Holding steady: Little change in intensity or timing of bird migration over the Gulf of Mexico
Holding steady: Little change in intensity or timing of bird migration over the Gulf of Mexico
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DOI：
10.1111/gcb.14540
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发表时间：
2019-03-01
影响因子：
11.6
通讯作者：
Farnsworth, Andrew
中科院分区：
文献类型：
--
作者：
Horton, Kyle G.;Van Doren, Benjamin M.;Farnsworth, Andrew
量化迁徙的时间和强度对于了解景观和气候变化对候鸟种群的影响至关重要。数十亿只鸟类在西半球迁徙，但要准确估计一种迁徙物种的种群规模，更不用说数百种了，这存在许多障碍。在这里，我们量化的时间，强度和分布的鸟类迁徙通过在西半球最大的迁徙走廊之一，墨西哥湾（海湾）。我们进一步评估通过海湾的迁移时间或强度是否发生了变化。为了实现这一目标，我们将公民科学（eBird）观测与21年的天气监测雷达数据（1995 - 2015）相结合。我们预测在整个时间序列中，移民时间没有变化，移民强度下降。我们估计，每年春天，平均有21亿只鸟类经过这一地区，前往新北繁殖地。每年，这些人中有一半在4月19日至5月7日的18天内经过该地区。海湾西部地区的平均通过率比中部和东部地区高5.4倍。我们没有发现每年移民人数（2007 - 2015）或每年移民高峰时间（1995 - 2015）的总体变化。然而，我们发现，随着时间的推移，该地区最早的季节性运动明显提前（1.6天十年（-1））。此外，身体质量和迁移距离解释了物候变化的幅度，最迅速的进展发生在一个大的身体较短距离的移民组合。我们的研究结果提供了基线信息，可用于促进我们对气候变化，城市化和能源开发对北美候鸟种群的发展影响的理解。
Quantifying the timing and intensity of migratory movements is imperative for understanding impacts of changing landscapes and climates on migratory bird populations. Billions of birds migrate in the Western Hemisphere, but accurately estimating the population size of one migratory species, let alone hundreds, presents numerous obstacles. Here, we quantify the timing, intensity, and distribution of bird migration through one of the largest migration corridors in the Western Hemisphere, the Gulf of Mexico (the Gulf). We further assess whether there have been changes in migration timing or intensity through the Gulf. To achieve this, we integrate citizen science (eBird) observations with 21 years of weather surveillance radar data (1995-2015). We predicted no change in migration timing and a decline in migration intensity across the time series. We estimate that an average of 2.1 billion birds pass through this region each spring en route to Nearctic breeding grounds. Annually, half of these individuals pass through the region in just 18 days, between April 19 and May 7. The western region of the Gulf showed a mean rate of passage 5.4 times higher than the central and eastern regions. We did not detect an overall change in the annual numbers of migrants (2007-2015) or the annual timing of peak migration (1995-2015). However, we found that the earliest seasonal movements through the region occurred significantly earlier over time (1.6 days decade(-1)). Additionally, body mass and migration distance explained the magnitude of phenological changes, with the most rapid advances occurring with an assemblage of larger-bodied shorter-distance migrants. Our results provide baseline information that can be used to advance our understanding of the developing implications of climate change, urbanization, and energy development for migratory bird populations in North America.