Pearse Aaron T, Szymanski Michael L, Anchor Cynthia A, Anteau Michael J, Murano Rocco M, Brandt David A, Stafford Joshua D
U.S. Geological Survey, Northern Prairie Wildlife Research Center Jamestown North Dakota USA.
North Dakota Game and Fish Department Bismarck North Dakota USA.
Ecol Evol. 2023 Oct 25;13(10):e10605. doi: 10.1002/ece3.10605. eCollection 2023 Oct.
Annual phenology and distributions of migratory wildlife have been noticeably influenced by climate change, leading to concerns about sustainable populations. Recent studies exploring conditions influencing autumn migration departure have provided conflicting insights regarding factors influencing the movements of Mallards (), a popular game species. We determined factors affecting timing and magnitude of long-distance movements of 97 juvenile Mallards during autumn-winter across the midcontinent of North America marked with implanted transmitters in North and South Dakota, 2018-2019. Factors influencing variation in movement timing, along with direction and magnitudes, depended on type of movement (i.e., regional [25-310 km], initial migration, or subsequent migration movements [>310 km]). Photoperiod influenced probability of initiating all movements, although the effect was most influential for regional movements. Minimum temperature most influenced initial migration events (probability of movement increased 29% for each 1°C decrease); favorable winds also increased likelihood of initial migration events. Probability of subsequent migration events increased 80% for each 1 cm increase in depth of snow. Subsequent migration movements also were 2.0 times more likely to occur on weekend days, indicating disturbance from humans may influence movements. Migration distances increased 166 km for each 1°C reduction in minimum temperature. We also observed markedly different autumn-winter distributions of marked birds between years. Median locations during autumn-winter 2018-2019 were ~250 km farther north and ~300 km farther west during mid-December-January compared to the same time in 2019-2020. Concurrently, harvest rates for marked females and males were 10% and 26% during autumn-winter 2018-2019 and 26% and 31% during autumn-winter 2019-2020. Climate-related changes may result in increasingly variable autumn-winter distributions, with implications for wildlife recreationalists, conservation planners, and harvest managers.
候鸟的年度物候和分布受到气候变化的显著影响，引发了对种群可持续性的担忧。最近关于影响秋季迁徙出发条件的研究，对于影响绿头鸭（一种受欢迎的狩猎鸟类）迁徙的因素给出了相互矛盾的见解。我们确定了2018 - 2019年在北达科他州和南达科他州为97只幼年绿头鸭植入发射器后，影响它们秋冬季节在北美大陆中部进行长距离迁徙的时间和规模的因素。影响迁徙时间变化以及方向和规模的因素，取决于迁徙类型（即区域迁徙[25 - 310千米]、首次迁徙或后续迁徙[>310千米]）。光周期影响所有迁徙开始的概率，尽管这种影响对区域迁徙最为显著。最低温度对首次迁徙事件影响最大（每降低1°C，迁徙概率增加29%）；有利的风向也增加了首次迁徙事件的可能性。雪深每增加1厘米，后续迁徙事件的概率增加80%。后续迁徙活动在周末发生的可能性也高出2.0倍，这表明人类干扰可能影响迁徙。最低温度每降低1°C，迁徙距离增加166千米。我们还观察到不同年份标记鸟类的秋冬分布存在明显差异。与2019 - 2020年同期相比，2018 - 2019年秋冬季节的中位数位置在12月中旬至1月期间向北约远250千米，向西约远300千米。与此同时，2018 - 2019年秋冬季节标记雌性和雄性绿头鸭的狩猎率分别为10%和26%，2019 - 2020年秋冬季节则为26%和31%。与气候相关的变化可能导致秋冬分布愈发多变，这对野生动物爱好者、保护规划者和狩猎管理者都有影响。
