White-rumped Swallows Research Articles

Are nest defense behaviours and fitness components linked in white-rumped swallows (Tachycineta leucorrhoa)?

Abstract How are personalities maintained in wild animal populations? A possible mechanism is the existence of trade-offs between fitness components (survival and reproductive success) among behavioural types. We investigated this trade-off in white-rumped swallows (Tachycineta leucorrhoa) by capturing adults and monitoring their reproduction over time. We focused on the personality trait of nest defence against a human. We found that swallows with different levels of nest defence had similar probability to return from migration between two years (a proxy for survival). In one year, swallows that defended their nests more boldly were also more likely to succeed. However, nest defence was not linked to nestling weight or number of fledglings. Thus, we found no evidence of a trade-off between fitness components. It is possible that the investigated relationships become relevant only in extreme years that severely alter the costs and benefits of this behaviour.

Ecological opportunities and individual condition as predictors of extra-pair paternity in a south-temperate swallow (Tachycineta leucorrhoa)

Ecological opportunities and individual condition as predictors of extra-pair paternity in a south-temperate swallow (<i>Tachycineta leucorrhoa</i>)

Parenting styles in white‐rumped swallows (Tachycineta leucorrhoa) show a trade‐off between nest defense and chick feeding

AbstractStudies about personalities in wild animals usually focus on five categories of behavioral traits that do not easily accommodate all aspects of parental care, a class of behaviors with direct consequence to reproductive success. Parental care can vary consistently between individuals and constitute parenting styles. Here we investigate the consistency of four behaviors of parental care across two breeding seasons of white‐rumped swallows Tachycineta leucorrhoa in southern Brazil. These behaviors are a prospection of potential nest‐sites, nest defense against predators or conspecifics, and chick feeding. If these first three behaviors are consistent, they can be classified according to the standard categories of personality as exploration, boldness, and aggressiveness, respectively. We find that all behaviors, except exploration, are consistent between individuals in the long term. We also show that, besides individual identity, couple identity is an important component explaining variation in behavior. This pattern can arise if behavior influences pair formation or if behavior is a consequence of a common environment affecting the couple. We show that, depending on the parental task, males or females are more consistent, suggesting that sexes are adopting different strategies of parental care allocation. We then investigate if there is a trade‐off between nest defense and chick feeding. We find that birds that defend more also feed the brood less often and suggest that testosterone might be the mechanism modulating this trade‐off. Lastly, we discuss the implications of our results to mate choice and highlight the need for studies linking parenting styles to fitness in swallow species.

Sexual differences in the effect of previous breeding performance on nest-box reuse and mate retention in White-rumped Swallows (Tachycineta leucorrhoa)

ABSTRACTIn birds, the selection of nesting sites and mates has a profound influence on the daily interactions of individuals. Both behaviours are energetically costly and time-consuming and can strongly affect the Darwinian fitness of individuals. Using a 12-year dataset on banded returning breeders, we explored variables associated with nest-box choice and mate choice in the White-rumped Swallow, a socially monogamous migratory passerine. Females reusing nest-boxes, but not males, produced significantly more fledglings than did those that changed nest-boxes. Females and males that retained mates produced significantly more fledglings than did those that divorced. General linear mixed models revealed that the number of fledglings produced in previous seasons significantly explained the reuse of particular nest-boxes by females, but not by males. Mate choice by females was not strongly affected by either past breeding performance or nest-box reuse, but nest-box reuse alone predicted mate choice by males. Nest-box reuse by males was apparently more related to retention of female partners. This study revealed that sexual differences in the nesting and mating decisions were guided by the use of information on past breeding performance in a subtropical, secondary cavity nester.

White-rumped swallows prospect while they are actively nesting

Nest prospecting, that is, visiting potential future nest sites, may be a widespread bird behavior. Here we describe apparent prospecting while nesting by white-rumped swallows (Hirundinidae, Aves). In southern Brazil, birds tagged with passive-integrated transponders (PIT-tags) and breeding in nest boxes with PIT-tag readers: (1) often visited nest boxes that were in use by apparently unrelated birds (54 % of nests were visited at least once), (2) visited other boxes while caring for their own nestlings, (3) tended to have smaller broods than birds that were not recorded visiting, and (4) did not have a preference for any particular box. These patterns do not indicate any clear explanation for nest visiting, but they do show that prospecting is done by floaters (non-breeders) as well as actively breeding individuals. We suggest that these visits occur when time is available and that visitors may be assessing the availability of future nest sites.

Two new and two redescribed species of Anonchotaenia (Cestoda: Paruterinidae) from South American birds

Morphological examination of novel specimens of paruterinid cestodes from passerine birds from Brazil and Chile and of museum specimens from Paraguay revealed two new species: Anonchotaenia prolixa sp. n. from Elaenia albiceps chilensis Hellmayr from Chile, and Anonchotaenia vaslata sp. n. from Tyrannus melancholicus (Vieillot) (type host) and Myiodynastes maculatus (Statius Muller) from Paraguay. The generic diagnosis of Anonchotaenia Conn, 1900 is amended, prompted by the presence of the armed cirrus and the elongated cirrus sac of A. prolixa. Two species were redescribed: Anonchotaenia brasiliensis Fuhrmann, 1908 from Tachyphonus coronatus (Vieillot) and Thraupis cyanoptera (Vieillot) (new host records) from Brazil, and Thraupis sayaca (Linnaeus) and Volatinia jacarina (Linnaeus) from Paraguay (new host and geographic records); and Anonchotaenia macrocephala Fuhrmann, 1908 from Tachycineta leucorrhoa (Vieillot) (new host record) from Brazil, Tachycineta meyeni (Cabanis) from Chile (new host and geographic record) and Stelgidopteryx ruficollis (Vieillot) from Paraguay (new host and geographic record). Scanning electron microscopy of A. brasiliensis and A. macrocephala revealed less microthrix variation than has been reported for other cyclophyllidean taxa. Sequence data were generated for nuclear ssr- and lsr-DNA and mitochondrial rrnL and cox1 for A. prolixa, A. brasiliensis, and A. macrocephala. Maximum likelihood and Bayesian inference analyses supported each species as distinct, but revealed cryptic diversity among A. brasiliensis specimens from different host families. New host records of A. brasiliensis and A. macrocephala prompted a formal assessment of host specificity. Anonchotaenia prolixa was found to be oioxenous (HS(S) = 0), A. vaslata and A. macrocephala were found to be metastenoxenous (HS(S) = 3.000 and 3.302, respectively), whereas A. brasiliensis was found to be euryxenous (HS(S) = 5.876). Anonchotaenia brasiliensis has been found parasitising several species of different passerine families that participate in mixed-species foraging flocks in the Atlantic Forest. A diversity of species of other families join these flocks and are among the substantial number of South American passerine species yet to be examined for cestodes.

Yolk mass variation in White-Rumped Swallows (Tachycineta leucorrhoa)

Egg mass production is costly, but hatching from heavier eggs could be beneficial for the nestling's phenotype and fitness. Egg mass could be influenced by proximate causes, like food abundance, female condition, environmental conditions, and/or by ultimate causes, such as females depositing resources differentially within a clutch to increase the biological fitness of some eggs. Yolk mass, although poorly studied, is the source of nutrients for the embryo, so its mass should be more influential for the nestlings than total egg mass. We used a technique that allowed us to measure yolk size without destroying the eggs. We studied yolk mass in 212 eggs of White-rumped Swallows (Tachycineta leucorrhoa) and found that yolk mass was influenced by laying order, with last laid eggs having heavier yolks than first laid eggs, and the pattern was consistent with egg mass variation. Food abundance also affected yolk mass: when insect availability was high the yolks were heavier. We conclude that embryos in the last laid eggs have more resources from which to develop, and excluding food abundance, neither environmental conditions nor female's condition affected yolk mass. We encourage other researchers to study yolk mass given that multiple variables affected total egg mass.

Insights into life history theory: a brood size manipulation on a southern hemisphere species, Tachycineta leucorrhoa, reveals a fast pace of life

Life history traits exhibit substantial geographical variation associated with the pace of life. Species with a slow pace are expected to invest more in their future/residual reproductive value and are more common at tropical latitudes, whereas species from high latitudes, with a faster pace, are expected to prioritize the current reproductive effort. Most evidence supporting this pattern comes from studies conducted in tropical and north temperate species; very little is known about patterns in southern South American species. Here, we describe the life history of a southern swallow Tachycineta leucorrhoa and use an experimental approach to test their breeding strategy over four breeding seasons. We manipulated brood size for 105 nests of white‐rumped swallows to measure whether costs of reproduction were borne by adults or nestlings as alternative selection strategies towards maintaining residual or current reproductive value. Adults increased their feeding effort in enlarged broods, at least enough to maintain nestlings’ development/growth. In addition, adults decreased the number of visits to the nest (without having a negative effect on nestlings) in reduced broods. We did not detect differences in fledging success among treatments, suggesting there were no differences in nestlings’ survival. However, enlarged broods more frequently incurred in complete nest failure, suggesting only some adults were able to cope with increased costs of reproduction. We conclude this species is characterized by a fast pace of life similar to their northern congeners and less like its tropical ones. This is one of the first studies to use an experimental approach to test a life history hypothesis of pace of life using data from a southern South American species. We encourage researches to include southern species when evaluating latitudinal variations as we still do not have enough evidence to assume all southern subtropical species are indeed similar to tropical ones.

Breeding Biology of the White-Rumped Swallow (Tachycineta Leucorrhoa; Hirundinidae) in a Wetland: A Comparative Approach

We studied the reproductive biology of the White-rumped Swallow (Tachycineta leucorrhoa) in a colony of 50 nests boxes located in a wetland of the Paraná River, Santa Fe, Argentina between 2004 and 2006. The nest boxes were checked regularly and reproductive parameters, as well as morphological data of eggs and nestlings, were recorded. The species had an average clutch size of 4.7 eggs whose volumes and weight means were 2.04 cm3and 2.17 g. respectively. The incubation period averaged 15.9 days and decreased with the clutch size. The mean nestling period was 23.8 days. Clutch size, number of nestlings per nest and the nestling period decreased with the advance of the breeding seasons, while the incubation time increased. Breeding parameters showed a similarity with those reported for the population from Chascomús site, although the eggs were 5% heavier, the incubation period took one more day and the reproductive success was also higher. With the closely related species Tachycineta meyeni, the studied species showed a lower clutch size. Finally, considering another closely related species Tachycineta bicolor, the White-rumped Swallow showed the reproductive life history traits characteristic of species in the southern hemisphere. We provide new information for this species nesting on wetlands, a fact that contributes to the understanding of changes in the life history of the Tachycineta genus along the American continent.

Heterozygosity and fitness benefits of extrapair mate choice in White-rumped Swallows (Tachycineta leucorrhoa)

Female birds that engage in extrapair mating may choose extrapair mates that are genetically compatible, increasing their fitness through genetic benefits, such as increased heterozygosity, to their offspring; or choose mates that are heterozygous at one or more loci. Here, we describe the extrapair mating system, explore the fitness benefits of extrapair mating and test the heterozygosity hypothesis in White-rumped Swallows (Tachycineta leucorrhoa) breeding in Argentina using a panel of microsatellite loci. Extrapair offspring accounted for 56% of the nestlings and 77% of the broods in our population. Within broods, 1–4 males fathered extrapair offspring, and in 29% of nests, all offspring were from extrapair sires. We found that broods with extrapair offspring fledged overall more young than broods with no extrapair offspring but that the young that died were more heterozygous than the ones that fledged. Although extrapair offspring had a higher probability of surviving than within-pair offspring, these 2 groups did not differ in their level of heterozygosity. Neither the heterozygosity of the social mate nor the genetic similarity of the social pair predicted the presence of extrapair young. Instead, females chose social mates that were significantly less genetically similar to them. Our results do not support the heterozygosity hypothesis and contradict 2 of its main predictions.

Apparent survival and return rate of breeders in the southern temperate White‐rumped Swallow Tachycineta leucorrhoa

Life‐histories and demographic parameters of southern temperate bird species have been little studied. We estimated return rates between years and sexes, and adult apparent survival and recapture probabilities with mark–recapture data on White‐rumped Swallows and found a lower return rate of unsuccessful females. There was little support for influences of sex or year on survival rates. The estimates were equivalent to the lowest value reported for a northern congener, in contrast to the prediction of geographical variation under life‐history theory.

Insects found in birds' nests from Argentina: Tachycineta leucorrhoa leucorrhoa (Vieillot, 1817) [Aves: Hirundinidae], a new host for Acanthocrios furnarii (Cordero &amp;amp; Vogelsang, 1928) [Hemiptera: Cimicidae

Nest-boxes used by the White-rumped Swallows, Tachycineta leucorrhoa leucorrhoa (Vieillot, 1817) [Aves: Hirundinidae] were sampled during two consecutive breeding seasons in the province of Buenos Aires, Argentina. A total of 11 taxa of insects were found in the nests of this species: 10 in the order Coleoptera: Coccinellidae [Cycloneda ancoralis; Scymnus sp.]; Cavognathidae [Cavognatha sp.]; Aphodiidae [Aphodius sp.]; Dermestidae [Trogoderma sp.; Dermestes maculatus]; Histeridae [Saprinus sp.]; Carabidae [Notaphus fisheri; Bradycellus sp.]; Elateridae [undetermined sp.]; Undetermined family (larvae), and one in the order Hemiptera: Cimicidae [Acanthocrios furnarii]. These insects were differentiated from prey remains, sometimes entire specimens. The species of Cimicidae appeared in two different nests built in the same box by the same female. The composition of the insect fauna found in swallows’ nests is similar to those in natural birds’ nests from the same province, but the diversity, abundance and richness in swallows’ nests inside boxes were lower.

Differences in rates of nest-visitation and removal of faecal sacs by male and female White-rumped Swallows

Despite being a common and widespread species, the White-rumped Swallow (Tachycineta leucorrhoa) is one of the least-studied members of its genus. We examined the rates of nest-visitation and nest-sanitation of male and female White-rumped Swallows during the nestling period, in 23 nests, and compared them with those of the extensively studied Tree Swallow (Tachycineta bicolor). White-rumped Swallow pairs increased the rate of nest-visitation as nestlings grew older, as was found in Tree Swallows. Females made significantly more visits to the nest than males, and the asymmetry was maintained irrespectively of the age of nestlings. These results are similar to those reported from Tree Swallows in the eastern United States, but differ from the equality of roles found in Ontario, Canada. Female and male White-rumped Swallows removed faecal sacs at the same rate when nestlings were young (Day 4) but by Day 12 females had quadrupled their effort whereas the rate of sanitation by males remained constant. Overall, female White-rumped Swallows made a significantly larger parental investment than males (as measured by number of visits to nests and, thus, presumably rates of feeding, and in contribution to nest-sanitation) and, in this respect, the asymmetry in parental investment is greater than that reported for Tree Swallows.

Breeding biology of the White‐rumped Swallow Tachycineta leucorrhoa in Buenos Aires Province, Argentina

We conducted a study of the breeding biology of the White‐rumped Swallow Tachycineta leucorrhoa nesting in nestboxes in a flat, farming landscape in Buenos Aires Province, Argentina. White‐rumped Swallow nesting attempts were detected from the end of September to mid December, with most clutches laid during October. Birds laid clutches of 4–6 eggs with a mode of five eggs; most broods hatched synchronously (58%), but hatching spread could last up to 4 days. Nestling growth curves adjust well to logistic functions, and at day 15 nestlings attain the asymptotic weight of 21.6 g. Clutch size in White‐rumped Swallows declined significantly as the season progressed. In addition, late‐season eggs were smaller and late‐season nestlings had a shorter nestling period and lower weight at day 15, probably leaving the nest lighter than early‐season nestlings. These data suggest that the Swallows would benefit greatly from laying early in the season, which would provide nestlings with better survival prospects. However, both major sources of nest mortality, interspecific competition for nest‐sites and nestling mortality during bad weather, decreased through the season. White‐rumped Swallows follow the pattern found for other southern species, as it has smaller clutch size, lower growth rate and remains longer at the nest than its Northern Hemisphere congener the Tree Swallow Tachycineta bicolor.

Brood parasitism of White-rumped Swallows by Shiny Cowbirds

Swallows and martins are infrequent hosts of the generalist brood parasite Shiny Cowbird (Molothrus bonariensis). We monitored 50 nesting attempts by White-rumped Swallows (Tachycineta leucorrhoa) over a two-year period in Argentina and detected low rates of brood parasitism (three nests, or 6%). Of the three nests parasitized, cowbirds (N= 1 per nest) successfully fledged from two. Eight of 13 swallow eggs in these three nests were punctured by cowbirds, and all but one swallow nesting starved at the two parasitized nests. At least two factors may contribute to the low frequency of parasitism of White-rumped Swallows by Shiny Cowbirds, including the inability of the larger cowbirds to enter some nest cavities and the aggressive nest defense behavior of adult swallows. SINOPSIS Las golondrinas son hospedadores infrecuentes del Tordo Renegrido (Molothrus bonariensis), un parasito de cria generalista. A lo largo de dos anos supervisamos 50 intentos de nidificacion de la Golondrina Ceja Blanca (Tachycineta leucorrhoa) y detectamos una baja frecuencia de parasitismo (tres nidos, o el 6%). Los tordos (N = 1 por nido) abandonaron con exito dos de estos tres nidos. Ocho de los 13 huevos de golondrina presentes en los nidos parasitados fueron picados por los tordos y todos los pichones de golondrina, excepto uno, murieron de inanicion. Al menos dos factores pueden contribuir a la baja frecuencia de parasitismo del Tordo Renegrido sobre la Golondrina Ceja Blanca, incluyendo la imposibilidad del parasito de entrar en algunas cavidades pequenas y el comportamiento agresivo de defensa que realizan los adultos del hospedador.

Helpers liberate female fairy-wrens from constraints on extra-pair mate choice

In cooperatively breeding superb fairy-wrens (Malurus cyaneus), all males contribute to the feeding and defence of young. Despite the expectation that such paternal care should be directed only to relatives, DNA fingerprinting revealed that most offspring (76%, 138 out of 181) were sired by extra-group males that contributed no care, and that almost all broods (95%, 38 out of 40) contained young sired by extra-group fathers. This is the highest known incidence of cuckoldry. This remarkable mating system is produced by female control of fertilization and consistent preference for certain extra-group male genotypes. This choice leads to the production of sons that also gain extra-group fertilizations. One constraint on the extra-pair mate choice of females is the level of parental assistance received from males. Males living in pairs contribute relatively more parental care and are more likely to gain paternity in one of their broods (85%, 11 out of 13) than dominant males in multi-male cooperative groups (30%, 8 out of 27). In groups helpers compensate for the lower parental assistance of dominant males, so the total feeding rate is similar between pairs and groups. This suggests that females allow males in pairs more paternity to ensure their assistance with parental care. Helpers provide an alternative source of paternal investment, and allow females to express unrestricted mate choice. Mating options for females in other species with female control of fertilization may also reflect a trade-off between acquiring the genes of high-quality males for their offspring and parental care of those offspring.