Prey preferences and recent changes in diet of a breeding population of the Northern Goshawk Accipiter gentilis in Southwestern Europe

Abstract

Prey preferences and recent changes in diet of a breeding population of the Northern Goshawk Accipiter gentilis in Southwestern Europe. Bird Study, 64(4), pp. 464-475.

Deforestation May Trigger Black-and-Chestnut Eagle (Spizaetus isidori) Predation on Domestic Fowl

“…Thus, at least during the time when prey items were recorded in Gachalaẃ here trophic niche breadth values suggest that this eagle was more selective about the prey it consumed, S. isidori ate G. gallus as its main prey, and this species contributed more biomass, perhaps requiring a lower energetic expenditure to find, capture, and handle. According to the optimal diet theory (Sih & Christensen, 2001), during their reproductive season, organisms prefer to feed on prey that provide more energy per unit time, considering the costs associated with locating, capturing, handling, and transporting prey to the nest (Rebollo et al, 2017).…”

“…The trophic niche breadth of S. isidori in Ciudad Bol ıvar and Jard ın-the localities with the largest proportion of forest on their landscapes and where the eagle hunted a wider variety of prey-compared with values calculated for Gachala ( Table 1), suggest plasticity on the part of this eagle that allows it to feed on different types of prey as a function of what is available in environments modified by humans. This could be related to changes in the composition of the landscape induced by anthropic processes that can lead to variations in the availability of prey eaten by raptors (i.e., Garcia-Heras, Mougeot, Simmons, & Arroyo, 2017;Murgatroyd, Avery, Underhill, & Amar, 2016;Rebollo et al, 2017). In Spain and Azerbaijan, in the face of changes in food availability induced by humans, a species with a mainly carrion-feeding habit such as the Griffon Vulture (Gyps fulvus) ate mainly domestic animals (Karimov & Guliyev, 2017;Margalida et al, 2014).…”

Assessing the ability of novel ecosystems to support animal wildlife through analysis of diurnal raptor territoriality

“…[ 45 ] and Rebollo et al . [ 46 ]). The observed average reproductive success (2.3 fledglings per active nest, [ 26 ]) is also high in the European context, where the corresponding values are 1.8 in northern, central and western Europe, and 1.6 in southern Europe [ 58 ].…”

“…We attribute the observed decline in the number of breeding pairs of Goshawks during the study period not to declining habitat suitability but rather to illegal human activities. We observed Goshawks caught in Swedish traps within the study area, likely reflecting the fact that 20% of the Goshawk diet in the study area is domestic prey ( S2 Table ) [ 46 ]. This decline in the Goshawk breeding population did not significantly affect the regular spatial distribution of active breeding pairs during the study period, though the decline may cause measurable effects if it continues.…”

“…For example, Fasola and Zanghellini [ 41 ] reported elevational differences among these species, and Newton [ 42 ] reported that Sparrowhawks use younger forest stands than Goshawks. The three species show some overlap in diet, with Goshawks feeding on medium-sized birds and mammals, Sparrowhawks on small birds [ 42 – 46 ] and Buzzards on small and medium-sized mammals and reptiles [ 47 , 48 ]. More than 70 species of birds, mammals and reptiles were consumed by the three raptor species in the studied area (see S2 Table ).…”