白腹锦鸡(Chrysolophus amherstiae)的夜栖地选择

2005年4月～2006年9月,结合无线电遥测技术,采用系统搜索法和繁殖期跟踪法对四川石棉县栗子坪自然保护区白腹锦鸡的夜栖地选择进行了研究。共发现24个夜栖地。以夜栖树为中心做r=7.5m大样方,随机在其中做4个1m×1m和4个0.5m×0.5m小样方,测量乔木、灌木和草本植物的各项参数;做128个非活动区对照样方和258个日栖地样方,分别随机选取等量样方与夜栖地样方相比较。结果表明:白腹锦鸡夜栖地多在针阔混交林和针叶林中,栖树以针叶树为主,繁殖期内成对个体同树共栖的栖位距离较近,栖枝雄高雌低。影响白腹锦鸡夜栖地选择的主要因素依次为:地形、栖树、隐蔽条件和遮蔽特征。与对照样方相比,白腹锦鸡夜栖地选择较矮而疏的乔木和少量倒木的环境;与日栖地样方相比,选择较矮、疏和较低盖度灌木草本植物的环境,有一定的空间分离。     

陕西黄龙山林区褐马鸡春季夜栖地选择

2006年4～6月,在陕西黄龙山林区,对褐马鸡(Crossoptilon mantchuricum)春季夜栖地的选择进行了研究.共记录到22个夜栖地,以夜栖树为中心做一个10 m×10 m样方,测定夜栖地海拔、坡向、坡度、坡位、地貌特征、夜栖树高度和胸径、乔木层盖度、乔木的数量、灌木层盖度、草本盖度、水源距离、人为干扰距离、林缘距离、栖枝高度和栖位上盖度等参数;通过9条样带测定54个随机样方,除栖枝高度和栖位上盖度外,指标相同.结果表明,褐马鸡春季夜栖地多偏向以坡度较大、山坡和山脊、接近水源、远离林边、人为干扰距离较远、乔木盖度和密度较大、栖树胸径较大、灌木层盖度和草本层盖度较小为主要特征的地方.主成分分析表明,前5个特征值的累积贡献率达到72.746%,可以较好地反映褐马鸡春季夜栖地生境特征.根据载荷系数绝对值大小,将褐马鸡春季夜栖地生境选择影响因子分别命名为地形和林下植被因子、气象因子、稳定性因子和水因子.影响褐马鸡夜栖地选择的关键因素是安全、舒适和栖息地转换的方便程度.     

海南原鸡繁殖期夜栖地的选择

原鸡Gallus gallus在繁殖期的日常活动趋向于以夜栖地为中心,因此夜栖地的研究对原鸡的繁殖和保育具有重要意义.2008年2～5月在海南大田自然保护区,采用野外观察和样方调查相结合的方法,对原鸡的夜栖地利用进行了研究,共记录到15个夜栖地.结果表明: 1) 原鸡在繁殖期多结成2～6只(3.3±1.5, n=13)的繁殖群,在同一棵树或邻近几棵树上集群夜栖; 2) 落叶季雨林和灌丛草地是原鸡繁殖期夜栖的主要植被类型; 3)原鸡多以小刺竹Bambusa bambos作为夜栖树,占53.3%,其次是厚皮树Lannea coromandelica,占20.0%; 4)原鸡倾向于选择灌木生长茂密、地面草本稀疏的生境作为夜栖地,并栖息在胸径均值为8.4 cm±3.5 cm的乔木或灌木的枝条上,栖枝均高为4.4 m±0.8 m; 5)主成分分析表明,影响原鸡夜栖地选择的主要因子依次为:栖树高、栖枝高度、栖树胸径、栖枝层盖度、草本层盖度、栖枝下方盖度和栖枝上方盖度.据此分析认为:繁殖期原鸡警惕性高,夜栖地多选择易于隐蔽和转移的生境.     

澳门路氹城黑脸琵鹭春季栖息地利用

黑脸琵鹭是全球最濒危的鸟类之一,其栖息地的研究对于该种群的保护和恢复具有重要意义。2013年1月4—5日,对澳门地区的黑脸琵鹭进行了同步调查;3—5月,于路氹城黑脸琵鹭集中分布地放置4台红外相机对其进行监测。结果表明,澳门地区黑脸琵鹭的最高数量为55只,其昼栖地以生态一区为主;黑脸琵鹭在黄昏时飞离生态一区(17∶00左右),夜间返回生态一区栖息,与以往的报道不同(夜栖地与昼栖地不同)。出现了新的夜栖地利用模式,即夜栖地和昼栖地相同,可能是黑脸琵鹭对澳门适宜夜栖地较少的一种适应。     

城市绿地中鹊鸲繁殖期和非繁殖期夜栖地选择

夜栖地是昼行性鸟类夜间重要的栖息场所,鸟类对夜栖地的选择有明显偏好性。随着城市化加剧,城市绿地逐步成为城市鸟类生存的庇护所,如何适应城市环境的干扰并安全夜栖于城市绿地中是鸟类在不同生活史阶段均需面临的问题。为探讨城市绿地中鸟类的夜栖地选择,本研究于2014年3月至2015年2月在广西宜州市区龙江河畔,采用系统调查法对鹊鸲(Copsychus saularis)繁殖期和非繁殖期的夜栖树种、夜栖地特征的17个生态因子进行了比较。结果显示:鹊鸲共选择15种夜栖树,繁殖期和非繁殖期的树种选择差异极显著,2个时期均选择5种夜栖树,其中利用频次较高的是桂花(Osmanthus fragrans)、杧果(Mangifera indica)和佛肚竹(Bambusa ventricosa)。主成分分析发现,繁殖期和非繁殖期夜栖地选择的主要因素均是栖树、栖枝隐蔽性以及周围安全性因素,其他栖枝、水源和食物因素次之,最后为干扰因素;其中,栖树和栖枝高度、乔木、草本和栖枝下方盖度等9个生态因子在2个时期间具有差异性。城市鹊鸲在生活史不同阶段选择最适夜栖地,体现出对强干扰城市生境的适应性。在未来城市绿化配置和建设中需增加具不同栖枝、树高和盖度特征的乔木树种,提高灌木和草本植被多样性,以满足不同鸟类对城市绿地中夜栖地的需求。     

云南蒙自钳嘴鹳夜栖地利用及夜栖树选择

动物对夜栖地选择的灵活程度是其分布和扩散的重要因素之一。钳嘴鹳(Anastomus oscitans)为中国新分布种,要了解其扩散趋势,掌握其夜栖地需求至关重要。2015年11月至2018年7月在云南蒙自坝区,使用卫星跟踪技术对6只钳嘴鹳进行了夜栖地利用和夜栖树选择研究,结果表明:(1)钳嘴鹳可以在多种生境中夜栖,包括林地、沼泽、岛屿等。从群体水平上分析,钳嘴鹳主要夜栖于沼泽中,利用率为(51.19±12.34)%,其次为林地(31.55±11.34)%和岛屿(17.26±5.70)%;从个体水平上来看,不同钳嘴鹳的夜栖地利用方式差异较大,其中4只主要利用沼泽,而另外2只主要利用林地;(2)随机森林分析表明:影响钳嘴鹳夜栖树选择的首要因子为距觅食地距离,其次为树高、地径和最低枝高度,而人为干扰因子的影响较弱。综合来看,钳嘴鹳对夜栖地类型以及夜栖树均表现出了极强的适应性和可塑性,这可能是其能够快速扩散的重要原因之一。同时也表明夜栖树并不能成为一个有力的限制因子,钳嘴鹳有可能继续向国内的南方湿地区扩散。     

四川雉鹑的冬季夜栖地选择

四川雉鹑(Tetraophasis szechenyii)是中国特有物种,国家Ⅰ级重点保护野生动物,对其冬季夜栖地选择的了解,有助于理解物种的生存策略,为物种保护提供参考。利用徒步跟踪和无线电遥测的方法,我们于2006年9月到2007年4月在四川省雅江县帕姆岭进行了野外研究。采用卡方检验、配对样本t检验和二元逻辑斯缔回归等方法对数据进行分析。结果发现:(1)四川雉鹑利用鳞皮冷杉(Abies squamata)和大果红杉(Larix potaninii var.macrocarpa)两种树夜栖,卡方检验分析发现四川雉鹑对这两树种没有明显的选择偏好(χ2=0.745,df=1,P=0.388);(2)夜栖树的胸径为(25.8±1.3)cm,夜栖枝条离地高度为(6.3±0.3)m,直径为(3.3±0.1)cm;(3)与对照样地相比,夜栖地生境一般靠近林缘,乔木的平均胸径大、林下盖度小、倒木数量多,夜栖树胸径大、最近乔木胸径大和最近乔木距离远;(4)逻辑斯缔回归分析表明:夜栖树第一枝距地面高为冬季四川雉鹑夜栖地选择的关键因子;倒木数量、平均乔木胸径、最近林缘距离为次关键因子,该模型对夜栖地的预测正确率为80.9%。冬季四川雉鹑选择夜栖地是安全、能量和地点转移三个因素综合作用的结果,在不同的环境下,同一物种对环境会有不同的适应策略。     

再引入黑颈长尾雉夜栖行为与夜栖地选择

2003年4月～2005年3月,通过野外观察、无线电遥测和样方调查,对广西岑王老山自然保护区再引入黑颈长尾雉的夜柄行为和夜柄地进行了研究.共观察记录到10个夜栖地,黑颈长尾雉夜间主要在树上栖息,偶尔在地上柄息,在针叶林为独栖(1只/树),在阔叶林独柄或者2～3只/树.黑颈长尾雉夜柄地选择受到柄树的高度、大小,灌术、乔木、草本层的盖度,水源距离及栖枝高度等因素的影响.黑颈长尾雉夜栖地的栖树具有一定的高度(雌:4.96±1.39 m,雄:5.52±1.95 m)和胸围大小(雌:21.4±8.29 cm,雄:23.50±8.39 cm);乔木层(78.00%±8.23%)和灌木层(44.50%±29.67%)盖度较大,草本层盖度较低的环境作为夜栖地;与水源具有一定的距离(348.50±308.30)m;夜栖地的坡度(44.80.±14.73.)和栖枝的高度(2.40±0.74 m).     

红喉雉鹑繁殖季的夜栖行为与夜栖地选择

红喉雉鹑（Tetraophasisobscurus）是中国特有种,国家一级重点保护野生动物,研究其繁殖季的夜栖地选择,能丰富该物种的基础资料,理解其生存策略,为该物种的保护和深入研究提供科学依据。2021年和2022年的3～7月,采用跟踪观察和系统搜索法,对四川王朗国家级自然保护区繁殖期红喉雉鹑的夜栖行为和夜栖地选择进行了调查,共记录夜栖地样方34个。采用卡方检验、配对样本T检验、Mann-WhitneyU检验和逻辑斯蒂回归模型方法对数据进行分析。红喉雉鹑主要夜栖于方枝柏（Sabina saltuaria）等针叶树,常见1只单独夜栖或2只共同夜栖,未见有集群夜栖;夜栖树通常位于上坡位,距离林缘和最近乔木较近,具有较大的胸径和郁闭度,栖枝距离地面高度6.6 m左右,栖枝长度约1.66m;夜栖地具有较大的坡度和落叶盖度,而灌木盖度较小。安全因素（夜栖树胸径、坡度）和食物因素（落叶盖度）是红喉雉鹑选择夜栖地的最关键因素。     

应用资源选择函数对褐马鸡冬季夜栖地选择的研究

2006年11月至2007年1月,在陕西黄龙山腹地的北寺山林区,对褐马鸡Crossoptilon mantchuricum冬季夜栖地的选择进行了研究。共记录到34个夜宿地,以夜宿树为中心各做一个10m×10m样方,测定夜栖地海拔、坡向、坡度、坡位、夜栖树高度和胸径、乔木层盖度、乔木数量、灌木层盖度、草本盖度、离最近水源距离、离林间道路的距离、离最近林缘的距离、离最近居民点距离等参数;对照样方采用随机抽样法,在研究区域内设置同样数目的对照样方,测定同样指标。结果表明,褐马鸡冬季夜栖地选择的资源选择函数为:logit(p)=-11.537 2.245×坡度 3.452×乔木盖度 2.001×乔木数量-2.903×与最近居民点的距离。根据拟合出的资源选择函数,褐马鸡冬季对夜栖地的选择概率为P=elogit(p)/(1 elogit(p)),模型的正确预测率可达到93.8%。模型表明,冬季褐马鸡夜栖地的选择概率与坡度、乔木盖度和栖树数量呈正相关,与距居民点距离呈负相关。     

Roost site selection by Little Owls Athene noctua in relation to environmental conditions and life‐history stages

Roost site selection is a state‐dependent process, affected by the individual's costs and benefits of roosting at a specific site in the available environment. Costs and benefits of different roost sites vary in relation to intrinsic factors and environmental conditions. Thus, the cost–benefit functions of roost sites are expected to differ between seasons and life‐history stages, resulting in adjustments in roost site selection. Studying roost site selection throughout the year therefore provides information about year‐round habitat requirements at different life‐history stages. However, little is known about the roosting behaviour of birds. Here, the roost site selection of Little Owls Athene noctua was studied by repeated daytime location of 24 adult and 75 juvenile radiotagged individuals from July to November. Little Owls preferred sheltered roost sites such as tree cavities with multiple entrances. They increasingly used sheltered sites from summer to winter and preferentially used sheltered roost sites with low ambient temperatures. Juveniles used significantly less sheltered sites during dispersal than before and afterwards, and used less sheltered sites than adults within their home‐range. The survival probability of birds roosting frequently at exposed sites was reduced. Roost site selection is probably driven by the two mechanisms of predator avoidance and thermoregulation, and the costs of natal dispersal may include increased predation threat and higher energy expenditure for thermoregulation. We suggest that adequate roost sites, such as multi‐entrance tree cavities, are an important habitat requirement for Little Owls and that habitat quality can be affected by manipulating their availability.     

Wintering forest birds roost in areas of higher sun radiation

We analyze environmental determinants of roost site selection by tree gleaning passerines wintering in a Mediterranean montane oakwood at a craggy area of high variation in altitude and hill-shading pattern. We hypothesize that in temperate latitudes of cold winter climate, birds should spend the night in areas of low altitudes, higher temperatures, and higher solar radiation in order to minimize thermoregulation costs during resting time and to improve foraging conditions just before and after roosting. We study night occupation of woodland locations by the presence of feces in 159 wooden nest boxes (i.e., under identical controlled roosting situations). We employ GIS methods to quantify solar radiation at each location surrounding the nest boxes and data loggers to measure air temperature in the field. Birds prefer to roost in forest patches with higher solar radiation, where the period of light available for foraging is extended and thermoregulation costs during daytime are minimized. They also selected woodland patches with taller trees, a pattern consistent with their foraging preferences for trunks and branches. Other environmental variables played a negligible role in determining the selection of roost sites. Here, we show, for the first time, the importance of sun radiation determining where to spend the night in wintering birds and call attention on considering the thermal space in forest management. Forest management should preserve woodland patches with taller trees more exposed to solar radiation to enhance winter habitat suitability for birds in these Mediterranean oakwoods.     

Using infrared thermography to detect night‐roosting birds

Most birds sleep while roosting at night. Although a widespread behavior, few investigators have studied the nocturnal roosting behavior of birds. Studies conducted to date have either focused on species that roost communally or used radio‐telemetry to locate sleeping individuals of a few focal species. Portable thermal cameras capable of detecting infrared (IR) heat signals may provide a more efficient and less invasive means of detecting nocturnal‐roosting endotherms such as birds. Our objective was to assess the efficacy of using thermal cameras to detect roosting birds in a woodland bird community in southeastern Australia. To better understand the limitations of using thermography to detect roosting birds, paired bird surveys were conducted along 44 transects from May to September 2016 using both traditional survey techniques during the day and surveys with a thermal camera at night. We detected 195 birds representing 21 species at nocturnal roosts using IR thermography, with the detection rate of birds during nocturnal surveys approximately one‐third (29.1%) that during diurnal surveys. Detection rates during nocturnal surveys declined more steeply with distance from observers than for diurnal surveys. Detection rates were significantly higher during diurnal surveys for 14 species of woodland birds, but did not differ between diurnal and nocturnal surveys for eight other species. Roost height, roost visibility, bird mass, and cluster size (i.e., two or more birds in physical contact) did not differ between species categorized as having high or low detectability during nocturnal surveys. Variability among species in nocturnal‐detectability could not be attributed to roost‐site visibility, roost height, or bird size. Positive detection biases associated with diurnal behavior, such as movement and vocalizations, and limitations of current IR technology, e.g., low resolution, likely contributed to overall lower detection rates during nocturnal surveys. However, our results suggest that infrared thermography can be an effective and useful technique for detecting roosting birds and studying roosting behavior, as well as for population monitoring under certain conditions.     

COMMUNAL ROOSTING BEHAVIOUR OF THE AUSTRALASIAN HARRIER CIRCUS APPROXIMANS IN NEW ZEALAND

The Australasian Harrier Circus upproximans habitually roosts communally in New Zealand but not in Australia. As many as 100 birds can occupy a roost in a small area of swamp. They start to assemble about one hour before dark and communal aerial displays in the vicinity of the roost are an integral part of the roosting behaviour. Roosts may be occupied all the year round, non-breeding birds continuing to roost communally throughout the summer. In New Zealand the habit is neither connected with migration nor is it an anti-predator device. It is considered that the abundance of food caused by the spread of introduced mammals and the large increase of habitat created by European settlement has built the harrier population up to such a size that the number required to elicit the response of communal roosting occurs at all times of year in most districts. Numbers within individual roosts fluctuate throughout the year and it is suggested that communal displays before roosting may provide the necessary feed-back for the initiation of population adjustments.     

Roosting behavior of a Neotropical migrant songbird, the northern waterthrush Seiurus noveboracensis, during the non-breeding season

Several species of Nearctic-Neotropical migratory songbirds appear to form roosting aggregations while on their wintering grounds but little is understood about the ecology of this behavior. We studied roosting behavior and patterns of roost habitat selection in the northern waterthrush Seiurus noveboracensis , during three winter years (2002–2004) in Puerto Rico using radio telemetry. Overall, red mangrove was selected for roosting disproportionately to its availability. Regardless of diurnal habitat used, 87% (n=86) of northern waterthrush selected dense stands of coastal red mangrove for roost sites. Individuals traveled up to 2 km to access roost sites in this habitat on a daily basis. The majority (8 of 14) of individuals roosted alone, while others roosted in loose aggregations near communal roosts of gray kingbirds Tyrannus dominicensis . Patterns of roost site selection did not vary by sex. Individuals showing aggressive response to playback during the day, however, selected roost sites significantly closer to the coast. Several additional migratory and resident bird species also used red mangrove for night-time roosting habitat. Red mangrove may be a critical nocturnal roosting habitat for bird populations that live in proximity to coastal areas in the Neotropics. The benefits of nocturnal roosting behavior as well as why individuals appear to select red mangrove remain poorly understood.     

WINTER ROOSTING AND FEEDING BEHAVIOUR OF PIED WAGTAILS MOTACZLLA ALBA NEAR OXFORD, ENGLAND

This study presents data on the roosting and feeding behaviour of Pied Wagtails around Oxford, England. During the winter of 1977–78, from two to 1200 wagtails roosted in a Phragmites reed-bed. Use of this roost was greatest during mild, windless weather and the birds apparently used alternate roosts during harsh weather. Movement between roosts sometimes occurred between sunset and sunrise. Morning ‘departure group’ size, number leaving per unit time and diversity of departure directions increased with roost size. Wagtails quickly left the vicinity in the morning. In the afternoon, they joined one or more pre-roost gatherings before entering the roost for the night. Behaviour upon arrival at the roost was variable: birds might enter the reeds quickly or circle in large groups before landing. Aerial revolutions and generally ‘restless’ behaviour often accompanied increases in roost size. Wagtail feeding rates varied significantly between and within habitats. Number of wagtails feeding on the flooded Port Meadow, located 2–3 km south of the main roost, varied from about five to over 60 on different days; these numbers were not correlated with feeding rates. In contrast, the number of birds feeding at a sewage farm was nearly constant all winter. Some wagtails show high fidelity to feeding areas but others do not. Five short-term food supplementation experiments indicated that wagtails knowledgeable about a dense food source are not followed in the morning by naive birds. Results of this study are discussed in relation to the predation, physiology and information centre hypotheses that have been suggested to explain communal roosting in birds. I conclude that the communal roosting system of Pied Wagtails has physiological and anti-predator functions. Wagtails appear to choose certain roosts because of the protection that they provide from adverse climate and predation.     

Microclimate of tree cavities during winter nights—implications for roost site selection in birds

We examined the relationships between cavity temperature, ambient temperature outside the cavity and structural characteristics of 70 cavities measured for 1 night to determine if cavity roosting birds may potentially select warmer tree cavities for wintertime roosting. The mean temperature increment of the cavity (=cavity-ambient temperature) varied from −2.4 to 4.9°C and increased with higher day-to-night fluctuations in the ambient temperature, smaller cavity entrance and better health status of the cavity tree. Cavities in healthy trees were warmer than those in dead trees, but this difference disappeared with rising mean ambient temperatures. This interaction between the effects of tree health status and mean ambient temperature, as well as the effect of day-to-night fluctuations in the ambient temperature, were supported by the analysis of repeated measurements of temperature taken on 12 consecutive nights in five cavities. The variability in cavity microclimates makes the selection of warmer roost sites possible, and the predictors of microclimate may provide indirect cues to prospecting birds.     

Structure of a Brambling Fringilla montifringilla roost according to sex, age and body-mass

In a winter roost of several hundreds of thousands of Bramblings Fringilla montifringilla , the composition of birds roosting at the periphery and of birds flying into the centre of the roost was studied regarding sex, age, size and body-mass. At the periphery of the roost, more females were present than in the centre, and their proportion increased with decreasing density at the periphery. No significant difference in age classes was found between centre and periphery, but adults flew into the roost later than first year birds. Within sex-age classes, birds in the centre were heavier but not larger than birds at the periphery. The difference in body-mass between centre and periphery was more pronounced in small than in large birds within each sex-age class.
Because strong competition for particular positions within the roost was observed, it is inferred that the quality of roosting positions varied and that females and/or light birds were displaced toward the periphery. Predation and microclimate are discussed as possible reasons for the variation in the quality of roosting positions and for the lower energy reserves of birds roosting at the periphery.     

Factors influencing perch selection by communally roosting Turkey Vultures

ABSTRACT Many birds roost communally during at least part of their annual cycle, suggesting that for them the advantages of living in a group outweigh the disadvantages. However, perch sites within a roost may vary in quality because of differences in degree of exposure to the elements, predators, and fecal droppings. Individuals should select perches in the roost that minimize costs while enabling them to experience the benefits of communal roosting. We studied communally roosting Turkey Vultures (Cathartes aura) in northeastern Iowa (USA) from late August to mid‐October, when hatching‐year (HY) birds had joined the roost and were distinguishable from after‐hatching‐year (AHY) birds. On 82 d during our 4‐yr study (2004–2007), we noted the age class and perch position of vultures on two communication towers used as a preroost site. Perches used by vultures were classified as top‐level (with no perches above them) or lower‐level (with other perches above them). Top‐level perches were preferred by Turkey Vultures. Of 1713 birds recorded, 71% were on top‐level perches, even though only 39% of available perches were top‐level. Vultures did not use lower perches if top perches on that tower were unoccupied. The percentage of birds using lower perches increased as the number of vultures present increased, suggesting that top‐level perches were occupied first. AHY birds used top‐level perches more often than expected and HY birds used top‐level perches less often than expected, implying that age‐related dominance affected perch selection. On 61 of 82 d (74%), top‐level perches of both towers were occupied and, on 8 d (10%), only top perches on one tower were occupied. However, on 13 d (16%), both top‐level and lower‐level perches were occupied on one tower while no vultures perched on the other tower, suggesting that social attraction to other vultures can override a general preference for top‐level perches. Thus, our results provide evidence that social attraction, age‐related dominance, and preference for higher perches are proximate factors influencing perch selection in communally roosting Turkey Vultures. Ultimate factors that may be responsible for Turkey Vultures preferring higher roosting perches are reduced risk of predation, less exposure to fecal droppings that might reduce their plumage quality, and better visual information for locating food sources.     

Mechanisms for the formation and maintenance of traditional night roost aggregations in a territorial damselfly

Communal roosting has been studied extensively in birds, but the mechanisms and functions of this taxonomically widespread behaviour pattern remain poorly understood. We studied the roosting behaviour of rubyspot damselflies, Hetaerina americana, in relation to sex and territorial status, and conducted field experiments to test for specific mechanisms of roost formation and maintenance. Both sexes tended to return close to their previous night's roost, but only males were significantly more roost site faithful than chance expectations based on individual day ranges. Males were more roost site faithful when they held mating territories. After acquiring a territory, males usually began roosting closer to the territory after a delay of a few days. Roosts were not located at sites that reduced the daily commuting distance between hunting areas and territories; males generally hunted closer to their territories than to their roosts. In field experiments, sites 'seeded' with synthetic models of male rubyspots attracted more recruits than vacant control sites and control sites seeded with nonrubyspot (clear-winged) damselfly models. Sites seeded repeatedly with rubyspot models often remained popular for roosting after the models were removed, suggesting that the models established new traditional roosts. These results indicate that conspecific attraction and individual spatial memory together may be sufficient to explain, at a proximate level, the traditional night roost aggregations of this species. We discuss these results in relation to functional hypotheses for roost site choice and fidelity. Copyright 2000 The Association for the Study of Animal Behaviour.