Biology subjects

Meissner, W.

Publications and source records attributed to Meissner, W..

3 recordsLinked to original sources

bioRxiv2024

The intensity of supplementary feeding in an urban environment impacts overwintering Mallards Anas platyrchynhos as wintering conditions get harsher

Although urbanization poses various threats to avifauna, some bird species, including Mallards, are attracted to towns and cities as their winter habitats due to favourable temperatures and abundant anthropogenic food. In this study, we investigated how population dynamics changed in relation to winter harshness and intensity of supplementary feeding. The results indicated that the number of Mallards increased with the feeding intensity but the pattern differed in response to worsening of wintering conditions on water bodies with distinct supplementary feeding intensity. The ponds with low feeding intensity were occupied by fewer but more stable populations, suggesting the presence of natural food resources there, available for small number of individuals, regardless of winter conditions. On the ponds with medium feeding intensity, we observed a bell-shaped relationship between the number of ducks and ice cover. Unpredictable anthropogenic food on those ponds might not provide sufficient food resources, forcing birds to relocate when wintering conditions worsen. In such conditions, the ponds with a high feeding intensity attracted more ducks. We demonstrated that the wintering population of Mallards in urban areas is not solely influenced by ambient temperature but is also significantly affected by the intensity of supplementary feeding.

ecology↗

bioRxiv2024

The interplay between moult of flight feathers and fuelling conducted on the breeding grounds of the Great Snipe Gallinago media from the eastern European, lowland population

The Great Snipe as a long-distant migrant wintering in Africa, faces the challenge of accumulating sufficient energy reserves before the departure from European breeding grounds. Despite possible trade-offs in resource allocation, this species additionally initiates moult of flight feathers before southward migration. Here we discuss the strategy of flight feather moult and fuelling, exploring their scheduling, constrained by the timing of breeding and departure for female and male Great Snipes from the European lowland population. We found significant intrasexual differences in both moult initiation date and moult duration. Males start flight feather replacement more than two weeks earlier and moult faster compared to females. However, neither sex completed this process on breeding grounds before the migration, as late in the season all males and half of the females had suspended their primary moult, with the remaining females not moulting at all. Moult of secondaries occurred exceptionally in the studied population. We observed a non-linear energetic stores gain in the studied period, where both sexes maintained a stable and low body condition until the end of July, coinciding with the primary moulting period. Subsequently, there was an increase in body condition, of approximately 1% of the lean body mass per day, indicating a shift towards fuelling for migratory flight. The overlap between stages of maintaining a stable and low body condition and moulting suggests a resource allocation towards feather growth before initiating fuelling. Our study describes moult strategy in Great Snipe conducted on their breeding grounds, highlighting the intrasexual differences, likely resulting from different parental duties of males and females of this lekking species.

ecology↗

bioRxiv2023

Highly pathogenic avian influenza causes mass mortality in Sandwich tern (Thalasseus sandvicensis) breeding colonies across northwestern Europe

AO_SCPLOWBSTRACTC_SCPLOWIn 2022, highly pathogenic avian influenza (HPAI) A(H5N1) virus clade 2.3.4.4b became enzootic and caused mass mortality in Sandwich terns and other seabird species across northwestern Europe. We present data on characteristics of the spread of the virus between breeding colonies and the number of dead adult Sandwich terns recorded at breeding sites throughout northwestern Europe. Within two months after the first mortalities were reported, in total 20,531 adult Sandwich terns were found dead, which is >17% of the total northwestern European breeding population. Losses are likely higher, as we expect that many victims were not found (mortality rate might be up to 74% of the breeding population). Inside the colonies almost all chicks died. After the peak of the outbreak, in a colony established by late breeders, 25.7% of adults showed immunity against HPAI subtype H5. Removal of carcasses helped in reducing the spread of the disease and consequently total mortality. More research on the sources and modes of transmission, incubation times, effective containment and immunity is urgently needed to combat this major threat for colonial seabirds.

ecology↗