Philip U. Alkon
The Wilson Journal of Ornithology 127 (2), 181-199, (1 June 2015) https://doi.org/10.1676/wils-127-02-181-199.1
KEYWORDS: Alectoris chukar, behavior, chukar, density dependence, Israel, population dynamics, social organization
A 2-year field study of a free-ranging population of Chukar (Alectoris chukar cypriotes), occupying Mediterranean habitat in Israel’s Lower Galilee, yielded unique insights on (1) the array and context of specific behaviors of wild birds, (2) the complex dynamics of their social processes, and (3) the interaction of behavioral and population dynamics. Systematic observations of individually marked wild birds clarified the function of several prominent displays (e.g., waltzing as a male courtship display) and vocalizations (e.g., the chuk-ar call as an individual announcement that varied widely in form and function). Behavioral relationships among birds were complex, and Chukars demonstrated individual differences in demeanor and status. Strong social bonds among adult males and brood mates were significant cohesive forces, and adult males exhibited strong site affinities from year to year. Chukars spent autumn and winter in coveys of 10–20 birds having heterogeneous gender and age compositions, and occupied separate but overlapping ranges of 4–8 ha. Adult males displayed and threatened conspecifics more than did females during most seasons, but broody hens were aggressive towards other birds. Overt social interactions were most intense while coveys disbanded in early spring, during breeding, and in post-breeding covey formation. Paired males closely accompanied females within restricted nesting territories, but most left their mates during incubation. Large late-summer aggregations of Chukars occurred at open water and in fallow fields where intense social interactions preceded the establishment of permanent covey ranges. The study population underwent an inverse, density-dependent fluctuation that was mediated by behavioral processes. A low overwintering population in Year 1 exhibited little social strife and no population change preceded an orderly and productive breeding season. The subsequent dense population in Year 2 exhibited heightened social strife in winter, a large decline in numbers with the onset of pairing, considerable disturbance of nesting pairs, and lowered reproductive success.