The origin of out‐of‐range pelicans in Europe: wild bird dispersal or zoo escapes?

Abstract

We tested whether spatial and annual patterns of occurrence of out‐of‐range Great White Pelecanus onocrotalus, Dalmatian Pelecanus crispus and Pink‐backed Pelicans Pelecanus rufescens recorded in Europe between 1980 and 2004 supported a natural vagrancy theory. Candidate variables tested were those likely to influence dispersal and escape probability (distance to the usual breeding/wintering range, national captive stock), and wild breeding population sizes and their movements (size of breeding colonies, climate conditions on wintering grounds or during dispersal). Spatial vagrancy patterns supported the hypothesis of wild birds dispersing from their normal range, with decreasing national totals with increasing distance to the usual range for the three species. Annual out‐of‐range numbers of Great White Pelican were predicted by breeding colony size and breeding success in Greece, with a further effect of Sahel rainfall during the previous year. Annual numbers of Dalmatian Pelican were related to the North Atlantic Oscillation index and to breeding success in Greece. Finally, annual numbers of Pink‐backed Pelican were predicted by summer Sahel rainfall, which is known to drive dispersal of the species northwards into the sub‐Sahelian steppes during wet summers there. Hence, annual vagrancy patterns in Europe were well predicted for all three species by population size indices, reproductive success and/or climatic components, which presumably influence survival and/or dispersal. We therefore consider that vagrancy patterns were driven by wild birds, whereas escapes – even if potentially numerous – do not create sufficient ‘noise’ to hide these patterns.

The risk of zoological parks as potential pathways for the introduction of non-indigenous species

“…Reports of animals escaping from zoos have been previously documented worldwide (Csurhes 2003;Jiguet et al 2008). The data presented here relates to the risk of potential escape of zoo animals due to lack of security at their enclosures, instead of examples about actual escapes.…”

“…These centers house great numbers of wildlife species in their facilities, and although some of them have native fauna in their collections, most animal species are not indigenous to the place where the zoological park is located, therefore becoming a potential source of NIS if animals escape (IUCN 2002a). In fact, animal escapes from zoological parks worldwide have been previously documented (Csurhes 2003;Jiguet et al 2008), and some of these escaped species have become invasive (Roll et al 2008;Clergeau and Yésou 2006;Jousson et al 2000). In Europe, 82 non-indigenous terrestrial vertebrate species have been introduced as a consequence of escapes from zoological parks, becoming such centers the second most important known pathway for the introduction of NIS in this region (DAISIE 2008).…”

First archaeogenetic results verify the mid‐Holocene occurrence of Dalmatian pelican Pelecanus crispus far out of present range

“…However, to explain range shifts not only an increasing annual temperature, but also a row of biotic and abiotic as well as anthropogenic factors have to be considered (Ławicki ; for pelicans cf. Jiguet et al ).…”

“…Over the long term the current climate change might provoke a new range expansion to the north. In the last decades, there were occasional observations of P. crispus in Hungary and Poland (Jiguet et al ), and the first certified record both for Germany and Denmark occurred in 2006 (Wegst ). In this perspective, the Dalmatian pelican is an excellent example that an understanding of the way bird species have responded to past climate changes has relevance for models about their reaction to the current climate development (Stewart et al ).…”

<b>Sightings of the Great White Pelican <I>Pelecanus onocrotalus</I> (Linn. 1758) (Aves: Pelicaniformes: Pelicanidae) in Pallikaranai Marshlands, Tamil Nadu, India</b>

“…It occurs in scattered colonies or as a migrant in many African countries (Kenya, Sudan and Morocco), Greece, Turkey, Iran; Black, Caspian and Aral Seas; Kazakhstan, Kuwait, India, and Vietnam (Crivelli et al 1991;Jiguet et al 2008). In India it occurs from Punjab to Assam (Ali & Ripley 1978), with an exception of a single record from southern India (Grimmett et al 1999).…”