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The spreading of invasive species in new continents can vary from slow and limited diffusion to fast colonisations over vast new areas. We studied the sacred ibis Threskiornis aethiopicus along a 31-year period, from 1989 to 2019, with particular attention to the first area of release in NW Italy. We collected data on species distribution through observations by citizen science projects, population density by transects with distance method, breeding censuses at colonies, and post breeding censuses at roosts. The birds counted at winter roosts in NW Italy increased from a few tens up to 10,880 individuals in 2019. Sacred ibises started breeding in 1989, with a single nest in north-western Italy. The number of breeders remained very low until 2006, when both overwintering and breeding sacred ibises started to increase exponentially and expand their range throughout northern Italy with isolated breeding cases in central Italy. In 2019, the number of nests had increased to 1249 nests in 31 colonies. In NW Italy, the density of foraging birds averaged 3.9 ind./km 2 in winter and 1.5 ind./km 2 in the breeding period, with a mean size of the foraging groups of 8.9 and 2.1 birds respectively. Direct field observations and species distribution models (SDM) showed that foraging habitats were mainly rice fields and wetlands. A SDM applied to the whole Italian peninsula plus Sardinia and Sicily showed that the variables best related to the SDM were land class (rice fields and wetlands), altitude, and the temperature seasonality. The areas favourable for species expansion encompass all the plains of Northern Italy, and several areas of Tuscany, Latium, Sardinia, and Apulia.

In European wetlands, at least 40 bird species are exposed to the risk of lead poisoning caused by ingestion of spent lead gunshot. Adopting a methodology developed in North America, we estimated that about 700,000 individuals of 16 waterbird species die annually in the European Union (EU) (6.1% of the wintering population) and one million in whole Europe (7.0%) due to acute effects of lead poisoning. Furthermore, threefold more birds suffer sub-lethal effects. We assessed the economic loss due to this lead-induced mortality of these 16 species by calculating the costs of replacing lethally poisoned wild birds by releasing captive-bred ones. We assessed the cost of buying captive-bred waterbirds for release from market surveys and calculated how many captive-bred birds would have to be released to compensate for the loss, taking into account the high mortality rate of captive birds (72.7%) in the months following release into the wild. Following this approach, the annual cost of waterbird mortality induced by lead shot ingestion is estimated at 105 million euros per year in the EU countries and 142 million euros in the whole of Europe. An alternative method, based upon lost opportunities for hunting caused by deaths due to lead poisoning, gave similar results of 129 million euros per year in the EU countries and 185 million euros per year in the whole of Europe. For several reasons these figures should be regarded as conservative. Inclusion of deaths of species for which there were insufficient data and delayed deaths caused indirectly by lead poisoning and effects on reproduction would probably increase the estimated losses substantially. Nevertheless, our results suggest that the benefits of a restriction on the use of lead gunshot over wetlands could exceed the cost of adapting to non-lead ammunition., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Local recruitment and immigration play an important part in the dynamics and growth of animal populations. However, their estimation and incorporation into open population models is, in most cases, problematic. We studied factors affecting the growth of a recently established colony of Eurasian spoonbill (Platalea leucorodia) and assessed the contribution of local recruits, i.e. birds born in the colony, and immigrants, i.e. birds of unknown origin, to colony growth. We applied an integrated population model that accounts for uncertainty in breeding state assignment and merges population surveys, local fecundity and individual longitudinal data of breeding and non-breeding birds, to estimate demographic rates and the relative role of recruitment and immigration in driving the local dynamics. We also used this analytical framework to assess the degree of support for the 'performance-based' and 'conspecific attraction' hypotheses as possible mechanisms of colony growth. Among the demographic rates, only immigration was positively and significantly correlated with population growth rate. In addition, the number of immigrants settling in the colony was positively correlated with colony size in the previous and current year, but was not correlated with fecundity of the previous year. Our results suggest that the variation in immigration affected colony dynamics and that conspecific attraction likely triggered the relevant role of immigration in the growth of a recently formed waterbird colony, supporting the need of including immigration in population analysis., (© 2017 The Authors. Journal of Animal Ecology © 2017 British Ecological Society.)

Understanding the migration routes of the Central European Spoonbill population is important for their conservation. Here we analysed movements of 3186 individuals of Eurasian Spoonbills marked with colour rings in the Carpathian Basin (Hungary, Croatia and Serbia) between 2003 and 2015, and a satellite tagged individual, which was equipped in Italy in 2013, and later moved to the Carpathian Basin. Migration routes of these Spoonbills predominantly followed the Adriatic Flyway, however, some birds were also found to both east and west from this flyway. We identified 59 stopover sites, 55 of which were located along the Adriatic Flyway. Colourringed juveniles (1cy), on average, spent 4.0±0.9 (SE) days on the stopover sites along the Adriatic Flyway during autumn migration, while non-juveniles (> 1cy) spent 2.6±1.0 (SE) days during autumn and 2.1±0.4 (SE) days during spring migration there. These durations were not significantly different. Duration of stops of the satellite tracked individual was between 7 and 15 days during autumn and between 1 and 12 days during spring migration. Our results indicate the existence of two alternative routes of the Adriatic Flyway between the Carpathian Basin and the wintering areas in southern Italy and the central part of coastal North-Africa. The North-Adriatic Flyway includes stopover sites in north-eastern Italy at the river mouth of River Isonzo, Lagunes of Venice and wetlands around River Po. The South Adriatic Flyway leads through the Balkan Peninsula, with stopover sites at the karst lakes of Bosnia and Herzegovina, mouth of the river Neretva (Croatia), Ulcinj Salinas (Montenegro) and wetlands in Gulf of Manfredonia (Italy). This hypothesis was also supported by the migration of the satellite tagged individual, the paths of which was described here in detail. The average coordinates of spring and autumn stopover sites were located at different parts of the flyway: it was in south-western Italy during autumn migration, while it was close to the western coast of the Balkan Peninsula during spring migration. We found examples for Spoonbills using the same migration paths along the same route year by year on both spring and autumn migration, but also noticed shifts between routes. Some observations indicate that individuals may show site fidelity to stopover sites between years, although the sample size was low for statistical significance. [ABSTRACT FROM AUTHOR]