Hunting efficiency of Red-footed Falcons in different habitats

Abstract

The paper provides an empirical analysis of the macroeconomic factors that enhance revenue gap in South Africa using the multivariate cointegration techniques for the period 1965 to 2012. The results from the cointegration analysis indicate that the revenue gap in South Africa is negatively associated with the level of imports while positively related to external debt and underground economy. The former finding is consistent with the notion that imports are subjected to more taxation than domestic activities because of certain features of international trade that tend to make tax evasion difficult. On the other hand, the positive relationship between external debt and tax gap shows that the South African government relies upon external debt to finance its budget deficit resulting from missing revenues. Furthermore, the observed negative effect of the post-apartheid dummy confirms that the tax policy reforms that South Africa introduced following the liberation in 1994 have led to a reduction in missing revenues. The results from the Granger causality test also show that there is a unidirectional causality running from imports and underground economy to revenue gap, while revenue gap on the other hand is found to Granger-cause national income and external debt in South Africa.

Breeding habitat and nest‐site selection by an obligatory “nest‐cleptoparasite”, the Amur FalconFalco amurensis

“…It could also refer to an increase in the number of gradients from patch to patch along with changes in biotic and abiotic factors such as vegetation characteristics and humidity. Nevertheless, magpies and Amur Falcon might regularly take advantage of edge habitats, because insects' abundance and detectability might be especially high in those ecotones (Birkhead, ; Palatitz et al, ).…”

“…Consequently, the overall habitat use and foraging strategies might change in relation to changes in prey abundance and detectability, which is influenced by the actual vegetation cover in proceeding stages of the growing season (Palatitz et al, ). Above all, Amur Falcons may offset a less optimal set of habitat arrangements by their gregarious behavior, flock formation, and their ability to fly over a distance, where abundance and particularly detectability of prey items are sufficient (Palatitz et al, ). However, our study assumes that variables at the landscape scale, such as those referring to structurally complex landscapes with proportions of wetlands, shrubs, and cultivated fields, helped to classify nests of Amur Falcons.…”

“…Considering the proportion of bare soil within the home ranges, this habitat of mostly fallow land may be supportive for ground-foraging activities. This has been described for magpies and Red-footed Falcons (a close relative of the Amur Falcon), especially when soil invertebrates are driven to the surface due to high groundwater levels, providing excellent feeding opportunities (Birkhead, 2010;Palatitz et al, 2015). The importance of agricultural fields might be explained for a similar reason: When the soil is ploughed and during harvest, prey resources might then be exposed for possible predation (Palatitz et al, 2015;Weaver, 2015).…”

“…This has been described for magpies and Red-footed Falcons (a close relative of the Amur Falcon), especially when soil invertebrates are driven to the surface due to high groundwater levels, providing excellent feeding opportunities (Birkhead, 2010;Palatitz et al, 2015). The importance of agricultural fields might be explained for a similar reason: When the soil is ploughed and during harvest, prey resources might then be exposed for possible predation (Palatitz et al, 2015;Weaver, 2015). Amur Falcon home ranges were also found to be positively associated with shrubs, which might also be associated with prey availability, since habitat heterogeneity might lead to increased insect abundance (Tews et al, 2004).…”

“…Thus, the nests at the outer margin did not cover the full home ranges compared to nests in the center of the study area. A structurally complex landscape, Falcon might regularly take advantage of edge habitats, because insects' abundance and detectability might be especially high in those ecotones (Birkhead, 2010;Palatitz et al, 2015).…”