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1.
    
Amelia Wein  Raoul Schwing  Ludwig Huber 《Ibis》2020,162(3):1012-1023
Vocal behaviour of nesting altricial birds is subject to selection pressure from several sources. Offspring beg to attract parents’ attention, thus increasing the chances of being fed, but also increasing the chances of being detected by predators. Research on passerines has shown that parents may reduce the risk of nest predation by alarm calling to warn nestlings to be quiet, and by producing food calls which solicit begging when parents are present to defend the nestlings. Both nestlings and parents may reduce the risk of predator detection by producing calls of low amplitude and high entropy which are acoustically difficult to locate. Although extensive research has been undertaken on nesting passerine vocalizations, little is known about parrots in this regard, and studies are needed to determine whether parrots show similar adaptations. We investigated the calling behaviour of Kea Nestor notabilis mothers during the nesting period to determine whether maternal vocalizations were adapted in a way that could increase the chance of brood success. A microphone was installed inside the nest to record calls produced both inside the nest and in the direct vicinity. Our prediction was that calls outside the nest would be easy to locate and could function as alarm calls to alert conspecifics or distract the predator, whereas calls inside the nest would be difficult to locate and could serve to communicate with nestlings without alerting predators. Our results accorded with these predictions. Calls produced outside the nest were loud and tonal, and corresponded to previously described Kea alarm calls. Calls produced inside the nest, however, were high-entropy and low-amplitude calls, and formed a distinct structural category. We thus provide the first evidence that a parrot species has a vocal category for communication inside the nest, and that calls within this category are structured in a way that could reduce the risk of nest predation.  相似文献   

2.
Capsule Habitat associations of breeding birds in a complex coastal environment are clear, interpretable and mostly consistent between years.

Aims To match archive territory mapping data with historical aerial photographs and develop data handling and analytical techniques for the study of bird–habitat relationships.

Methods Bird registrations were digitized from archive British Trust for Ornithology Common Birds Census maps and habitat characteristics from contemporaneous aerial photographs. The resulting maps were overlaid and ranks of habitat preference for 15 species calculated using compositional analysis. Similarity analysis identified species with consistent habitat profiles across years. Cluster analysis identified groups of species with similar patterns of habitat use.

Results A total of 5400 registrations of 15 species in 14 habitats were analysed. Of these, 13 species showed stable patterns of habitat association across survey years. Clear differences and similarities in habitat preferences among the species were identified. The results may be used to inform conservation and management programmes in this and similar environments.

Conclusions Extensive archives of bird survey data can be used to study bird–habitat relationships and to measure the effects of natural and anthropogenic environmental change if contemporaneous aerial photographs can be sourced.  相似文献   

3.
郭宗明  陈伟  胡锦矗 《四川动物》2006,25(4):858-861
2005年4~6月,在四川南充市西华师范大学新校区、西南石油学院和嘉陵江中坝区域内对棕头鸦雀(Paradoxornis webbianus)的繁殖行为进行了观察研究。结果表明,棕头鸦雀4月开始繁殖。影响巢址选择的生境因子主要有7种。雌雄鸟参与筑巢,营巢期5~6 d。窝卵数4~5枚(n=5)。雌雄鸟孵卵,孵卵期13~14 d。孵化率89.47%(n=4)。雌雄参与育雏,育雏期12~13 d。雏鸟离巢率88.24%(n=4)。雏鸟形态生长曲线呈“S”型。  相似文献   

4.
濒危植物南川升麻传粉生物学的研究   总被引:9,自引:0,他引:9  
南川升麻(CimicifugananchuanensisHsiso)的繁育系统以异交为主,传粉昆虫主要为蝇类,盛花时的访花频率平均每花每天11次,雄蕊脱落后约06次;单穗升麻(C.simplexWormsk)以虫媒为主,风也可以帮助其花粉在近距离传播。单穗升麻的传粉昆虫有蝇类和蜂类,盛花时的访花频率蝇类为1.4次,蜂类为1.2次。南川升麻和单穗升麻都是靠大的花序和气味来吸引传粉昆虫,报酬是退化雄蕊基部分泌的蜜液。自然条件下南川升麻每个柱头上平均有4枚花粉,结籽率平均为64%,而单穗升麻每个柱头上平均有17枚花粉,结籽率平均为459%。南川升麻有性生殖中传粉的限制是其致濒的重要因素之一。  相似文献   

5.
    
The pollination biology of Cimicifuga nanchuanensis Hsiso, an endangered species and C. siraplex Wormsk, a widespread species as a control, has been studied. Protandry occurs in both species, the former goes further than the latter. The breeding system of C. nanchuanensis is dominantly xenogamous. The average visitation rate of flies as the main pollinators is 1.1 and 0.6 per flower per day at anthesis and after stamen shedding respectively. C. simplex is mainly an entomophilous plant. However, wind pollination could occur within a short distance. Moreover, a certain ratio of self pollination exists also in this species. The mean visitation rates of flies and bees, the main pollinators of C. simplex, are 1.4 and 1.2 respectively at anthesis. The pollinating insects of both plant species are attracted by their big inflorescences and the fragrant odor. Nectar, the reward for pollinators, produces in the secretory cells at the base of the spoonform staminode. In natural conditions, an average of 17 pollen grains are found on the surface of a stigma resulting in a mean seed set rate of 45.9 %. Pollination limitation (very few pollinators and their low efficiency of pollination) in C. nanchuanensis is one of the weak links in its life cycle and one of the reasons for the endangerment of this species.  相似文献   

6.
From April to July 2003 and 2004,we surveyed the nest-site selection of the White Eared pheasant (Crossoptilon crossoptilon) in the Zhujie Monastery and in the mountain facing it in Sichuan Province,China.In this paper,we studied the nest characteristics and the clutch size of the pheasant.Habitat sampling method was used to determine the variables that might affect the nest-site selection of the White Eared pheasant.Chi-square test was used to identify which habitat type was likely to be preferred by the bird.Independent-samples t test and Mann-Whitney U test were used to find which variables were important for the birds'nest-site selection.A total of 13 nests were found.Oak shrub was greatly preferred as nest sites (84.62%).Nests under a rock wall (7.69%) and a fallen tree (7.69%) were also found.The average clutch size of a White Eared pheasant is 7.33±0.54 (range,5-11;n=12).Laying period was between April 27 and May 21.In the Zhujie area,1 nest was in the forest and 11 nests were in oak shrubs.The species preferred oak shrub as its nesting habitat (X2=8.333,dr=l,P<0.05).The bird was more likely to place its nest in sites with a high coverage,I.e.0.5,1,and 2 m above the ground (independent-samples t test,P<0.05),and with a large shrub diameter (Mann-Whitney U test,P<0.05).The species are more likely to prefer sites with plant cover,shrub cover (independentsamples t test,P<0.05),and shrub height (Mann-Whitney U test,P<0.05) in a relatively small range.  相似文献   

7.
2015年和2016年的5-7月,在浙江清凉峰国家级自然保护区野外调查期间发现一处北红尾鸲Phoenicurus auroreus巢址,并对其繁殖习性进行了观察。结果表明:北红尾鸲在本地为冬候鸟,但首次发现该种鸟类夏季在此繁殖;北红尾鸲的繁殖期为5月下旬至7月中旬,5月下旬开始营巢,持续10 d左右,巢穴外径7.5 cm×5.8 cm、巢深3.2 cm,巢材由苔藓、体羽、禾本科杂草茎等组成;6月中旬产卵,窝卵数为4~5枚(2015年产卵4枚、2016年产卵5枚),孵化期11~12 d,巢内育雏14 d。推测冬候鸟北红尾鸲在此繁殖可能与气候变化有关。  相似文献   

8.
Threatened populations are vulnerable to the effects of genetic drift and inbreeding, particularly when gene flow is low and the effective population size is small. Estimates of effective population size (N e ) provide important information on the status of endangered populations that have experienced severe fragmentation and serve as indicators of genetic viability. Genetic data from microsatellite loci were used to estimate N e for the 2 remaining populations of the endangered ocelot (Leopardus pardalis albescens) occurring in the United States. Several methods were used to calculate N e , resulting in estimates ranging from N e  = 8.0 (95% CI: 3.2–23.1) to 13.9 (95% CI: 7.7–25.1) for the population located at the Laguna Atascosa Wildlife Refuge in Cameron County, Texas. The ocelot population in Willacy County, Texas, had N e estimates of 2.9 (95% CI: 1.7–5.6) and 3.1 (95% CI: 1.9–13.5), respectively. Estimates of N e in both populations were below the critical value recommended for short-term viability.  相似文献   

9.
激光生物学效应的研究   总被引:1,自引:5,他引:1  
本文较系统地报道了CO_2激光,He-Ne激光的生物学作用,证明激光确能导致生物体内生理生化的变化,确能诱发染色体畸变和基因突变。作者认为激光作为育种上一种新的诱变因素是有根据的。  相似文献   

10.
2012-2013年繁殖季节,在成都市四川大学望江校区观察了白颊噪鹛Garrulax sannio的繁殖行为,与已有的研究结果相比,结果显示:(1)白颊噪鹛巢材选择广泛,可就地利用多种材料,包括各种生活垃圾;(2)白颊噪鹛在市区主要营巢于高大乔木树种上,在市郊营巢于竹林或较低矮乔木树种;(3)影响其巢址选择的主要因素为胸径、巢位高度、树高;(4)孵卵时间为11~12 d,较1950年代(15~17 d)明显缩短;(5)育雏时间为12 d,但市区白颊噪鹛在卵质量、育雏期日喂食频次、出巢日雏鸟体质量和体长上均高于市郊;(6)市区白颊噪鹛繁殖成功率(73.3%)高于市郊(23.1%)。在城市化进程中,市区白颊噪鹛较市郊个体产生了行为的适应性变化,这些行为变化是其成为城市优势种的重要原因。  相似文献   

11.
12.
    
We examined avoidance, tolerance, and resistance strategies of nestling and adult tree swallows Tachycineta bicolor in response to ectoparasitic blowflies Protocalliphora sialia. Tree swallows avoided settling in north‐facing nest boxes early in the breeding season. These boxes were more likely to be parasitized later in the season, suggesting that box selection may facilitate blowfly avoidance. After experimentally manipulating blowfly intensity, we found that nestlings were generally tolerant of parasitism. Parasites significantly reduced nestling blood hemoglobin but had no effect on nestling body mass, primary feather growth, age at fledging, or fledging success. Parents of parasitized nestlings did not increase their food provisioning rate to promote nestling tolerance. Adult female tree swallows demonstrated both tolerance and resistance: blowfly parasitism had no effect on adult hemoglobin and body mass, and those with higher P. sialia‐binding antibody levels had fewer blowfly larvae in their nests. Nestling antibodies were unrelated to blowfly intensity. Despite considerable variation among years, our results suggest that the costs of blowfly parasitism to nestling and adult tree swallows are modest, and limited to blood loss in nestlings. Future work should examine the effects of reduced blood hemoglobin on fledgling survival and the importance of parasite‐specific antibodies.  相似文献   

13.
14.
    
In birds, the quality of offspring immediately prior to fledging is an important determinant of survival and fecundity. Factors that alter offspring quality at fledging may thus be expected to become strong nest-site selection pressures. However, this fitness component is often overlooked when parental nest-site selection and breeding success are considered. Previous research has found that the frequency of nestbox occupations by great tits Parus major is lower for boxes facing south-southwest than for boxes facing other directions although, curiously, there is no corresponding difference in breeding success (mean number of young to fledge). In this study, we used measures of offspring quality to determine whether there was any association with nestbox orientation that might explain the apparent avoidance of boxes facing south-southwest. Offspring quality correlated with orientation using several condition-related biometrics: (1) weight, (2) wing length, and (3) tarsus length. Fluctuating asymmetry of a bilateral trait (tarsus length) also correlated with orientation. Further analysis using Generalised Linear Mixed Modelling revealed that chicks from boxes facing south-southwest were of significantly lower quality (lighter, smaller and more asymmetrical) than chicks from boxes facing other directions. Crucially, the orientation of nestbox-avoidance and the orientation associated with lowest offspring quality were the same (southsouthwest). The correlation between nestbox avoidance patterns and offspring quality provides a potential evolutionary ecological explanation for the behavioural aversion of adults to nesting in boxes facing south-southwest. This highlights the importance of quantifying offspring quality, in addition to quantity, in studies of parental productivity and nest-site selection across taxa.  相似文献   

15.
濒危植物丰都车前的繁育系统与传粉生物学研究   总被引:1,自引:0,他引:1       下载免费PDF全文
万海霞  邓洪平  何平  蒋庆庆  刘钦 《生态学报》2018,38(11):4018-4026
丰都车前为三峡库区特有珍稀濒危植物,目前仅在重庆市江津支坪镇涂家村附近大中坝上有一小种群分布。以野生种群和移栽种群为对象,通过野外观察和人工授粉实验对丰都车前传粉生物学及繁育系统进行研究。结果表明:(1)丰都车前单花花期约4 d,花序花期约8 d,种群花期约3个月;单花开花进程可分为6个时期:花蕾期、雌蕊伸长期、雄蕊初露期、花瓣展开期、花瓣反折期、枯萎凋谢期。(2)花瓣展开前,柱头先伸出花冠,达最高可受性,之后花瓣展开雄蕊才露出,而此时大部分柱头已枯萎失活丧失可受性,只有少部分具可受性。表现出雌雄异熟的特征,一定程度避免了自交的发生。(3)花粉活力始于雄蕊初露期,花瓣展开、花药开裂时花粉活力最高,至枯萎凋谢前均具有活力。花粉活力最高期避开了柱头可受性最佳期,仅有少部分重叠。(4)繁育系统检测显示,花粉/胚珠比为15373.29,杂交指数为3。结合套袋实验表明,丰都车前可能同时具有风媒和虫媒传粉机制,传粉昆虫为中华蜜蜂、食蚜蝇,但数量偏少,不存在无融合生殖,异交为主,部分自交亲和,有时需要传粉者。(5)开花时期避开了其分布地洪水淹没期,能够顺利完成开花授粉及座果。综上所述,丰都车前的花部特征、开花物候和繁育系统为适应分布地夏季洪水水淹胁迫提供了一定的生殖保障,促进了该种群的续存。  相似文献   

16.
    
Nest-site selection is the principal way in which secondary cavity-nesting species mitigate the negative effects of factors such as predation, parasitism and exposure on reproductive success. Large-bodied secondary cavity-nesting birds rely on large cavities in mature trees that are often absent or reduced in anthropogenically disturbed forests. Hence, the availability of high-quality nest-sites may be limited for these species, potentially reducing reproductive success. The aim of this study was to investigate nest-site selection and the effect of nest-site features on reproductive success in the critically endangered Great Green Macaw Ara ambiguus in northern Costa Rica. We show that Great Green Macaws select nest-sites according to the characteristics of the cavity and the tree in which they are located. Moreover, reproductive success is a function of certain cavity features. However, the availability of high-quality cavities, those with features associated with higher reproductive success, is potentially limited. By studying nest-site selection and productivity together, we have identified that the availability of high-quality cavities could potentially limit the future recovery of the critically endangered Great Green Macaw.  相似文献   

17.
王海涛  高玮  万冬梅  刘多  邓文洪 《生态学报》2003,23(7):1377-1385
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  相似文献   

18.
《Ostrich》2013,84(3):239-245
The breeding ecology of the Great-crested Grebe Podiceps cristatus was investigated over four consecutive years (2009-2012) at Lake Tonga, north-east Algeria. In all four years, the egg-laying period was relatively short, spanning two months (end of March to end of May), and bimodal. Nests were mainly located in Phragmites australis, over water of substantial depth (178 ± 43?cm, N=209), far from the shore and in habitat with low vegetation cover (12.37 ± 7.67%, N=209). The overall clutch size was 3.73 ± 0.92 eggs (N=127) and it decreased marginally over time. The overall nesting success was 70.4% (N=209), with nest failure caused mainly by predation (65%) and flooding (23%). Breeding outcome was significantly and positively related to nest size, with bigger nests conferring better survival to eggs and young probably through affording better protection during spells of adverse weather. However, the benefits of bigger nests may be confounded by the age or intrinsic quality of birds. The location of nests in P. australis, rather than other vegetation types, increased nesting success marginally but significantly. Two cases of interspecific mixed clutches involving the Great-crested Grebe were recorded.  相似文献   

19.
濒危植物银杉的群落及其演替趋势   总被引:1,自引:0,他引:1       下载免费PDF全文
  相似文献   

20.
濒危药用植物八角莲生态生物学特征   总被引:6,自引:0,他引:6       下载免费PDF全文
通过样地调查和相关资料分析,对八角莲(Dysosma versipellis)生态生物学特征的研究表明,八角莲生境群落是以热带和温带植物为主的常绿和落叶阔叶混交疏林灌丛和竹林,上层乔灌木植物多为当地优势种。适宜生长的基质土壤为黄棕壤,pH为5.40-6.59,有机质、有效N、P、K和全N、P、K养分含量高(分别为19.36%、840 mg kg-1、46 mg kg-1、310 mg kg-1和9 970 mg kg-1、1 217 mg kg-1、2 603 mg kg-1)。繁殖障碍、遗传结构不利等自身因素和人类过度采挖、生境破坏等是导致八角莲濒危的主要原因。因此,其保育策略应以迁地保育和就地保育相结合,以迁地保育为主。  相似文献   

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