Nesting of the Eurasian spoonbill (Platalea leucorodia) on the Utlyukskiy Liman (Zaporozhye region)

In the 70s of the XXth century, the nesting of the Eurasian spoonbill in Ukraine was known only in the lower reaches of the Danube and Dniester, and at the beginning of the XXIst century, it began to spread to the East and the Eurasian spoonbill began to nest on the Tiligulskiy Liman, Karkinit Bay, Western and Eastern Sivash. Since 2016, the Eurasian spoonbill has been observed during the breeding season in the upper reaches of the Utlyukskiy Liman and the estuarine areas of the Bolshoy and Maly Utlyuk Rivers. According to observations that were held in 2016-2020, first there were: a pair with unproven nesting (2016), then flocks of up to 17-26 individuals (2018-2019). In 2020, both individual pairs with nesting behavior and flocks were found near a mixed colony of the Gray heron and the Great egret. Finally, on 24.05.2020, the Eurasian spoonbill nests were found in this colony. Among the 8 nests, one contained 2 eggs and two chicks, four nests contained 4 eggs and the other three - 3 ones. Nests are located on the periphery of the heron colony on clump of reeds. The height of the nesting platforms is about 4-70 cm above the water level, the minimum distance between the nests is about 4 m. It is possible that the flock of 26 adult and young individuals, that was observed on 2.08.2018, consisted of local nesting birds. Thus, another nesting location was found in the South of Ukraine.

Migratory behaviour and survival of Great Egrets after range expansion in Central Europe

Great Egret Ardea alba is one of few Western Palearctic species that underwent a rapid range expansion in the recent decades. Originally breeding in central and eastern Europe, the species has spread in northern (up to the Baltic coast) and western (up to the western France) directions and established viable breeding populations throughout almost entire continent. We monitored one of the first Great Egrets colonies established in Poland to infer migratory patterns and survival rates directly after range expansion. For this purpose, we collected resightings from over 200 Great Egret chicks marked between 2002–2017 in central Poland. Direction of migration was non-random, as birds moved almost exclusively into the western direction. Wintering grounds were located mainly in the western Europe (Germany to France) within 800–950 km from the breeding colony. First-year birds migrated farther than adults. We found some, although relatively weak, support for age-dependent survival of Great Egrets and under the best-fitted capture-recapture model, the estimated annual survival rate of adults was nearly twice higher than for first-year birds (φad = 0.85 ± 0.05 vs. φfy = 0.48 ± 0.15). Annual survival rate under the constant model (no age-related variation) was estimated at φ = 0.81 ± 0.05. Our results suggest that Great Egrets rapidly adapted to novel ecological and environmental conditions during range expansion. We suggest that high survival rate of birds from central Poland and their western direction of migration may facilitate further colonization processes in western Europe.

Waterbirds catch and release a poisonous fish at a mudflat in southeastern Australia

Several waterbird species prey on fishes, and usually use only one sensory mode to detect this prey: herons hunt visually guided, whereas ibises mostly search tactilely guided. I report herein events in which a heron and an ibis caught and released a poisonous fish at a mudflat in southeastern Australia. A Great Egret (Ardea alba) that targeted small gerreid fishes caught and immediately released the very toxic pufferfish Tetractenos hamiltoni, with bill washing and discomfort movements afterwards. Two Australian White Ibises (Threskiornis molucca) that probed for bottom-dwelling fishes and crabs caught and handled these pufferfishes for about 60 s, before releasing them. Next, the birds dipped the bill in the water and resumed hunting. Pufferfishes are rarely preyed on by birds, but an Australian bird that feeds on this fish type is the Silver Gull (Chroicocephalus novaehollandiae), which eats the pufferfish Torquigener pleurogramma when it is nontoxic or less harmful.