Effect of Black Flies on Wild Turkey Nest Success

Nesting birds often cope with harassment from biting insects; however, it is difficult to determine how biting insects affect reproductive success and subsequent population growth of wild birds. Black flies (Diptera: Simuliidae) are hematophagous (blood-feeding) insects and many depend on the blood of birds for reproduction. In Illinois, black flies typically emerge between May - June which overlaps the nesting period of many avian species. Vast quantities of black flies have the potential to increase the rate of nest abandonment, compromise the reproductive success of breeding pairs, and cause nestling mortality. For a recreationally and economically important species, such as the eastern wild turkey (Meleagris gallopavo silvestris), identifying factors that could influence reproductive success and population dynamics is important. Our main objective was to determine if black fly abundance influenced reproductive parameters (e.g., nesting rate, nest success, and nest survival) of wild turkeys in two regions of Illinois with differing abundances of flies (western region – high abundance; south-central region – low abundance). We captured female turkeys in January – March 2017 – 2019 and fitted each hen with a µGPS unit. We viewed GPS data to determine the initiation and termination of nests, and surveyed nest sites to determine nest fate. Both regions had similar nest initiation dates for initial and renesting attempts. Overall apparent reproductive success was comparable between regions (10% in the western region and 14% in the south-central region). We found that nest predators were responsible for >40% of nest failures. Even with the disparity in black fly numbers between regions, there was no evidence that black flies affected nest fate (ß = 0.11±0.11 SE; P = 0.29).