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Capsule: Nest site selection of Black-bellied Sandgrouse Pterocles orientalis in an Algerian arid environment is dictated by a combination of topography, human presence, landscape and space.Aims: T...

The sandgrouse, family Pteroclididae, are a group of birds adapted to open, arid habitats and powerful fliers but information on their plumage development and moult is scarce. In this study, the annual cycle of body plumage development, sequence and duration of primary flight feathers moult were investigated in Black-bellied Sandgrouse Pterocles orientalis, from hatching to the adult stage. Body plumage differed among juvenile, immature and subadult birds before their first breeding season. Yearling Black-bellied Sandgrouse showed three annual moults with only the pre-breeding one being complete. Juvenal body plumage was acquired shortly before the first attempts to fly at 5–6 weeks of age. The acquisition of definitive adult body plumage took place after the breeding season in late August, when birds were about 10–12 months old. The species typically replaced all primaries annually with a gradual descendent moult at a slow rate, taking 10–11 months for their completion, from December to September, including the breeding period. This study provides the first detailed analysis of flight feather development and moulting in the Black-bellied Sandgrouse, which provides useful ageing criteria based on the patterns of both primary growth and moult.Keywords: duration, feathers, moult, plumage, sandgrouse, sequence

In the present study, a histological and morphometric investigation of testes in yearling male Black-bellied Sandgrouse Pterocles orientalis was performed during the reproductive period. The trial ...

The Lleida plain is a flat and dry region in Western Catalonia (NE Spain), at the eastern edge of the Ebro Valley depression. The central part of the area is now devoted to intensively irrigated farmland, but a surrounding belt of steppe and pseudo-steppe and low intensity farming, mainly occupied by winter cereal, olive trees and almond trees, remains. The area still hosts a rich community of steppe land birds. Some are dependent on low intensity dry cereal farming and fallow, such as the little bustard (Tetrax tetrax), Montagu’s harrier (Circus pygargus) and calandra lark (Melanocorypha calandra). Other, such as the pin-tailed sandgrouse (Pterocles alchata) and black-bellied sandgrouse (Pterocles orientalis) inhabit the few remaining large spots of fallow land, while the Dupont’s lark (Chersophilus duponti) and lesser short-toed lark (Alaudala rufescens) are both associated to the remaining patches of natural steppes or halophytic vegetation. The greater short-toed lark (Calandrella brachydactyla) and the European thick-knee (Burhinus oedicnemus) favour areas of little disturbed wastelands, fallow or ploughed land. Although more generalist, the lesser kestrel (Falco naumanni) or the European roller (Coracias garrulus) also find in these low intensity farming areas one of their last strongholds in Catalonia. The single remaining Iberian population of lesser grey shrike (Lanius minor), on the verge of extinction, is also located within these steppes. All these species experienced severe population declines during the last decade of the twentieth century and the first decade of the twenty-first. Strong opposition to the Segarra-Garrigues irrigation system, launched at the start of the twenty-first century and aiming to transform most of the remaining steppes of the Lleida plain into intensified irrigated crops, has boosted many conservation actions, which are reversing or halting the negative trends for some of these species. These actions include, among others, the declaration of eight Special Protection Areas (SPAs), the renting or acquisition and management of steppe-land and fallow land, the provision of nesting sites, the implementation of breeding programs to reintroduce or reinforce some populations, or the mitigation of power lines to reduce collision risk. Although there is room for some optimism, the persisting intensification of agriculture outside and inside the SPAs, and the industrial and urban development of the area are still of great concern. We need a change in the rural development concept, from one that values only economic services to one that values social and ecological services as well, if we want some room for steppe-land birds in the Lleida plain.

As a result of convergent evolution, sandgrouse share similarities with some other precocial landbirds, namely Galliformes and precocial waders (Charadriiformes). They are birds of arid lands and hence their chicks face problems of predation risk and shortage of food and water, exacerbated by the patchy and unpredictable distribution of these resources. We therefore hypothesised that sandgrouse would be more precocious at hatching than precocial galliformes and charadriiformes living in more favourable habitats. Patterns of growth for body mass, wing, leg and sternum were described for the black-bellied sandgrouse Pterocles orientalis by a logistic model. Post-hatching development was characterised by the ratio of exponential growth rate (EGR) to relative size (Ln(W/A)) (W: Weight and A: Asymptotic size) at a given age. Developmental trajectories, indicating the degree of the development of precocity, were derived from these relationships as the slopes of least square regression of EGR on relative size. We also characterised the post-hatching development of body size in terms of maturation time. Growth parameters were compared to those of the Galliformes and precocial Charadriiformes using interspecific allometric relationships. Black-bellied sandgrouse hatched with relatively well developed body mass and legs, which accords with their faster post-hatching maturation. The development of body mass and wing reached their asymptotic sizes on steeper developmental trajectories than did the leg. The mean growth rate constant for the wing was the highest compared to those of the sternum and leg which were similar. In contrast to the leg, wing and sternum showed biphasic growth patterns. The black-bellied sandgrouse shows growth rates and a maturation degree at hatching that are intermediate between their convergent Galliformes and precocial Charadriiformes. It exhibits a developmental strategy in which both precocial legs and wings allow early development of either walking or flying. This constitutes an adaptive strategy to arid environments with low and unpredictable resource availability and high predation risk.

Archaeological excavations at the site of Shahr-i Sokhta yielded many bird remains. The excellent state of preservation allowed for the identification of 2875 specimens attributed to 43 different species. The avifaunal assemblage is mainly characterized by aquatic species, such as the Eurasian coot (Fulica atra), representing 60% of the identified remains, and the Anseriformes. The presence of cinereous vulture (Aegypius monachus), see-see partridge (Ammoperdix griseogularis), black-bellied sandgrouse (Pterocles orientalis) and spotted sandgrouse (Pterocles senegallus) suggests that near the urban center there were also some very arid and semi-desert areas. The bird remains of Shahr-i Sokhta confirm the existence of environmental and climatic conditions that can still be found in central and northern Iran, near the Caspian Sea. With the exception of the Suliformes, Pelecaniformes and Accipitriformes, there is evidence that most species were hunted for their meat. Furthermore, eggshell fragments found at the site suggest that eggs were collected and used as food. Taphonomic analysis showed that the Gruiformes and the Anseriformes were eaten, while the other species were exploited for non-food purposes. The use of bird bones as raw material is indicated by the presence of anthropic marks on the ulnae of large birds. Copyright © 2014 John Wiley & Sons, Ltd.

Niche theory predicts that coexisting species with similar trophic requirements should demonstrate resource partitioning, particularly where resources are scarce. Conversely, this is not expected between species that do not share primary resources. This study analyses the patterns of spatial coexistence and habitat selection, on two spatial scales, of three species of semidesert regions in Morocco: the Black-bellied Sandgrouse (Pterocles orientalis), the Stone Curlew (Burhinus oedicnemus) and the Cream-coloured Courser (Cursorius cursor). Co-occurrence analysis results point to between-species segregation on a macrohabitat scale. Hotelling's T test of the species-presence data showed a pattern of macrohabitat selection that diverged from habitat availability for the three species with differences among them. Both the classification tree and the pattern of microhabitat selection obtained by model averaging showed scant overlap between the Sandgrouse and the Courser, suggesting habitat partitioning between them on a fine scale. Our results confirm spatial segregation of the three species, especially between species with different trophic strategies: the Sandgrouse versus the Stone Curlew and the Courser. The latter two species were best segregated on a microhabitat scale, supporting the conclusions that macro- and microhabitat selection are major factors in bird community configuration in arid ecosystems and contributing to reduce potential competition., This study was funded by the Agencia Española de Cooperación Internacional via a project within the PCI programme (Code A/3895/05). The Terrestrial Ecology Group (TEG) is partly supported by the REMEDINAL-2 research network of the Comunidad de Madrid-European Social Fund (Code S-2009/AMB/1783).

Habitat selection is an inherently scale-sensitive process in which detected selection patterns frequently depend on the scale of analysis employed. We used a multi-scale modelling approach to identify how the distributions of two sympatric birds are shaped by differential selection at the landscape, land use and microhabitat scales and by human infrastructures as possible sources of disturbance. We studied two threatened steppe birds, the pin-tailed sandgrouse (PTS) and black-bellied sandgrouse (BBS) in central Spain. Land use gradients explained most of the variation in PTS and BBS occurrence, but there was cross-scale interdependence between the lower (microhabitat) and upper (landscape) spatial scales for the PTS. Synergies between the three scales highlighted the importance of integrating habitat scales in a single modelling framework. The process of habitat selection was also modulated by human disturbance. Both species selected ploughs of large size distant from houses, tracks and other infrastructures, although BBS exhibited broader habitat tolerance than the PTS, and was more sensitive to human disturbance. At microhabitat scale, PTS selected ploughs with greater green vegetation cover and insect abundance and fallows with lower dry vegetation cover and height but greater stone cover. This might reflect a trade-off between camouflage (vegetation and stone cover for concealment) and visibility for predator detection and escape. Ploughs and fallows should be maintained by means of traditional 2-year rotations and low management during the breeding season. Ongoing urbanization trends and infrastructure development inside protected areas should be limited. Multi-scale models were key to identify scale-specific factors that determine sandgrouse habitat preferences and conservation requirements at appropriate levels, and are recommended to better guide regional and local conservation efforts of threatened species., This study is a contribution to the CGL2008-04282/BOS Project funded by the Spanish Ministry of Science. A. Benítez-López was supported by the CGL2008-04282/BOS Project and by the 2012-BIN-4462 research Grant conceded by the UCLM. F. Mougeot was supported by a distinguished visitor award from the University of Cape Town (2015).

SummaryWe estimated the breeding population size and assess the habitat relationships of Black-bellied Sandgrouse in the Eastern Canary Islands (Fuerteventura, Lanzarote and La Graciosa, Spain) by means of a survey based on 1,787 0.5-km line transects and distance sampling done in 2005 and 2006. The population comprised 2,906 individuals (90% CI: 2,363–3,562), which is much higher than the numbers estimated in previous reports based on partial surveys, and constitutes 20% of the total Spanish population. Sandgrouse in the Canaries are currently restricted to Fuerteventura, where 70% of the population gathers in four areas that encompass just 16.7 % of the island and are largely within Special Protection Areas classified under the EU Birds Directive (except the area of Tefia-Ampuyenta, first in absolute number of individuals). The environmental characteristics that maximize the probability of occurrence of the sandgrouse in Fuerteventura (probability = 0.196) are: treeless non-cultivated areas of sandy soils without bare bedrock, with a rock cover less than 44%, located in non-coastal areas with an average terrain slope less than 27.5%, at more than 400 m from the nearest urban area, with less than 795 m of dirt roads per 20 ha, with at least 0.9% of shrub cover and a NDVI index higher than 53. Sandgrouse were closer to human settlements in midsummer than in March, perhaps being attracted to artificial pools surrounding villages. Similar habitat characteristics exist in nearby Lanzarote, where the species could hypothetically reach densities as high as 4–5 birds km−2. Possible reasons for the absence of sandgrouse in this island are discussed.

Capturing and marking free-living birds permits the study of important aspects of their biology but may have undesirable effects. Bird welfare should be a primary concern, so it is necessary to evaluate and minimize any adverse effects of procedures used. We assess short-term effects associated with the capture, handling and tagging with backpack-mounted transmitters of Pin-tailed Pterocles alchata and Black-bellied Pterocles orientalis Sandgrouse, steppe birds of conservation concern. There was a significantly higher mortality (15%) during the first week after capture than during the following weeks (, F. Casas was supported by a JAE-Doc contract funded by CSIC and the European Social Fund (ESF) and by the Steppe-Ahead project funded by FGCSIC. Funding came from the Dirección General de Investigación (projects CGL2007-66322/BOS and CGL2008-04282/BOS), Consejería de Educación y Ciencia de Castilla-La Mancha (projects PAI08-0171-9582 and PAC06-137) and Bardenas Reales Biosphere Reserve (projects UCTR09-0268, UCTR110053 and UCTR120308).

Predictive species' distribution models may answer ecological questions about habitat selection, co-occurrence of species and competition between them. We studied the habitat preferences and segregation of two sympatric species of declining sandgrouse, the black-bellied sandgrouse (Pterocles orientalis) and the pin-tailed sandgrouse (Pterocles alchata), during the breeding season. We developed predictive models that related sandgrouse presence to environmental variables at three different spatial levels: large geographical, landscape and microhabitat scales. At the large geographical scale, differences between sandgrouse distributions, in the Iberian Peninsula, seem to be explained mainly in terms of bioclimatology: pin-tailed sandgrouse appear to be a more thermophilous species and occupy warmer sites usually located in flatter areas. At the landscape spatial level, in those areas that exhibit environmental conditions allowing for both species' co-existence at a large geographical scale, black-bellied sandgrouse appear to be more tolerant to environmental variation than pin-tailed sandgrouse. At the microhabitat level, however, differences between species could be related to different flocking behaviour as a consequence of different sensitivities to vegetation structure and predators. Thus, the observed spatial distribution patterns are the result of different ecological factors that operate at different spatial levels. Conservation guidelines for these species should therefore consider their habitat preferences at large geographical, landscape and microhabitat scales. © 2014 Springer-Verlag Berlin Heidelberg.

Sandgrouse are birds of arid environments adapted to cope with extreme temperature variations. We used temperature data-loggers to remotely study incubation rhythms by pin-tailed and black-bellied sandgrouse in Spain. In both species, mates switched incubation roles twice a day, between 08:00 and 10:00 and between 19:30 and 21:30, when the nest and ambient temperature were most similar. During mate switches, sandgrouse preferred to risk a cooling rather than a warming of eggs. In the pin-tailed sandgrouse, the timing of morning switches was consistent within-pairs, while the timing of evening switches was more related to sunset time. Absences lasted longer following a disturbance than during a mate switch. During disturbances, changes in nest temperatures depended on the changes in outside temperature, and negatively correlated with absence duration. Absences following a disturbance were shorter when the outside temperature was higher. Nesting success was low (19%), with no noticeable effect of data-loggers. Our study highlights some of the constraints that birds breeding in arid environments, such as sandgrouse, face during incubation. It also stresses out the importance of evaluating the consequences of disturbances during incubation, in particular nest visits. Temperature data-loggers can provide an easy and effective way of monitoring nests, without the need of repeated nest visits., This study was funded by the Spanish “Ministerio de Educacion y Ciencia” (project CGL2008-04282/BOS and intramural GranGanga grant to FM) and the “Comunidad de las Bardenas Reales de Navarra” (project UCTR110053). FC was supported by a JAE-Doc grant (“Junta para la Ampliación de Estudios”, European Social Fund). This study also contributes to Steppe-Ahead, a project funded by the FGCSIC.

Ascertaining which niche processes allow coexistence between closely related species is of special interest in ecology. We quantified variations in the environmental niches and densities of two congeneric species, the pin-tailed and the black-bellied sandgrouse (Pterocles alchata and Pterocles orientalis) in allopatry and sympatry under similar abiotic, habitat and dispersal contexts to understand their coexistence. Using principal component analysis, we defined environmental gradients (niche dimensions) including abiotic, habitat and anthropogenic variables, and calculated niche breadth, position and overlap of both species in sympatry and allopatry. Additionally, sandgrouse density was modelled as a function of the niche dimensions and the density of the other species. We found evidence that each species occupies distinct environmental niches in sympatry and in allopatry. The black-bellied sandgrouse exploits a broader range of environmental conditions (wider niche breadth) while the pin-tailed sandgrouse reaches high densities where conditions seem to match its optimum. In sympatry, both species shift their niches to intermediate positions, indicating the importance of abiotic factors in setting coexistence areas. Environmental conditions determine regional densities of pin-tailed sandgrouse whereas biotic interactions explain the density of the black-bellied sandgrouse in areas with abiotic conditions similarly conducive for both species. Highly suitable areas for the pin-tailed sandgrouse fall beyond the upper thermal limit of the black-bellied sandgrouse, leading to niche segregation and low densities for the latter. Finally, local niche shift and expansion plus possible heterospecific aggregation allow the pin-tailed sandgrouse to thrive in a priori less favourable environments. This work provides insight into how different mechanisms allow species coexistence and how species densities vary in sympatry compared to allopatry as a result of environmental filtering and biotic interactions., Financial support was provided by the Dirección General de Investigación (project CGL2008-04282/BOS) and the HNV project (Spanish Ministry of Rural and Marine Environment). A. Benítez-López was supported by the 2012-BIN-4462 research grant awarded by the Universidad de Castilla-La Mancha.

Knowledge of the factors determining species distributions is essential for developing conservation strategies. SandgrousePterocles alchata andP. orientalis are threatened in Spain, the stronghold of European populations. Spatial modelling was used to: (1) assess the relative importance of abiotic, anthropogenic and geographical factors in the distribution of both sandgrouse species, (2) determine the most important anthropogenic predictors for each species occurrence, and (3) identify areas where conservation efforts should be prioritized. Abiotic and anthropogenic factors explained most of the variation in sandgrouse distributions. Both species were associated with arid flatlands, arable land cover being the most important anthropogenic variable determining their distribution. The Common Agricultural Policy (CAP) is the main driver of agricultural management in Europe, and may thus have a direct effect on sandgrouse distributions. P. orientalis exhibited broader habitat tolerance than P. alchata; the latter species tolerates warmer climates. Consequently, the network of core and marginally suitable areas identified for each species differs, and connectivity between the populations of these areas seems unlikely. Potential future changes in sandgrouse distribution will probably be directed principally by the synergistic effects of climate change and expected land-use transformations resulting from the new CAP and ongoing population growth, urbanization and infrastructure development., This research was jointly funded by the Dirección General de Investigación (project CGL2008–04282/BOS) and HNV project (MARM).

The landscape requirements are analysed and population sizes are estimated for the pin-tailed and black-bellied sandgrouse during the breeding season in peninsular Spain. The estimated populations in the 26 study zones, which comprise the main breeding areas of Spain, are c. 13,000 individual pin-tailed sandgrouse and 3500 black-bellied sandgrouse. The overall population estimate for peninsular Spain is Pin-tailed sandgrouse abundance is positively correlated with the area of fallow and stubble, while black-bellied sandgrouse abundance is positively correlated with the amount of medium/long-term fallow land and the proportion of land used for dry pasture. All of these landscape variables have undergone profound changes in Spain since the 1960s due to agricultural intensification. The effects of European Union agricultural regulations on this problem are discussed. The voluntary set-aside Regulation, R. 797/85/EEC and 1094/88/CEE, has received very little acceptance. Regulation R. 1765/92/EEC, compulsory withdrawal of cropland, involves the ploughing-up of fallows and thus the loss of an important habitat for both species, especially for pin-tailed sandgrouse. Agri-environmental schemes linked to R. 2078/92/EEC potentially have the most positive effects, although it is still too early to evaluate their impact on bird populations.

The night-lighting technique is routinely used to catch birds. We improved this technique using a thermal infrared camera to catch steppe birds such as the sandgrouse. Target birds were located by an observer using the thermal camera, and approached and dazzled by another observer carrying a spotlight attached to a helmet and a hand-held net together with a playback noise to camouflage the footsteps of the observer. Using this improved technique, we caught on average 1. 14 individuals per 3-h capture session (N = 81) and a total of 92 sandgrouse in 2007-2010 (86 pin-tailed sandgrouse Pterocles alchata and six black-bellied sandgrouse Pterocles orientalis). Capture rate and success were negatively influenced by moonlight (lowest during full moon nights). Our night-lighting technique is a highly selective and harmless method to capture sandgrouse and can be used for other small/medium-sized open-land birds or mammals., Funding came from the Dirección General de Investigación (projects CGL2007-66322/BOS and CGL2008-04282/BOS), Consejería de Educación y Ciencia de Castilla-La Mancha (projects PAI08-0171-9582 and PAC06-137) and Bardenas Reales Natural Park (project CTR09-0268).

Sandgrouse of the genus Pterocles are good models for studying adaptations to deserts, with 14 species living in different parts of a habitat spectrum ranging from semiarid to extreme desert. To evaluate possible differences in bioenergetic and thermoregulatory ability within the group, we studied two species, black-bellied sandgrouse (Pterocles orientalis) and pin-tailed sandgrouse (Pterocles alchata). These two species are partly sympatric, but the latter also occurs in hotter and more arid regions than the former. Black-bellied sandgrouse had a mean resting metabolic rate (RMR) similar to the allometric prediction (5.53 m W g⁻¹ by day, 5.04 mWg⁻¹ at night; 97% and 110% of allometric prediction, respectively), whereas mean RMR in pin-tailed sandgrouse was lower than predicted (4.04 mW g⁻¹ by day; 62% of allometric prediction). Similarly, the pin-tailed sandgrouse was the better thermoregulator of the two species, especially at high temperatures, with a well-developed evaporative cooling ability. At 40°C...

Recopilación de datos morfométricos y observaciones detalladas sobre la ecología general de la Ganga ortega (Pterocles orientalis), obtenidos a lo largo de varias salidas de campo cerca Toro (Zamora) y a diferentes enclaves de la provincia de Valladolid, entre el 22 de agosto de 1951 y el 21 de febrero de 1954. Incluye ilustraciones a tinta de dos plumas de la especie., Compilation of morphometric data and general ecology detailed observations of the Black-belled Sandgrouse (Pterocles orientalis), obtained through many field trips to places near Toro (Zamora) and different habitats of the province of Valladolid, between the 22nd of August of 1951 and the 21st of February of 1954. Ink illustrations of two feathers are included.

International audience; Aspects of the breeding biology of the Black-bellied Sandgrouse Pterocles orientalis were investigated in an and area of west-central Morocco in the 2003 and 2004 seasons. Back-dating clutches and broods indicated that successful nesting lasted 13-18 weeks from mid-April to late August. The clutch frequency distribution showed two successive high and less important peaks in May and July, respectively. Among 50 nests 10.5%, 36.8% and 52.7% in 2003 and 9.7%, 25.8% and 64.5% in 2004 were found with one, two and three eggs per clutch, respectively. The mean clutch size was 2.55 eggs +/- 0.50 (SD). The eggs' mean weight was 25.14 g +/- 1.77 and measured 47.31mm +/- 1.67 in length and 31.42mm +/- 1 in width. The mean egg volume was 23.86 cm(3) +/- 1.83. The incubation period was about 26 d and the average hatchability rate was 62.5%. The differences in the breeding biology patterns between the population of west-central Morocco and those from other localities could be attributed to the geographic variation in environmental conditions. The data obtained are helpful for the conservation and reinforcement of declining populations of the Black-bellied Sandgrouse in west-central Morocco.

Undulating ground resembles cover in offering opportunities for vertebrate predators to remain hidden from prey and vice versa. Some species prefer to forage in the open so as to avoid being surprised by predators while others remain close to cover and use it as a refuge when attacked. To determine if topography was important in influencing the sites chosen by sandgrouse for drinking, we measured a range of variables at water-holes used by blackbellied, pin-tailed and crowned sandgrouse (Pterocles orientalis, P. alchata and P. coronatus) in Spain and Israel. All species drank at sites reasonably close to their feeding and nesting areas. In Spain, water-hole selection was quantified using stepwise logistic and linear regression analysis. The amount of dead ground surrounding each water-hole (i.e. ground not visible to drinking sandgrouse) was the most important factor influencing the birds' choice. These regression relationships were used to predict the pattern of use of water-holes at two localities in Israel. The agreement between observed and expected levels of exploitation was good, confirming the strong aversive influence of dead ground. Predatory birds were the biggest source of disturbance at drinking sites. By choosing sites with the least dead ground, sandgrouse probably reduced their risk of being surprised by predators while drinking.