Avian Communication and Behaviour in Dynamic Environments.

行为的灵活性可能使物种能够适应不断变化的或新的环境，我们将在入侵城市地区、将活动范围扩大到新区域或与密切相关(但通常是孤立的)物种接触的山雀和麻雀物种中进行调查。 黑帽、栗背和山地山雀往往通过提供喂食器和巢箱来吸引它们在城市绿地定居，但这种定居使它们受到与城市化相关的噪音水平增加和栖息地变化的影响。虽然这些物种定居在城市空间，但它们改变发声的能力可能会影响它们对不同环境的补偿能力。我们和其他研究表明，低频城市噪音掩盖了低音发声，这将有利于在定居的个人/群体中转向更高频率和更响亮的信号。黑帽山雀在春季发出信号时主要使用远距离鸣叫；山地山雀交替使用歌声和较短距离的chick-a-dee叫声；栗背山雀缺乏歌声，只发出chick-a-dee叫声。使用便携式扬声器广播城市噪音，我们将测试雄性动物动态调整信号以避免掩盖的能力，并确定适应的灵活性是否因物种而异。我们还将测试雌鸟和雄鸟的感知能力，以区分嵌入城市噪音中的鸟类的歌声，以及已经定居在城市景观中的鸟类是否会发出不太容易被掩盖的歌声。 城市发展和林业实践也会影响物种相互作用的可能性。黑帽山雀喜欢不同的栖息地，通常没有重叠的分布。然而，接触地点发生在低海拔落叶林(黑帽生境)与高海拔针叶林(山地生境)毗邻的地方，这可能是城市化或林业相关的土地开垦造成的。在一个接触种群中，山地山雀(从属物种)会改变它们的歌声和鸣叫方式，以避免与黑帽山雀的信号重叠。尽管有这些调整，我们发现雌性山雀和雄性黑帽山雀之间的额外配对导致杂交后代出现在山雀巢中，而不是黑帽山雀巢中。我们将使用遗传分析来探索这些模式在新的研究群体中的共性，并确定杂交后代是否患有减少的后代或成年条件。我们将向黑帽山雀播放山雀的歌声，以确定改变歌声是否足以减少这种社会优势物种的攻击性。我们还将在山地山雀的领地内回放黑帽山雀的歌声，以确定鸟类是否会在有占主导地位的竞争对手在场的情况下动态调整信号。 落基山脉北部的伐木和大坝建设被认为可能是栖息地走廊的来源，这些走廊让白喉麻雀等东部物种能够在不列颠哥伦比亚省中北部建立少量繁殖种群。这一小群西部麻雀唱着一种独特的方言，不同于整个加拿大东部常见的歌曲，可能是这种西部种群的创始人效应加上对歌曲的行为学习造成的。我们将结合遗传分析、羽毛中独特的同位素水平和安装在候鸟身上的光敏地理定位器背包来确定落基山脉两侧种群的隔离程度，以及这如何影响这一外围种群的歌唱方言的进化和传播。

Behavioural flexibility may enable species to cope with changing or novel environments, which we will investigate among chickadee and sparrow species that have invaded urban areas, expanded their range into novel regions, or come into contact with closely-related (but typically isolated) species. Black-capped, chestnut-backed and mountain chickadees are often attracted to settle in urban greenspace through provision of feeders and nestboxes, but such settlement subjects them to the increased noise levels and altered habitats associated with urbanization. Though these species settle in urban spaces, their capacity to alter vocalizations may affect their ability to compensate for the different environments. Our and other studies show low-frequency urban noise masks lower-pitched vocalizations, which would favour shifts to higher-frequency and louder signals among settling individuals/populations. Black-capped chickadees primarily use long-range songs during spring signalling; mountain chickadees alternate the use of song and shorter-range chick-a-dee calls; and chestnut-backed chickadees lack song and produce only chick-a-dee calls. Using portable speakers broadcasting urban noise, we will test the capacity of males to dynamically adjust their signals to avoid masking, and determine whether the flexibility to adjust differs between species. We will also test the perceptive ability of both females and males to distinguish songs of birds embedded in urban noise, and whether birds that have already settled in urban landscapes produce songs that are less easily masked. Both urban development and forestry practices can also affect likelihood of species interactions. Black-capped and mountain chickadees prefer different habitats and typically do not have overlapping distributions. However, contact sites occur where the lower-altitude deciduous forests (black-capped habitat) abut higher-altitude coniferous forests (mountain habitat), which can arise from land clearing associated with either urbanization or forestry . In one contact population, mountain chickadees (the subordinate species) alter their songs and song/call usage to avoid signal overlap with black-capped chickadees. Despite these adjustments, we found that extra-pair matings between female mountain and male black-capped chickadees resulted in hybrid young appearing in mountain, but not black-capped, nests. We will use genetic analysis to explore the generality of these patterns in new study populations, and determine whether hybrids suffer reduced offspring or adult condition. We will playback mountain chickadee songs to black-capped chickadees to determine whether altering songs is sufficient to reduce aggression from the socially-dominant species. We will also playback black-capped chickadee song bouts within territories of mountain chickadees to determine whether birds dynamically adjust signalling in the presence of a dominant competitor. Logging and dam construction in the northern Rockies have been implicated as the likely source of habitat corridors that have allowed eastern species, like white-throated sparrows, to establish small breeding populations in north central British Columbia. This small western population of sparrows sings a distinctive dialect from the common song heard throughout eastern Canada, and may result from founder effects of this western population coupled with behavioural learning of songs. We will use a combination of genetic analyses, distinctive isotope levels in feathers and light-sensing geolocator backpacks mounted on migrating birds to determine the degree to which populations on either side of the Rockies are isolated, and how this affects the evolution and spread of song dialects in this peripheral population.