Factors modulating home range and resource use: a case study with Canarian houbara bustards

ABSTRACT: The home range of an animal is determined by its ecological requirements, and these may vary depending on many intrinsic and extrinsic factors, which are ultimately driven by food resources. Investigating the effects of these factors, and specifically how individuals use food resources within their home ranges is essential to understand the ecology and dynamics of animal populations, and to establish conservation measures in the case of endangered species. Here, we investigate these questions in the Canarian houbara bustard, an endangered subspecies of African houbara endemic to the Canary Islands.We are grateful to A. Rodríguez, T. Díaz-Valera and F. Corujo for their collaboration during the fieldwork, E. Arrondo for helping with the AcceleRater software, and A. Perona for his help and tips about the “rhr package”, M. A. Cabrera for managing capture permits and for his support during the project, F. Crespo, M. Armas, A. Ibarguren and M. Gil for their assistance during the preparation of the project, the guards of the Cabildo of Lanzarote, Timanfaya National Park and La Graciosa, including TRAGSA personnel, the veterinarian C. M. Suárez, and all authorities of the Government of the Canary Islands for their collaboration. We also thank J. M. Poveda and F. Suárez of GRAFCAN for providing images and ortophotos of the islands. Two anonymous reviewers and the associate editor provided useful comments that helped to improve our manuscript. This study was funded by Red Eléctrica de España (REE) through a contract with Agencia Estatal Consejo Superior de Investigaciones Científicas (CSIC)

Factors modulating home range and resource use: a case study with Canarian houbara bustards

ABSTRACT: The home range of an animal is determined by its ecological requirements, and these may vary depending on many intrinsic and extrinsic factors, which are ultimately driven by food resources. Investigating the effects of these factors, and specifically how individuals use food resources within their home ranges is essential to understand the ecology and dynamics of animal populations, and to establish conservation measures in the case of endangered species. Here, we investigate these questions in the Canarian houbara bustard, an endangered subspecies of African houbara endemic to the Canary Islands.We are grateful to A. Rodríguez, T. Díaz-Valera and F. Corujo for their collaboration during the fieldwork, E. Arrondo for helping with the AcceleRater software, and A. Perona for his help and tips about the “rhr package”, M. A. Cabrera for managing capture permits and for his support during the project, F. Crespo, M. Armas, A. Ibarguren and M. Gil for their assistance during the preparation of the project, the guards of the Cabildo of Lanzarote, Timanfaya National Park and La Graciosa, including TRAGSA personnel, the veterinarian C. M. Suárez, and all authorities of the Government of the Canary Islands for their collaboration. We also thank J. M. Poveda and F. Suárez of GRAFCAN for providing images and ortophotos of the islands. Two anonymous reviewers and the associate editor provided useful comments that helped to improve our manuscript. This study was funded by Red Eléctrica de España (REE) through a contract with Agencia Estatal Consejo Superior de Investigaciones Científicas (CSIC)

Human decimation caused bottleneck effect, genetic drift, and inbreeding in the Canarian houbara bustard

An endangered subspecies of the African houbara bustard, the Canarian houbara (Chlamydotis undulata fuertaventurae), is endemic to the Canary Islands off southern Morocco (Lanzarote, Fuerteventura, and La Graciosa islands). This population decreased over the last centuries because of hunting and egg collection, and was close to extinction in Lanzarote around the middle of last century. Later, the species recovered because of hunting bans, but in Fuerteventura a significant decline has again occurred in the last decades and houbaras are on the brink of extirpation on that island. We describe the genetic characteristics and recent evolutionary history of this subspecies to provide essential information for the evaluation of the conservation actions implemented and for the development of new measures to prevent further declines and local extirpations. We amplified microsatellite loci to infer genetic variability, population structure, and gene flow. The subspecies exhibited relatively high genetic variability but reduced heterozygosity. In spite of high gene flow among locations and islands, we identified 2 genetic units: 1 comprising La Graciosa and Fuerteventura islands, and the other restricted to Lanzarote. We detected genetic bottlenecks and subsequent inbreeding in both units, with a reduced effective number alleles in Lanzarote compared to Fuerteventura‐La Graciosa. This genetic structure may be explained by human‐induced historical population declines and an associated bottleneck effect, particularly in Lanzarote. Conservation measures should aim to recover the houbara population of Fuerteventura, improving survival of adults and juvenile productivity, and to ensure that genetic flow continues among breeding locations and islands to recover the original population structure (an unique genetic unit over the range of the species) and prevent further genetic deterioration, which could lead to extirpation of this endemic subspecies

Uso del espacio y comportamiento reproductivo de la avutarda hubara (Chlamydotis undulata fuertaventurae)

Comprender los cambios en el uso del espacio y el comportamiento reproductivo de las especies, sobre todo de aquellas que se encuentran amenazadas, es crucial no solo para mejorar el conocimiento sobre las mismas, sino para poder aplicar medidas de conservación que eviten su declive y posible extinción. Esta tesis doctoral tiene como objetivo profundizar en la ecología espacial y el comportamiento reproductivo de la avutarda hubara canaria (Chlamydotis undulata fuertaventurae; en adelante, hubara canaria), subespecie endémica de las islas Canarias, catalogada como amenazada a nivel global por la UICN y en peligro de extinción a nivel nacional. Mediante los datos obtenidos con el marcaje y seguimiento de individuos adultos marcados con emisores GSM/GPRS, se pretende conocer los patrones y procesos biológicos y ecológicos que ayuden a diseñar nuevas estrategias de conservación. Tras la Introducción (Capítulo I) y la Metodología General (Capítulo II), la tesis doctoral está estructurada en 4 capítulos de resultados. El Capítulo III aborda las ventajas del uso de las nuevas tecnologías para realizar una investigación sobre la ecología y el comportamiento de los individuos. Esta investigación identifica y clasifica distintas pautas de comportamiento de la hubara canaria a través del acelerómetro (ACC). Utilizando la relación de nuestras observaciones de campo con los segmentos del ACC, se clasificaron las categorías de comportamiento a partir de los perfiles de aceleración. Se utiliza el software AcceleRater y el modelo conocido como RBF SVM (Núcleo de Función de Base Radial/Máquinas de Vectores de Apoyo) para identificar siete comportamientos con más del 90 % de precisión. La asociación de estos comportamientos con su localización GPS nos ha permitido localizar los lugares específicos donde cada individuo realiza cada comportamiento. Este método, que puede ser utilizado en otras especies, podrá servir para aumentar nuestro conocimiento sobre la especie de estudio, investigando la ecología espacial y el comportamiento reproductivo de los individuos marcados. En el Capítulo IV, se aborda el patrón de migración de la subespecie. Los resultados muestran la existencia de migración parcial en la población de estudio, siendo aproximadamente un tercio los individuos que se mueven a otras zonas una vez concluida la reproducción y mostrando una gran fidelidad, tanto a las zonas reproductivas como no reproductivas. Estos patrones de migración parecen estar producidos por las diferencias en la productividad vegetal entre las zonas reproductivas y las no reproductivas, según estimaciones derivadas de los índices NDVI y SAVI. Estos resultados sugieren que la migración parcial se produce como un mecanismo de adaptación a la distinta abundancia de alimento en verano en las diferentes zonas. Además, se profundiza sobre la cantidad de áreas no reproductivas que son utilizadas, observando que una de las zonas no reproductivas es seleccionada por más de la mitad de los individuos migradores. Esta zona presenta un mosaico de parcelas con vegetación natural, mayoritariamente de aulagas (Launaea arborescens), con barbechos y cultivos en regadío. Un resultado relevante es que la mayoría de los vuelos migratorios se realizaron en horario nocturno. En el Capítulo V, se investigan la selección de recursos y las áreas de campeo de los individuos. Se caracterizan el tamaño y la forma de los territorios utilizados, diferenciando entre individuos reproductores y no reproductores y también entre diferentes periodos del año (estación reproductiva y no reproductiva). El tamaño de las áreas de campeo varió en función de la temporada y el estado reproductivo del individuo. Los resultados mostraron que durante la época reproductiva ambos sexos utilizaron casi exclusivamente terrenos con vegetación natural, seleccionando como hábitats de alimentación matorrales de baja densidad, pastos y barbechos verdes. Sin embargo, durante la época no reproductiva (mayo-octubre), se desplazaron a matorrales de alta densidad, pero también en parte a tierras cultivadas y barbechos verdes, mostrando preferencia por las parcelas de regadío. Esta investigación aporta datos sobre los requerimientos ecológicos de la hubara canaria, que son importantes para el diseño de planes de conservación. En el Capítulo VI, se aborda la actividad nocturna (detectada previamente en el capítulo IV), investigando el tipo y la intensidad de dicha actividad. Los resultados muestran que, a pesar de que la hubara se considera un ave exclusivamente diurna, presenta cierta actividad por la noche. Los machos realizan comportamientos reproductivos, con mayor o menor intensidad en función de la fase lunar. La intensidad de la vocalización es mayor en las noches de luna llena, alcanzando niveles similares a los del amanecer, momento del día en el que hasta la fecha se había registrado la máxima actividad sexual en esta especie. Estos resultados sugieren que la luz de la luna puede ayudar a los machos que se exhiben no solo a detectar a los depredadores, sino a comunicarse visualmente con las hembras que se acercan, pudiendo llegar a lograr cópulas nocturnas sin la interferencia de machos vecinos. Tras los capítulos de resultados, se expone la Discusión General (Capitulo VII) y las Conclusiones (Capítulo VIII). Esta tesis pone de manifiesto la necesidad de comprender el uso del espacio y el comportamiento reproductivo de las aves para poder realizar una gestión adecuada. La hubara canaria se encuentra en un preocupante estado de conservación, debido principalmente a la fragmentación del hábitat, las molestias antropogénicas y la mortalidad no natural causada por choques con tendidos eléctricos y telefónicos y con vehículos. Estos problemas no parece que vayan a resolverse en breve, y por ello, las implicaciones para la conservación que se desprenden de esta tesis deberían tenerse en cuenta y aplicarse en un futuro próximo, para así evitar el declive de un ave endémica de las islas.Understanding the changes in the use of space and the reproductive behavior of species, especially those that are threatened, is crucial to improve not only our knowledge about their ecology, but also to be able to apply conservation measures to avoid their decline and extinction. This doctoral thesis aims to deepen in the spatial ecology and reproductive behavior of the Canarian Houbara bustard (Chlamydotis undulata fuertaventurae, hereafter Canarian houbara), a subspecies endemic to the Canary Islands and listed as globally threatened by the IUCN and endangered at the national level. Through the data obtained with the marking and long-term monitoring of adult individuals marked with GSM/GPRS transmitters, the aim is to understand biological and ecological patterns and processes that will help to design new conservation strategies. After the Introduction (Chapter I) and the General Methods (Chapter II), the doctoral thesis is structured in 4 chapters of results. The Chapter III, addresses advantages of using new technologies to conduct research on the ecology and behavior of individuals. This research identifies and classifies different behavioral patterns of the Canarian houbara by means of the accelerometer (ACC). Using the relationship of our field observations to the ACC segments, we classified the behavioral categories based on acceleration profiles. AcceleRater software and the model known as RBF SVM (Kernel Radial Basis Function/Support Vector Machines) are used to identify seven behaviors with more than 90 % accuracy. The association of these behaviors with their GPS lo- cation allows locating the specific places where each behavior is being performed. This method, which can be applied in other species, may be used to increase our knowledge about our study species by investigating their spatial ecology and reproductive behavior. In the Chapter IV, the migration pattern of the subspecies is investigated. The results show the existence of partial migration in the study population, with approximately one third moving to other areas once the breeding season is over, and showing high site fi- delity to both, their breeding and non-breeding areas. These migration patterns seem to be determined by differences in plant productivity between breeding and non-breeding areas, according to estimates derived from NDVI and SAVI indices. These results suggest that partial migration occurs as an adaptive mechanism to the differences in food abundance in summer in the different zones. In addition, the number of non-breeding areas that are used is studied, observing that one of the non-breeding areas is selected by more than half of the migrating individuals. This zone presents a mosaic of natural vegetations fields of Launaea arborescens, with fallow land and irrigated crops. A surprising result was that most of the migratory flights took place at night. In the Chapter V, resource selection and home range are investigated. The size and shape of the territories of adult individuals are characterized, differentiating between breeding and non-breeding periods. The size of the home ranges varied according to the season and the reproductive status of the individual. The results showed that during the breeding season both sexes used almost exclusively natural vegetation land, selecting low-density shrublands, grasslands and green fallows as foraging habitats. However, during the non-breeding season (May-October), they moved to areas with cultivate land and green fallows with high-density shrublands, showing a preference for irrigated fields as foraging sites. This research provides important insights into the ecological requirements of the Canarian houbara, that could be important for the design of conservation plans. In the Chapter VI, we describe the types and intensity of nocturnal activity, which we already mentioned in Chapter IV. The results show that although the Canarian houbara is considered an exclusively diurnal bird, they are active also at night. Males perform reproductive behaviors, with variable intensity depending on the lunar phase. The intensity of vocalizations is higher on full moon nights, reaching similar levels to displays performed at dawn, the period of the day when houbaras were assumed to reach peak display intensity. These results suggest that moonlight may help displaying males not only to detect predators, but also to communicate visually with approaching females, ultimately leading to nocturnal copulations without being interrupted by neighbor males. Following the results chapters, the General Discussion (Chapter VII) and Conclusions (Chapter VIII) are presented. This thesis highlights the need to understand the use of space and the reproductive behavior of birds in order to be able to carry out an adequate management. The Canarian houbara is in a worrying state of conservation, mainly due to habitat fragmentation, anthropogenic disturbances and mortality caused by collisions with power lines, telephone lines and vehicles. These problems are not likely to end soon, and therefore, the conservation implications of this thesis should be taken into account and applied in the near future, in order to avoid the decline of a bird endemic to the islands.El desarrollo de las investigaciones ha sido posible gracias al proyecto: Áreas de campeo y movimientos de la hubara canaria (Chlamydotis undulata fuertaventurae), financiado por Red Eléctrica de España a través de un contrato con la Agencia Estatal Consejo Superior de Investigaciones Científicas (CSIC). Los trabajos se han llevado a cabo gracias al apoyo de dicha financiación.Peer reviewe

Uso del espacio y comportamiento reproductivo de la avutarda hubara (Chlamydotis undulata fuertaventurae)

Tesis Doctoral inédita leída en la Universidad Autónoma de Madrid, Facultad de Ciencias, Departamento de Ecología. Fecha de Lectura: 20-12-2022Esta tesis tiene embargado el acceso al texto completo hasta el 20-06-202

Alzacola rojizo – Cercotrichas galactotes (Temminck, 1820)

Aves - Orden Passeriformes - Familia Turdidae en la Enciclopedia Virtual de Vertebrados Españoles, http://www.vertebradosibericos.org/.Cercotrichas es un género de aves paseriformes pertenecientes a la familia Muscicapidae, que incluye cinco especies (Del Hoyo et al., 2016). Cercotrichas galactotes (Temminck, 1820) fue descrito a partir de ejemplares procedentes de Algeciras.Peer reviewe

La población de avutarda hubara de Lanzarote: tamañp, proporción de sexos, productividad y propuesta de un nuevo método de censo

[EN] Lanzarote island, in the Canary archipelago, is the main stronghold of the Canariansubspecies of the African Houbara Bustard Chlamydotis undulata fuertaventurae. The size of this popu-lation has been estimated several times in recent decades, based on extrapolations of bird densitiesobtained in small sampling areas. Here we present the results ofthe first complete census of the Houbarapopulation of this island, based on car transects combined with frequent and prolonged scanning stops,and carried out during the mating season, in January-February 2018. Based on a count of 370 birds (161males, 209 females) we estimate a total population of 440-452 Houbara Bustards on the island. For thefirst time, a sex-ratio figure was obtained for this species: 1.41 females per male. The annual productionof juveniles was recorded for three years and varied between 5.83 and 19.57 juveniles per hundredfemales. The census method used in this study is proposed as an alternative to the line transects usedpreviously, since it avoids possible methodological flaws that probably overestimate the population.The present method also enables sex ratio and productivity to be determined, and it established thelocations of most displaying males. These are important parameters for evaluating the conservationstatus and reproductive performance of this endangered subspecies of the African Houbara[ES] La isla de Lanzarote acoge en la actualidad el mayor contingente de la subespecie deavutarda hubara Chlamydotis undulata fuertaventurae. En las últimas décadas se han publicado variasestimaciones del tamaño de esta población, basadas en extrapolaciones realizadas a partir de zonas de muestreo. En este trabajo presentamos los resultados del primer censo completo de hubara canaria enesta isla, realizado durante el periodo de reproducción, en enero-febrero de 2018.A partir de los 370individuos censados, de los que 161 fueron machos y 209 hembras, se estimó el tamaño de la poblaciónen 440-452 individuos. Por primera vez para esta especie se ha obtenido el dato de proporción de sexos,que resultó ser de 1,41 hembras por macho. Además, se aportan valores de productividad juvenil de tresaños, con un mínimo de 5,83 y un máximo de 19,57 jóvenes por cada cien hembras en la población. Elmétodo utilizado en este estudio se propone como alternativa al utilizado en muestreos anteriores, quehan podido sobreestimar el tamaño real de la población. Además, el censo completo permite obtenervalores de proporción de sexos y productividad juvenil, así como la localización de la mayor parte delos machos adultos territoriales, parámetros todos ellos necesarios para evaluar el estado de conser-vación de esta subespecie amenazada de hubara.Peer reviewe

Moonlight triggers nocturnal display in a diurnal bird

The importance of nocturnal display in diurnal birds has been neglected for a long time, owing to the difficulties in recording behaviour by night. Using loggers with an accelerometer (ACC) we studied nocturnal display in male African houbara bustards, Chlamydotis undulata, ssp. fuertaventurae. Diurnal display of male houbaras consists of a visual component, the display run, and an acoustic component, the boom. Nocturnal display runs were only recorded twice, both on full moon nights. Nocturnal booming intensity was highest on full moon nights when it reached similar levels to those during peak diurnal display at dawn. The more favourable physical conditions for sound transmission and the reduced acoustic competition with wind and other birds at night have been proposed to explain nocturnal vocalizing. Minimizing copulation disruptions, a frequent intramale competition mechanism in bustards, could be an additional advantage of nocturnal display. However, these factors do not explain why vocal activity is highest on full moon nights. We suggest that moonlight may help displaying males to detect predators, as well as to communicate visually with approaching females. Moonlight also allows males to combine booms with visual signals produced by the white neck feathers exposed during booming into more efficient multimodal signals. Moonlight would thus ultimately lead to males achieving nocturnal copulations, which indeed might be more frequent than previously thought, according to rates of nocturnal ACC-recorded precopulatory movements. Finally, nocturnal booming sequences had almost twice as many booms as diurnal ones, which suggests that nocturnal vocalizations transmit higher-quality information about signalling males than diurnal vocalizations. Nocturnal booming significantly increased the total display time of male houbara bustards; thus, future studies should investigate whether nocturnal vocal activity represents an important contribution to individual fitness in this and other nocturnally vocalizing diurnal species.The study was funded by Red Eléctrica de España (REE) through a contract with Agencia Estatal Consejo Superior de Investigaciones Científicas (CSIC)

Anthropogenic mortality threatens the survival of Canarian houbara bustards

Abstract Anthropogenic mortality is a major cause of global mortality in terrestrial vertebrates. Quantifying its impact on the dynamics of threatened species is essential to improve their conservation. We investigated cause-specific mortality in Canarian houbara bustards (Chlamydotis undulata fuertaventurae), an endangered subspecies endemic to the Canary Islands. We monitored 51 individuals tagged with solar-powered GSM/GPRS loggers for an average of 3.15 years, and recorded 7 casualties at aerial lines (13.73% of the sample; 5 at power lines, 2 at telephone lines), 1 (1.96%) at a wire fence, 4 road kills (7.84%) and 1 case of predation by cat (1.96%). Cox proportional hazards models showed that anthropogenic and natural annual mortality rates were similar (respectively, 6.20% and 6.36% of the individuals). We estimate that 33–35 houbaras die each year in the Canary Islands due to anthropogenic causes. Population viability models using these data and juvenile productivity values obtained over seven years predicted the extinction of the species in 50 years. Eliminating anthropogenic mortality, the population could be recovered, but would still require management actions to improve habitat quality. Conservation measures to reduce anthropogenic mortality due to power line fatalities, roadkills and predation by cats, as well as to increase productivity, are urgently needed, particularly on Fuerteventura, where houbaras are on the brink of extinction