Data from: Preen oil chemical composition encodes individuality, seasonal variation and kinship in black kites Milvus migrans

Evidence that bird odour can encode social information that can be used in chemical communication is growing, but is restricted to a few taxonomic groups. Among birds, diurnal raptors (i.e. birds from the Accipitriformes and Falconiformes order) have always been considered as mainly relying on their visual abilities. Although they seem to have a functional sense of smell, whether their odour can convey social information has yet to be determined. Combining gas-chromatography-mass-spectrometry (GCMS) and microsatellite data, we tested whether chemical compounds from preen gland secretions can encode sex, age, individuality, seasonal differences and genetic relatedness in the gregarious accipitriform black kite Milvus migrans. While no differences in preen oil composition were found between age classes, an individual signature was detected. While a seasonal variation was found in both sexes, compounds differ between sexes in the non-breeding season. Finally, a significant correlation between chemical proximity and genetic proximity was detected in male-male dyads and male-female dyads but not in female-female dyads. Our study provides the first evidence in raptors that preen secretion can convey information that may potentially be used in individual recognition, reproductive synchronization and inbreeding avoidance, and suggests that raptors may rely upon their olfactory abilities more than previously thought. This study opens promising avenues for further studies in raptor chemical communication.

越来越多的证据表明，鸟类气味可编码用于化学通讯的社会信息，但此类研究目前仅局限于少数分类类群。在鸟类中，昼行性猛禽（即隶属于鹰形目Accipitriformes与隼形目Falconiformes的鸟类）长期以来被认为主要依赖视觉能力。尽管这类猛禽看似具备功能健全的嗅觉系统，但其气味是否能够传递社会信息仍有待探明。本研究结合气相色谱-质谱联用（gas-chromatography-mass-spectrometry, GCMS）与微卫星（microsatellite）数据，以群居性鹰形目鸟类黑鸢（Milvus migrans）为研究对象，检测其尾脂腺分泌物中的化学物质是否能够编码性别、年龄、个体特征、季节差异与遗传相关性。结果显示，不同年龄组的尾脂油成分无显著差异，但可检测到个体特征信号；两性个体均存在季节变化，但非繁殖期雌雄的化学物质组成存在差异；最后，研究在雄性-雄性配对与雄性-雌性配对中检测到化学相似性与遗传相似性间存在显著相关，而雌性-雌性配对中未发现此关联。本研究首次在猛禽类群中提供证据，表明尾脂腺分泌物可传递可用于个体识别、繁殖同步以及近交回避的信息，同时提示猛禽对嗅觉能力的依赖程度可能远超此前认知。本研究为猛禽化学通讯领域的后续研究开辟了极具前景的方向。