Extrapair paternity in relation to sexual ornamentation, arrival date, and condition in a migratory bird

We tested the novel hypothesis that arrival date in migratorybirds represents a reliable indicator of male quality that canbe used by females as a cue in extrapair mating decisions. Secondarysexual characters are often condition-dependent, and competitionfor early arrival leads to condition-dependent migration. Hence,both secondary sexual characters and arrival date are predictedto be condition-dependent indicators of male phenotypic quality.We studied the relationship between expression of a secondarysexual character, arrival date, and condition, respectively,and extrapair paternity in a Spanish population of barn swallows,Hirundo rustica. By using microsatellite markers to determinepaternity, we showed that 17.8% of all offspring (N = 674) and32.4% of all broods (N = 170) were due to extrapair paternity.Quasi-parasitism (in which the male nest owner fathered theoffspring, but the eggs were laid by another female) occurredin 2.6% of all nestlings and 2.9% of all broods. Individualswere consistent in the frequency of extrapair paternity amongfirst, second, and third broods. Males with long outermost tailfeathers, arriving early and in prime body condition, had littleextrapair paternity in their nests. This was also the case whencontrolling for the confounding effects of male age. Partialcorrelation analysis was used to investigate the direct andindirect effects of tail length, arrival date, and body conditionon extrapair paternity. Body condition accounted for most ofthe variance in extrapair paternity, whereas tail length andarrival date accounted for a smaller proportion of the variance.Body condition was strongly correlated with tail length andarrival date. However, because females cannot directly assesscondition or arrival date (males arrive before females), femalesmay obtain an indirect measure of condition and migration abilityfrom tail length and other phenotypic traits of males. Thissuggests that extrapair paternity depends on the effects ofcondition, through its indirect effects on arrival date, taillength, and other variables.     

Segregation in the African wintering ranges of English and Swiss Swallow Hirundo rustica populations: a stable isotope study

Capsule Stable isotope analysis of Swallow feathers, grown in Africa, revealed significant differences between populations breeding in Switzerland and England.

Aims To investigate the extent to which Swallow populations breeding in Switzerland and England are separated on their African wintering grounds.

Methods Swallows were caught at breeding colonies, biometric measurements were taken and feathers, grown in Africa, were collected. Feathers were combusted in a Carlo Erba C/N/S analyser and the δ¹³C and δ¹⁵N signatures were measured using a mass spectrometer.

Results The δ¹³C signatures of Swiss birds were significantly more depleted than those of birds from England. The δ¹⁵N signatures did not differ between the two populations.

Conclusion Birds from Switzerland and England probably winter in geographically distinct parts of Africa. The Swiss birds probably feed on prey that are more reliant on C₃ vegetation, from woodlands, than the prey of English birds, which are more reliant on C₄ vegetation, from grasslands.     

南充金腰燕、家燕繁殖生态比较及易卵易雏实验

2004年3～10月对四川南充地区家燕、金腰燕的繁殖生态进行了观察,比较了其繁殖生态习性及雏鸟的生长特性,进行了家燕、金腰燕之间的易卵易雏实验.结果表明,家燕于2月中旬迁入南充,9月中旬开始迁离;金腰燕迁来较家燕晚,2月底～3月初迁入,9月中旬迁离.家燕于4月初产卵;金腰燕在4月上旬产卵.金腰燕卵的各项量衡度均较家燕的大,出壳时金腰燕雏鸟体重也比家燕雏鸟稍重.金腰燕雏鸟的体长、翅长、尾长、外部器官及体重的增长较家燕的快.而易卵、易雏的金腰燕雏鸟增长曲线则在金腰燕和家燕的雏鸟之间.易卵易雏的实验表明,在孵卵和育雏过程中,金腰燕与家燕之间彼此互换卵可以接受,易换雏鸟也可以接受.     

广西弄岗家燕种群的卵胚胎心率

: 2014年4-7月,利用红外胚胎心率测量仪对广西弄岗地区家燕Hirundo rustica的卵胚胎心率进行了测量。该种群的家燕在孵化的第4天才开始出现卵胚胎心率,且卵胚胎心率随孵化天数呈上升趋势,并在第13天达到最高值(280.5 BPM±23.0 BPM,t=3.855,P<0.002)。家燕的卵胚胎心率日均增长为16.1 BPM±3.4 BPM,但与其卵容量和卵质量均不存在相关性(卵容量1.74 cm3±0.08 cm3,r=0.093,P=0.827; 卵质量1.51 g±0.09 g,r=0.043,P=0.920)。     

Senescent sperm performance in old male birds

Senescence is the deterioration of the phenotype with age caused by negative effects of mutations acting late in life or the physiological deterioration of vital processes. Birds have traditionally been assumed to senescence slowly despite their high metabolic rates, high blood sugar levels and high body temperature. Here we investigate the patterns of age‐related performance of sperm of a long distance migrant, the barn swallow Hirundo rustica, varying in age from 1 to 6 years, analysed by the computer‐assisted sperm analysis equipment. Sperm showed deteriorating performance in terms of linear movement, track velocity, straight line velocity and reduced proportions of rapidly moving, progressive and motile sperm with age. In a second series of experiments, we assessed performance of sperm from the same males in neutral medium and in medium derived from the reproductive tract of females in an attempt to test if sperm of old males performed relatively better in female medium, as expected from extra‐pair paternity being negatively related to male age, but not to female age. Older males showed consistently better performance in female medium than in neutral medium in terms of track velocity, straight line velocity and reduced proportions of rapidly moving, progressive and motile sperm, whereas young males showed better performance in neutral medium. These results provide evidence of declining sperm performance for important reproductive variables not only with age, but also with the sperm of old males performing differentially better in female medium than young males.     

家燕的繁殖生态及雏鸟生长发育

20 0 4年3～1 0月对南充地区家燕(Hirundorustica)的繁殖生态进行了观察,研究了雏鸟生长发育模式。结果表明,家燕2月中旬迁来,9月中旬迁飞。一般年产卵2窝。4月初已见产卵,卵长径(1 9 1 8±0 90 )mm ,短径(1 4 1 8±0 41 )mm ,卵重(2 5 7±0 3 8)g。孵卵期(1 6±1 )d ,育雏期2 2～2 3d。雏鸟体长及外部器官的形态学参数可以用Logistic曲线方程很好地拟合,体长、翅长及1 3日龄前的体重增长曲线均呈“S”型。     

哈尔滨家燕mandschurica亚种繁殖生态特征

许多鸟种因具有较强的适应性而分布广泛,例如家燕(Hirundo rustica)。在不同纬度地区研究其繁殖生态学特征有助于了解家燕对不同环境的适应。家燕mandschurica亚种在国内仅分布于黑龙江省,且该亚种的繁殖资料少有报道,为此,于2016和2017年每年的4至10月,在哈尔滨对其繁殖生态特征开展研究,并与国内目前已发表的家燕gutturalis亚种繁殖生态特征进行对比。家燕mandschurica亚种4月底或5月初迁来哈尔滨,9月下旬或10月初南迁;窝卵数为4～6枚(n=19);卵长径(18.7±1.4)mm(15.9～22.5 mm)、卵短径(13.0±0.5)mm(12.2～14.2 mm),卵重(1.6±0.1)g(1.3～1.9 g),n=35;孵卵期为(16±2)d(14～18 d,n=19);育雏期为(17±1)d(16～18 d,n=6)。雏鸟的体长、翅长及尾羽长的生长曲线能与Logistic较好地拟合;体重、嘴峰和跗跖在5日龄左右生长最快,体长和翅长在7日龄左右增长最快,雏鸟的生长模式符合能量分配假说。与我国南方的家燕gutturalis亚种相比,在哈尔滨繁殖的mandschurica亚种的卵更小、更轻,二者孵卵期相似,但后者育雏期更短。这或许与不同地区食物丰富度及亲鸟喂食策略有关。     

大杜鹃对家燕的巢寄生

了解杜鹃(Cuculus spp.)对不同宿主鸟类的巢寄生,是研究杜鹃与其宿主之间协同进化的重要基础资料。大杜鹃(Cuculus canorus)和家燕(Hirundo rustica)分布遍及全国,且为同域分布,但两者之间的寄生现象尚未有过系统调查。2012年和2014年4~8月,对繁殖于吉林市昌邑区桦皮厂镇(34°58′44.18″N,126°13′26.83″E,海拔184 m)和海南岛的家燕种群进行调查,结果表明,吉林市昌邑区桦皮厂镇家燕种群的寄生率为2.4%(1/42),而在海南岛所调查的1 719个家燕巢未发现杜鹃寄生现象。同时在网络上搜集家燕巢寄生的报道案例,共记录到13巢家燕被大杜鹃寄生繁殖,均发生在北方的家燕种群。     

Parasites differentially increase the degree of fluctuating asymmetry in secondary sexual characters

The degree of fluctuating asymmetry has been demonstrated to reflect the ability of individuals to cope with different kinds of environmental stress (Parsons 1990). Parasites and diseases are one kind of environmental stress which most individuals encounter during their lifetime. Parasites have also been suggested to play an important role in sexual selection and the development of ornaments, since the full expression of ornaments may reflect the ability of hosts to cope with the debilitating effects of parasites. Here I report for the first time that a parasite, the haematophagous tropical fowl mite Ornithonyssus bursa (Macronyssidae, Gamasida), directly affects the degree of fluctuating asymmetry in a secondary sexual character of its host, the elongated tail of the swallow Hirundo rustica (Aves: Hirundinidae). I experimentally manipulated the mite load of swallow nests during one season by either increasing or reducing the number of mites, or keeping nests as controls. The degree of fluctuating asymmetry was measured in the subsequent year after the swallows had grown new tail ornaments under the altered parasite regime. The degree of fluctuating asymmetry was larger at increasing levels of parasites for male tail length, but not for the length of the shortest tail feather or wing length or for tail and wing length in females. These results suggest that the degree of fluctuating asymmetry in tail ornaments, but not in other feather traits, reliably reveals the level of parasite infestation. This has important implications for the ability of conspecifics to use the size and the expression of ornaments in assessment of phenotypic quality and thus in sexual selection.