Health status of free-ranging ring-necked pheasant chicks (Phasianus colchicus) in North-Western Germany.

Being a typical ground-breeding bird of the agricultural landscape in Germany, the pheasant has experienced a strong and persistent population decline with a hitherto unexplained cause. Contributing factors to the ongoing negative trend, such as the effects of pesticides, diseases, predation, increase in traffic and reduced fallow periods, are currently being controversially discussed. In the present study, 62 free-ranging pheasant chicks were caught within a two-year period in three federal states of Germany; Lower Saxony, North Rhine-Westphalia and Schleswig-Holstein. The pheasant chicks were divided into three age groups to detect differences in their development and physical constitution. In addition, pathomorphological, parasitological, virological, bacteriological and toxicological investigations were performed. The younger chicks were emaciated, while the older chicks were of moderate to good nutritional status. However, the latter age group was limited to a maximum of three chicks per hen, while the youngest age class comprised up to ten chicks. The majority of chicks suffered from dermatitis of the periocular and caudal region of the head (57-94%) of unknown origin. In addition, intestinal enteritis (100%), pneumonia (26%), hepatitis (24%), perineuritis (6%), tracheitis (24%), muscle degeneration (1%) and myositis (1%) were found. In 78% of the cases, various Mycoplasma spp. were isolated. Mycoplasma gallisepticum (MG) was not detected using an MG-specific PCR. Parasitic infections included Philopteridae (55%), Coccidia (48%), Heterakis/Ascaridia spp. (8%) and Syngamus trachea (13%). A total of 8% of the chicks were Avian metapneumovirus (AMPV) positive using RT-PCR, 16% positive for infectious bronchitis virus (IBV) using RT-PCR, and 2% positive for haemorrhagic enteritis virus (HEV) using PCR. All samples tested for avian encephalomyelitis virus (AEV), infectious bursal disease virus (IBDV) or infectious laryngotracheitis virus (ILTV) were negative. The pool samples of the ten chicks were negative for all acid, alkaline-free and derivative substances, while two out of three samples tested were positive for the herbicide glyphosate. Pheasant chick deaths may often have been triggered by poor nutritional status, probably in association with inflammatory changes in various tissues and organs as well as bacterial and parasitic pathogens. Theses impacts may have played a major role in the decline in pheasant populations

Feralisation - The Understudied Counterpoint to Domestication

Feralisation is a complex process that occurs when a domestic population is returned to the wild. It impacts species invasion biology, speciation, conservation and hybridisation and can be thought of as the reverse of domestication. Domestication has been an area of intense interest and study ever since Darwin, and useful as a model for evolution and the effects of strong directional selection. Despite domestication being used to study genes affecting a large number of traits that change with selection, little is known about the genomic changes associated with feralisation. Much of the current work on the genetics of feralisation has focused on the detection of early hybrids (F1 or F2) between wild and domestic populations. Feralisation can lead to large changes in morphology, behaviour and many other traits, with the process of feralisation involving the sudden return of both natural and sexual selection. Such evolutionary forces influence predatory, foraging and male choice decisions and exert strong effects on once domesticated, now feral, individuals. As such, feralisation provides a unique opportunity to observe the genomic and phenotypic responses to selection from a known (domesticated) standpoint and identify the genes underlying these selective targets. In this review, we summarise what is known in particular regarding the genomics of feralisation, and also the changes that feralisation has induced on brain size and behaviour.https://nsuworks.nova.edu/cnso_bio_facbooks/1026/thumbnail.jp