Nest location, clutch size and nest success in the Scarlet Ibis Eudocimus ruber

Breeding success and nest-site characteristics were studied during the 1996–1997 breeding season in a colony of Scarlet Ibises Eudocimus ruber in south-eastern Brazil to test the hypothesis that nest-site characteristics and clutch size affect nest success. Two nesting pulses produced young, the earlier being more successful. Predation accounted for most failures during the first pulse, wind destruction during the second. A third pulse with few nests produced no young. Adult Ibises abandoned nests when they lost sight of other incubating birds. Logistic regression analysis indicated that nest success during the first pulse was positively related to clutch size, number of nests in the nest tree and in the nearest tree, and negatively to the distance to the nearest neighbour. During the second pulse there were significant negative associations between success, nest height and distance to the fourth nearest nest, and a positive association between success and nest cover. The results agree with the 'selfish herd' hypothesis, indicating that nest aggregation may increase breeding success, but the nest-site characteristics affecting success can differ over the course of one breeding season.     

Coping with Shifting Nest Predation Refuges by European Reed Warblers Acrocephalus scirpaceus

Predation, the most important source of nest mortality in altricial birds, has been a subject of numerous studies during past decades. However, the temporal dynamics between changing predation pressures and parental responses remain poorly understood. We analysed characteristics of 524 nests of European reed warblers monitored during six consecutive breeding seasons in the same area, and found some support for the shifting nest predation refuge hypothesis. Nest site characteristics were correlated with nest fate, but a nest with the same nest-site attributes could be relatively safe in one season and vulnerable to predation in another. Thus nest predation refuges were ephemeral and there was no between-season consistency in nest predation patterns. Reed warblers that lost their first nests in a given season did not disperse farther for the subsequent reproductive attempt, compared to successful individuals, but they introduced more changes to their second nest sites. In subsequent nests, predation risk remained constant for birds that changed nest-site characteristics, but increased for those that did not. At the between-season temporal scale, individual birds did not perform better with age in terms of reducing nest predation risk. We conclude that the experience acquired in previous years may not be useful, given that nest predation refuges are not stable.     

The influence of nest-site characteristics on the nesting success of the Karoo Prinia (Prinia maculosa)

Choice of nest site has important consequences for nest survival. We examined nest-site characteristics relative to nest success in Karoo Prinias breeding in coastal dwarf shrubland, where high nest predation is the main cause of nest failure. Initially, we compared nests that failed during the building, laying, incubation and nestling stages and those from which young were successfully raised, to test whether nests that survived to progressive stages in the nesting cycle differed in their nest-site characteristics. Subsequently, we compared the characteristics of successful nests with those of unsuccessful nests. The nest-site characteristics considered included nest height, nest-plant height, nest-plant species, distance from lateral foliage edge, nest concealment, nest-patch heterogeneity and vegetation cover at four different heights. We were unable to distinguish between the nest-site characteristics of nests that failed during the various stages of the nesting cycle. Concealment was the main nest-site characteristic that differentiated successful nests from unsuccessful nests, with successful nests being located in more concealed sites. The other variables that contributed to the discrimination between successful and unsuccessful nests by discriminant function analysis included nest-plant type and distance from edge, which are also directly related to concealment. This suggests that nest concealment is the most important variable influencing nesting success at this site, which has a preponderance of visually-oriented predators.     

利用天然树洞繁殖的五种鸟的巢位特征及繁殖成功率

对吉林省左家自然保护区次生阔叶林中的大山雀 ( Parusmajor)、沼泽山雀 ( Paruspalustris)、普通跓( Sitta europacea)、白眉姬? ( Ficedula zanthopygia)和灰椋鸟 ( Sturnus cineraceus) 5种利用天然树洞繁殖的次级洞巢鸟进行了巢位选择和繁殖成功率研究。本研究中共发现 1 41巢。五种鸟对树洞类型的选择存在种间差异 ,普通跓不利用裂洞 ,沼泽山雀不利用啄洞 ,其它 3种鸟对 3种洞均有利用 ,但有一定的倾向性。对 5种鸟 9个巢位变量的比较中 ,只有洞口方向差异不显著 ( p >0 .0 5 ) ,其它 8个变量均差异显著 ( p<0 .0 5 ) ,该结果说明 5种次级洞巢鸟对巢位的选择具有其各自的需求。洞口横径、洞口纵径、洞处树直径、洞内径、巢距地高是巢位选择重要变量 ,它们决定不同种类对树洞的利用。巢损失多数出现在产卵之前和孵化阶段 ,44个繁殖失败的巢中有 35个在这两个阶段损失。大山雀的巢成功率最低 ,灰椋鸟的巢成功率最高。 5种鸟的孵化率都超过 90 %。人为破坏和动物捕食是繁殖失败的主要原因 ,占总数的 61 .4%。洞巢鸟巢位选择中的重要变量影响繁殖成功。普通跓繁殖是否成功受洞口横径和巢高影响 ,沼泽山雀受洞口纵径、树胸径和洞内径影响 ,大山雀受洞口横径、巢高和洞内径影响 ,灰椋鸟受洞内径和洞深影     

Do Fleas,and/or Old Nest Material,Influence Nest-site preference in Hole-nesting Passerines?

This study examined nest-site choice in a migratory population of pied flycatchers (Ficedula hypoleuca) and sympatric populations of three resident tit species (Parus major, P. caeruleus and P. palustris) in central Sweden. All four species are secondary-cavity nesters which naturally breed in pre-formed tree cavities but readily use artificial nest boxes. We asked whether flycatchers and tits discriminate between nest boxes that: 1. Are ‘empty’; 2. Contain old nests without ectoparasites (fleas Ceratophyllus sp.); or 3. Contain old nests with ectoparasites. We found that pied flycatchers preferred nest boxes containing old nests, regardless of whether these nests held parasites. In contrast, tits did not discriminate between the three types of boxes. Tits may pay a cost for their lack of choosiness: after the breeding season, tit nests contained more fleas than flycatcher nests. Nevertheless, parasites did not affect the choice of a nest site in any of the species studied. We suggest that the migratory flycatchers are in a hurry to start breeding upon arrival and use the presence of an old nest as a shortcut cue to assess nest-site quality. Also, they may save valuable time by copying the choice of previous breeders. Non-migratory tits may have more time to inspect nest sites, but do not seem to use the same cues in nest-site selection as the pied flycatcher.     

Selection through predation, snowfall and microclimate on nest-site preferences in the Water Pipit Anthus spinoletta

Nest-site characteristics can have a strong impact on reproductive success in birds. Nest sites should simultaneously protect from predators, offer shelter and provide a favourable microclimate. We studied the relationship between three agents of natural selection (predators [i.e. Adders and birds/mammals], snowfall and microclimate), nest-site characteristics and reproductive success to determine whether these influenced preference for specific nest-site characteristics in the Water Pipit Anthus spinoletta . Pooled over all nests, the relative importance as agents of natural selection decreased from mammalian/avian predation (15% of all nests) through Adder predation (12%) to snowfall (7%), but there were clear differences in space and time. Predation by Adders selected for nest sites surrounded by few medium-sized shrubs. Selection by mammalian and avian predators favoured no specific nest-site characteristics. Protection from snowfall was best in nests surrounded by relatively few medium-sized shrubs. Microclimate had a strong influence on nestling survival and duration of nestling period. In nests on ENE-facing slopes, where maximum temperatures were reached in the morning, nestling survival was higher than on WSW-facing slopes, where temperature maxima occurred in the afternoon. Our results indicate that weak, but significant, directional selection is acting on preference for certain nest-site characteristics through effects on survival and development of nestlings. As predation and snowfall are unpredictable, the evolution of an optimal nest placement strategy is unlikely on a small scale. On a larger scale, however, choice of one breeding area over another may be favoured because of predictable differences between locations in terms of survival and nestling development.     

四川瓦屋山金色林鸲的巢址选择和繁殖记录

2010~2011年4~7月,在四川省瓦屋山自然保护区对金色林鸲(Tarsiger chrysaeus)的繁殖生态和巢址选择进行了研究。共发现26巢,金色林鸲2010年和2011年的繁殖成功率分别为43.8%和44.4%,孵化率分别为52.5%和60.0%;育雏成功率分别为85.7%和100.0%。主成分分析表明,影响金色林鸲巢址选择的主要因子包括巢位因素、苔藓盖度因素和乔木郁闭度因素。步道两侧的土坎为金色林鸲巢址选择提供了适宜条件。在瓦屋山,人类活动是影响金色林鸲繁殖、巢址选择、巢的分布和数量的重要因素,并存在两面性;人行步道的修建为金色林鸲提供了更多适宜的巢址,而游客的频繁活动限制了金色林鸲的繁殖活动。     

Do parasitic common goldeneye Bucephala clangula females choose nests on the basis of host traits or nest site traits?

Conspecific brood parasitism (CBP) is an important alternative breeding strategy for gaining reproductive output in birds. While interactions between hosts and parasites and consequences of CBP to breeding success of both parties have been studied a lot, the roles of host characteristics and nest site characteristics in CBP have received less attention. We studied the relative importance of host‐related traits, such as female condition and breeding experience, and nest‐site‐related factors, such as overall nest site preference and occupation rate, in explaining the occurrence of CBP in a common goldeneye Bucephala clangula population. We used spatially and temporally extensive data sets, analysed the data with generalized linear mixed models that allowed us to account for the non‐independency of individual nesting attempts across females and nesting sites, and used an information theoretic approach in model selection and inference. About half of the nests were parasitized annually during the seven year study period. The occurrence of CBP decreased with advancement of the breeding season but late nests were also frequently parasitized. We found that the occurrence of CBP was better explained by nest‐site characteristics than host traits, implying that parasitic females target a given nest based on factors related to the nest site itself rather than on the host. Our results suggest that more attention should be paid to factors associated with nest site attractiveness and quality when studying laying decisions of parasites and the occurrence of CBP in general.     

Traditional versus non-traditional nest-site choice: alternative decision strategies for nest-site selection

In order to understand habitat selection, it is important to consider the way individual animals assess the suitability of a future reproductive site. One way of investigating mechanisms (such as those involved in nest site selection) is to examine breeding success and habitat characteristics in terms of animals returning to a place where they have already reproduced and using the same location over successive years or searching for new alternatives. This approach seems especially suitable for testing recent hypotheses suggesting that nest site selection is an integrative process that includes the use of social information (e.g. past breeding success of conspecifics). Determining the factors that elicit conservative or innovative behaviour regarding nest-site selection could be important for improving our understanding of habitat selection decisions in animals. More than half of the nests of the long-distance migratory lesser grey shrike Lanius minor, are built in the same or neighbouring trees. We found no evidence that habitat characteristics influence nest-site tradition. On the contrary, social information in terms of the presence of conspecifics and past reproductive success in terms of complete nest failures due to nest predation (but not detailed information such as variation in fledgling number) influenced nest-site tradition. Hence, social information and past reproductive success may play a role in nest-site choice in this species. Our results further demonstrate that previous experience with a nest site does not appear to be beneficial.     

Old nests are cues for suitable breeding sites in the Eurasian penduline tit Remiz pendulinus

Nest-sites often have a major influence on avian reproductive success. The use of reliable cues that assist nest-site selection should thus be favoured by natural selection. The old nests have been known to serve as a cue in nest-site selection in several species. To find out whether the old nests act as cue in nest-site selection in the Eurasian penduline tit Remiz pendulinus , we carried out two experiments in southern Hungary, where the penduline tits breed around fishponds and build sophisticated pendulous nests on tree branches that often hang over water. In April 2006, we choose 20 groups of two nearby trees, and hung an old nest on one of the trees in each group. The male penduline tits choose 12 of these groups to build a new nest, and every of the twelve nests were built on trees with an old nest. This suggests that the old nests serve as a cue in the selection of breeding sites for males when they enter a habitat. To find out whether the old nests are cues of plentiful nest building material, or to signal high quality breeding areas, we carried out a second experiment in 2007 by selecting 13 groups of three nearby trees. A "worn-out" old nest was hung on one of the trees, a "re-utilize" type of old nest on another tree, whereas the third tree was left without an old nest in each group. The rationale was that while the worn-out material of the old nests is of no use in building the new nests, material of the "re-utilize" nests is good enough to be used for building new nests. Males built a new nest in 10 of the 13 groups, and eight of the new nests were built on trees with an old nest. Of the eight new nests, five were built on trees with a "worn-out" old nest and three on trees with a "re-utilize" type of old nest. It appears that for the penduline tit males it is the presence of an existing old nest and not the quality of the old nest material that serves as cue during the selection of the suitable breeding sites.     

吉林向海自然保护区占用喜鹊巢繁殖的鸟类巢记述

部分鸟类在繁殖过程中,为避免被捕食、减少繁殖投入等而选择占用其他鸟类的巢。2014~2016年每年的4~8月,在吉林向海国家级自然保护区记录到4种占用喜鹊巢进行繁殖的鸟类,其中绿头鸭(Anas platyrhynchos)8巢,纵纹腹小鸮(Athene noctua)4巢,长耳鸮(Aiso otus)5巢,麻雀(Passer montanus)6巢。大部分(82.6%)为利用喜鹊的废弃旧巢,而绿头鸭(1巢)、长耳鸮(2巢)和纵纹腹小鸮(1巢)少数侵占喜鹊当年新建的巢。     

Landscape and anti-predation determinants of nest-site selection, nest distribution and productivity in a Mediterranean population of Long-eared Owls Asio otus

Nest predation is an important determinant of owl breeding success. We studied Long-eared Owl Asio otus productivity and attributes of nest-sites at the microhabitat and landscape scales in a Mediterranean locality over an 8-year period. We examined the effect on nest location and productivity of protective cover in concealing the nest from aerial and terrestrial predators. A dense cover of ivy and tree-foliage at canopy level favoured nest location but not productivity. By contrast, high shrub cover beneath the nest was selected by Owls and was positively related to both the site reoccupancy rate and the overall number of young fledged. Pre-fledging Owls use the ground, where they are exposed to terrestrial predators, which are much more abundant in the study area than are aerial predators. Our results therefore support the hypothesis that Owls adapt nest-site choice to local sources of predation risk. As reported elsewhere, Long-eared Owls in our study area showed restricted territoriality and nested in clusters. As active nest-sites during the same breeding season were more than 1 km apart on average, and their productivity was never greater for clustered nests than for more isolated nests, nest aggregation could not be interpreted as a case of facultative colonial breeding, which has been reported for this species in other areas. Neither landscape variables indicative of the availability of foraging areas nor structural attributes that protect young from predators explained the remarkable scarcity of nests in half of the study area. Unmeasured factors such as human disturbance could explain the pattern of distribution of Long-eared Owl nests.     

Factors affecting nesting success of a bird assembly in the central Monte Desert, Argentina

We estimated nesting success of a breeding bird assemblage in the central Monte Desert in four breeding seasons (1995–1999). We analyzed the effect of year, period within the breeding season, nest type, and nest location on daily survival rates (DSR). Averaged nesting success of passeriforms in natural habitats was very low (<20% on average, n=12 species). DSR tended to be lower during the egg-laying stage in Furnariidae, Rhinocryptidae, Mimidae, and Emberizidae. Tyrannidae had the highest DSR for all nesting stages and Emberizidae the lowest. Predation was the main cause of nest failure (>90% on average, n=12 species). DSR differed among years, being higher in the driest year (1995) and lower in the most humid year (1997). Nests initiated in the first half of the breeding season had higher DSR than those initiated in the second half. Closed nests had similar survival rates to open nests. DSR differed according to species of plant that supported the nest. Nest predation in the central Monte Desert may be an important selective pressure in birds' life history, which is in accordance with other results for South American temperate birds.     

The presence of kleptoparasitic fledglings is associated with a reduced breeding success in the host family in the barn owl

Fledgling birds sometimes abandon their own nest and move to neighboring nests where they are fed by host parents. This behaviour, referred to as ‘nest‐switching’, is well known in precocial birds that are mobile soon after hatching and can easily reach foster nests. In contrast, due to the difficulty of observing nest‐switching in territorial altricial birds, the causes and consequences of moving to others’ nests are poorly known in this group of birds. Nest‐switchers can be adopted by the foster parents or they can steal food from the host parents meant for their offspring, a form of kleptoparasitism, which may result in reduced breeding success of the host nest. In Israel, 12 barn owl fledglings left their natal nests and were found in 9 host nests out of 111 monitored nests (8.1%). Nest‐switchers that fledged earlier in the breeding season flew shorter distances to reach host nests probably because the density of nests with younger nestlings is higher early in the season. The number of host nestlings fledged and the percentage of nestlings fledged was lower in host nests than in nests without switchers. The occasional nest‐switchers were always older than host nestlings (respectively 80 and 50 days of age, on average) and host parents fledged fewer young when nest‐switchers occupied host nests with younger nestlings. This suggests that nest‐switchers are kleptoparasites because the presence of the older alien fledglings is associated with a lower breeding success of the host parents.     

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。     

Philopatry, Dispersal Patterns and Nest-site Reuse in Lesser Grey Shrikes (Lanius minor)

To nest in the same breeding area, territory or even nest-site in successive years may provide a possibility to look at mechanisms involved in breeding habitat selection and could also be an important tool for conservation, management and restoration attempts. In this study we examine site fidelity towards the breeding area as well as the nesting site in a dense and stable population of the Lesser Grey Shrike Lanius minor, a long-distance migrant and highly endangered passerine species, at its present northern border of its breeding range. Overall we recovered 48 out of 146 (32.8%) adults between 1996 and 2000. Recovery rate is significantly higher for males (31 of 77, 40.25%) than for females (17 of 69, 24.6%). Recovery rate of nestlings is much lower since only 51 of 790 (6.5%) were recovered and there is no significant sex difference. Furthermore, our results from 1989 to 2000 revealed that more than 30% (97/319) of the nests were built in the same nest tree in successive years and more than half (183/319 = 57.4%) of the nests in the same or neighboring trees (up to 20 m), but very seldom by the same individuals. The fact that nest reuse in successive years is almost exclusively done by different individuals suggests habitat copying and public information of individual birds. Due to optimal ecological breeding conditions other parameters like inbreeding avoidance or increased genetic variability could be important factors in nest-site selection strategies and consequently result in a “disperse over stay strategy”.     

Causes of variable reproductive performance by Southern Ground‐hornbill Bucorvus leadbeateri and implications for management

Range occupancy of the cooperatively breeding Southern Ground‐Hornbill Bucorvus leadbeateri in South Africa has decreased by 65% in the last three generations and the effective management of the remaining populations is hampered by a lack of fundamental understanding of the factors determining reproductive performance. We examined the influence of social and environmental factors on the species' reproductive success in South Africa using data gathered from 23 groups over eight breeding seasons. Some groups had access to artificial nest‐sites, others did not. High rainfall (> 500 mm) over the breeding season led to a decrease in reproductive success, with groups being most successful in years when rain in the vicinity of the nest ranged from 300 to 500 mm. Groups breeding in natural nests were successful only when the proportion of open woodland surrounding the nest‐site was high. Those that bred in artificial nests, where overall breeding success was more than twice as high as those in natural nests, were less dependent on the availability of open woodland. Large groups (more than three birds) bred more successfully than groups comprising only two to three individuals. Group size, helper effects and rainfall cannot be managed to increase the productivity of Ground‐Hornbills but the fact that the availability of artificial nest‐sites and the amount of open woodland around the nest‐site both contribute positively to breeding performance identifies practical and simple management options for increasing the reproductive output of Southern Ground‐Hornbill populations.     

Breeding ecology of Styan's Bulbul Pycnonotus taivanus in Taiwan

The breeding ecology of Styan's Bulbul Pycnonotus taivanus , an endemic species in Taiwan, was studied in Kenting, Taiwan. The duration of the breeding season of Styan's Bulbul stretched from March to July in 1983. The average clutch size was 3.3 eggs ( n =34), and hatching success was 60%. The average number of nestlings at hatching was 2.7 per clutch, and 73% of the young fledged. Styan's Bulbuls selected their nest sites among dense vegetation. In the study area, 75% ( n =84) of nests were found in the Indiapoon Beautyleaf tree Calophyllum inophyllum , which had a relative vegetation density of only 33.5%. Factor analysis was used to analyse 13 nest-site characteristics of 63 nests, and five factors accounted for 69% of the variation.     

Breeding success and nest-site characteristics of Red-breasted Flycatchers Ficedula parva in a primeval forest

Capsule Predation is a major factor influencing the breeding success of Red-breasted Flycatchers under natural conditions.

Aims To examine the breeding success of Red-breasted Flycatchers in relation to nest-site characteristics and time of breeding.

Methods Data were collected during seven breeding seasons under natural conditions in Bia?owie?a National Park. We used survival time analysis to estimate changes in survival probability over time and breeding success in relation to first-egg date and nest-site characteristics.

Results Offspring fledged successfully from 51% of clutches, but the Kaplan–Meier estimate of survival was lower at 0.43. Of the unsuccessful clutches, 82% were lost to predators. The highest probability of loss was during egg-laying and in the second half of incubation. Breeding success was influenced by the height of the nest above the ground, but no relation to other nest-site characteristics was found.

Conclusion To avoid predation Red-breasted Flycatchers build nests in various sites that are more open than most cavity-nesting species. The position of the nest-sites allows the sitting female to observe her surroundings and to escape rapidly from the nest, giving the chance for a replacement clutch.     

Nest-site characteristics of the Red-knobbed Hornbill Aceros cassidix and Sulawesi Dwarf Hornbill Penelopides exarhatus

Nest-site characteristics of two hornbill species, the Red-knobbed Hornbill Aceros cassidix and the Sulawesi Dwarf Hornbill Penelopides exarhatus , are presented and compared at two sites in north Sulawesi, Indonesia. Seventy-four Red-knobbed Hornbill and 12 Sulawesi Dwarf Hornbill nests were located. Sulawesi Dwarf Hornbill nests were at lower densities and more evenly spaced than Red-knobbed Hornbill nests. Although selective, neither species appeared to be nest-site limited, except perhaps for the Red-knobbed Hornbill in hill forest. Principal components analysis indicated that Red-knobbed Hornbills were 'catholic' in their preferences, although nests were generally in tall, mature specimens of large girth, located high and in the upper half of the tree. The Sulawesi Dwarf Hornbill nested exclusively in live trees and nests were on average located half way up in tall canopy trees with large girths. Within certain parameters, both species were flexible with respect to their nest cavity size and shape requirements; Red-knobbed Hornbills choose sites with larger entrances and internal dimensions. Discriminant function analysis produced parsimonious models for each site, with high rates of correct classification, based on structural, floristic and breeding success parameters. Lack of transference of predictive powers of the models between sites demonstrates the apparent variability in hornbill nesting behaviour and indicates the need for caution when extrapolating models to other sites. Possible factors affecting the nesting density and distribution of each hornbill species are discussed.