Avian influenza outbreak and mass mortality in Dalmatian pelicans at Prespa National Park

Avian influenza outbreak and mass mortality in Dalmatian pelicans at Prespa National Park

An avian influenza outbreak is currently in progress at the Prespa National Park, in the Lesser Prespa Lake Dalmatian pelican (DP) colony, severely affecting the DP population.

Mass mortality events started about a week after the first DPs had arrived in Prespa from their wintering grounds in NE Greece and W Turkey. The first 11 deaths of adult DPs in full breeding plumage were recorded on 17/02. The number increased to 60 on 23/02 and a careful drone photo screening of the colony on 25/02 documented a total of 209 dead DPs. Several alive DPs displayed neurological symptoms (i.e., not being able to hold their heads up). A new drone photo session on 3/3 documented a total of 574 dead DPs, and almost a week later, on 9/3, the death toll reached 1,003 DPs! All pelicans were adult birds in breeding plumage and the carcasses were located on the nesting islands or close by in the water. A few other waterbird species have also been recorded dead, though in very small numbers up to now.

The first laboratory results from the National Reference Laboratory for Avian Influenza were announced on 02/03, indicating the highly pathogenic H5N1 strain of avian influenza.

In the same time, mass mortality of DPs is recorded in several adjacent wetlands used by pelicans: more than 70 dead DPs have been recorded so far at Lakes Chimaditida (a smaller DP breeding colony) and Zazari, and 60 more at Lake Kastoria, another nearby feeding site. Starting on 8/3 mass deaths are also recorded at Lake Kerkini (33 so far), a major wintering/staging and feeding wetland for pelicans, also hosting a breeding colony. Pelicans nesting at Prespa travel daily to wetlands between Prespa and Kerkini to feed –the two wetlands lying 180 km apart- using throughout the breeding season a variety of wetlands in between.

Currently, more and more DPs arrive at Prespa from Kerkini Lake and other wintering wetlands, though the bad weather of the last two weeks appears to have delayed the arrival of the bulk of the DP population. In addition, the first four great white pelicans (GWP) have already arrived in Prespa, with the majority expected later in March and April. GWPs arrive in Prespa from their wintering grounds in Sub-Saharan Africa, passing through Israel and Turkey. Recently, large-scale mortality caused by avian influenza H5N1 was recorded in Israel (in late 2021 and early 2022), primarily in cranes, but also in GWPs and other waterbird and raptor species.

The rapid progress of the phenomenon is particularly worrying for the breeding population of the DP in Greece and the Black Sea-Mediterranean flyway in general, as the establishment of new DP colonies in Greece and the increased numbers of breeding pairs at colonies in Turkey during the last two decades are largely attributed to the phenomenal increase in the Prespa colony since the 1980s.

The collection and management of the carcasses to prevent the spread of infection to other waterbirds, raptors, scavengers etc. is being organized and should start any day now, under the auspices of the Greek Ministry of Environment, coordinated by the regional authorities in collaboration with various bodies including the army and local veterinary services, the Municipality of Prespa, the Prespa National Park Management Authority and the SPP. This is a very challenging task, at an operational level at least (a huge number of large, heavy birds in the middle of a lake), but it is a necessary measure in order to minimise dispersal to other wetlands, protect humans and biodiversity at Prespa, as well as to protect the “next wave” of pelicans and other migratory waterbirds and raptors arriving soon.

The SPP has been working for 32 years for the conservation of the two species of pelicans, these emblematic waterbirds. During the current severe avian influenza outbreak, the SPP is in close contact with collaborating bodies in other Greek wetlands, and at transboundary level, as well as with international collaborators through a number of networks, such as the PELECANUS GROUP, an exchange forum of pelican experts and conservationists from 22 countries. Furthermore, the SPP is in close contact with an advisory panel of researchers in avian diseases, who generously share their time and expertise.

At local level, the SPP, the Prespa National Park Management Authority and the Municipality of Prespa, co-ordinated their actions from the beginning of the outbreak, based on the Plan for Co-ordinated Action prepared by the SPP in the framework of the LIFE Prespa Waterbirds project, which aimed to assist the remotely located veterinary authorities in the case of a zoonotic disease affecting the populations of pelicans or other Prespa waterbirds.

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