Much of the growing interest in avian chemical signals has focused on the role of kin recognition or mate attraction, often with an emphasis on males, with uropygial gland secretions perhaps providing information about an individual’s identity and quality. Yet, data collected to date suggest sexual dimorphism in uropygial glands and secretions are often emphasized in female, rather than in male birds. That is, when a sexual difference occurs (often during the breeding season only), it is the female that typically exhibits one of three patterns: (1) a larger uropygial gland, (2) a greater abundance of volatile or semi-volatile preen oil compounds and/or (3) greater diversity of preen oil compounds or associated microbes. These patterns fit a majority of birds studied to date (23 of 30 chemically dimorphic species exhibit a female emphasis). Multiple species that do not fit are confounded by a lack of data for seasonal effects or proper quantitative measures of chemical compounds. We propose several social functions for these secretions in female-based patterns, similar to those reported in mammals, but which are largely unstudied in birds. These include: (1) intersexual advertisement of female receptivity or quality, including priming effects on male physiology, (2) intrasexual competition, including scent marking and reproductive suppression or (3) parental behaviors, such as parent-offspring recognition and chemical protection of eggs and nestlings. Revisiting the gaps of chemical studies to quantify the existence of female social chemosignals and any fitness benefit(s) during breeding are potentially fruitful but overlooked areas of future research.

对禽类化学信号越来越多的关注都集中在亲属识别或伴侣吸引的作用上，通常侧重于男性，尿py腺分泌物可能提供有关个体身份和质量的信息。然而，迄今为止收集的数据表明，尿道腺的性二态性和分泌物通常在雌性而不是雄性鸟类中被强调。也就是说，当发生性别差异时（通常仅在繁殖季节期间），通常是女性表现出以下三种模式之一：（1）尿道腺较大，（2）挥发性或半挥发性物质的含量较高油化合物和/或（3）各种油类化合物或相关微生物的多样性。这些模式适合迄今研究的大多数鸟类（30种化学双态物种中有23种表现出雌性优势）。缺乏适合季节影响的数据或化学化合物的正确定量测量方法，会使多种不适合的物种感到困惑。我们以女性为基础的模式为这些分泌物提出了几种社会功能，类似于哺乳动物中报道的功能，但在鸟类中却很少研究。这些包括：（1）雌性的雌性接受性或品质的广告，包括对雄性生理的初步影响；（2）雌性竞争，包括气味标记和生殖抑制；或（3）父母行为，例如父母对子代的识别和化学保护鸡蛋和雏鸟。重新审视化学研究的差距以量化雌性社会化学信号的存在以及在育种过程中的任何健康益处可能是富有成果的，但却是未来研究中被忽视的领域。