Parasitic Chatter: addressing concerns of recent parasite findings in Northern Bobwhite
A recent article in the the Sporting Classics Daily cited the eyeworm (Oxyspirura petrowi) and a parasitic cecal worm (Aulonecephalus pennula) as the cause for population declines in Texas. Naturally these reports of parasites in bobwhites has created a flurry of concern and questions relevant to bobwhite populations here in the Red Hills and Albany plantation area. The eyeworm reported in Texas and Oklahoma has not been detected so far in our area or on the East Coast to our knowledge—we have and will continue to send samples annually to be tested for disease and parasites. Whereas we value and support all research aimed at advancing the needle forward in understanding the ecology, conservation and management of bobwhite, we caution the interpretation of these findings as unequivocal explanations for quail declines in the Southeast or other regions.
The most recent findings of presence and prevalence of parasites in bobwhite is not by any stretch novel. Parasites are not only relatively common in quail and other game birds but have been known to exist since the early 1900s (Kobayashi 1927, Cram 1937), and more ubiquitously reported in quail in the 1960s and 70s (Kellogg and Calpin 1971). Recent claims not only contradict past findings that parasitic worms are an infrequent cause of mortality (Davidson et al. 1980, 1982, and 1991, and Brennan 1999), but do so without empirical data linking the presence of said parasites to survival, reproduction and recruitment in bobwhite populations. One big difference in western bobwhite populations compared to the Red Hills is the “boom or bust” cycles common in Texas, which is linked tightly to rainfall. Environmental conditions during periods of extended drought may render bobwhite more vulnerable to disease and parasites due potential altered physiological tolerances related to heat and water stress. Regardless of these environmental stressors, the lack of data on the demographic effects limits inference on how these parasites truly impact bobwhite populations in Texas and other parts of the range.
Despite range-wide bobwhite declines, properties in the Red Hills continue to experience some of the highest bobwhite densities ever recorded historically, which is a direct testament that habitat management still works when applied correctly. We recognize that research on this topic is ongoing, but we have not yet seen evidence of population-level impacts on bobwhites. Therefore, we urge you to stay the course in continuing to implement sound habitat management as well as incorporate supplemental feeding and predation management to mitigate natural cyclic declines common in bobwhite populations.