Response of Hooded Crow Corvus corone cornix and Magpie Pica pica to exposure to artificial nests

Abstract

Capsule Hooded Crow activity increased markedly and instantly after exposure of artificial nests, whereas Magpies showed no response to the nests, but seemed negatively influenced by Hooded Crows.

Artificial Ground Nest Survival in two Abandoned Farmland Habitats on Šolta Island (Croatia)

“…A Hooded Crow was present in the experimental area all of the time. We observed that the activity of this bird increased markedly and instantly after the exposure of artificial nests, as also reported by Olsen and Schmidt (2004). The majority of the nests were discovered and robbed already on the first day which is in line with the conclusions by Gö ransson and Loman (1986) who claim that predation rates were usually highest at the beginning of the period of exposure.…”

“…Although predation is often the most important cause of nest failure in declining ground-nesting birds in agricultural landscapes, the causes of predation and the identity of predators are often unknown (Draycott et al, 2008). In the absence of predator mammals, their nests are mostly threatened by certain larger bird species particularly, corvid species that have long been considered important predators of the eggs of ground-nesting birds, including game birds (Tapper et al, 1996;Olsen and Schmidt, 2004). One of the potential nest predators on the island could be the Hooded Crow (Corvus cornix) (Figure 2), which nests in low numbers (Sušić et al, 1990).…”

Ground Nest Depredation by European Black-Billed MagpiesPica pica: An Experimental Study with Artificial Nests

“…In addition, magpies preferentially approached first to the quail nest versus the chicken nest. Obviously, the possibility of the immediate carrying of the egg away increases food attractiveness in magpies and in other corvid species (Montevecchi 1976, Olsen & Schmidt 2004, Schaefer 2004). This predation behaviour apparently enables the birds to avoid conflict with the incubating parents (Purger et al 2004a), food loss due to other competitors (e.g.…”

“…behavioural, Olsen & Schmidt 2004;landscape, Andrén & Angelstam 1988, Yahner & Mahan 1996, Davison & Bollinger 2000, even though some researchers have doubts about their applicability, mainly due to their insufficiency in simulating predation rate on natural nests (Jobin & Picman 2002, Pärt & Wretenberg 2002. Nevertheless, this approach is still accepted as a useful tool for relative comparison of nest predation (Grégoire et al 2003), predator identification (Gustaffson 2005, Purger et al 2008, and behaviour (Maier & DeGraaf 2000, Purger et al 2004a because analogous experiments on natural nests are time-consuming and, in particular, methodologically difficult (Burke et al 2004).…”

Survival chances of ground nests in three different habitats in Krka National Park (Croatia)

“…Yellow-legged Gulls Larus cachinnans, once a Magpie Pica pica, Ravens Corvus corax and Jackdaws Corvus monedula too (12,13). Olsen and Schmidt suggested that Hooded Crow activity increased markedly and instantly after the exposure of artificial nests, whereas Magpies showed no response to the nests, but seemed to be negatively influenced by Hooded Crows (19). Despite the fact that we used brown eggs, which have better survival chances than white ones (20), the light-coloured inside of already broken eggs, may have called the attention of larger birds.…”