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Thursday, 26 June 2014

Ardeola Journal: June 2014, Volume 61, Issue 1: Contents and Abstracts


Published by: Spanish Society of Ornithology/BirdLife

Table of Contents

June 2014 : Volume 61 Issue 1


Demographic and Breeding Performance of a New Kelp Gull Larus dominicanus Colony in Patagonia, Argentina Full Access
Nora Lisnizer , Pablo García-Borboroglu and Pablo Yorio
pg(s) 3–14

Understanding the processes involved in the establishment and persistence of new seabird colonies is important for improving conservation and management strategies. Over the past few decades, kelp gull Larus dominicanus numbers have increased in Patagonia, Argentina, and new colonies have been reported. We studied a recently established colony to analyse aspects of its population dynamics and breeding biology. The number of breeding pairs at Punta Loma increased from 13 to 233 in the seven years after the colony was established (2004–2011) and the number of chicks fledged per nest was low (< 1 chick per nest) compared to that of other long-established kelp gull colonies in the region. Modelled estimates of abundance assuming closed population dynamics for the Punta Loma colony were lower than observed (70% lower or more), suggesting that the observed growth cannot be explained by local productivity alone. Immigration from other colonies was likely to be the main factor responsible for the observed growth, being considerably higher than local recruitment. This study constitutes the first characterisation of demographic processes occurring during the initial years following colony establishment in kelp gulls. The main findings include rapid population growth driven by immigration and poor breeding performance potentially linked to a high proportion of young breeders. Our results highlight the key role of source-sink dynamics on the growth and persistence of new seabird colonies.
Abstract & References : Full Text : PDF (191 KB) 

Age and Sex Differences in Fuel Load and Biometrics of Aquatic Warblers Acrocephalus paludicola at an Autumn Stopover Site in the Loire Estuary (NW France) Full Access
Dariusz Jakubas , Katarzyna Wojczulanis-Jakubas , Julien Foucher, Joanna Dziarska-Pałac and Hubert Dugué
pg(s) 15–30


The aquatic warbler Acrocephalus paludicola is the only globally threatened passerine breeding in Europe. We studied morphometric traits of 176 individuals captured at one of the key European autumn stopover sites, the Loire estuary on the Atlantic coast of France, in relation to age (first-year and older) and sex (based on molecular determination). We found significant sex differences in wing length, third primary feather length and body mass, with males being longer-winged and heavier than females; adult females also had deeper bills. However, high overlap in all measurements between the sexes meant the best discriminant functions based on wing length and bill depth (adults) and wing length (inmatures) correctly classified only 87% and 75% of individuals, respectively. The mean potential non-stop flight range of autumn staging birds at the Loire estuary with high fuel load was estimated at 1,178 km for adults and 926 km for immatures. We conclude that in autumn migrant aquatic warblers probably do not fly directly to wintering grounds in west Africa. Instead they gain significant body mass for onward migration at a few key stopover sites in western Europe and the southern Mediterranean region. Conservation of a series of important refuelling stopover sites, especially wet grassland habitats, along the migration route is therefore essential for effective protection of the aquatic warbler.
Abstract & References : Full Text : PDF (365 KB) 

Habitat-Related Effects on Temporal Variations in Red-Legged Partridge Alectoris rufa Abundance Estimations in Olive Groves Full Access
Jesús Duarte, Miguel Ángel Farfán, John E. Fa and Juan Mario Vargas
pg(s) 31–43

Surveys are very important tools for population monitoring, conservation and species management. Censuses aid in the sustainable harvesting of game species. Our aim in this study was to test whether some factors related to habitat and agricultural practices of olive cultivation may influence red-legged partridge abundance estimates. We investigated the effects of time of day and season of the year in which censuses are conducted, as well as of the reduction of herbaceous cover and the installation of irrigation systems, on red-legged partridge abundance estimates. In surveys conducted in winter, no differences were found in the estimates of abundance and density between partridge censuses at dawn and dusk. In surveys conducted in summer, the estimates made at dusk were significantly higher than those at dawn. The coefficients of variation of the estimates were lower at dusk in the two seasons. In winter, partridge abundance was not related to any of the factors studied. However, in summer partridge observations were related to the distances to the border of the olive grove, where herbaceous vegetation persists, and to water sources. There was an interaction between the time of the census and the habitat preferences of partridges. During the morning, partridges were more active and moved towards the borders of the grove. At dusk partridges were less active and returned to the olive grove. The results suggest that habitat use by red-legged partridges undergoes spatial and temporal adjustments in olive groves that seem to be related to some habitat features of the groves associated with agricultural practices. The temporal and spatial behaviour of the birds in the groves can influence the accuracy of surveys. Differences in the results of censuses carried out at dawn and dusk indicate that the two may not be comparable and suggest the need to take time of day into account when designing a survey.
Abstract & References : Full Text : PDF (561 KB)

Spatial Patterns of Genetic Diversity in Mediterranean Eagle Owl Bubo bubo Populations Full Access
Mario León-Ortega, Mercedes González-Wangüemert, José E. Martínez and José F. Calvo
pg(s) 45–62


Little information is available on the patterns of genetic connectivity in owls. We studied the genetic structure of the eagle owl Bubo bubo (Linnaeus, 1758) in southeastern Spain at two different spatial scales. Seven microsatellites previously described for this species were used, although only six loci amplified correctly. The observed low genetic variation could be explained by the short dispersal distance, high mortality rate and high degree of monogamy shown by this large nocturnal predator. As expected, the highest genetic isolation was detected in the geographically most isolated population. Significant genetic differentiation was found among study units separated by less than 50 km. The territorial analysis showed interesting connectivity patterns related with the gene flow and turnover rate of the breeding individuals. The lowest genetic diversity was found in the region with the largest population, which could imply incipient inbreeding.

Abstract & References : Full Text : PDF (339 KB)

Reverse Movements of Red Knots Calidris canutus During Northward Migration in Argentina Full Access
Verónica L. D'Amico, Patricia M. González , R. I. Guy Morrison and Allan J. Baker
pg(s) 63–76


Migratory birds are sometimes known to make reverse movements to seek better fuelling sites before undertaking long-distance migratory flights across ecological barriers. Red knots Calidris canutus rufa regularly make prodigious migratory flights of ∼ 8,000 km from southern South America to North America; these flights depend critically on the birds being able to store adequate fuel at southern staging sites. Knots staging at San Antonio Oeste (SAO) in northern Patagonia in Argentina could potentially backtrack ∼200 km southwards to complete refuelling at Península Valdés (PV). We therefore analysed resightings of birds individually marked in SAO or the flyway at these two staging sites in 2006, 2007, 2009 and 2010 to investigate whether reverse movements occurred between them. In the four-year period, 63 detected individuals backtracked south from SAO to PV in one or more years. These movements occurred in all years of the study thus demonstrating the annual occurrence of flights of ∼200 km in the opposite direction to the normal northward migration. There was no significant difference in body condition (mass), sex or day of first sighting in SAO between birds that made or did not make reverse movements to PV. However, individuals (N = 11) that backtracked to PV from SAO had significantly lower hematocrit levels at the time of capture than SAO resident birds (N = 205). Because migrating shorebirds have been shown to restore low hematocrit levels before undertaking rapid fuel storage to power long flights, we hypothesise that red knots backtracking to PV were probably behind schedule on migration, and thus may have traded-off the small cost of a ∼200 km flight for the increased foraging time and high quality soft-shell prey available late in the season at PV. This hypothesis helps to explain the later staging phenology of red knots using PV, and its role as an alternative staging area in the northward migration.

Abstract & References : Full Text : PDF (267 KB)

Inferring the Migratory Status of Woodland Birds using Ringing Data: The Case of a Constant-Effort Site Located in the Iberian Highlands Full Access
Iván de la Hera, Jordi Gómez, Teresa Andrés, Pablo González-Ocio, Pablo Salmón, Mikel Salvador, Azaitz Unanue, Francisco Zufiaur and Alejandro Onrubia
pg(s) 77–95


Understanding the spatiotemporal distribution of birds is crucial for effective management and conservation of their populations. However, we still have only limited knowledge not only of the wintering destinations of many Iberian breeding migrants but also of aspects as general as the migratory behaviour of the populations of many common avian species that breed in the Iberian highlands. We used bird-ringing data to shed light on the migratory status (migratory, partially-migratory or sedentary) of the breeding populations of 13 common species occurring year-round in a woodland located on an Iberian plateau (Garaio, Araba, Spain; 574 m.a.s.l.), where ringing activities have been carried out over the last 20 years. To assess the extent to which birds breeding on this site remain in the area during winter and/or are replaced by conspecifics coming from other areas, we analysed: (1) changes in relative abundance of birds between summer and winter, (2) the frequency of sedentary individuals (birds captured both in summer and winter period in the study area) in relation to the number of individuals captured only in summer (summer visitors) or in winter (wintering birds), and (3) variation in wing length among summer, wintering and sedentary birds. Our results revealed great variation among species in the intensity of migratory behaviour, and a general arrival of foreign conspecifics during the winter for most of the species studied. Likewise, our study represents an illustrative example of how long-term ringing can be used to shed light on the migratory status of bird populations.

Abstract & References : Full Text : PDF (784 KB) 

Habitat Preferences for Territory Selection by the Endangered Eastern Iberian Reed Bunting Emberiza Schoeniclus witherbyi Full Access
Pablo Vera , Eduardo J. Belda, Laura Kvist, S. Ignacio Encabo, Marcial Marín and Juan S. Monrós
pg(s) 97–110


Given the 80% decline of the eastern Iberian reed bunting Emberiza schoeniclus witherbyi breeding population in recent decades, our aim was to identify the habitat components selected during territory establishment and to characterise the vegetation features that are positively or negatively selected at the territory scale. GLMM were used to explain the occurrence of territories in 11 wetlands. Fourteen variables with four vegetation dominance categories were analysed with respect to habitat composition, while occupancy of seven vegetation classes and 12 reed structural parameters were analysed with respect to habitat structure. The proportion of reed-cattails (Typha) measured by the habitat approach was the variable with the greatest likelihood of being the model that best fitted our data, but showed poor discriminative ability. The proportion of reed with tussocks was higher in occupied territories than in non-occupied territories. The main results are consistent with a previous study of habitat preference at a wetland scale and seem to be associated both with reduced predation risk and provision of nesting and feeding opportunities. Management guidelines to enhance the presence of the vegetation classes preferred by the species are discussed.


The use of a Low Cost High Speed Camera to Monitor Wingbeat Frequency in Hummingbirds (Trochilidae) Full Access
Ronny Steen
pg(s) 111–120

Wingbeat frequency is an important parameter when studying flight performance in hummingbirds and could be put into an ecological and evolutionary context to investigate the decisions that a hummingbird takes regarding foraging efficiency. Previous studies of wingbeat frequencies in hummingbirds have been undertaken with captive birds, most probably due to limitations of experimental design and/or less mobile equipment. In the present paper I describe how I used a budget camera, which captured 220 frames per sec (fps), to film hummingbirds in order to quantify wingbeat frequency under natural conditions in Costa Rica. With this equipment I was able to obtain detailed information about stationary hovering flight in three different species; the charming hummingbird Amazilia decora, purple-throated mountain-gem Lampornis calolaema and violet sabrewing Campylopterus hemileucurus. Wingbeat frequency was higher for the purple-throated mountain-gem and the charming hummingbird compared to the larger violet sabrewing. It did not differ between the purple-throated mountain-gem and the charming hummingbird, which are more similar in size. In the purple-throated mountain-gem I found a higher wingbeat frequency and increased body inclination while hover-feeding compared to hovering in front of the feeder; hence it may be more costly to hover while feeding. It is hoped that the video techniques used here will encourage researchers to record wingbeat frequencies across a range of animal taxa.
Abstract & References : Full Text : PDF (185 KB)

Promiscuous Brown Booby Sula leucogaster Females Perform Reverse Mounting Full Access
Natalia Gañán, Víctor Argáez, Nadia Neri, Natalia Lifshitz and Roxana Torres
pg(s) 121–125


Reverse mounting (RM), i.e. where the female mounts the male, has been recorded in some bird species, yet the potential function of this behaviour is not clear. Here, we describe the frequency of RM in the brown booby Sula leucogaster and the behavioural context in which it occurs. We found that 12% (4 out of 33) of focal pairs performed RM. Time spent at the territory and intra-pair courtship and copulations did not differ between RM and non-RM pairs. Females that performed RM were more prone to engage in extra-pair courtship than females that did not perform RM, and male partners of females that performed RM were more likely to engage in extra-pair copulations; however, the probability of laying a clutch did not differ between RM and non-RM pairs. Hence, in the brown booby our data suggest that it is unlikely that RM plays a role during courtship by strengthening pair formation or pair bonds. The potential functional role and the mechanisms modulating RM in promiscuous females need to be further investigated.

Abstract & References : Full Text : PDF (211 KB)

Characteristics of Sand Martin Riparia riparia Colonies in Artificial River Walls Full Access
Jon Etxezarreta and Juan Arizaga
pg(s) 127–134


Artificial structures play a significant role as optional breeding places for the sand martin. However, it is virtually unknown which factors determine habitat selection in these artificial sites and to what extent the species selects the same key features that it would in its natural habitat. We compared 16 variables from artificial walls with pipes in channelled rivers between walls holding (N = 56) or not holding (N = 50) a sand martin breeding colony. The presence of colonies was negatively associated with the distance of the breeding wall from the water and positively associated with flooding risk. Bibliographic data were used as a reference for the characteristics of natural breeding habitat. The sand martin selected similar key factors in artificial habitats as when breeding in a natural setting. These factors could probably be linked to limiting predator access to the colony and the occurrence of periodical rinsing episodes that may minimise parasite loads in nesting cavities.

Abstract & References : Full Text : PDF (177 KB)

Haemosporidians in Iberian Bluethroats Luscinia svecica Full Access
M. Ángeles Rojo, Francisco Campos, Tomás Santamaría and M. Ángeles Hernández
pg(s) 135–143


Haemosporidian infection (Plasmodium spp., Haemoproteus spp. and Leucocytozoon spp.) was analysed in 101 bluethroats Luscinia svecica captured in the Iberian Central Range during the 2007 and 2008 breeding seasons. Of them, 58.4% were infected with single infections of haemosporidians distributed betweenPlasmodium. spp. (42.9%), Haemoproteus spp. (30.3%) and Leucocytozoon spp. (14.3%). A smaller percentage harboured double infections (12.5%): in these double infections, three birds were found to be infected with Haemoproteus spp.-Haemoproteus spp., two with Haemoproteus spp.-Plasmodium spp. and two withLeucocytozoon spp.-Plasmodium spp. Twentyseven different mitochondrial DNA haplotypes of malaria parasites were found: a) eight belonging to Plasmodiumspp., two of which (P-SGS1 and P-WW3) have previously been recorded in bluethroats in Sweden, and one which has been identified in this study for the first time (P-LSV10); b) thirteen belonging to Haemoproteus spp., four of which (WW2, EMSPO03, RW1 and ARW1) have previously been recorded in birds with migratory habits and nine which are described for the first time in this study (H-LSV01 — H-LSV09); and c) six haplotypes of Leucocytozoon spp., of which one (Leucocytozoon lBT2) has previously been recorded in bluethroats in Sweden and another is described for the first time in this study (L-LSV11). Our results show that body condition did not differ between infected and uninfected birds.

Abstract & References : Full Text : PDF (312 KB)

Leucocyte Levels in Some Antarctic and Non-Antarctic Penguins Full Access
Verónica L. D'amico, Marcelo Bertellotti, Julia I. Díaz, Néstor Coria, Virginia Vidal and Andrés Barbosa
pg(s) 145–152


We studied leucocyte levels in several Antarctic and non-Antarctic penguins. A total of 107 blood samples of chinstrap Pygoscelis antarctica, gentoo P. papuaand Adélie P. adeliae penguins at Isla 25 de Mayo/King George Island (South Shetland Islands, Antarctica) and Magellanic penguins Spheniscus magellanicusat Península Valdés (Chubut, Argentina), were collected and analysed during the 2009–2010 breeding season. We observed that chinstrap and Adélie penguins had lower total leucocyte counts than Magellanic and gentoo penguins. We provide some potential explanations for species differences in leucocyte levels.

Abstract & References : Full Text : PDF (111 KB)

Seasonal Space use and Territory Size of Resident Sparrows in the Central Monte Desert, Argentina Full Access
M. Cecilia Sagario and Víctor R. Cueto
pg(s) 153–159


Knowledge of space use and territoriality of New World birds largely derives from studies in temperate North America and the tropics, whereas it remains poorly studied in temperate South America, particularly in arid environments. Here we studied the seasonal space use and territory size among resident individuals of three sparrows in a temperate semi-desert of Argentina: the ringed warbling-finch Poospiza torquata, the rufous-collared sparrow Zonotrichia capensis and the manycoloured Chaco-finch Saltatricula multicolor. Both territorial behaviour and use of space of the three species showed seasonal changes. The ringed warbling-finch and the rufous-collared sparrow used larger areas during the non-breeding season than during the breeding season, while the many-coloured Chaco-finch used areas of similar size in the two periods. Defence activities were absent for all three species during the non-breeding season. During the breeding season, each species defended territories that were smaller for the rufous-collared sparrow (0.79 ± 0.04 ha) than for the ringed warbling-finch (1.35 ± 0.04 ha) and the many-coloured Chaco-finch (1.21 ± 0.07 ha). Seasonal territoriality and territory size reported for resident individuals were similar to those reported for north-temperate sparrows in xeric environments.

Abstract & References : Full Text : PDF (287 KB)

Seasonal Shift in the Diet Composition of European Bee-Eaters Merops apiaster at the Northern Edge of Distribution Full Access
Susanne Arbeiter, Hannah Schnepel, Karl Uhlenhaut, Yves Bloege, Martin Schulze and Steffen Hahn
pg(s) 161–170


European bee-eaters Merops apiaster forage almost exclusively on airborne insects caught on the wing. The availability of this food might be temporally limited due to adverse weather conditions, especially at climatically sub-optimal breeding sites. We determined seasonal variation in the diet composition in adult and nestling bee-eaters at the species' northernmost breeding colonies by analysing food remains from pellets and by direct observation. Adult bee-eaters preyed on a wide range of insect species with more than 97% belonging to the taxonomic orders Hymenoptera, Odonata and Coleoptera. We observed consistent seasonal changes in adult diet composition from the pre-incubation to the late chick rearing period. The dry mass proportion of dragonflies decreased remarkably in the adult diet as chick rearing started, whereas the consumption of small Hymenopterans increased by the end of the chick provisioning period. Additionally, we found differences in the diet composition of adults and nestlings. The higher amount of bumblebees and dragonflies in the nestling diet was temporally associated with a decrease of these components in the adult diet, indicating that breeding birds preferentially feed larger prey items to their offspring than those that they consume themselves.


The 1902 Convention for the Protection of Birds in Historical and Juridical Perspectiveal Full Access
Michael J. Bowman
pg(s) 171–196


AbstractRecent contributions to this journal have discussed the impact, actual and potential, of the first significant treaty in the field of avian conservation, the 1902 Paris Convention for the Protection of Birds Useful to Agriculture. This article seeks to expand upon that discussion by providing further information on the nature and development of the international legal system, highlighting in particular the various factors that affect the practical impact that such instruments are likely to exert. It suggests in particular that, in addition to the rigour and suitability of the substantive provisions, it is necessary to consider the effectiveness of the mechanisms established for the treaty's implementation, and the number and identity of the states that can be persuaded to participate, since the importance accorded to state comsovereignty within the international legal order is such that relatively little can be achieved without their individual consent. It has taken many decades of experimentation for treaty negotiators to devise legal instruments that are capable of bringing about significant progress in the conservation field, and the pioneering nature of the 1902 Convention was such that its practical impact was always likely to be limited. Its true significance is therefore primarily historical, serving as a form of stepping stone to the more advanced instruments of the modern era.
Noticiario Ornitológico Full Access
Blas Molina, Javier Prieta y Juan Antonio Lorenzo (Canarias)
pg(s) 197–231
Citation : Full Text : PDF (1888 KB)

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