Data from: Subarctic singers: Humpback whale (Megaptera novaeangliae) song structure and progression from an Icelandic feeding ground during winter

Humpback whale songs associated with breeding behaviors are increasingly
reported outside of traditional low latitude breeding grounds. Songs from
a subarctic feeding ground during the winter were quantitatively
characterized to investigate the structure and temporal changes of the
songs at such an atypical location. Recordings were collected from 26.
January to 12. March, 2011, using bottom mounted recorders. Humpback songs
were detected on 91% of the recording days with peak singing activities
during 9.–26. February. The majority of the recordings included multiple
chorusing singers. The songs were characterized by a) common static themes
which transitioned consistently to predictable themes, b) shifting themes
which occurred less predictably and c) rare themes. A set median sequence
was found for four different periods (sets) of recordings (approximately 1
week each). The set medians were highly similar and formed a single
cluster indicating that the sequences of themes sung in this area belonged
to a single cluster of songs despite of the variation caused by the
shifting themes. These subarctic winter songs could, thus, represent a
characteristic song type for this area which is comparable to extensively
studied songs from traditional low latitude breeding grounds. An increase
in the number of themes per sequence was observed throughout the recording
period including minor changes in the application of themes in the songs;
indicating a gradual song progression. The results confirm that continual
singing of sophisticated songs occur during the breeding season in the
subarctic. In addition to being a well-established summer feeding ground
the study area appears to be an important overwintering site for humpback
whales delaying or canceling their migration where males engage in active
sexual displays, i.e. singing. Importantly, such singing activity on a
shared feeding ground likely aids the cultural transmission of songs in
the North Atlantic.

与繁殖行为相关的座头鲸（Humpback whale）歌声，在传统低纬度繁殖场以外区域的报道正日益增多。本研究对冬季亚北极摄食场采集的座头鲸歌声开展定量特征分析，以探究该非典型区域内歌声的结构与时序变化规律。研究于2011年1月26日至3月12日期间，利用海底挂载式记录仪采集声学录音数据。座头鲸歌声在91%的有效录音日均有检出，其鸣唱活动峰值出现在2月9日至26日期间。多数录音可采集到多头同步鸣唱的个体。该类歌声具有三类特征：a）常见的静态主题单元，可稳定过渡至可预测的主题单元；b）可预测性较低的动态主题单元；c）罕见主题单元。研究在四个连续录音时段（每个时段约持续1周）中，分别提取了对应的序列中位数特征。各时段的序列中位数特征高度相似，共同形成单一聚类簇，表明尽管动态主题单元带来了一定变异，但该区域内鸣唱的主题序列仍归属于单一歌声类群。因此，这些亚北极冬季鸣唱可被视为该区域特有的歌声类型，其特征可与已被广泛研究的传统低纬度繁殖场座头鲸歌声相媲美。在整个录音周期内，单序列包含的主题单元数量呈上升趋势，同时歌声中主题单元的使用模式也存在细微变化，这表明座头鲸歌声正经历渐进式演化。本研究结果证实，亚北极区域在繁殖季期间仍存在持续鸣唱复杂歌声的行为。该研究区域不仅是公认的夏季摄食场，同时似乎也是座头鲸重要的越冬场所——部分个体在此推迟或取消迁徙，雄性个体在此开展主动的求偶展示（即鸣唱行为）。值得注意的是，在共享摄食场开展的此类鸣唱活动，或有助于北大西洋海域座头鲸歌声的文化传播。