayesian and Maximum Likelihood methods to compare the cytochrome b and cytochrome oxidase I sequences from Townsend’s Shearwaters with archived mitochondrial sequences from other taxa in the genus Puffinus. Townsend’s and Newell’s Shearwaters show little genetic differentiation; hence, there is no justification to consider them as different species. Additionally, differences in morphology and ecology might be the result of founder effects and phenotypic plasticity; proven migratory potential provides support to the current taxonomic assessment that considers these birds as conspecifics. We recommend the continued treatment of Townsend’s and Newell’s Shearwaters as two subspecies of P. auricularis. We also advocate treating the Rapa Shearwater (P. myrtae) as a distinct species.

Evolutionary status of Icelandic Redpolls Carduelis flammea islandica (Aves, Passeriformes, Fringillidae)
Julien Amouret, Katja Steinauer, Gunnar T. Hallgrimsson… 

The Icelandic Redpoll Carduelis flammea islandica is one of three subspecies of Carduelis flammea. The other two are C. f. rostrata, breeding in Greenland, and C. f. flammea, widely distributed at high latitudes in both North America and Eurasia. Recent studies on variation of the mtDNA control region and microsatellites among C. f. r. and C. f. f. and related species (Arctic Redpoll Carduelis hornemanni and Lesser Redpoll Carduelis cabaret) did not reveal clear genetic differentiation among the species. Here we include DNA sequences of mtDNA and nuclear markers of the Icelandic subspecies (C. f. islandica) and from additional samples of the other species and subspecies to evaluate further their taxonomic status within the complex, with special emphasis on C. f. islandica. Mitochondrial and nuclear variation is large within species and does not provide support for the current subspecies and the species classification. Significant differences in haplotype frequencies of the combined genetic data are observed between the C. flammea subspecies, and C. cabaret. The slight genetic differentiation within the redpoll complex could result from introgression and/or incomplete lineage sorting following recent and rapid diversification in morphology, possibly driven by environmental factors.

Taxonomy of the Pyrrhura perlata-coerulescens complex (Psittaciformes: Psittacidae) with description of a hybrid zone
Marina Somenzari, Luís Fábio Silveira 

The Pyrrhura lepida species complex currently consists of four taxa: P. l. lepida, P. l. coerulescens, P. l. anerythra, and P. perlata. It occurs south of the Amazon River, and is distinguished within the genus by a dark red upper tail and black under tail, as well as by having wider rectrices. The aim of this paper was to describe the morphological variation present in these taxa, and to revise their taxonomy and geographic distribution. Morphometric data revealed the absence of sexual dimorphism and did not allow the diagnosis of any taxon. Furthermore, morphological analysis, according to patterns of plumage of 174 specimens, resulted in the recognition of only three valid taxa that should be treated as full species: P. perlata, P. anerythra and P. coerulescens. A small hybrid zone between the latter two species was detected west of the mouth of the Tocantins River, and its establishment seems to be related to an already known geological shift in the course of the Tocantins River.

Evidence of the former existence of an endemic macaw in Guadeloupe, Lesser Antilles
Monica Gala, Arnaud Lenoble 

The discovery of a bone referred to the genus Ara Lacépède, 1799 from a Pleistocene fossil-bearing deposit on Marie-Galante demonstrates macaws to have been present in Guadeloupe before any Amerindian settlement. This directly contradicts the hypothesis that macaws described in historical records concerning the Lesser Antilles were introduced by native peoples from South America. The fossil bone is a terminal phalanx similar in size to a large macaw. Based on its size and geographic arguments, the fossil bone found on Marie-Galante can be attributed to an endemic large macaw (Lesser Antillean Macaw, Ara guadeloupensis Clark in Auk 22:266–273, 1905) presumed to have inhabited the Guadeloupe Islands. This discovery currently provides the strongest evidence supporting the former existence of this now-extinct macaw.

Testing the neoflightless hypothesis: propatagium reveals flying ancestry of oviraptorosaurs
Alan Feduccia, Stephen A. Czerkas 

Considerable debate surrounds the numerous avian-like traits in core maniraptorans (oviraptorosaurs, troodontids, and dromaeosaurs), especially in the Chinese Early Cretaceous oviraptorosaur Caudipteryx, which preserves modern avian pennaceous primary remiges attached to the manus, as is the case in modern birds. Was Caudipteryx derived from earth-bound theropod dinosaurs, which is the predominant view among palaeontologists, or was it secondarily flightless, with volant avians or theropods as ancestors (the neoflightless hypothesis), which is another popular, but minority view. The discovery here of an aerodynamic propatagium in several specimens provides new evidence that Caudipteryx (and hence oviraptorosaurs) represent secondarily derived flightless ground dwellers, whether of theropod or avian affinity, and that their presence and radiation during the Cretaceous may have been a factor in the apparent scarcity of many other large flightless birds during that period.

Intensity of haemosporidian infection of parids positively correlates with proximity to water bodies, but negatively with host survival
Tatjana Krama, Ronalds Krams, Dina Cīrule, Fhionna R. Moore… 

In birds, haemosporidian parasites have been found to have direct pathogenic effects on the host with important consequences for their fitness. However, less is known about distribution patterns of parasite vectors, which may significantly affect parasite prevalence, infection intensity and, thus, pathogenicity in hosts. Here, we tested for relationships between infection intensity, survival, predation and distance from water bodies of mixed-species tit flocks. We found that the prevalence of Haemoproteus and Plasmodium infections decreased with increasing distance from forest lakes and bogs outside the bird breeding season. Haemoproteus and Plasmodium parasites were found to be associated with a low survival rate of willow tits (Poecile montanus) in the vicinity of water bodies, while crested tits (Lophophanes cristatus) were affected only by Haemoproteus. Crested tits, a dominant species of parid social groups, had a lower parasite prevalence and they survived better than the subordinate willow tit. This can be explained by the crested tits foraging higher in the pine canopy as parasite vectors supposedly cannot reach hosts in the upper canopy as equally as in lower parts of the canopy. We show that individuals staying in flocks further from the forest water bodies and spending more time foraging in the upper parts of the canopy have higher chances of survival into the next breeding season. This suggests that different forest and canopy areas may differ in terms of parasite risk and associated mortality. Finally, we found that the infection status of parids increases the probability of predation by the pygmy owl (Glaucidium passerinum). We conclude that distance from water bodies and foraging location in the forest canopy may affect the intensity of parasite infection with fitness consequences in wintering parids.

Comparison of the numbers of free (surface) macrophages in the respiratory systems of three species of birds in an urban and a rural area of South Africa
Lindi Steyn, John N. Maina 

The main cellular line of defence of the lung consists of the free (surface) macrophages (FMs). The cells engulf foreign agents (biological and particulate) and destroy or sequester them. The goal of this study was to determine whether the numbers of FMs are good indicators of air pollution and whether birds may flourish in or prefer less polluted areas. The numbers of FMs in the respiratory systems in three species of birds, namely the House Sparrow (Passer domesticus), the Cape Glossy Starling (Lamprotornis nitens) and the Laughing Dove (Streptopelia senegalensis), from an urban and a rural area of South Africa were counted. Statistically significantly greater numbers of FMs occurred in the respiratory systems of the urban birds. For both the rural and the urban areas, the Laughing Doves had the most body mass normalized and total lung volume normalized FMs followed by the Cape Glossy Starlings, with the House Sparrows having the lowest number. The greater numbers of FMs in the urban birds can possibly be ascribed to the high levels of air pollution in the Johannesburg-Vaal Triangle industrial conurbation compared to the rural, near pristine area of Vaalwater. The differences in the number of FMs in species from the same locality may be partly ascribed to behavioural differences: the House Sparrows have a limited operation range while the Cape Glossy Starlings and the Laughing Doves have wider ranges. FMs may be good bio-indicators of air pollution. Studies of more species of birds in different rural and urban habitats are warranted to confirm the observations made here.

The frequency distribution of lead concentration in feathers, blood, bone, kidney and liver of golden eagles Aquila chrysaetos: insights into the modes of uptake
Lukas Jenni, Milena M. Madry, Thomas Kraemer, Jacqueline Kupper… 

Several cases of acute lead poisoning of golden eagles Aquila chrysaetos have been documented in the Alps. The question, however, remains how often golden eagles take up lead (once, chronically or episodically) and whether this uptake is in fatal or sublethal amounts. We approached this question by examining the level and frequency distribution of lead concentration in different tissues and in three segments of flight feathers in 41 golden eagles found dead, injured or moribund in the Swiss Alps. The frequency distribution of lead concentration in the blood, liver, kidney, wing coverts and shaft of flight feathers were all right-skewed. The highest values in blood, kidney and liver reached levels typical for acute fatal poisoning. In contrast, the frequency distribution of lead in bones was more symmetrical, but 71 % had bone lead concentrations >10 µg/g, which are considered elevated, and 29 % >20 µg/g, values often observed in cases of lethal poisoning. In 22 % of individuals, only one segment of a flight feather had a high lead concentration, while the other two segments had a low concentration. These findings indicate an episodic intake of lead of various amounts that may be immediately fatal (generating high blood levels) or sublethal. The patterns of lead in flight feathers and in bone suggest a repeated sublethal lead intake by the same individual. Such an episodic lead uptake seems only possible through ingestion of lead particles from carcasses or offal left behind by hunters. This also constitutes a risk to other scavengers, notably to the bearded vulture Gypaetus barbatus for which several high bone lead values have been found.

Bergmann on the move: a temporal change in the latitudinal gradient in body mass of a wild passerine
Jon E. Brommer, Ilpo K. Hanski, Jaana Kekkonen, Risto A. Väisänen 

The latitudinal gradient in body mass, which many organisms show (Bergmann’s rule), is thought to be a response to local environmental conditions varying across latitude. Hence, temporal changes in environmental conditions are expected to lead to a shift in Bergmann’s rule. We compared house sparrow Passer domesticus body mass measures taken in 1984/85 with measures in 2009 to show that the mean body mass decreased in eight and nine populations (for females and males, respectively) out of ten Finnish populations. Consequently, the latitudinal cline in body mass shifted poleward. The decrease in body mass was large (1.5 g reduction in a 33-g bird). Temperatures during sampling did not differ between sampling periods, suggesting that at least the immediate effect of temperature did not explain the reduction in body mass. House sparrows have declined in abundance in Finland and worldwide in recent decades. We here suggest that the deterioration of the (unknown) environmental conditions associated with this population decline (which may include climatic drivers) has led to a poleward shift in Bergmann’s rule in house sparrows.

Heritability of telomere length in the Zebra Finch
Els Atema, Ellis Mulder, Hannah L. Dugdale, Michael Briga… 

Telomere length predicts survival in birds, and many stressors that presumably reduce fitness have also been linked to telomere length. The response to selection of telomere length will be largely determined by the heritability of this trait; however, little is known about the genetic component of telomere length variation in animals other than humans. Moreover, published heritability estimates of telomere length are based on telomere measurements with techniques that do not distinguish between terminal telomeres, which are susceptible to age and stress, and the interstitial telomeric repeats, which are relatively inert. Heritability estimates that combine interstitial and terminal telomeres are difficult to interpret in species such as birds, where interstitial telomeres are often numerous. We estimated the heritability of terminal telomere length in a captive Zebra Finch population of cross-fostered (half-)siblings using data obtained with an electrophoresis technique that excludes the interstitial repeats from the measurements. We used both a Bayesian quantitative genetic ‘animal’ model and a frequentist sibling regression approach to estimate heritability. With the animal model, we estimated a high heritability of telomere length (h 2 = 0.99, 95 % credible interval = 0.87–1), but had insufficient statistical power to separate parental and permanent environment effects. The frequentist approach yielded similar heritability estimates, although with large confidence intervals. We used general linear mixed models to disentangle variance components of telomere length. The relative contributions of the individual, mother and father to telomere length variation were statistically indistinguishable at 23–31 %. Chicks were cross-fostered 4-days after hatching, and no effect of rearing nest was found, indicating that any undetected environmental effects exerted their influence prior to, or soon after, hatching. Thus, we conclude that telomere length resemblance between relatives is high and proportional to their relatedness, but we cannot conclusively distinguish between genetic and other forms of inheritance.


A high-accuracy, time-saving method for extracting nest watch data from video recordings
Dean R. Evans, Sarah L. McArthur, Jacob M. Bailey, John S. Church… P

Understanding inter- and intraspecific variation in parental care has been an important focus in studies of avian behaviour and evolution. Unfortunately, typical methods for quantifying parental care, such as field observation and video recordings, can be extremely time-consuming. Here, we demonstrate that utilizing behavioural analysis software, such as EthoVision XT, can reduce time required for video data extraction by 37−69 %. This method is highly accurate; results and error rates did not differ from those of manual observation. We suggest this method could be beneficial and time-saving for studies analyzing large amounts of video recordings.

No comments:

Post a comment