Predation of artificial ground nests in Australian tropical savannas: inverse edge effects

Abstract

Depredation of artificial ground nests was examined in tropical savanna in northern Australia to assess potential predation pressures on nests of the partridge pigeon (Geophaps smithii), a declining tropical granivore. Predation rates were examined at two sites, Kakadu National Park (which supported a relatively high density of partridge pigeons) and Berry Springs (which had greater habitat fragmentation and comparatively low partridge pigeon density). The effects of distance from road, understorey structure, topography and nest-microsite concealment on nest predation rates were examined. Artificial-nest predation rates were greater at 150 m from roads than <1 m from the roadside. Predation rates did not vary with understorey structure, topography, or level of nest concealment. There was marked variation between sites, with predation levels at Kakadu more than double those recorded for Berry Springs. Discerning predator identity, or even the size of a predator, from marks left in clay eggs proved difficult and was possible for ~35% of predation events. Of these, 42% of predation events involved predators of a size we considered too small to take a natural partridge pigeon nest. We suggest that extrapolation from artificial to natural ground-nest predation rates be undertaken with caution for landscapes such as Australia’s tropical savanna, which supports a high diversity and abundance of small potential predators of artificial nests. There was no evidence of predation by birds, and the methodology proved inadequate for identifying predation by feral cats (Felis catus).

Influence of roads on bird nest predation: An experimental study in the Iberian Peninsula

“…However, other authors (Lahti, 2001;Fraser and Whitehead, 2005) have concluded that there is no increase in nest predation rates near habitat edges. Our data do not support this latter hypothesis because we observed a strong variation in the results, both between roads and between years.…”

Experimental Evidence that Sexual Displays are Costly for Nest Survival

“…Several parameters are known to affect nest success, some of which may facilitate nest detection by predators. Among them, nest-site characteristics are thought to determine nest fate, and these may include nest concealment (Schieck & Hannon 1993;but see Gö tmark et al 1995), distance to habitat edge (Winter et al 2000) or even differences at the macrohabitat scale (Tarvin & Garvin 2002;Fraser & Whitehead 2005). Another factor that seems to be important but that has been poorly studied is nest substrate, which can provide protection against both predators as well as climatic factors (Best & Stauffer 1980;Collias & Collias 1984;Young et al 1990;Murphy et al 1997).…”

“…1995), distance to habitat edge (Winter et al. 2000) or even differences at the macrohabitat scale (Tarvin & Garvin 2002; Fraser & Whitehead 2005). Another factor that seems to be important but that has been poorly studied is nest substrate, which can provide protection against both predators as well as climatic factors (Best & Stauffer 1980; Collias & Collias 1984; Young et al.…”

The role of nest‐site selection and cereal production in differential nest predation in Common Quail Coturnix coturnix and hybrid quail C. coturnix × C. japonica

“…, Bátari & Báldi ) but a great deal of evidence rejects its ubiquity (Storch , Bro et al . , Lahti , Fraser & Whitehead ). Edge vegetation structure (Angelstam , Lahti , Schneider et al .…”