Nest Monitoring and Predator Visitation at Nests of Banded Dotterels

Abstract

We used videocameras to monitor 39 nests of the Banded Dotterel (Charadrius bicinctus), a ground-nesting plover endemic to New Zealand that suffers from predation by introduced mammals. To test whether monitoring nests increased the chances of nests being visited by predators, 22 of the video-monitored nests were approached on foot daily to simulate conventional monitoring and 17 unapproached nests were monitored using videocameras only. The proportions of approached nests (46%) and unapproached nests (41%) that were visited by predators did not differ significantly, nor was there any evidence that predators used human scent trails to locate nests. This study provides some evidence that monitoring Banded Dotterel nests by regularly checking them does not influence their risk of predation.Control de Nidos y Visita de Depredadores a Nidos de Charadrius bicinctusResumen. Usamos cámaras de video para controlar 39 nidos de Charadrius bicinctus, un ave endémica de Nueva Zelandia que anida en el suelo y es depredada por mamíferos introducidos. Diariamente nos acercamos a pie a 22 de los nidos controlados con cámaras para simular el modo convencional de seguimiento, y controlamos 17 nidos usando sólo las cámaras y sin acercarnos a ellos con el fin de examinar si el control convencional de nidos incrementa la probabilidad de visita de depredadores. La proporción de nidos personalmente examinados (46%) y no examinados en persona (41%) que fueron visitados por depredadores no difirió significativamente, y no hubo evidencia que los depredadores usan rastros de olores humanos para localizar los nidos. Este estudio sugiere que controlar regularmente los nidos de Charadrius bicinctus no influencia su riesgo de depredación.

Effect of camera monitoring on survival rates of High-Arctic shorebird nests

“…Moreover, despite smaller sample sizes, the same conclusion was reached for real shorebird nests, where differences in nest survival between nests monitored with and without cameras were minimal compared to natural interannual variation. The results of our experiments conducted in the open Arctic tundra thus concur with those of most studies conducted in temperate regions and suggest that nest survival is not significantly affected by the presence of cameras (Brown et al 1998, Thompson et al 1999, Pietz and Granfors 2000, Keedwell and Sanders 2002, Coates et al 2008).…”

“…Our results, and those of several other studies, indicate that the negative effects of camera monitoring on nest survival, if any, appear to be minimal relative to the benefits (Cutler and Swann 1999, Thompson et al 1999, Pietz and Granfors 2000, Keedwell and Sanders 2002, Liebezeit and Zack 2008, Richardson et al 2009). We were able to detect changes in predator composition between years for artificial nests and confirm the identity of predators for real nests.…”

“…Keedwell and Sanders (2002) reported no differences between video‐monitored and human‐visited nests for a ground‐nesting shorebird (Banded Dotterels, Charadrius bicinctus ) targeted primarily by mammalian predators. However, these authors suggested that sample sizes (limited by the number of cameras) may have been too small to detect differences.…”

“…Recently, many investigators have monitored nests with cameras to identify predators and limit the number of nest visits (McQuillen and Brewer 2000, Keedwell and Sanders 2002, Sanders and Maloney 2002, Stake and Cimprich 2003, Richardson et al 2009). Monitoring nests with cameras can decrease the number of visits to nests, while simultaneously recording otherwise unobtainable information on feeding ecology, nesting behavior, and nest predation (Cutler and Swann 1999).…”

Does human scent bias the survival of bird nests?

“…Whether or not the behavioural responses or olfactory acuities of dogs are comparable to those of non-domesticated mammalian nest predators, studies of canine olfaction nonetheless point to sources of human scent potentially available to nest predators. For example, observations that predators travel to nests while evidently ignoring paths created by field researchers have prompted some investigators to discount the possibility that predators use human-scent cues to locate nests (Nams 1997, Keedwell & Sanders 2002. However, as Whelan et al (1994) hypothesized and as canine studies indicate (Kalmus 1955), cues other than trail-laden odours may be used to locate a human-scent source.…”