河南新乡黄河湿地鸟类国家级自然保护区苍鹭巢特征与巢址选择

河南新乡黄河湿地鸟类国家级自然保护区是我国候鸟迁徙中线的必经之路,鸟类物种丰富。目前,该湿地的人为干扰现象日益突出,对鸟类栖息和繁殖造成了影响。苍鹭Ardea cinerea是该湿地鸟类的重要代表,其繁殖活动与栖息环境密切相关。为了解干扰鸟类繁殖的主要因素、有效管理保护区、维持湿地的鸟类多样性,于2017年5—8月,采用GPS定位、样方调查等方法对保护区陈桥东湖苍鹭繁殖地内的巢特征、巢址区和对照区生态因子进行了调查。研究结果表明:苍鹭筑巢位置对芦苇phragmites australis丛有极高的偏爱;巢材主要是芦苇;巢口向上呈浅盘状,巢内径、巢外径、巢高、巢深分别为(39.00±3.28)cm、(79.10±15.39)cm、(31.00±19.80)cm和(5.00±1.43)cm。对比苍鹭巢址区与对照区生态因子发现,巢址区植被密度、植被高度和植被盖度显著低于对照区(P0.05);水深、巢距人为活动不频繁地距离和巢距人为活动频繁地距离显著高于对照区(P0.05)。采用AIC信息准则法对可能影响苍鹭巢址选择的生态因子进行Logistic回归分析,结果发现,植被状态和干扰因子是制约苍鹭巢址选择的关键因素。建议通过采取适当扩大水域面积及水生植物面积、封锁湿地中的道路、定期蓄水、处理好湿地保护与旅游开发之间的关系等措施来改善苍鹭等鸟类的栖息环境,保护保护区鸟类多样性。     

龙凤保护区普通鸬鹚巢特征与巢址选择

巢址选择作为鸟类繁殖的重要环节,是动物生态学关注的热点问题。为探究中等体型湿地鸟类普通鸬鹚的巢址选择偏好及主要影响因子,2019年4—10月运用秩和检验、主成分分析等方法对黑龙江龙凤保护区内普通鸬鹚巢特征、巢址特征、巢址选择进行了分析。结果表明：(1)普通鸬鹚偏好选择巢树乔木相对较矮(P<0.05)、周围灌木相对较矮(P<0.01)、植被盖度较低(P<0.01)、人为干扰距离较远(P<0.01)、距水面距离较远(P<0.05)的区域筑巢;(2)影响普通鸬鹚巢址选择的因子为隐蔽因子(20.634%)、巢稳定因子和干扰因子(27.614%)、植被因子(13.901%)、水因子(5.782%)和巢忠诚度(5.069%)。进一步分析表明：(1)普通鸬鹚倾向选择粗细适中的巢材,巢材来源于优势植被,巢深随纬度增高而增大;(2)巢区植被特征符合普通鸬鹚对能量支配的权衡,巢区粪便对该特征有强化作用。基于上述结果,建议龙凤保护区在巢区内加种高大乔木。     

震旦鸦雀在镶嵌型芦苇收割生境中的巢址选择

大规模的芦苇收割会对在该生境中繁殖的鸟类产生严重影响。为降低芦苇收割对鸟类繁殖的负面影响,许多地区的湿地管理者逐渐采用了镶嵌型的芦苇收割方式。但是,这种新的芦苇管理方式对鸟类繁殖期生境选择的作用机理尚不清楚。震旦鸦雀是一种主要分布在我国东部、完全依赖芦苇生境而生存的珍稀鸟类,已被IUCN定为全球性近危物种。大规模的芦苇收割导致其适宜生境丧失,被认为是该物种面临的一个主要威胁。选择山东黄河三角洲国家级自然保护区为研究地区,采用AIC信息准则法,从巢址微生境、巢域斑块和全模型3个水平上对可能影响震旦鸦雀巢址选择的生境因子进行了逻辑斯蒂回归分析,并重点探讨芦苇镶嵌收割对其巢址选择的影响以及不同水平的相互效应。结果发现,震旦鸦雀的巢址选择受巢址微生境和巢域斑块尺度双重水平的影响,但巢址微生境因子的影响要大于巢域斑块因子。在巢址微生境水平上,影响震旦鸦雀巢址选择的因素有:1.5—2.5 m旧芦苇的密度、2.5 m以上新芦苇的密度、香蒲密度和巢的可见度;在巢域斑块水平上,影响因素包括芦苇生境类型、旧芦苇斑块面积的比例和植被盖度;在综合模型中,影响因素有1.5—2.5 m旧芦苇的密度、2.5 m以上新芦苇的密度、香蒲密度、巢的可见度和植被盖度。综上,震旦鸦雀倾向于在植被盖度较高、具有一定比例(18.3%)旧芦苇面积、1.5—2.5 m旧芦苇密度较高、可见度较低的生境斑块中筑巢。研究中,78.7%(n=141)的震旦鸦雀将巢筑在新旧芦苇混合的微生境中,其中36.9%的巢址附近旧芦苇的比例在一半以上;53.2%(n=111)的巢筑于新、旧两种芦苇茎秆之上,22.3%的巢的支撑芦苇中旧芦苇所占比例在一半以上。研究结果表明,旧芦苇在震旦鸦雀巢址选择和筑巢过程中发挥了重要作用。由于大范围的芦苇收割在微生境水平上可降低1.5—2.5 m旧芦苇的密度,在巢域斑块尺度上可降低旧芦苇斑块面积的比例,因此建议,在震旦鸦雀的繁殖地,未来的芦苇收割应采用镶嵌收割的形式,并至少应保留面积在20%以上的结构较好的旧芦苇斑块,以供震旦鸦雀选择巢址和繁衍后代。     

盐城滨海海堤林中黑尾蜡嘴雀和黑卷尾的巢址选择与生态位

繁殖期鸟类的巢址选择受到很多因素的影响。许多雀形目鸟类选择在树上营巢,但开阔的沿海地区通常缺乏成片的自然林地,人工种植的廊道状海堤林则成为多种雀形目鸟类的营巢地。2018年4-8月在江苏省大丰麋鹿国家级自然保护区境内的海堤林中,对繁殖鸟类巢的分布及两种优势繁殖鸟类---黑尾蜡嘴雀(Eophona migratoria)和黑卷尾(Dicrurus macrocercus)的巢址选择进行了研究,分析了两种鸟类的生态位重叠情况。结果表明:海堤林生境中共发现10种繁殖鸟的127个巢,鸟巢多数位于5 m以上的空间;影响黑尾蜡嘴雀巢址选择的主要因素是巢树和灌木等,巢位置、乔木和安全等因素是次要因素(前5主分量累计贡献率为71.9%);影响黑卷尾巢址选择的主要是巢树因素和灌木因素,巢向、乔木因子是次要因素(前5主分量累计贡献率78.0%);在巢址生态位分化上:两种鸟类的巢向(Utest,Z=-3.013,P<0.01)、巢高(Utest,Z=-6.718,P<0.01)、巢位置(Utest,Z=-5.402,P<0.01)、隐蔽性(Utest,Z=-4.081,P<0.01)选择上存在极显著的差异,两者在这些因子存在生态位分化;两种鸟类在12个巢址因子选择上的生态位重叠值都较大(最小值为0.500,最大值为0.998),存在激烈的种间竞争;在滨海地区,海堤林是依赖树木筑巢繁殖鸟类的重要栖息地,需要加强保护与管理。     

黑眉苇莺存在对东方大苇莺巢材的盗窃行为

筑巢是大多数鸟类繁殖成功的必要条件,筑巢花费精力较少的鸟类可以将更多的时间投入到后期繁殖中。因此,对于筑巢繁殖的鸟类来说,如何快速有效地建筑一个巢尤为重要。然而,对雀形目鸟类快速和投机筑巢的行为报道较少。2021年6至8月,在黑龙江扎龙国家级自然保护区,通过录像对繁殖期东方大苇莺（Acrocephalus orientalis）和黑眉苇莺（A. bistrigiceps）的筑巢行为进行研究,记录到黑眉苇莺盗取东方大苇莺巢材料的行为。根据视频内容和现场观察,本研究初步描述了黑眉苇莺偷窃行为的全过程。最后,通过文献查阅,对报道过巢材盗窃行为的部分雀形目鸟类进行了统计。本文研究结果为进一步确定雀形目鸟类的巢材盗窃行为的流行程度提供了基础信息。     

盐城滨海海堤林中黑尾蜡嘴雀和黑卷尾的巢址选择与生态位

繁殖期鸟类的巢址选择受到很多因素的影响。许多雀形目鸟类选择在树上营巢,但开阔的沿海地区通常缺乏成片的自然林地,人工种植的廊道状海堤林则成为多种雀形目鸟类的营巢地。2018年4—8月在江苏省大丰麋鹿国家级自然保护区境内的海堤林中,对繁殖鸟类巢的分布及两种优势繁殖鸟类———黑尾蜡嘴雀(Eophona migratoria)和黑卷尾(Dicrurus macrocercus)的巢址选择进行了研究,分析了两种鸟类的生态位重叠情况。结果表明:海堤林生境中共发现10种繁殖鸟的127个巢,鸟巢多数位于5 m以上的空间;影响黑尾蜡嘴雀巢址选择的主要因素是巢树和灌木等,巢位置、乔木和安全等因素是次要因素(前5主分量累计贡献率为71.9%);影响黑卷尾巢址选择的主要是巢树因素和灌木因素,巢向、乔木因子是次要因素(前5主分量累计贡献率78.0%);在巢址生态位分化上:两种鸟类的巢向(U_(test),Z=-3.013,P0.01)、巢高(U_(test),Z=-6.718,P0.01)、巢位置(U_(test),Z=-5.402,P0.01)、隐蔽性(U_(test),Z=-4.081,P0.01)选择上存在极显著的差异,两者在这些因子存在生态位分化;两种鸟类在12个巢址因子选择上的生态位重叠值都较大(最小值为0.500,最大值为0.998),存在激烈的种间竞争;在滨海地区,海堤林是依赖树木筑巢繁殖鸟类的重要栖息地,需要加强保护与管理。     

筑巢投入与巢材组成对大山雀繁殖产出的影响

鸟类在筑巢期投入能量的多少会影响其繁殖成效,巢材组成的差异也会影响其最终繁殖产出。本文以大山雀(Parus major)为研究对象,通过探究巢重及巢材组成对其繁殖的影响,以揭示筑巢投入和巢材对繁殖产出的影响。对2015年收集到的35巢进行了分析。结果表明:巢材总重与出飞数、出飞成功率及繁殖成功率呈极显著的负相关;羽毛重及其所占总重的比例与窝卵数、出雏数及出飞数呈显著的正相关,与产首枚卵的日期呈显著的负相关;植物茎重及其所占总重的比例与窝卵数及出雏数呈显著的正相关。本研究表明,大山雀亲鸟筑巢消耗的能量越多,子代出飞情况反而越差;同时,巢内保温性和支撑性巢材越多,繁殖产出越大。     

新疆阜康地区家麻雀的巢址选择

2013年7月和2014年5~7月,在新疆阜康地区对家麻雀(Passer domesticus)的巢址选择进行调查,以分析影响家麻雀巢址选择的生态因子。在研究区内共找到75个家麻雀的自然巢,筑巢生境为农田和防护林带,均在白杨(Populus adenopoda)林和胡杨(P.euphratica)林中的树上筑巢。其中,繁殖成功巢40个,繁殖失败巢20个,15个巢未记录到繁殖结果。在研究区内的居民房屋、墙洞等没有发现家麻雀的巢。采用逻辑斯蒂回归和主成分分析方法对筑巢地海拔(m)、筑巢树种、筑巢树高(m)、巢距路距离(m)、巢距地面高度(m)、巢上方盖度(%)、筑巢树胸径(m)、最近邻巢的距离(m)这些家麻雀的主要巢址参数进行分析,结果表明,影响新疆阜康地区家麻雀巢址利用的主要因素为巢距地面高度(m)、巢上方盖度(%)和巢距路距离(m)。对家麻雀繁殖成功巢(n=40)和繁殖失败巢(n=20)的巢址参数进行比较,两者差异不显著,因而推测,在研究区域的尺度内,家麻雀的巢址选择并不是影响其繁殖成效的主要因素。     

家燕营巢特征及其对城市环境的适应性

城市面积在全球范围内迅速扩张,一些鸟类种群通过改变营巢特征,在与自然生境截然不同的城市中筑巢繁殖。但目前城市环境对于鸟类营巢影响的研究较缺乏。为了解鸟类营巢对城市环境的适应,于2016、2019年在黑龙江哈尔滨的城市与乡村环境,分别测量家燕（Hirundo rustica）巢（如,大小及形状）及巢址特征等（如,距地面和屋顶距离）参数,以探究：（1）家燕巢特征在乡村及城市生境是否存在差异？（2）家燕巢特征在年际间是否存在变化？并为城市家燕种群的保护提供理论依据及合理建议。研究采用Kruskal-Wallis秩和检验以及Wilcoxon秩和检验比较分析所测量的巢特征参数在城乡之间、年际间的差异,并对组间参数进行线性判别分析（LDA,Linear Discriminant Analysis）。结果发现,城乡间具有显著差异：（1）与乡村相比,城市巢距离屋顶更远,距地相对更近（P<0.05）;（2）城市巢更浅（P<0.05）;（3）从2016到2019年,城市和乡村巢都变得更深,半径更大（P<0.05）。根据这些发现,推测城市楼房建筑的楼道为家燕繁殖提供了相对更为封闭、安全的环境,旧巢及较为丰富的支撑物为家燕提供了适宜的巢址,有可能节省亲鸟在营巢上的繁殖投入;但同时应当警惕门窗关闭、资源受限、人为干扰等不利因素可能造成的生态陷阱。     

若尔盖湿地保护区黑颈鹤巢期及影响因子

对鸟类巢期的研究不仅可以丰富鸟类繁殖生物学资料,也可为理解和研究鸟类的生态适应与进化提供重要线索和依据。2013—2014年3月份至7月份,在若尔盖湿地保护区及周边对55对繁殖黑颈鹤的营巢时长进行了研究,调查结果显示:黑颈鹤的营巢时长在0.5—40 d之间,平均巢期为(6.7±9.3)d;在其营造的4种巢型中,巢期长短依次为:泥堆巢草堆巢草墩巢岛地巢,且差异性极显著(P0.001),巢期与巢型显著相关(r=0.728);在其营巢的3种巢址生境中,巢期长短依次为:湖泊生境沼泽生境河流生境,且差异性极显著(P0.001),巢期与巢址生境显著相关(r=0.315);从不同营巢月份看,巢期长短依次为:4月份巢5月份巢6月份巢,且差异性极显著(P0.01),巢期与筑巢月份显著相关(r=0.664);巢期与巢体积大小具有显著相关性(r=0.856),即营巢时间越长巢体积越大。黑颈鹤的营巢时间长短主要受营巢生境、月份和做巢类型的影响。     

Incorporation of cigarette butts into nests reduces nest ectoparasite load in urban birds: new ingredients for an old recipe?

Birds are known to respond to nest-dwelling parasites by altering behaviours. Some bird species, for example, bring fresh plants to the nest, which contain volatile compounds that repel parasites. There is evidence that some birds living in cities incorporate cigarette butts into their nests, but the effect (if any) of this behaviour remains unclear. Butts from smoked cigarettes retain substantial amounts of nicotine and other compounds that may also act as arthropod repellents. We provide the first evidence that smoked cigarette butts may function as a parasite repellent in urban bird nests. The amount of cellulose acetate from butts in nests of two widely distributed urban birds was negatively associated with the number of nest-dwelling parasites. Moreover, when parasites were attracted to heat traps containing smoked or non-smoked cigarette butts, fewer parasites reached the former, presumably due to the presence of nicotine. Because urbanization changes the abundance and type of resources upon which birds depend, including nesting materials and plants involved in self-medication, our results are consistent with the view that urbanization imposes new challenges on birds that are dealt with using adaptations evolved elsewhere.     

Are house sparrow populations limited by the lack of cavities in urbanized landscapes? An experimental test

Current urban policies are associated with deep changes in urban structures, which may impoverish urban biodiversity. A major concern is the disappearance of nesting sites for wild vertebrate species living in urban areas. New urban structures without any cracks or cavities may especially preclude cavity nesters from breeding in cities and they may cause population declines. In that context, we experimentally investigated this question in an urban exploiter bird species (the house sparrow Passer domesticus), which is dramatically declining in most European cities. To test if the lack of cavities is limiting house sparrow populations in urban areas, we equipped 11 sites along an urbanization gradient with nest boxes and we then evaluated the rate of occupancy of these nest‐boxes. This urbanization gradient was characterized by very rural places (isolated farms) and moderately urbanized areas (town of medium size, i.e. 60 000 inhabitants). Surprisingly, rural nest boxes were more occupied than urban ones, suggesting that cavity availability is probably more constraining in rural areas relative to urban ones. Therefore, our study suggests that urban house sparrow populations are probably not constrained by a lack of nesting sites in medium size cities with urban designs similar to our city of interest (Niort, western France). This hypothesis definitely needs now to be tested in further urban landscapes (e.g. large cities and urban landscapes with other architecture and management policies).     

Urban living influences the nesting success of Darwin’s finches in the Galápagos Islands

Urbanization is expanding worldwide with major consequences for organisms. Anthropogenic factors can reduce the fitness of animals but may have benefits, such as consistent human food availability. Understanding anthropogenic trade‐offs is critical in environments with variable levels of natural food availability, such as the Galápagos Islands, an area of rapid urbanization. For example, during dry years, the reproductive success of bird species, such as Darwin''s finches, is low because reduced precipitation impacts food availability. Urban areas provide supplemental human food to finches, which could improve their reproductive success during years with low natural food availability. However, urban finches might face trade‐offs, such as the incorporation of anthropogenic debris (e.g., string, plastic) into their nests, which may increase mortality. In our study, we determined the effect of urbanization on the nesting success of small ground finches (Geospiza fuliginosa; a species of Darwin''s finch) during a dry year on San Cristóbal Island. We quantified nest building, egg laying and hatching, and fledging in an urban and nonurban area and characterized the anthropogenic debris in nests. We also documented mortalities including nest trash‐related deaths and whether anthropogenic materials directly led to entanglement‐ or ingestion‐related nest mortalities. Overall, urban finches built more nests, laid more eggs, and produced more fledglings than nonurban finches. However, every nest in the urban area contained anthropogenic material, which resulted in 18% nestling mortality while nonurban nests had no anthropogenic debris. Our study showed that urban living has trade‐offs: urban birds have overall higher nesting success during a dry year than nonurban birds, but urban birds can suffer mortality from anthropogenic‐related nest‐materials. These results suggest that despite potential costs, finches benefit overall from urban living and urbanization may buffer the effects of limited resource availability in the Galápagos Islands.     

Use of mistletoes by the Grey Go‐away‐bird (Corythaixoides concolor,Musophagidae) in a semi‐arid savannah,south‐west Zimbabwe

Mistletoes are preferred nesting sites for many bird species in a range of habitats. However, no studies have examined the use of mistletoes by nesting birds in the semi‐arid savannah. We studied nesting in mistletoe and its role in determining nesting success in the Grey Go‐away‐bird in south‐west Zimbabwe. We modelled the effects of mistletoe, mistletoe abundance, nest microclimate, concealment and nest height on daily survival rates (DSR) using program MARK. A constant survival model was best fitted for the Grey Go‐away‐bird suggesting a constant nest survival rate across the nesting period. Mistletoe nests had lower DSR than nests placed elsewhere in the canopy. Mistletoe abundance and nest height had a positive association with DSR whereas visibility distance, microclimate and concealment were negatively associated with DSR. Overall, survival for nests in mistletoe was 22.1% compared with 90.5% for nests in other substrates over the 50‐day nesting period. In conclusion, the low nest survival in mistletoe suggests either that the factors used to select mistletoe as nest sites by these birds are poor predictors of nest success or that nesting in mistletoe may be maladaptive.     

Decaying trees improve nesting opportunities for cavity‐nesting birds in temperate and boreal forests: A meta‐analysis and implications for retention forestry

Many studies have dealt with the habitat requirements of cavity‐nesting birds, but there is no meta‐analysis on the subject and individual study results remain vague or contradictory. We conducted a meta‐analysis to increase the available evidence for nest‐site selection of cavity‐nesting birds. Literature was searched in Web of Science and Google Scholar and included studies that provide data on the habitat requirements of cavity‐nesting birds in temperate and boreal forests of varying naturalness. To compare nest and non‐nest‐tree characteristics, the following data were collected from the literature: diameter at breast height (DBH) and its standard deviation (SD), sample size of trees with and without active nest, amount of nest and available trees described as dead or with a broken crown, and amount of nest and available trees that were lacking these characteristics. Further collected data included bird species nesting in the cavities and nest‐building type (nonexcavator/excavator), forest type (coniferous/deciduous/mixed), biome (temperate/boreal), and naturalness (managed/natural). From these data, three effect sizes were calculated that describe potential nest trees in terms of DBH, vital status (dead/alive), and crown status (broken/intact). These tree characteristics can be easily recognized by foresters. The results show that on average large‐diameter trees, dead trees, and trees with broken crowns were selected for nesting. The magnitude of this effect varied depending primarily on bird species and the explanatory variables forest type and naturalness. Biome had lowest influence (indicated by ΔAIC). We conclude that diameter at breast height, vitality, and crown status can be used as tree characteristics for the selection of trees that should be retained in selectively harvested forests.     

A habitat island approach to conserving birds in urban landscapes: case studies from southern and northern Europe

Wildlife conservation in urban habitats is increasingly important due to current urbanization trends. We review the different approaches to studying birds in urban landscapes, and point out the importance of the habitat island ecological theory as a research framework for the management and conservation of urban birds. Based on two comprehensive research projects conducted at urban parks in Spain (Madrid) and Finland (Oulu and Rovaniemi), several different issues related to bird conservation in cities are discussed, main findings of these projects are presented, and future research needs are suggested. Urban parks are important biodiversity hotspots in cities. Fragmentation conditions have the same deleterious effects to urban birds as in other fragmented landscapes. Park size accounts for species accumulation in urban parks; this pattern being highly nested. Urban parks of 10–35 ha would contain most of the species recorded in cities, but other indicators related to the probabilities of persistence of the target species should be obtained. Wooded streets can increase urban landscape connectivity by providing alternative habitat for feeding and nesting during the breeding season. Because increasing the size of parks is difficult in cities, enhancement of habitat diversity and resource availability for birds within parks (e.g. nest boxes, winter feeding tables, etc.) appears to be a straightforward way of increasing urban bird diversity. However, human disturbance (pedestrians) should be controlled since it can negatively influence many urban birds. We present a conceptual model for urban bird conservation, which includes three aspects (management, environmental education and research) and new alternatives to promote the involvement of different sectors of the society.     

Cavity-nesting birds are limited by nesting habitat in Neotropical agricultural landscapes

Most studies comparing biodiversity between natural and human-modified landscapes focus on patterns in species occurrence or abundance, but do not consider how different habitat types meet species' breeding requirements. Organisms that use or nest in tree cavities may be especially threatened by habitat conversion due to the loss of their nesting sites. Although cavity-nesting bird diversity is highest in the tropics, little is known about how tropical birds use cavities, how agriculture affects their reproductive biology, and how effective nest boxes could be as a conservation strategy in tropical agriculture. Here, we explored how habitat conversion from tropical forests to pasture affects the abundance, nesting habitat availability, and nest success of cavity-nesting birds in Northwest Ecuador. We conducted bird surveys and measured natural cavity availability and use in forest and agriculture. We also added artificial nest boxes to forest and agriculture to see whether cavity limitation in agriculture would elicit higher use of artificial nest boxes. We found evidence of cavity limitation in agriculture—there were many more natural cavities in forest than in agriculture, as well as more avian use of nest boxes placed in agriculture as compared to forest. Our results suggest that it is important to retain remnant trees in tropical agriculture to provide critical nesting habitat for birds. In addition, adding nest boxes to tropical agricultural systems could be a good conservation strategy for certain species, including insectivores that could provide pest-control services to farmers. Abstract in Spanish is available with online material.     

Buildings promote higher incubation temperatures and reduce nest attentiveness in a Neotropical thrush

Incubation is an energetically costly parental task of breeding birds. Incubating parents respond to environmental variation and nest‐site features to adjust the balance between the time spent incubating (i.e. nest attentiveness) and foraging to supply their own needs. Non‐natural nesting substrates such as human buildings impose new environmental contexts that may affect time allocation of incubating birds but this topic remains little studied. Here, we tested whether nesting substrate type (buildings vs. trees) affects the temperature inside the incubation chamber (hereafter ‘nest temperature’) in the Pale‐breasted Thrush Turdus leucomelas, either during ‘day’ (with incubation recesses) or ‘night’ periods (representing uninterrupted female presence at the nest). We also tested whether nesting substrate type affects the incubation time budget using air temperature and the day of the incubation cycle as covariates. Nest temperature, when controlled for microhabitat temperature, was higher at night and in nests in buildings but did not differ between daytime and night for nests in buildings, indicating that buildings partially compensate for incubation recesses by females with regard to nest temperature stability. Females from nests placed in buildings exhibited lower nest attentiveness (the overall percentage of time spent incubating) and had longer bouts off the nest. Higher air temperatures were significantly correlated with shorter bouts on the nest and longer bouts off the nest, but without affecting nest attentiveness. We suggest that the longer bouts off the nest taken by females of nests in buildings is a consequence of higher nest temperatures promoted by man‐made structures around these nests. Use of buildings as nesting substrate may therefore increase parental fitness due to a relaxed incubation budget, and potentially drive the evolution of incubation behaviour in certain urban bird populations.     

Nesting Success in Crimson Finches: Chance or Choice?

In avian systems, nest predation is one of the most significant influences on reproductive success. Selection for mechanisms and behaviours to minimise predation rates should be favoured. To avoid predation, breeding birds can often deter predators through active nest defence or by modifying behaviours around the nest (e.g. reducing feeding rates and vocalisations). Birds might also benefit from concealing nests or placing them in inaccessible locations. The relative importance of these strategies (behaviour vs. site selection) can be difficult to disentangle and may differ according to life history. Tropical birds are thought to experience higher rates of predation than temperate birds and invest less energy in nest defence. We monitored a population of crimson finches (Neochmia phaeton), in the Australian tropics, over two breeding seasons. We found no relationship between adult nest defence behaviour (towards a model reptile predator) and the likelihood of nest success. However, nest success was strongly related to the visibility of the nest and the structure of the vegetation. We found no evidence that adult nest building decisions were influenced by predation risk; individuals that re‐nested after a predation event did not build their nest in a more concealed location. Therefore, predator avoidance, and hence nest success, appears to be largely due to chance rather than due to the behaviour of the birds or their choice of nesting sites. To escape high predation pressures, multiple nesting attempts both within and between seasons may be necessary to increase reproductive success. Alternatively, birds may be limited in their nest‐site options; that is, high‐quality individuals dominate quality nest sites.