Characterization of male courtship home ranges and short-distance migration corridor in a remnant MacQueen's Bustard population

Abstract

Anthropogenic land alterations result in extensive habitat and biodiversity losses. In the Negev desert of Israel, habitat loss and environmental disturbances have driven the population of MacQueen's Bustard, AKA Asian Houbara (Chlamydotis macqueenii), one of Israel's flagship species, to the verge of extinction. Although this remnant population is considered sedentary, observations suggest that a large part of the population performs short-distance migration between the breeding and post-breeding grounds in the northwestern Negev using short flights and on-foot movements. We utilized GPS data from nineteen males equipped with GSM-GPS devices and Maximum Entropy species distribution models to characterize, for the first time, the 1) male home ranges during the courtship period and 2) critical corridors utilized when performing short flights and on-foot movements between the breeding and post-breeding grounds in the northwestern Negev. The most influential predictors of male courtship areas were elevation, January precipitation, and soil type, displaying the range of environmental conditions best suitable for establishing a male courtship home range along the steep climate and topographic gradients characterizing the Negev desert of Israel. Zooming into the northwestern Negev, where most of the population occurs, showed that the most influential predictor variable was soil type. A compositional analysis indicated two groups of courting males in the northwestern Negev and a third group in the Negev Highlands. The first group, comprising ten males occupying a land unit dominated by loess-derived soils, significantly preferred loessial serozem soils. The second group, including six males occupying a land unit dominated by sand-derived soils, significantly preferred sand dunes and sandy regosols. The third group, comprising three Negev Highlands males, showed a preference for regosol-reg and desert alluvium soils. The home range sizes of courting males were positively correlated with their body masses. The total distance each of the migrating males covered while wandering until arriving at the post-breeding ground was, on average, 171.39 km, and it comprised primarily on-foot movements (68 %) rather than short flights (32 %). Areas of relatively uniform elevation and gentle/simple topography characterized the on-foot movement corridors utilized during the short-distance migration between the breeding and post-breeding grounds in the northwestern Negev, possibly reflecting a preference for vast, unobstructed areas that enhance the field of vision while on the ground. A common finding across both activity seasons was a distinct avoidance of agricultural lands and favoring open natural habitats. Some courtship sites and on-foot movement corridors are primarily found outside nature reserves. Therefore, we call for protecting these critical areas and preventing their destruction.