TL;DR: This study studied the flight behavior of a flock of juvenile Northern bald ibis (Geronticus eremita) during a human-guided autumn migration and shows that direct reciprocation can enable cooperation between animals in a natural context.
Abstract: One conspicuous feature of several larger bird species is their annual migration in V-shaped or echelon formation. When birds are flying in these formations, energy savings can be achieved by using the aerodynamic up-wash produced by the preceding bird. As the leading bird in a formation cannot profit from this up-wash, a social dilemma arises around the question of who is going to fly in front? To investigate how this dilemma is solved, we studied the flight behavior of a flock of juvenile Northern bald ibis (Geronticus eremita) during a human-guided autumn migration. We could show that the amount of time a bird is leading a formation is strongly correlated with the time it can itself profit from flying in the wake of another bird. On the dyadic level, birds match the time they spend in the wake of each other by frequent pairwise switches of the leading position. Taken together, these results suggest that bald ibis cooperate by directly taking turns in leading a formation. On the proximate level, we propose that it is mainly the high number of iterations and the immediacy of reciprocation opportunities that favor direct reciprocation. Finally, we found evidence that the animals' propensity to reciprocate in leading has a substantial influence on the size and cohesion of the flight formations.
TL;DR: The Quaternary karstic site of Sierra de Quibas (Abanilla, Murcia, Spain) has provided a wide faunistic list with 53 species distributed among gastropods, myriapods, amphibians, reptiles, birds and mammals.
Abstract: The Quaternary karstic site of Sierra de Quibas (Abanilla, Murcia, Spain) has provided a wide faunistic list with 53 species distributed among gastropods, myriapods, amphibians, reptiles, birds and mammals Especially interesting among the gastropods is Palaeoglandina that became extinct in Europe during the Pliocene It remains as a relict genus in the Pleistocene of the Iberian Peninsula Two of the birds, Gypaetus barbatus and Geronticus eremita, and a snake, Elaphe cf E sealaris, are scarcely represented in the fossil record For several birds, it is the first record in the Lower Pleistocene of the Iberian Peninsula Among the mammals, the presence of the Cercopithecine Macaca sylvanus is especially relevant one The assemblage of the taxa Arvicola deucalion, Castillomys rivas rivas, Eliomys intermedius, Equus altidens and Capra sp aff C alba allows the correlation with Plines 1, Orce 3 and Venta Micena, among other sites Therefore Quibas can be dated before the end of Lower Pleistocene, between 13 and 1 Ma A dry paleoclimatic regime, very similar to the current climate in the geographical area, though perhaps slightly wetter and warmer, can be inferred from the faunistic assemblage The environment of the karstic cavity was a rocky place with open brushwood areas, but in the proximities there were wetlands and woodlands, as can be inferred from the presence of birds and micromammals characteristic of these habitats
TL;DR: The conclusion was that the haematocrit is sensitive to variations in body condition since it responds to mass-loss processes corresponding to phases of mobilization of fat reserves, a situation prior to the mobilization of muscle proteins when there is a manifest deterioration of the individual's aspect.
Abstract: We study the usefulness of the haematocrit as a predictor of body condition in birds, using a captive population of the endangered species Northern Bald Ibis (Geronticus eremita). This population is 14% of the worldwide captive population, which is far greater than the known free-living population. The haematocrit, body mass and body condition index responded in the same sense to two different nutritional periods, and there was a statistically significant relationship between changes in condition index and haematocrit of individual birds between the two periods. We discuss the relationship of these parameters with subcutaneous fat and muscle mass, and analyse the individuals' nutritional status in each of the periods studied. The conclusion was that the haematocrit is sensitive to variations in body condition since it responds to mass-loss processes corresponding to phases of mobilization of fat reserves, a situation prior to the mobilization of muscle proteins when there is a manifest deterioration of the individual's aspect.
TL;DR: The locality of Ahl at Oughlam, situated at the southeastern limit of the city of Casablanca (Morocco) at about 34 degrees north, is dated by the biochronology of its rich mammalian fauna to about 2.5 Ma as mentioned in this paper.
Abstract: The locality of Ahl at Oughlam, situated at the southeastern limit of the city of Casablanca (Morocco) at about 34 degrees north, is dated by the biochronology of its rich mammalian fauna to about 2.5 Ma. At the present time it is 6.5 km from the Atlantic Ocean but it was on the seashore when the fossil material was deposited. Among the seabirds are Phoebastria anglica, Phoebastria sp. cf. P. albatrus, Phoebastria sp. cf. P. nigripes, Pelagornis mauretanicus, Calonectris sp. cf. C. diomedea, Morus peninsularis, Morus sp. cf. M. bassanus, Catharacta sp. cf. C. skua, Alca ausonia. Among the landbirds are Struthio asiaticus, Geronticus olsoni n.sp., several anseriforms, Plioperdix africana n.sp., several otidids, Agapornis atlanticus n.sp., Tyto balearica, T. alba, Surnia robusta, and a few Passeriformes. The Recent species of albatrosses Phoebastria albatrus and P. nigripes live in the North Pacific but were also present in the North Atlantic until the Middle Pleistocene. The marine avifauna shows many similarities with that of the Yorktown Formation, in North Carolina. Unlike the mammals, which include many genera in common with the African faunas, the landbirds have more affinities with the Palaearctic region than with the Ethiopian region. They include several extinct genera or species that have been described, or identified, in the Pliocene of the Palaearctic region. The terrestrial avifauna is very different from all those that have been described from the upper Miocene and Pliocene of Africa
TL;DR: The recovery in the Souss-Massa region remains precarious because the population is concentrated in a few places where adverse changes are possible, however, it could provide opportunities for natural extension of the range to formerly occupied sites further north in Morocco.
Abstract: Summary The Northern Bald Ibis or Waldrapp Geronticus eremita is a species of arid semi-deserts and steppes, which was formerly widely distributed as a breeding bird across North Africa, the Middle East and the European Alps. Just over 100 breeding pairs now remain in the wild at two sites in Morocco whilst two further wild pairs remain in Syria. There is also a population in Turkey, which is maintained for part of the year in captivity, and a large captive population in zoos. The species is classified by IUCN as ‘Critically Endangered’, the highest threat category. The wild population has grown during the past decade, which represents the first evidence of population growth in the species’ recorded history. Conservation action in Morocco has contributed to this recovery. A large part of the contribution of research to conservation action has been to establish and document the value of simple site and species protection. Quantitative assessments of the importance of sites for breeding, roosting and foraging have helped to prevent disturbance and the loss of sites to mass-tourism development. Wardening by members of the local community have reduced disturbance by local people and others and increased the perceived value of the birds. Monitoring has suggested additional ways to improve the breeding status of the species, including the provision of drinking water and removal and deterrence of predators and competitors. These actions have been evaluated by subsequent testing. Steppe and two-year fallows were shown to be the key feeding habitats, and maintaining such non-intensive land uses in future may present major management challenges. The recovery in the Souss-Massa region remains precarious because the population is concentrated in a few places where adverse changes are possible. However, it could provide opportunities for natural extension of the range to formerly occupied sites further north in Morocco.