Phenological shifts may ameliorate negative effects of climate change or create carryover effects and mismatches that decrease fitness. Identifying how phenological shifts affect performance is critical for understanding how individuals and populations will respond to climate change, but requires long-term, longitudinal data. Using 34 yr of data from the Magellanic penguin (Spheniscus magellanicus) colony at Punta Tombo, Argentina, we examined the consequences of the delayed onset of breeding (i.e., arrival and egg-laying dates) that has occurred at the colony since 1983. To understand how the delay propagates through the rest of the reproductive cycle, we identified phenological trends in hatch and fledge dates. Median hatch dates were 0.29 d later each year, amounting to a 10-d shift over the course of the study. Median fledge dates did not shift over the 34-yr period, however, thus shortening the median nestling period duration by 14%. We tested several predictions regarding performance outcomes of the compressed nestling period, finding that later-hatched chicks fledged significantly younger than earlier-hatched chicks, and that younger fledglings left the colony with smaller bills and with more chick down. Interestingly, although younger chicks fledged significantly lighter and in worse body condition than older fledglings early in the study, this trend reversed over time, with younger chicks actually fledging heavier and in better body condition in more recent years. Smaller and lighter fledglings were less likely to recruit to the colony as adults. We find that delayed breeding has significantly compressed nestling periods at Punta Tombo, influencing chick growth and fledgling condition. These findings highlight the importance of studying phenology across multiple life events to understand the consequences of phenological shifts for organismal fitness.

中文翻译：

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麦哲伦企鹅物候变化和压缩繁殖期的后果

物候变化可能会改善气候变化的负面影响或产生降低适应度的遗留效应和错配。确定物候变化如何影响性能对于了解个人和人群将如何应对气候变化至关重要，但需要长期的纵向数据。使用来自麦哲伦企鹅 ( Spheniscus magellanicus ) 的 34 年数据) 在阿根廷蓬塔汤博 (Punta Tombo) 的殖民地，我们检查了自 1983 年以来在该殖民地发生的延迟繁殖（即到达和产卵日期）的后果。为了了解延迟如何在繁殖周期的其余部分传播，我们确定了孵化和羽化日期的物候趋势。孵化日期中位数每年晚 0.29 天，相当于研究过程中的 10 天轮班。然而，中位出雏日期在 34 年期间没有变化，因此将中位雏鸟期持续时间缩短了 14%。我们测试了几个关于压缩雏鸟期表现结果的预测，发现后期孵化的雏鸡比早期孵化的雏鸡更年轻，而且年轻的雏鸟带着更小的喙和更多的雏鸟离开殖民地。有趣的是，尽管在研究早期，年轻的雏鸡比年长的雏鸡明显更轻且身体状况更差，但这种趋势随着时间的推移而逆转，近年来年轻的雏鸡实际上更重且身体状况更好。较小和较轻的雏鸟成年后不太可能招募到殖民地。我们发现延迟繁殖显着压缩了蓬塔通博的雏鸟期，影响了雏鸡的生长和雏鸟条件。这些发现强调了跨多个生命事件研究物候学以了解物候变化对有机体适应性的影响的重要性。近年来，年轻的小鸡实际上更重且身体状况更好。较小和较轻的雏鸟成年后不太可能招募到殖民地。我们发现延迟繁殖显着压缩了蓬塔通博的雏鸟期，影响了雏鸡的生长和雏鸟条件。这些发现强调了跨多个生命事件研究物候学以了解物候变化对有机体适应性的影响的重要性。近年来，年轻的小鸡实际上更重且身体状况更好。较小和较轻的雏鸟成年后不太可能招募到殖民地。我们发现延迟繁殖显着压缩了蓬塔通博的雏鸟期，影响了雏鸡的生长和雏鸟条件。这些发现强调了跨多个生命事件研究物候学以了解物候变化对有机体适应性的影响的重要性。