惊飞距离--杭州常见鸟类对人为侵扰的适应性

惊飞距离是指人在鸟类惊飞之前能接近鸟类的距离,反映了鸟类对人为侵扰的适应程度。2002年9月至2003年1月,在杭州6个区的调查中共见到42种鸟类,以其中的9种优势种兼广布种为研究对象分析了鸟类沿侵扰梯度惊飞距离的变化及影响惊飞距离的主要因子。根据植被类型、建筑比例、干扰因素等差异,将栖息地分为5类：建筑区,城市园林,西部山区,水荡,农田。选取体重、活动高度、观测点可视度、引人注目程度、迁徙状态作为探讨惊飞距离的5个变量。研究结果表明：①不同栖息地的人为侵扰程度有极显著差异：建筑区的人为侵扰程度与城市园林有显著差异,西部山区、农田和水荡之间无显著差异。②在不同栖息地中,惊飞距离具有显著差异;随着人为侵扰程度的提高,同种鸟类在不同栖息地中的惊飞距离呈减小趋势。③鸟类对人为侵扰的惊飞距离与选取变量问的关系显著：体形大小、观测点可视度与惊飞距离呈显著正相关,活动高度与惊飞距离呈显著负相关,而引人注目性与惊飞距离不相关。说明多数鸟类对人为侵扰已有了一定的适应性;体形较大、在植被稀疏的栖息地中以及靠近地面活动的鸟类惊飞距离较大,对人为侵扰的适应性较差。     

鸟类交通致死原因的种间行为差异分析(英文)

鸟类和其他动物经常死于车撞, 每年因车撞而死亡的个体可达数百万只。为什么有的物种比其他物种更易于死于车撞的问题,迄今未研究过。该文推测物种本身所具有的冒险行为可能是这些物种的某些个体更常死于车撞的一个原因。此外,不同物种个体在公路上的行为、个体数量、栖息地偏好、繁殖社会性以及健康状况都可能是影响个体车撞风险的潜在因素。2001—2006 年,对丹麦一个农村地区进行定期统计取样, 得到该地区不同种鸟类个体被车撞死事件发生的频率,以及周边环境中 50 种鸟类的个体数量数据, 并利用这些数据来检验我们的预测。车撞频率随鸟类个体数量线性增加和位于道路上或者低空飞越道路的个体所占比例增加,这两个因素几乎无法解释鸟类车撞频率差异。在考虑到丰富度这个因素后,发现那些鸟类惊飞距离短、面对潜在危险而更具有冒险性的物种个体更易遭遇车撞而亡。另外, 独居的物种、疟原虫感染率高的物种及因体型大而拥有大法氏囊的物种个体死于车撞的频率更高。这些发现表明, 一系列反映冒险行为、视敏度和健康状况的因子导致某些鸟类物种易受到车撞影响。     

青藏高原两种雪雀惊飞距离的比较研究

在分析鸟类对人类干扰耐受程度的研究中,惊飞距离是常用的衡量指标之一,它是指人在鸟类惊飞之前能接近鸟类的距离,反映了鸟类对人为侵扰的适应程度。本文通过对青藏高原广泛分布的白腰雪雀Montifringilla taczanowskii和棕颈雪雀M.ruficollis惊飞距离的比较研究,旨在探讨2种鸟类对人类干扰适应性的差异。结果显示,体型较大的白腰雪雀的惊飞距离(12.50 m±0.36 m,n=46)显著大于棕颈雪雀的惊飞距离(11.03 m±0.43 m,n=33);觅食个体的惊飞距离显著小于观望个体(P0.001);随着入侵者起始距离的增加,2种雪雀惊飞距离逐渐增大(P0.001)。结果表明,鸟类初始状态和入侵者起始距离能够显著影响鸟类的惊飞距离,体型较大的鸟类对人类干扰的适应性较差。     

非致命性捕食风险对鸟类的影响

非致命性捕食风险是捕食者对猎物产生的间接的、非致命性的捕食压力,对维持捕食者-猎物种群数量的相对稳定具有重要意义。鸟类拥有较复杂的反捕食对策,是研究非致命性捕食风险的理想对象。本文综述了非致命性捕食风险对鸟类影响的研究进展。研究者通过多种方法模拟非致命性捕食风险,发现不同鸟类的耐受性不仅会影响个体适合度,也会影响其种群数量动态。鸟类对非致命性捕食压力的行为响应受诸多因素影响,包括鸟类自身状态,栖树高度,集群大小等。研究鸟类对非致命性捕食风险的响应,对完善捕食风险权衡理论,建立种群数量预测模型,以及探讨人类与鸟类共存机制具有重要意义,同时可为生态旅游中提出合理的接近距离、制定有效的保护管理措施提供科学指导。     

北京城区麻雀的逃逸距离及其影响因素

行为的改变促进野生动物与人类共存,其中逃逸距离的改变是鸟类适应城市生境的重要机制。本研究量化城市常见鸟类麻雀Passer montanus的逃逸距离,并分析其影响因素。2019年夏季对北京城区14个公园和15个高校的1 326只麻雀的观测发现,麻雀的警戒距离为5.67 m±1.13 m、惊飞距离为4.92 m±1.12 m、飞逃距离为6.51 m±1.75 m。麻雀的逃逸距离受到麻雀群体大小、捕食风险和生境特征的共同影响:警戒距离、惊飞距离和飞逃距离均随着危险稀释而减小;警戒距离随着生境中庇护场所的减少而增加;惊飞距离随着人类干扰的增多而减小;当生境中捕食者较多时,麻雀选择较近的飞逃距离。本研究有助于增进对逃逸距离在种内变异的了解,并可为探讨野生动物在城市生境的适应机制提供基础资料。     

动物觅食行为对捕食风险的反应

动物进行任何活动时均面临被捕食的风险 ,分析捕食风险与猎物觅食行为的关系 ,有助于揭示捕食者与猎物的协同进化机制。捕食风险具有限制或调节猎物种群数量的功能。在进化时间内 ,对猎物形态和行为特征的进化是潜在的选择压力之一 ,可利用环境因子作为信息源估测食物可利用性和捕食风险大小的动物 ,具有更大的适合度。信息源可分为包括视觉的、听觉的和化学的。动物进行觅食活动时 ,依据信息源的变化确定环境中捕食风险的大小 ,并根据自身的质量在捕食风险的大小之间做出权衡 ,通过食物选择、活动格局和栖息地利用等行为的变化降低捕食风险     

风险对两种南非蜥蜴逃跑启始距离和逃避策略的影响

逃避理论预测,不逃跑若增大适合度代价则导致逃跑启始距离加长,逃跑若增大代价则导致逃跑启始距离缩短。逃跑路径和去向等受生境结构影响。作者通过模拟捕食者逼近研究喀拉哈里树石龙子(Trachylepis sparsa)和黑环蜥(Cordylus niger)逃避策略和风险因子对逃跑启始距离的影响。与迂回逼近相比较,直接逼近不仅提高蜥蜴逃跑几率还能缩短其逃跑启始距离。喀拉哈里树石龙子在两种逼近方式下的逃跑启始距离有显著差异,这种差异对黑环蜥而言是边缘性的。喀拉哈里树石龙子以树为避所,树上个体可逼近的距离短于地面个体;快速逼近地面个体的逃跑启始距离比慢速逼近更长。习惯于有人环境的黑环蜥逃跑启始距离比人迹罕至环境中的个体更短。地面喀拉哈里树石龙子多遁至树上而很少逃入倒木或倒伏编巢中。树上喀拉哈里树石龙子通常奔逃至远侧和高处,有时遁入树洞或编巢中;黑环蜥则逃入石缝中。所有发现都证实逃避理论中有关逃跑启始距离的预测。逃跑策略的种间差异表明每一种蜥蜴都利用其生境中逃跑路径和避所的有利条件。在风险不同的生境中,生境结构可影响逃跑启始距离,似乎对逃跑策略亦有重要影响。     

麻雀幼鸟和成鸟逃逸距离的比较

逃逸是鸟类常用的反捕食手段。自然选择会优化鸟类的逃逸距离,以便在躲避被捕食风险和保持能量之间做出权衡。理论模型预测动物个体可依据期望寿命来调整自身的行为：期望寿命短的个体倾向于风险偏好,即逃逸距离短;而期望寿命长的个体倾向于风险回避,即逃逸距离长。同时,逃逸距离还受到外部因素（如人为干扰强度、鸟类群体大小）的影响。本研究在北京城区收集了麻雀（Passer montanus）145只成鸟和75只幼鸟的逃逸距离数据,发现麻雀成鸟比幼鸟有着更长的逃逸距离,且成鸟更可能是群体中首先逃逸的个体。此外,研究发现麻雀的逃逸距离随着人为干扰强度的增加而降低,随着群体大小增加而增加。本研究结果符合理论预期：存活率高的类群（成鸟）有着更长的逃逸距离。     

繁殖期两种百灵科鸟类对捕食风险的行为响应

生活史理论认为亲代对捕食风险的不同响应影响亲代资源在繁殖中的分配比例,为检验这一理论,于2002—2004年的4—9月以青藏高原高寒草甸的角百灵(Eremophilaalpestris)和小云雀(Alaudagulgula)为研究对象,通过捕食风险处理实验,研究了两种鸟对不同强度捕食压的响应。结果表明在自然条件下,二者繁殖行为存在显著差异,而在捕食压力下二者的行为反应没有差异。在捕食风险下,二者亲鸟缩短伴巢时间,减少递食率,延长消失时间;二者雄性的风险容忍度均低于雌性。此外,角百灵亲代对人类活动的响应较小云雀敏感。以上结果表明,这两种百灵科鸟类通过降低当前的繁殖投入和提高未来存活概率来响应捕食风险,支持上述生活史理论的观点。     

秦皇岛雀形目鸟类环志数量变化及其影响因素

鸟类种群数量变动及其机制是种群生态学研究的重要内容.本文分析了2005-2019年河北秦皇岛雀形目鸟类环志数量的变化,并探讨了数量变化的影响因素,以期为当地鸟类及其栖息地的保护提供基础资料.我们选择了环志数量较多的食虫鸟柳莺科、鹟科、绣眼鸟科、山雀科以及食谷鸟鹀科和燕雀科等雀形目鸟类,研究其环志数量变动趋势.结果 表明...     

Evolution of antipredator behavior in an island lizard species,Podarcis erhardii (Reptilia: Lacertidae): The sum of all fears?

Organisms generally have many defenses against predation, yet may lack effective defenses if from populations without predators. Evolutionary theory predicts that “costly” antipredator behaviors will be selected against when predation risk diminishes. We examined antipredator behaviors in Aegean wall lizards, Podarcis erhardii, across an archipelago of land-bridge islands that vary in predator diversity and period of isolation. We examined two defenses, flight initiation distance and tail autotomy. Flight initiation distance generally decreased with declining predator diversity. All predator types had distinctive effects on flight initiation distance with mammals and birds having the largest estimated effects. Rates of autotomy observed in the field were highest on predator-free islands, yet laboratory-induced autotomy increased linearly with overall predator diversity. Against expectation from previous work, tail autotomy was not explained solely by the presence of vipers. Analyses of populations directly isolated from rich predator communities revealed that flight initiation distance decreased with increased duration of isolation in addition to the effects of current predator diversity, whereas tail autotomy could be explained simply by current predator diversity. Although selection against costly defenses should depend on time with reduced threats, different defenses may diminish along different trajectories even within the same predator–prey system.     

Optimal flight initiation distance

Decisions regarding flight initiation distance have received scant theoretical attention. A graphical model by Ydenberg and Dill (1986. The economics of fleeing from predators. Adv. Stud. Behav. 16, 229-249) that has guided research for the past 20 years specifies when escape begins. In the model, a prey detects a predator, monitors its approach until costs of escape and of remaining are equal, and then flees. The distance between predator and prey when escape is initiated (approach distance = flight initiation distance) occurs where decreasing cost of remaining and increasing cost of fleeing intersect. We argue that prey fleeing as predicted cannot maximize fitness because the best prey can do is break even during an encounter. We develop two optimality models, one applying when all expected future contribution to fitness (residual reproductive value) is lost if the prey dies, the other when any fitness gained (increase in expected RRV) during the encounter is retained after death. Both models predict optimal flight initiation distance from initial expected fitness, benefits obtainable during encounters, costs of escaping, and probability of being killed. Predictions match extensively verified predictions of Ydenberg and Dill's (1986) model. Our main conclusion is that optimality models are preferable to break-even models because they permit fitness maximization, offer many new testable predictions, and allow assessment of prey decisions in many naturally occurring situations through modification of benefit, escape cost, and risk functions.     

The ontogeny of escape behavior,locomotor performance,and the hind limb in Sceloporus woodi

Flight initiation distance describes the distance at which an animal flees during the approach of a predator. This distance presumably reflects the tradeoff between the benefits of fleeing versus the benefits of remaining stationary. Throughout ontogeny, the costs and benefits of flight may change substantially due to growth-related changes in sprint speed; thus ontogenetic variation in flight initiation distance may be substantial. If escape velocity is essential for surviving predator encounters, then juveniles should either tolerate short flight initiation distances and rely on crypsis, or should have high flight initiation distances to remain far away from their predators. We examined this hypothesis in a small, short-lived lizard (Sceloporus woodi). Flight initiation distance and escape velocity were recorded on an ontogenetic series of lizards in the field. Maximal running velocity was also quantified in a laboratory raceway to establish if escape velocities in the field compared with maximal velocities as measured in the lab. Finally a subset of individuals was used to quantify how muscle and limb size scale with body size throughout ontogeny. Flight initiation distance increased with body size; larger animals had higher flight initiation distances. Small lizards had short flight initiation distances and remained immobile longer, thus relying on crypsis for concealment. Escape velocity in the field did not vary with body size, yet maximum velocity in the lab did increase with size. Hind limb morphology scaled isometrically with body size. Isometric scaling of the hind limb elements and its musculature, coupled with similarities in sprint and escape velocity across ontogeny, demonstrate that smaller S. woodi must rely on crypsis to avoid predator encounters, whereas adults alter their behavior via larger flight initiation distance and lower (presumably less expensive) escape velocities.     

The effect of vegetation cover on vigilance and foraging tactics in the fat sand rat Psammomys obesus

The combination of the visual obstruction and protection properties of vegetation is considered to be one of the most important factors determining the trade-off between vigilance and foraging in a prey species. In the Negev desert, diurnal fat sand rats construct their burrows in the ephemeral river beds ("wadis"), under dense and tall shrubs of Atriplex halimus, or on the open first fluvial terrace, covered with scattered low shrubs of Anabasis articulata. We tested the hypothesis that properties of the vegetation would affect the time budget of female sand rats. Sand rats spent more time aboveground, rested more, were less vigilant, and moved more slowly under the dense cover in the wadi than at the open terrace. No differences in the total foraging time were revealed, but foraging tactics varied between habitats: individuals in the wadi mainly fed aboveground, whereas those at the terrace mainly hoarded. Our results indicate that sand rats perceive the dense vegetation cover as good protection despite its visual obstructive nature, and that vigilance in Psammomys obesus is performed at the cost of resting rather than at the cost of foraging. Received: January 15, 2001 / Accepted: April 17, 2001     

Heart mass and the maximum cardiac output of birds and mammals: implications for estimating the maximum aerobic power input of flying animals

Empirical studies of cardiovascular variables suggest that relative heart muscle mass (relative M_h) is a good indicator of the degree of adaptive specialization for prolonged locomotor activities, for both birds and mammals. Reasonable predictions for the maximum oxygen consumption of birds during flight can be obtained by assuming that avian heart muscle has the same maximum physiological and biomechanical performance as that of terrestrial mammals. Thus, data on M_h can be used to provide quantitative estimates for the maximum aerobic power input (aerobic P_i,max) available to animals during intense levels of locomotor activity. The maximum cardiac output of birds and mammals is calculated to scale with respect to M_h (g) as 213 M_h^0.88+-0.04 (ml min^-1), while aerobic P_i,max is estimated to scale approximately as 11 M_h^0.88+-0.09 (W). In general, estimated inter-species aerobic P_i,max, based on M_h for all bird species (excluding hummingbirds), is calculated to scale with respect to body mass (M_b in kg) as 81 M_b^0.82+-0.11 (W). Comparison of family means for M_h indicate that there is considerable diversity in aerobic capacity among birds and mammals, for example, among the medium to large species of birds the Tinamidae have the smallest relative M_h (0.25 per cent) while the Otidae have unusually large relative M_h (1.6 per cent). Hummingbirds have extremely large relative M_h (2.28 per cent), but exhibit significant sexual dimorphism in their scaling of M_h and flight muscle mass, so that when considering hummingbird flight performance it may be useful to control for sexual differences in morphology. The estimated scaling of aerobic P_i,max (based on M_h and M_b in g) for male and female hummingbirds is 0.51 M_b^{0.83 +/-0.07} and 0.44 M_b^{0.85+- 0.11} (W), respectively. Locomotory muscles are dynamic structures and it might be anticipated that where additional energetic ''costs'' occur seasonally (e.g. due to migratory fattening or the development of large secondary sexual characteristics) then the relevant cardiac and locomotor musculature might also be regulated seasonally. This is an important consideration, both due to the intrinsic interest of studying muscular adaptation to changes in energy demand, but also as a confounding variable in the practical use of heart rate to estimate the energetics of animals. Haemoglobin concentration (or haematocrit) may also be a confounding variable. Thus, it is concluded that data on the cardiovascular and flight muscle morphology of animals provides essential information regarding the behavioural, ecological and physiological significance of the flight performance of animals.     

Optimal escape theory predicts escape behaviors beyond flight initiation distance： risk assessment and escape by striped plateau lizards Sceloporus virgatus

Escape theory predicts that flight initiation distance (FID=distance between predator and prey when escape begins) is longer when risk is greater and shorter when escape is more costly. A few tests suggest that escape theory applies to distance fled. Escape models have not addressed stochastic variables, such as probability of fleeing and of entering refuge, but their economic logic might be applicable. Experiments on several risk factors in the lizard Sceloporus virgatus confirmed all predictions for the above escape variables. FID was greater when approach was faster and more direct, for lizards on ground than on trees, for lizards rarely exposed to humans, for the second of two approaches, and when the predator turned toward lizards rather than away. Lizards fled further during rapid and second consecutive approaches. They were more likely to flee when approached directly, when a predator turned toward them, and during second approaches. They were more likely to enter refuge when approached rapidly. A novel finding is that perch height in trees was unrelated to FID because lizards escaped by moving out of sight, then moving up or down unpredictably. These findings add to a growing body of evidence supporting predictions of escape theory for FID and distance fled. They show that two probabilistic aspects of escape are predictable based on relative predation risk levels. Because individuals differ in boldness, the assessed optimal FID and threshold risks for fleeing and entering refuge are exceeded for an increasing proportion of individuals as risk increases[Current Zoology 55(2):123-131,2009].