Update on Dalmatian pelican mass mortality caused by avian influenza at Prespa and Greece

Update on Dalmatian pelican mass mortality caused by avian influenza at Prespa and Greece

Through its valuable network of collaborators and friends, the SPP has managed to document the development of the severe avian influenza outbreak across wetlands of northern Greece. The tragic death toll has risen to a total of 1,861 Dalmatian pelicans (DP) and 5 great white pelicans in a total of 12 wetlands in northern Greece. The Prespa colony accounts for 76% of the DP deaths (1,413 individuals). Another 15% (283 inds.) comes from the other three DP colonies of the eastern sub-population in Greece (Kerkini Lake, Karla reservoir and Chimaditida Lake), and the rest has been recorded in a variety of wetlands in-between Prespa and Kerkini, wetlands that are used by pelicans for feeding and resting throughout the breeding period.

In total, 1,352 DP carcasses (73% of the estimated total) have been removed from 7 wetlands so far, while collection efforts are still in progress, as the phenomenon has slowed down, but not ceased yet. At Prespa, where a huge number of DP carcasses (1,143) has already been removed, attempts are now focused on the collection from less accessible parts of the colony. These exact parts of the colony are the ones mostly used by great white pelicans, and there is now major concern for them, as they have started arriving at Prespa -already more than 100- while a couple of thousands are expected very soon.

Warmer and sunnier days are anticipated in the following week (currently at Prespa, low temperatures of the day are still around 0 °C), and hopefully the exposure of the virus to sunlight will result in hastened inactivation. Combined with the fact that a huge viral load has already been removed from the wetland, we are hopeful that bad days are behind us. Indeed, after more than a month of devastation and loss of pelicans, we are seeing signs of hope. Very few new deaths were recorded during the last drone count, while around 600 living DPs have settled again on Lesser Prespa Lake’s nesting islands. Furthermore, we estimate that a few more hundreds will arrive in the following days, based on our network’s observations.

The two colonies of the western sub-population in Greece (Amvrakikos wetlands and Messolonghi lagoons) fortunately remain intact, yet recently there have been worrying news from the DP colony in Karavasta lagoon, Albania, which belongs to the same sub-population, where the first AI case was recorded.

Only a handful of other species has been affected by the AI outbreak in Greek wetlands according to what we know (i.e. mute swan, great white egret, yellow-legged gull, common shelduck) and all in very small numbers. This fact raises the issue of Dalmatian pelican high vulnerability to AI (H5N1), which ought to be treated as a priority research topic. Large aggregations of nesting birds, early start of the breeding cycle, daily movements to other wetlands, and other behavioral traits of the DP, may all have been crucial factors, whose combination, had a determinant role in this year’s disaster. Nevertheless, it would be of great interest and conservation concern to understand how other factors (genetics? low innate immunity to this AI strain?) may have contributed.

The SPP has been working for 32 years for the conservation of the two species of pelicans, these emblematic waterbirds, and will strive to gain a deeper insight into this complex situation. For the time being, we continue to monitor the phenomenon closely and we will provide further updates.

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