Health surveillance of a potential bridge host: Pathogen exposure risks posed to avian populations augmented with captive-bred pheasants.

Augmentation of wild populations with captive-bred individuals presents an inherent risk of co-introducing novel pathogens to naïve species, but it can be an important tool for supplementing small or declining populations. Game species used for human enterprise and recreation such as the ring-necked pheasant (Phasianus colchicus) are commonly raised in captivity and released onto public and private wildlands as a method of augmenting naturalized pheasant populations. This study presents findings on pathogen exposure from three sources of serological data collected in California during 2014-2017 including (a) 71 pen-reared pheasants sampled across seven game bird breeding farms, (b) six previously released pen-reared pheasants captured at two study sites where wild pheasants occurred and (c) 79 wild pheasants captured across six study sites.

Serologic Surveillance of Wild and Pen-reared Ring-necked Pheasants ( Phasianus colchicus) as a Method of Understanding Disease Reservoirs.

We investigated exposure to infectious diseases in wild ( n=33) and pen-reared ( n=12) Ring-necked Pheasants ( Phasianus colchicus) in the Central Valley of California, US during 2014 and 2015. Serologic tests were positive for antibodies against hemorrhagic enteritis, infectious bursal disease, and Newcastle disease viruses in both wild and pen-reared pheasants.

Long-term and widespread changes in agricultural practices influence ring-necked pheasant abundance in California.

Declines in bird populations in agricultural regions of North America and Europe have been attributed to agricultural industrialization, increases in use of agrochemical application, and increased predation related to habitat modification. Based on count data compiled from Breeding Bird Survey (BBS) from 1974 to 2012, Christmas Bird Count (CBC) collected from 1914 to 2013, and hunter data from Annual Game Take Survey (AGTS) for years 1948-2010, ring-necked pheasants () in California have experienced substantial declines in agricultural environments. Using a modeling approach that integrates all three forms of survey data into a joint response abundance index, we found pheasant abundance was related to the amount of harvested and unharvested crop land, types of crops produced, amount of total pesticide applied, minimum temperature, precipitation, and numbers of avian competitors and predators.