• Genetic Variation among Island and Continental Populations of Burrowing Owl (Athene cunicularia) Subspecies in North America

      Macías-Duarte, Alberto; Conway, Courtney J.; Holroyd, Geoffrey L.; Valdez-Gómez, Héctor E.; Culver, Melanie; Univ Arizona, Sch Nat Resources & Environm, Arizona Cooperat Fish & Wildlife Res Unit (RAPTOR RESEARCH FOUNDATION INC, 2019-05-09)
      Burrowing Owls (Athene cunicularia) have a large geographic range spanning both North and South America and resident populations occur on many islands in the eastern Pacific Ocean and the Caribbean Sea. Many owl populations are isolated and disjunct from other populations, but studies on genetic variation within and among populations are limited. We characterized DNA microsatellite variation in populations varying in size and geographic isolation in the Florida (A. c. floridana), the Western (A. c. hypugaea), and the Clarion (A. c. rostrata) subspecies of the Burrowing Owl. We also characterized genetic variation in a geographically isolated population of the western subspecies in central Mexico (near Texcoco Lake). Clarion Burrowing Owls had no intrapopulation variation (i.e., fixation) at 5 out of 11 microsatellite loci, a likely outcome of genetic drift in an isolated and small population. The Florida subspecies had only polymorphic loci but had reduced levels of genetic variation compared with the more-widespread western subspecies that occurs throughout western North America. Despite the extensive geographic distribution of the Western Burrowing Owl, we found genetic differentiation between the panmictic population north of the Trans-Mexican Volcanic Belt and the resident Texcoco Lake population in central Mexico.
    • High Prevalence of Louse Flies on Osprey Nestlings in a Baja California Colony

      Rodríguez-Estrella, Ricardo; Rivera-Rodríguez, Laura B.; Univ Arizona, Sch Nat Resources & Environm (RAPTOR RESEARCH FOUNDATION INC, 2019-05-09)
      We studied the prevalence of a louse fly (Olfersia fumipennis) in a dense breeding colony of Ospreys (Pandion haliaetus) at San Ignacio Lagoon, Baja California Sur, Mexico. We determined fly prevalence and infestation intensity of 45 nestlings (age 32–59 d). We found louse flies in 65% of the nests sampled (n = 34). Louse fly prevalence in nestlings (n = 45) was 56%, the highest rate reported for any raptor species. Male and female nestlings showed similar levels of fly prevalence and infestation, possibly because the numbers of each sex in this population were similar. We found that louse flies had a spatially dispersed distribution, such that the proximity of any nest to any other within the colony did not influence the prevalence of louse flies nor the louse fly load. The productivity of nests with parasitized young (1.3 ± 0.5 young/nest) was similar to that of nests with young that were not parasitized (1.4 ± 0.6 young/nest; P > 0.05). In terms of spatial location, the overall productivity (number of young per successful nest) of the colony was affected by louse fly prevalence. The condition of coloniality (i.e., high density of nests) likely caused high overall louse fly prevalence. A high prevalence of parasitism might be part of the cost of nesting in colonial conditions. Additional studies on the prevalence of louse flies and the health and body condition of nestlings are needed to evaluate the health of Osprey populations.