Rappole John H, Warner Dwain W
Bell Museum of Natural History, University of Minnesota, 55455, Minneapolis, Minnesota, USA.
Oecologia. 1976 Sep;26(3):193-212. doi: 10.1007/BF00345289.
Populations of avian transients were studied at a stopover area in southern Texas during four consecutive migration seasons, fall, 1973-spring, 1975. We captured individuals by mist net for banding and fat level determination. Concurrently we made observations on behavior of free-flying birds.We worked intensively with a single species, the Northern Waterthrush (Seiurus noveboracensis) while gathering weight fat and behavioral data on other species as well. Many of the patterns of weight change and behavior seen in the Northern Waterthrush were observed in other common passerines which occurred as transients on our study site.Results showed that birds in Zugstimmung and Zugdisposition differ, not only physiologically but behaviorally as well. Individuals of normally non-gregarious species that are in Zugstimmung are gregarious and stay in an area for only a short period. Their habitat needs are broad since these birds are not dependent on the food resources of the area in which they stop while in this physiological state. In contrast, normally non-gregarious migrants in Zugdisposition are hyperphagic and aggressively territorial in defense of resources and may stay at the same site for several days. Their habitat needs are quite specific since they must increase food intake by as much as 40% to build up fat reserves. Not all individuals in Zugdisposition are able to find territories at the same time. Those birds unable to claim territories either continue to migrate or stay in an area as floaters, continually attempting to obtain territories. Weather conditions probably act as a third variable that must be balanced by the individual in a complex optimization strategy with physiological state and success in competition.
在1973年秋季至1975年春季的四个连续迁徙季节里，对得克萨斯州南部一个中途停留区的候鸟种群进行了研究。我们用雾网捕获个体以进行环志和脂肪水平测定。同时，我们对自由飞行的鸟类行为进行了观察。我们重点研究了单个物种——北水鸫（Seiurus noveboracensis），同时也收集了其他物种的体重、脂肪和行为数据。在北水鸫身上观察到的许多体重变化和行为模式，在我们研究地点作为候鸟出现的其他常见雀形目鸟类中也能看到。结果表明，处于迁徙兴奋期和迁徙准备期的鸟类不仅在生理上不同，行为上也存在差异。处于迁徙兴奋期的通常不群居的物种个体变得群居，并且只在一个区域停留很短时间。它们对栖息地的需求很广泛，因为这些鸟类在这种生理状态下并不依赖于它们停留区域的食物资源。相比之下，处于迁徙准备期的通常不群居的候鸟食量很大，会积极捍卫资源领地，可能会在同一地点停留数天。它们对栖息地的需求非常特定，因为它们必须将食物摄入量增加多达40%来积累脂肪储备。并非所有处于迁徙准备期的个体都能同时找到领地。那些无法获得领地的鸟类要么继续迁徙，要么作为流浪者留在一个区域，不断试图获得领地。天气条件可能是第三个变量，个体必须在一个复杂的优化策略中，将其与生理状态和竞争成功进行平衡。
