Quantification and characterisation of commensal wild birds and their interactions with domestic ducks on a free-range farm in southwest France

Abstract

The role of commensal birds in the epidemiology of pathogens in poultry farms remains unclear. Our study aimed to identify potential key species for interactions with domestic ducks on one free-range duck farm in southwest France. Methods combined direct individual observations on duck outdoor foraging areas, network analysis, and general linear mixed models of abundances. Results showed a wide diversity of wild bird species visiting foraging areas, heavily dominated in frequency by White wagtails (Motacilla alba) and Sparrows (Passer domesticus and Passer montanus). These also were the only species seen entering duck premises or perching on drinkers in the presence of ducks. Moreover, White wagtails were the species most frequently observed on the ground and in close proximity to ducks. Network analysis suggested the role of White wagtails and Sparrows in linking ducks to other wild birds on the farm. The abundance of White wagtails was positively associated with open vegetation, with the presence of ducks and particularly in the afternoon, while the abundance of Sparrows was positively associated only with the fall-winter season. By precisely characterising interactions, the study was able to identify few wild bird species which should be prioritized in infectious investigations at the interface with poultry.

Seasonal changes in bird communities on poultry farms and house sparrow—wild bird contacts revealed by camera trapping

“…Also, European starlings, a species closely related to the spotless starling have been experimentally shown to be able to transmit avian influenza virus to poultry ( 40 ). Species detected in free-range layer farms such as the white wagtail are consistent with the species detected in a study of free-living birds in enclosures of duck farms in France ( 5 ), while other species observed on the duck farms, such as cattle egrets, were observed less frequently.…”

“…However, although bidirectional exchange of pathogens at the interface has been demonstrated and the potential of bridge hosts is generally accepted ( 36 ) little information exists yet on the frequency of contact and potential of contamination of resident farm birds by visiting migratory birds. For this reason we used the pictures obtained to also study the contact of wild birds that visit farm premises, but are unlikely to enter the buildings and enclosures, with the house sparrow ( 4 , 5 , 21 ).…”

“…Another study in the Netherlands quantified wild bird access to a free-range commercial laying hen farm by installing video cameras at a critical point for avian influenza ( 4 ). In southwestern France, a study used individual direct observations of wild birds on a free-range duck farm ( 5 ). Additionally, a recent study in northwestern Italy employed direct observations and camera traps on turkey and broiler duck farms, as well as laying hen farms ( 22 ).…”

Backyard Poultry Flocks in Morocco: Demographic Characteristics, Husbandry Practices, and Disease and Biosecurity Management

“…This mixed confinement system creates conditions that increase the opportunity for contact between poultry of different flocks, and as shown in the results, increase their interactions with wild birds, and consequently, the risk of contamination and spread of diseases. Previous studies have already suggested that contact at the wild-domestic bird interface is more likely in free-range farming systems [19,31].…”

Impact of palmiped farm density on the resilience of the poultry sector to highly pathogenic avian influenza H5N8 in France

“…Therefore, one important question that should now be addressed is related to the impact of palmiped flock size on virus transmission risk. Additionally, during their first production stage, ducks raised for foie-gras have access to large outdoor fields, where they can have direct and indirect contacts with commensal wild birds [ 24 ] as well as with neighbouring farms via the environment, potentially contributing to the diffusion of HPAI viruses. However, the impact of outdoor grazing on the virus transmission dynamics still has not been clarified, mainly due to the unavailability of relevant data at the time the model of the 2016–2017 epidemic was developed.…”