Data from: Rock Wrens preferentially use song types that improve long distance signal transmission during natural singing bouts

When animals are capable of producing variable signals they may preferentially use some signal types over others. Among songbirds, individuals are known to alter song type form and usage patterns in contest and mating situations, but studies have not examined how song choice improves signal efficacy during broadcast song. For this study we investigated rock wren (<i>Salpinctes obsoletus</i>) song type use rates during natural singing bouts. We tested three hypotheses for adaptive song use during broadcast song: 1) birds improve signal content by increasing the use of high quality songs, 2) birds optimize for signal propagation by preferentially using songs that transmit well, and 3) birds maintain energy by reducing the use of costly songs. The study included 19,058 songs sung by 12 individuals, each of which had a measured song repertoire of between 52 and 117 song types which were produced at highly variable rates. Results indicated that rock wrens did not preferentially sing song types with shorter durations or fewer frequency switches, as would be expected if they selected song types to minimize delivery costs. They also did not favor songs with more rapid trills or more frequency switches, as would be expected if they adjusted song use primarily to indicate quality. Focal birds did preferentially sing significantly longer songs with lower bandwidths, lower frequencies, and slower trill rates. Results suggest that natural broadcast singing patterns are shaped more by the benefits of long distance transmission than by the benefits of advertising performance ability or the costs of song production.

当动物能够产生可变信号时，往往会优先选用特定信号类型，而非其他类型。在鸣禽类群中，已有研究证实个体在争斗与交配场景下会调整鸣唱类型的形式与使用模式，但目前尚无研究探讨鸣唱选择如何提升广播鸣唱过程中的信号效能。本研究针对自然鸣唱过程中的岩鹪鹩（<i>Salpinctes obsoletus</i>）鸣唱类型使用频率展开调查，针对广播鸣唱中的适应性鸣唱使用模式提出三项假设：其一，鸣禽通过增加优质鸣唱的使用比例以提升信号内容；其二，鸣禽优先选用传播性能更佳的鸣唱，以优化信号传播效率；其三，鸣禽通过减少高成本鸣唱的使用以节约能量。本研究共收录12只个体的19058段鸣唱，每只个体拥有52至117种鸣唱类型，且各类鸣唱的产出频率差异显著。研究结果显示，岩鹪鹩并未优先选择时长更短、频率转换更少的鸣唱类型——若其为最小化传递成本而选择鸣唱类型，本应出现此类偏好；同时，它们也未偏好颤鸣速率更快、频率转换更多的鸣唱，而若其主要通过调整鸣唱使用以展示自身品质，本应出现这类偏好。但受试个体确实优先选择鸣唱时长显著更长、带宽更低、频率更低且颤鸣速率更慢的鸣唱类型。研究结果表明，自然广播鸣唱模式更多受到长距离信号传播优势的塑造，而非展示个体表现能力的优势或鸣唱生产的成本因素。