Mortalidad de aves marinas producida por luces artificiales terrestres

Artificial lights at night cause high mortality of seabirds, one of the most endangered groups of birds globally. Fledglings of burrow-nesting seabirds, and to a lesser extent adults, are attracted to and then grounded (i.e., forced to land) by lights when they fly at night. We reviewed the current state of knowledge of seabird attraction to light to identify information gaps and propose measures to address the problem. Although species in families such as Alcidae and Anatidae can be grounded by artificial light, the most affected seabirds are petrels and shearwaters (Procellariiformes). At least 56 species of Procellariiformes, more than one-third of them (24) threatened, are subject to grounding by lights. Seabirds grounded by lights have been found worldwide, mainly on oceanic islands but also at some continental locations. Petrel breeding grounds confined to formerly uninhabited islands are particularly at risk from light pollution due to tourism and urban sprawl. Where it is impractical to ban external lights, rescue programs of grounded birds offer the most immediate and employed mitigation to reduce the rate of light-induced mortality and save thousands of birds every year. These programs also provide useful information for seabird management. However, these data are typically fragmentary, biased, and uncertain and can lead to inaccurate impact estimates and poor understanding of the phenomenon of seabird attraction to lights. We believe the most urgently needed actions to mitigate and understand light-induced mortality of seabirds are estimation of mortality and effects on populations; determination of threshold light levels and safe distances from light sources; documentation of the fate of rescued birds; improvement of rescue campaigns, particularly in terms of increasing recovery rates and level of care; and research on seabird-friendly lights to reduce attraction.RESUMEN: Las luces artificiales nocturnas causan una mortalidad alta de aves marinas, uno de los grupos de aves en mayor peligro de extinción a nivel mundial. Los polluelos de aves marinas que anidan en madrigueras, y en menor medida los adultos, son atraídos y forzados a aterrizar por las luces cuando vuelan de noche. Revisamos el estado actual del conocimiento sobre la atracción de las aves marinas por la luz para identificar vacíos de información y proponer medidas para resolver el problema. Aunque las especies de familias como Alcidae y Anatidae pueden ser forzadas a aterrizar por la luz artificial, las aves marinas más afectadas son los petreles y las pardelas (Procellariiformes). Por lo menos 56 especies de Procellariiformes, más de un tercio (24) de ellas amenazadas, son propensas al aterrizaje atraídas por las luces. Las aves marinas forzadas a aterrizar han sido halladas en todo el mundo, principalmente en islas oceánicas, pero también en algunas localidades continentales. Los sitios de anidación de los petreles confinados anteriormente a islas deshabitadas están particularmente en riesgo de sufrir contaminación lumínica debido al turismo y al crecimiento urbano. En donde no es práctico prohibir las luces externas, los programas de rescate de las aves accidentadas ofrecen la mitigación más inmediata y empleada para reducir la tasa de mortalidad inducida por la luz y salvar a miles de aves cada año. Estos programas también proporcionan información útil para el manejo de aves marinas. Sin embargo, estos datos están típicamente fragmentados, sesgados y son inciertos, y pueden llevar a estimaciones inexactas del impacto y a un entendimiento pobre del fenómeno de la atracción de las aves marinas por la luz. Creemos que las acciones necesarias de mayor urgencia para mitigar y entender la mortalidad de aves marinas producida por la luz son: la estimación de la mortalidad y los efectos sobre la población; la determinación de umbrales de niveles de luz y de distancias seguras a las fuentes de luz; el estudio del destino de las aves rescatadas; la mejora de las campañas de rescate, particularmente en términos de incrementar las tasas de recogida y el nivel de cuidado; y la investigación sobre las características de la luz para reducir la atracción de las aves marinas.This research was supported by a Marie Curie Intra European Fellowship within the 7th European Community Framework Programme (Project ID: 330655 FP7-PEOPLE-2012-IOF)info:eu-repo/semantics/publishedVersio

Impacts des éclairages urbains sur les pétrels de Barau, Pterodroma baraui sur l'Ile de la Réunion et mesures pour réduire ces impacts

L'île de la Réunion (55'30°E; 21'00°S) héberge deux espèces de pétrels endémiques, dont le pétrel de Barau, Pterodroma baraui. Cette espèce, classée «En danger» (IUCN 2000) est soumise à plusieurs menaces importantes: prédation par les mammifères introduits, braconnage et échouage. La mortalité des pétrels liée aux éclairages urbains est un phénomène récent lié à l'urbanisation de l'île. Les jeunes oiseaux, à leur envol, sont attirés par les éclairages et tombent au sol où ils risquent de mourir. Des campagnes de sauvetage sont organisées avec une mobilisation des habitants de l'île. Ainsi, 3 762 Pétrels de Barau ont été recueillis entre 1995 et 2004. Les principaux lieux d'échouage sont identifiés. Les types de structures les plus attractives sont, le réseau routier éclairé (37.8%), et les complexes sportifs (24.4%) (n = 1 652). Des expérimentations chez le Puffinus lherminieri bailloni montrent que les couleurs les moins attractives sont le rouge et le jaune, et, à l'opposé, le vert et le bleu. L'ensemble de ces résultats permet de proposer des mesures sur les éclairages urbains de manière à réduire leur impact sur les jeunes pétrels (volume d'éclairage, direction et concentration de l'éclairage, couleur des éclairages, interruptions temporaires…) dans les projets futurs d'aménagement. The island of Réunion (55'30E; 21'00S) has two endemic petrels, one of which is Barau's Petrel (Pterodroma baraui), classified as ‘Endangered' (IUCN 2000). This species is under threat from several sources: predation by introduced mammals, poaching, and strandings. Petrel deaths resulting from city lights is a recent phenomenon related to urbanisation of the island. Young birds on fledging are attracted by the lights, and fall to the ground where they risk being killed. Rescue operations have mobilised the local population, and between 1995 and 2004, 3 762 Barau's Petrels were retrieved. The main stranding sites were identified. The most attractive structures were the illuminated road network (37.8%) and sports complexes (24.4%) (n = 1 652). Experiments on Puffinus lherminieri bailloni showed that the least attractive lighting colours are red and yellow, the most attractive green and blue. These findings enable us to propose measures to ameliorate the impact of city lights on the young petrels, by adjusting the amount of lighting, its direction and intensity, the colours of the lights, and temporary black-outs at critical times. Ostrich 2007, 78(2): 449–45

Pesticides threaten an endemic raptor in an overseas French territory

International audienceThe Reunion harrier is an endangered raptor that is endemic to Reunion Island. Anticoagulant rodenticides (ARs) are widely applied on the island to prevent leptospirosis transmission to humans and limit the damage to sugarcane crops caused by rats and house mice. As these pesticides exhibit a high risk of secondary poisoning for rodent predators, we examined whether the Reunion harriers were exposed to and potentially poisoned by ARs. The AR concentrations in the livers of 58 harrier carcasses collected from 1999 to 2016 were measured. Both the temporal and spatial trends were analysed, and the influences of individual and landscape characteristics on the liver concentrations and potential poisoning were determined. AR residues were detected in 93% of the harriers. Difenacoum was the most frequently found (73% of positive races), while brodifacoum and bromadiolone showed the highest concentrations. Both the numbers of harriers exposed to ARs and of individuals that were potentially poisoned increased over time. This is particularly alarming as the number of harriers potentially poisoned by brodifacoum increased dramatically beginning in 2014. We also showed that the landscape composition of the townships influenced the AR exposure, as the concentrations increased with the proportion of urban areas and showed a peak at 25% of the township under sugarcane cultivation. We conclude that AR poisoning is likely a main threat for Reunion harrier conservation and propose several actions to limit poisoning

The decline of an urban Hooded Vulture Necrosyrtes monachus population in Dakar, Senegal, over 50 years

As in many West African cities, in Dakar Hooded Vultures Necrosyrtes monachus have always been characteristic urban scavengers. The recent decline of Hooded Vultures in other parts of Africa, mainly eastern Africa, has been the reason in 2015 for up-listing of its status by the IUCN in the Red List of Threatened Species to Critically Endangered. As the Hooded Vulture is still common in the Lower Casamance, Senegal, in the Western Region of The Gambia and in Guinea-Bissau, without clear signs of a recent decrease, a survey of its current status in Dakar was undertaken and compared with historical data over the past 50 years. A strong decrease of >85% was noted from 3 000 individuals in 1969 to 400 in 2016. This decline is on the high end of the decline noticed over much of its range but in striking contrast with the apparently stable populations along the West African coast more to the south (The Gambia to Guinea). Likely causes are (1) exponential urbanisation resulting in loss of feeding sites and reduced food availability, (2) increased poisoning of feral dogs with strychnine sulphate due to an upsurge of rabies and (3) increased disappearance of suitable trees for nesting and roosting.Keywords: cutting of trees, Hooded Vulture, Necrosyrtes monachus, poisoning, population estimate, slaughterhouse sanitation, urban developmen

25 years of light-induced petrel groundings in Reunion Island: Retrospective analysis and predicted trends

Artificial lights are known to induce mass mortality of petrels. This study analyzes this phenomenon in Reunion Island, where four species are impacted: the endemic Barau’s petrel (Pterodroma baraui) and Mascarene petrel (Pseudobulweria aterrima), the tropical shearwater (Puffinus bailloni) and the wedge-tailed shearwater (Ardenna pacifica). 40,036 birds were found grounded between January 1996 and December 2021, most of which were fledglings. Spatial distribution of groundings matched with the distribution and intensity of light pollution. With a mark and recapture method, we estimated that at least 3.93 % of Barau's petrels fledglings are affected by light-induced groundings each year. This method was also used to estimate Barau’s Petrel population around 33,000 breeding pairs. Time series analyses showed strong positive trends of the number of groundings for all species, which were positively correlated with the intensity of light pollution. All species showed a seasonal increase in groundings coinciding with their fledging periods. Interannual variations of Barau's petrel and wedge-tailed shearwater groundings were explained by moon phase at their fledging peaks. We built statistical models to explain year-to-year changes in the number of groundings for each species, and used them to predict the number of groundings in the next decades. We predicted that up to 87,000 petrels may be found grounded from 2022 to 2050 if nothing is done to reduce light pollution. These results and predictions underline the urgent need to strengthen the rescue campaign and to implement strong light reduction measures

Past volcanic activity predisposes an endemic threatened seabird to negative anthropogenic impacts

International audienceAbstract Humans are regularly cited as the main driver of current biodiversity extinction, but the impact of historic volcanic activity is often overlooked. Pre-human evidence of wildlife abundance and diversity are essential for disentangling anthropogenic impacts from natural events. Réunion Island, with its intense and well-documented volcanic activity, endemic biodiversity, long history of isolation and recent human colonization, provides an opportunity to disentangle these processes. We track past demographic changes of a critically endangered seabird, the Mascarene petrel Pseudobulweria aterrima , using genome-wide SNPs. Coalescent modeling suggested that a large ancestral population underwent a substantial population decline in two distinct phases, ca. 125,000 and 37,000 years ago, coinciding with periods of major eruptions of Piton des Neiges. Subsequently, the ancestral population was fragmented into the two known colonies, ca. 1500 years ago, following eruptions of Piton de la Fournaise. In the last century, both colonies declined significantly due to anthropogenic activities, and although the species was initially considered extinct, it was rediscovered in the 1970s. Our findings suggest that the current conservation status of wildlife on volcanic islands should be firstly assessed as a legacy of historic volcanic activity, and thereafter by the increasing anthropogenic impacts, which may ultimately drive species towards extinction

High genetic diversity despite drastic bottleneck in a critically endangered, long‐lived seabird, the Mascarene Petrel <i>Pseudobulweria aterrima</i>

International audienceThe Mascarene Petrel Pseudobulweria aterrima is a critically endangered seabird endemic to Reunion Island, with an extremely small population suffering several threats. Fifteen polymorphic microsatellite loci were isolated from this species to analyse genetic diversity, estimate contemporary effective population size, search for evidence of a population bottleneck and see whether results support the hypothesis that life history traits could preserve allelic diversity in small populations. Results from 22 individuals found grounded as a consequence of light pollution highlight a surprisingly high genetic diversity, an absence of inbreeding, a contemporary effective population size estimated at approximately 1211 individuals and a probable bottleneck around 10 000 generations ago. Additional studies on genetic diversity and structure from a larger number of samples are thus required to evaluate the evolutionary potential of this critically endangered species

Isolation and characterization of 50 microsatellite loci for two shearwater species, Ardenna pacifica and Puffinus bailloni

Background: Shearwaters (order Procellariiformes) are an excellent study system to investigate the genetic consequences of the co-called “seabird paradox”, as they are able to disperse long distances but many species exhibit natal and breeding philopatry. However, few microsatellite markers are currently available for these taxa, hampering genetic inferences. Methods and results: In this study, 25 novel microsatellite loci were isolated and characterized for each of two distantly related shearwater species: the wedge-tailed shearwater (Ardenna pacifica) and the tropical shearwater (Puffinus bailloni). Polymorphism tests were performed for a total of 91 A. pacifica individuals sampled at Reunion and Round Island, and 48 P. bailloni individuals from Reunion and Europa Island, in the western Indian Ocean. The analyses revealed 23 polymorphic loci for A. pacifica, with the number of alleles per locus (Na) ranging from 2 to 8 (mean = 3.957 ± 0.364). Nineteen polymorphic loci were found for P. bailloni, with Na varying from two to five (mean = 3.053 ± 0.247). The observed heterozygosity (Ho) was relatively low for the two species, with Ho ranging from 0.022 to 0.725 (mean = 0.326 ± 0.044) for A. pacifica and from 0.021 to 0.688 (mean = 0.271 ± 0.051) for P. bailloni, but comparable to the estimates available for other Puffinus species. Conclusions: The new microsatellite loci provide a valuable tool for further population genetic studies, and will allow for design of effective conservation and management plans for A. pacifica, P. bailloni and other closely-related species

The decline of an urban Hooded Vulture <i>Necrosyrtes monachus</i> population in Dakar, Senegal, over 50 years^§

<p>As in many West African cities, in Dakar Hooded Vultures <i>Necrosyrtes monachus</i> have always been characteristic urban scavengers. The recent decline of Hooded Vultures in other parts of Africa, mainly eastern Africa, has been the reason in 2015 for up-listing of its status by the IUCN in the Red List of Threatened Species to Critically Endangered. As the Hooded Vulture is still common in the Lower Casamance, Senegal, in the Western Region of The Gambia and in Guinea-Bissau, without clear signs of a recent decrease, a survey of its current status in Dakar was undertaken and compared with historical data over the past 50 years. A strong decrease of >85% was noted from 3 000 individuals in 1969 to 400 in 2016. This decline is on the high end of the decline noticed over much of its range but in striking contrast with the apparently stable populations along the West African coast more to the south (The Gambia to Guinea). Likely causes are (1) exponential urbanisation resulting in loss of feeding sites and reduced food availability, (2) increased poisoning of feral dogs with strychnine sulphate due to an upsurge of rabies and (3) increased disappearance of suitable trees for nesting and roosting.</p