The Chestnut-Collared Longspur in Manitoba
The Chestnut-Collared Longspur in Manitoba
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马尼托巴省的栗领长刺
DOI：
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发表时间：
1944
期刊：
影响因子：
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通讯作者：
R. D. Harris
中科院分区：
文献类型：
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作者：
R. D. Harris
春天。第一次到达是在1932年4月10日、1930年4月11日和1931年4月12日。主要的迁徙在一两天之后开始，一直持续到4月18日左右。从那以后，偶尔可以看到鸟儿从头顶飞过，但这种飞行似乎只是在当地游荡。在迁徙的第一天，通常不超过一只个体，但之后一天内会计数到10或12只。他们主要是在上午来的，有的是单独来的，有的是三三两两来的。秋天。这些鸟聚集成一群，然后转向南方。幼鸟是第一个聚集的，经常出现在筑巢区的外围。随着8月中旬筑巢期的结束，成年鸟加入了幼鸟的行列。然后，这个物种完全放弃了长满草的繁殖地，在邻近的沟渠、干涸的沼泽和类似的低洼、粗糙的地面上被发现（尽管很少有残茬或耕地）。这种相当显著的栖息地变化可能是由于秋季杂草种子的可用性，以及蚱蜢数量的减少，而蚱蜢是该物种夏季的主要食物；但原因可能远不止于此，它涉及到与移民相关的心理和生理变化。八月的最后半个月，幼鸟和老鸟一起在新栖息地里度过，成群结队、躁动不安，数量多达30只或更多。9月间，它们开始向南迁徙，我在温尼伯最后一次看到这些鱼是9月28日。
Spring. The first arrivals were noted on April 10 (1932), April 11 (1930), and April 12 (1931). The main migration began a day or two later, and lasted until about April 18. After that date, occasional birds were seen flying overhead, but such flights seemed to be only local wanderings. On the first day of migration, no more than a single individual was usually noted, but afterwards 10 or 12 were counted in a day. They arrived principally during the forenoon, either singly or in groups of two or three. Autumn. The birds collected into flocks before turning southward. Young birds were the first to gather, frequenting the outskirts of the nesting areas. With the termination of nesting about the middle of August, adults joined the flocks of juveniles. The species then entirely abandoned the grassy breeding grounds, and was found in adjacent ditches, dried-up sloughs, and similar low-lying, rough ground (though rarely stubble or plowed land). This rather remarkable change of habitat may be due to the availability of the autumii crop of weed seeds, combined with the reduced number of grasshoppers, which constitute the bulk of the species' food in summer; but the cause may lie deeper than that, and involve the psychological and physiological changes bound up with migration. Young and old together spent the last half of August in the new habitat, in loose, restless flocks numbering up to 30 or more individuals. During September, southward migration began, and the latest date on which I noted the species at Winnipeg was September 28.