Implications of vagrant Southeastern vireos and warblers in California
Implications of vagrant Southeastern vireos and warblers in California
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加利福尼亚州东南部绿鹃和莺的流浪现象的影响
DOI：
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发表时间：
1996
期刊：
影响因子：
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通讯作者：
Curtis A. Marantz
中科院分区：
文献类型：
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作者：
M. Patten;Curtis A. Marantz
1992年春天和夏天，史无前例的流浪绿鸟和林莺涌入加利福尼亚州。涉及的7种鸟类(白眼灰绿莺[Vireo griseus]、黄喉灰绿莺[V.flavifrons]、北美洲黄喉莺[Parula americana]、黄喉莺[Dendroica Dominica]、食虫林莺[Helmitheros vermivorus]、肯塔基林莺[Opororennis formosus]和白头林莺[Wilsonia citrina])都主要在美国东南部繁殖，这表明这是导致人口大量涌入的一个共同因素。此外，在过去20年里，加州记录到的所有七个物种的频率都在增加，这表明这些物种的种群数量有一个共同的趋势。我们研究了五个假设，可以解释这些物种在加州记录的数量增加：(1)观察者偏见，(2)农药引起的定向错误，(3)冬季范围的变化，(4)异常天气条件(包括全球变暖和厄尔尼诺-南方涛动)，(5)范围扩大到美国西部和/或美国东南部种群急剧增加。我们发现前三个假设很少或没有得到支持。异常的天气条件可能解释了1992年人口涌入的规模，但需要最后的假设来解释总体趋势。尽管现有数据不足以区分夏季分布转移和这些物种“正常”繁殖范围内的种群增长，但向西扩展范围的可能性是耐人寻味的。1996年3月15日收到，1996年6月25日接受。
ABsTRAc.-An unprecedented influx of vagrant vireos and wood-warblers into California occurred in the spring and summer of 1992. The seven species involved (White-eyed Vireo [Vireo griseus], Yellow-throated Vireo [V. flavifrons], Northern Parula [Parula americana], Yellowthroated Warbler [Dendroica dominica], Worm-eating Warbler [Helmitheros vermivorus], Kentucky Warbler [Oporornis formosus], and Hooded Warbler [Wilsonia citrina]) all breed primarily in the southeastern United States, suggesting a common factor for the influx. Furthermore, all seven species have been recorded in California with increasing frequency over the past two decades, suggesting a common trend in the populations of these species. We examined five hypotheses that could explain the increasing number of California records of these species: (1) observer bias, (2) pesticide-caused misorientation, (3) shifts in winter range, (4) anomalous weather conditions (including global warming and El Ninlo-Southern Oscillation), and (5) range expansions into the western United States and/or dramatic population increases in the southeastern United States. We found little or no support for the first three hypotheses. Anomalous weather conditions probably accounted for the magnitude of the 1992 influx, but the final hypothesis is needed to explain the overall trend. Although available data are not sufficient to distinguish between summer distributional shifts and population increases within the "normal" breeding ranges of these species, the possibility of westward range expansion is intriguing. Received 15 March 1996, accepted 25 June 1996.