Posso S R, Cintra F B, Frias J
Laboratório de Ecologia, Sistemática e Conservação de Aves Neotropicais, Departamento de Ciências Naturais, Universidade Federal de Mato Grosso do Sul, Três Lagoas, MS, Brazil.
Braz J Biol. 2012 May;72(2):235-41. doi: 10.1590/s1519-69842012000200002.
The foraging, territoriality and displacement of the Snail Kite were studied over 232 hours of observations in an urban lake during the dry and wet seasons. The temperature and rainfall variations were used to correlate with predation rates and the correlation coefficients were 0,39 and 0,34, respectively. Snail Kites spent more time foraging during the wet than the dry season when perching is more frequently recorded. The higher predation in the wet season can be explained by the higher abundance of apple snails and the energy demand for reproduction. In the wet season, the territories were smaller and the conspecific conflicts decreased as prey were more available. However, due to the lack of food in the dry season, intra-specific conflicts and expansion of male territories were observed and the female and immatures were expelled from their foraging area to another location. In this way, site tenacity of Snail Kites should be interpreted in relation to the variations on food and dominance gradients according to the temporal changes (time) and foraging sites (space).
在旱季和雨季，对城市湖泊进行了232小时的观察，研究了蜗牛鸢的觅食、领地行为和替代行为。利用温度和降雨变化与捕食率进行关联，相关系数分别为0.39和0.34。与旱季相比，蜗牛鸢在雨季花费更多时间觅食，而在旱季更多记录到其停歇行为。雨季较高的捕食率可以用苹果蜗牛的丰度较高以及繁殖的能量需求来解释。在雨季，领地较小，由于猎物更多，种内冲突减少。然而，由于旱季食物短缺，观察到种内冲突和雄性领地扩张，雌性和未成熟个体被赶出觅食区域到其他地方。因此，蜗牛鸢的栖息地忠诚度应根据时间变化（时间）和觅食地点（空间）的食物和优势梯度变化来解释。
