Search

Los pequeños peces pelágicos del Mediterráneo noroccidental constituyen unos elementos clave de los ecosistemas marinos, representan una fracción mayoritaria de las capturas pesqueras, y sirven como principal fuente de alimento de un elevado número de especies, entre las que destacan las aves marinas (Coll et al. 2015, Coll & Bellido 2020, Ouled-Cheikh et al. 2022). Debido a la influencia de diferentes ríos, entre los que destaca el río Ebro, esta zona es también una de las más importantes de todo el Mar Mediterráneo en términos de productividad y biomasa de pequeños peces pelágicos. Entre las especies de peces pelágicos más abundantes destacan la anchoa (Engraulis encrasicolus), la sardina (Sardina pilchardus) y la alacha (Sardinella aurita) (Coll & Bellido 2020). [...]

Spatial modelling is an important research tool to improve our knowledge about the distribution of wildlife in the ocean. Using different modelling techniques (MaxEnt and a generalized linear mixed model), a predictive habitat suitability model was developed for one of the most threatened seabirds in the world: the Balearic shearwater, Puffinus mauretanicus. Models were developed using a 10-year dataset from the Gulf of Cádiz (on the south-western Iberian Peninsula), a key foraging area for Balearic shearwaters during migration and the non-breeding season. Predictive habitat maps strongly matched the observed distribution patterns, pointing to bathymetric features as the main modelling drivers. The species was concentrated on shallow areas (up to approximately 100 m in depth) of the continental shelf, very close to the mouth of the Guadalquivir River. In contrast with previous studies, Balearic shearwater distribution in the highly dynamic Gulf of Cádiz was not correlated with areas of high chlorophyll a concentration. This lack of spatial correlation probably arises from the delay between the phytoplankton bloom and the response of the zooplankton and small fish that are preyed upon by Balearic shearwaters, which may result in important displacements of this trophic chain across the Gulf of Cádiz. The analysis presented contributes to a better understanding of the spatial distribution and ecology of the critically endangered top predator in the Gulf of Cádiz and offers important information to improve management plans.

1. Spatial modelling is an important research tool to improve our knowledge about the distribution of wildlife in the ocean. Using different modelling techniques (MaxEnt and a generalized linear mixed model), a predictive habitat suitability model was developed for one of the most threatened seabirds in the world: the Balearic shearwater, Puffinus mauretanicus. 2. Models were developed using a 10-year dataset from the Gulf of Cádiz (on the south-western Iberian Peninsula), a key foraging area for Balearic shearwaters during migration and the non-breeding season. 3. Predictive habitat maps strongly matched the observed distribution patterns, pointing to bathymetric features as the main modelling drivers. The species was concentrated on shallow areas (up to approximately 100 m in depth) of the continental shelf, very close to the mouth of the Guadalquivir River. In contrast with previous studies, Balearic shearwater distribution in the highly dynamic Gulf of Cádiz was not correlated with areas of high chlorophyll a concentration. 4. This lack of spatial correlation probably arises from the delay between the phytoplankton bloom and the response of the zooplankton and small fish that are preyed upon by Balearic shearwaters, which may result in important displacements of this trophic chain across the Gulf of Cádiz. 5. The analysis presented contributes to a better understanding of the spatial distribution and ecology of the critically endangered top predator in the Gulf of Cádiz and offers important information to improve management plans.

Human fisheries provide scavengers with abundant and predictable feeding opportunities that may schedule their behavioural patterns. Using miniaturized global positioning system (GPS) tracking technology, we evaluated how Audouin’s gull (Ichthyaetus audouinii), a Mediterranean endemic seabird that makes extensive use of feeding opportunities provided by fisheries, co-occurred (i.e. presumably interacted) with the most important fishing fleets operating off the NE Iberian Peninsula (i.e. diurnal trawlers and nocturnal purse seiners), both in space and time. Results showed that individuals were able to adapt their distribution and activity patterns to the scheduled routines of these fisheries. Waveform analyses based on co-occurring positions revealed that most interactions with trawlers occurred during the afternoon (16:00 h GMT + 1) when discarding occurs as vessels return to port. In contrast, gull-purse seiner interactions largely occurred at night (between 02:00 and 04:00 h) coinciding with the setting and hauling of the nets. Moreover, we found an individual component in seabird–fishery interactions, showing that there may be differential use of fisheries by individuals within the population. In addition to implications for our understanding of the behavioural ecology of this species, these results may have important management implications, particularly under the current European Union Common Fisheries Policy scenario of largely restricting discards

[ES]: Esta publicación trata sobre la ecología del movimiento de la cigüeña blanca (Ciconia ciconia) a lo largo de todo el ciclo anual: temporadas de cría y de invernada y ambas migraciones entre estas zonas. Se trata de la quinta monografía del programa Migra (www.migraciondeaves.org) desarrollado por SEO/BirdLife desde 2011, cuyo objetivo es conocer los movimientos y la migración de las aves presentes en España, y que para el estudio de esta especie ha contado con la colaboración de la organización suiza Storch Schweiz, la Estación Biológica de Doñana (EBD-CSIC), el Instituto MaxPlanck de Ornitología en Radolfzell (Alemania) y el Grupo SaBio del IREC (CSIC-UCLM-JCCM). La cigüeña blanca es un ave de gran tamaño, muy planeadora y que depende de las corrientes térmicas para el vuelo. Hasta hace relativamente poco tiempo, era considerada un migrador transahariano obligado que solo se observaba en territorio ibérico durante la época de reproducción. Sin embargo, en las últimas décadas está cambiando su comportamiento migratorio, y en la actualidad se cuenta con un importante número de aves que invernan en España, tanto aves nativas invernantes como ejemplares de origen centroeuropeo. Durante la migración transahariana la península Ibérica representa un área de paso obligado para las cigüeñas blancas de Europa Occidental y centroeuropeas, que viajan hasta el área de Gibraltar para cruzar el Estrecho entre finales de agosto y septiembre, más tarde que las aves ibéricas. Una vez en África continúan la migración atravesando el desierto del Sahara hasta llegar al Sahel, donde se encuentra la principal área de invernada de la población occidental. En España, la población reproductora se distribuye fundamentalmente en la mitad occidental de la Península y en el valle del Ebro. Además, cría en Galicia y en localidades aisladas de la fachada cantábrica, pero falta en grandes áreas de la costa mediterránea y este de la meseta. El último censo nacional corresponde a 2004, cuando, [EN]: The present publication describes the movement ecology of white storks (Ciconia ciconia) across the complete annual cycle: breeding and wintering seasons, and both migratory periods between wintering and breeding grounds. It is the fifth monograph published in the context of the Migra program (www.migraciondeaves.org/en/) run by SEO/BirdLife since 2011 in order to describe the movements and migratory routes of the avian species present in Spain. For this particular species SEO/BirdLife has received collaboration from the Swiss non-governmental organization Storch Schweiz, the Doñana Biological Research Station (EBD-CSIC), the Max-Planck Institute of Ornithology in Radolfzell (Germany), and the Health and Biotechnology Research Group of the Spanish Institute of Game and Wildlife Research (IREC, CSIC-UCLM-JCCM). The white stork is a large conspicuous soaring bird that depends on thermals and air currents for its flights. Until recently it was considered an obligatory trans-Saharan migrant that was only present in the Iberian Peninsula during the breeding season. However the white storks’ migratory behaviour has been changing throughout the past decades and at present a large number of birds winter in Spain, both native resident storks and birds from Central Europe that spend the winter in Spanish territory. During trans-Saharan migration the Iberian Peninsula constitutes an obligatory part of the route of white storks of Western and Central Europe that travel to Gibraltar and cross the strait between the end of August and September, later than storks from the Peninsula. Once in Africa these birds travel onwards crossing the Sahara to reach the Sahel zone, as sub-Saharan Africa is the primary wintering area of the western white stork population. In Spain the breeding population of white storks occupies predominantly the western half of the Iberian Peninsula and the Ebro river valley. In addition, they breed in Galicia and in the Cantabria part of the Atlantic coa

We studied the post-fledging movement of two sibling (male and female) juvenile Barbary Falcons (Falco peregrinus pelegrinoides) hatched in Lanzarote (Canary Islands) in 2011 using satellite tracking. Birds were tracked from fledging in May to the end of November, when the signals of both transmitters were lost. During the first 45 d following fledging, both birds behaved similarly and made some flights <70 km away from their nest, on the island where they hatched. However, after the dependence period, we found differences between the individuals. The female made several inter-island movements among the islands of the central archipelago (Gran Canaria, Tenerife and La Gomera) and returned to Lanzarote in October. In contrast, the male stayed close to his natal nest (<100 km) until the end of October, when he was detected in the middle of the Atlantic Ocean >3000 km from the nest, probably using a ship as a perch. Because Barbary Falcon populations of the Canary Islands are listed as >threatened> due to anthropogenic threats (e.g. collisions with human-made structures, illegal shooting, nest-robbing; and hybridization with escaped falconry falcons) and little is known about their post-fledging dispersal movements, more studies of such life-history characteristics, using ringing and remote sensing, are urgently needed to develop management actions for their conservation.

Marine megafauna, including seabirds, are critically affected by fisheries bycatch. However, bycatch risk may differ on temporal and spatial scales due to the uneven distribution and effort of fleets operating different fishing gear, and to focal species distribution and foraging behaviour. Scopoli's shearwater Calonectris diomedea is a long-lived seabird that experiences high bycatch rates in longline fisheries and strong population-level impacts due to this type of anthropogenic mortality. Analyzing a long-term data set on individual monitoring, we compared adult survival (by means of multi-event capture-recapture models) among three close predator-free Mediterranean colonies of the species. Unexpectedly for a long-lived organism, adult survival varied among colonies. We explored potential causes of this differential survival, by: (1) measuring egg volume as a proxy of food availability and parental condition; (2) building a specific longline bycatch risk map for the species; and (3) assessing the distribution patterns of breeding birds from the three study colonies via GPS tracking. Egg volume was very similar between colonies over time, suggesting that environmental variability related to habitat foraging suitability was not the main cause of differential survival. On the other hand, differences in foraging movements among individuals from the three colonies expose them to differential mortality risk, which likely influenced the observed differences in adult survival. The overlap of information obtained by the generation of specific bycatch risk maps, the quantification of population demographic parameters and the foraging spatial analysis should inform managers about differential sensitivity to the anthropogenic impact at mesoscale level and guide decisions depending on the spatial configuration of local populations. The approach would apply and should be considered in any species where foraging distribution is colony-specific and mortality risk varies spatiall

A comprehensive review of the natural history of the Cory's Shearwater Calonectris borealis in Spain.

Thebreeding foraging andpost-breedingdispersal movementsof five satellite-tagged Bulwer’s Petrels fromthe Canary Islands were recorded. Foraging trips lasted 5.6 days in average (n=3), while the meandistance covered was1261km,andforaging areas were located over the continental slope andthe adjacent pelagic waters, around 1200–2000 mdepth and up to 350 kmfromthe colony. After the chick-rearing period, birds dispersed southwestwards to the tropical waters of the central Atlantic