Effects of supplemental calcium on the reproductive output of a small passerine bird, the House Wren (Troglodytes aedon)

1996 ◽  
Vol 74 (2) ◽  
pp. 278-282 ◽  
Author(s):  
L. Scott Johnson ◽  
Robert M. R. Barclay
Keyword(s):  
Reproductive Output ◽  
Passerine Bird ◽  
Troglodytes Aedon ◽  
House Wren ◽  
House Wrens ◽  
Supplemental Calcium ◽  
Chicken Eggshell ◽  
Calcium Availability ◽  
Rich Material ◽  
Normal Food

The normal food of most small birds (insects, seeds, and fruit) contains relatively little calcium. Birds must therefore supplement their diets, and those of their dependent young, with bits of calcium-rich material such as bone, limestone, eggshells, and mollusk shells. In this study, the question of whether the availability of calcium constrains reproductive output in a Wyoming population of the House Wren (Troglodytes aedon), a small insectivorous passerine, was asked. A randomly selected group of breeding pairs was provided with a mix of crushed oystershell and chicken eggshell at their nests for the duration of their breeding cycles. Calcium-supplemented birds tended to lay more eggs per clutch and tended to raise fledglings with slightly longer feathers than unsupplemented control birds. Calcium-supplemented birds did not, however, lay larger eggs, produce more fledglings, or produce fledglings of greater mass than control birds. Unlike the situation in many anthropogenically acidified environments, calcium availability apparently does not constrain the reproductive output of House Wrens breeding in this one environment that appears to be relatively unaffected by acidic precipitation.

The Process and Causes of Fledging in a Cavity-Nesting Passerine Bird, the House Wren (Troglodytes aedon)

Ethology ◽  
2004 ◽  
Vol 110 (9) ◽  
pp. 693-705 ◽  
Author(s):  
L. Scott Johnson ◽  
Robin L. Rauch ◽  
Sara N. Dellone
Keyword(s):  
Passerine Bird ◽  
Troglodytes Aedon ◽  
House Wren ◽  
Cavity Nesting

Do House Wrens (Troglodytes aedon) add spider egg cases to their nests for heterospecific cleaning?

2019 ◽  
Vol 97 (1) ◽  
pp. 50-56
Author(s):  
C.L. Gable ◽  
T.J. Underwood ◽  
G.P. Setliff
Keyword(s):  
Dna Barcoding ◽  
Body Condition ◽  
Significant Relationship ◽  
The Body ◽  
Troglodytes Aedon ◽  
House Wren ◽  
Late Season ◽  
House Wrens ◽  
Significant Difference

House Wrens (Troglodytes aedon Vieillot, 1809) regularly add spider egg cases (Arachnida: Araneae) to their nests, which may be an example of heterospecific cleaning. This behavior involves one animal employing another to remove parasites from their nests. In House Wren nests, juvenile spiders hatching from egg cases may facilitate the reduction of mites that feed on nestlings. We tested this ectoparasite reduction hypothesis by monitoring House Wren nests for spider egg cases and by collecting completed nests to compare the number of spider egg cases and Dermanyssus hirundinis (Hermann, 1804) mites. No significant relationship was found between the number of spider egg cases and number of D. hirundinis mites in nests. We also found no significant relationship between the number of D. hirundinis mites in nests and the body condition of nestlings. Finally, no significant difference was found between the number of D. hirundinis mites in early versus late season nests, but significantly more spider egg cases were added to late season nests. Of a subsample of spider egg cases dissected, we found that 28% contained spider eggs or embryos. We also identified three species of juvenile spiders from House Wren nests using DNA barcoding. Overall, we found no evidence that spider egg cases reduce the number of D. hirundinis mites or engender better quality offspring in House Wren nests.

Parasitism of House Wren nests by Brown-headed Cowbirds: why is it so rare?

1997 ◽  
Vol 75 (2) ◽  
pp. 302-307 ◽  
Author(s):  
Stanislav Pribil ◽  
Jaroslav Picman
Keyword(s):  
Field Experiments ◽  
Molothrus Ater ◽  
Low Frequency ◽  
Nest Material ◽  
Nest Structure ◽  
Troglodytes Aedon ◽  
House Wren ◽  
House Wrens ◽  
Nest Desertion ◽  
Cowbird Parasitism

We tested five hypotheses that may explain why House Wren (Troglodytes aedon) nests are rarely parasitized by Brown-headed Cowbirds (Molothrus ater). House Wrens may prevent parasitism in five ways: (1) by choosing to nest in cavities with small entrances (inaccessible-entrance hypothesis), (2) by restricting the size of the entrance with nest material (nest-structure hypothesis), (3) by puncturing and ejecting parasitic eggs (puncture–ejection hypothesis), (4) by burying the parasitized clutch under a new nest (egg-burial hypothesis), or (5) by abandoning the parasitized nest altogether (nest-desertion hypothesis). We tested these hypotheses in field experiments and found that (i) female cowbirds cannot enter circular entrances smaller than 38 mm in diameter, (ii) wrens prefer cavities with small entrances (inaccessible to cowbirds) to those with large entrances (accessible to cowbirds), (iii) when forced to breed in cavities with large entrances, wrens do not reduce the entrance size with nest material, (iv) despite the unusual strength of cowbird eggs, wrens are physically capable of puncture–ejecting them, (v) wrens do not puncture–eject cowbird eggs from their own nests, (vi) wrens do not abandon parasitized nests or bury the parasitized clutches under new nests. These results are consistent with the inaccessible-entrance hypothesis. We propose that additional nesting adaptations, as well as active cowbird avoidance of House Wrens, may contribute to the low frequency of cowbird parasitism.

scholarly journals Evidence for heterozygote instability in microsatellite loci in house wrens

2010 ◽  
Vol 7 (1) ◽  
pp. 127-130 ◽  
Author(s):  
Brian S. Masters ◽  
L. Scott Johnson ◽  
Bonnie G. P. Johnson ◽  
Jessica L. Brubaker ◽  
Scott K. Sakaluk ◽  
...  
Keyword(s):  
Mutation Rate ◽  
Microsatellite Loci ◽  
Allelic Variation ◽  
Empirical Support ◽  
Mutation Rates ◽  
Troglodytes Aedon ◽  
House Wren ◽  
House Wrens ◽  
Factors Influencing ◽  
Two Populations

Microsatellite loci have high mutation rates and high levels of allelic variation, but the factors influencing their mutation rate are not well understood. The proposal that heterozygosity may increase mutation rates has profound implications for understanding the evolution of microsatellite loci, but currently has limited empirical support. We examined 20 microsatellite mutations identified in an analysis of 12 260 meiotic events across three loci in two populations of a songbird, the house wren ( Troglodytes aedon ). We found that for an allele of a given length, mutation was significantly more likely when there was a relatively large difference in size between the allele and its homologue (i.e. a large ‘allele span’). Our results support the proposal of heterozygote instability at microsatellite loci.

scholarly journals Feeding of House Wren Nestlings Afflicted by Hematophagous Ectoparasites: A Test of the Parental Compensation Hypothesis

The Condor ◽  
2002 ◽  
Vol 104 (1) ◽  
pp. 183-187 ◽  
Author(s):  
Brian L. Morrison ◽  
L. Scott Johnson
Keyword(s):  
Mass Gain ◽  
Food Delivery ◽  
Blow Fly ◽  
Troglodytes Aedon ◽  
House Wren ◽  
House Wrens ◽  
Significant Difference ◽  
Fly Larvae ◽  
Compensation Hypothesis

Abstract This study asked whether parent House Wrens (Troglodytes aedon) in a Wyoming population increased rates of food delivery to broods parasitized by hematophagous blow fly larvae and mites. We observed no significant difference in rates at which pairs fed nestlings at nests with naturally heavy infestations of fly larvae (6–19 larvae per nestling) and nests in which nestling exposure to larvae was experimentally eliminated or severely reduced (0–2 larvae per nestling). The apparent failure of parents to compensate nestlings for resources lost to parasites may, in part, explain the reduced rates of mass gain by parasitized nestlings that we observed and the presence of reduced hemoglobin levels in parasitized nestlings documented in a companion study. Parasitized nestlings may be too weak or anemic to intensify begging activity which would alert parents to their increased need for food. Alimentación de Polluelos de Troglodytes aedon Afectada por Ectoparásitos Hematófagos: Una Prueba de la Hipótesis de Compensación Parental Resumen. Nos preguntamos si los individuos parentales de Troglodytes aedon de una población de Wyoming aumentan las tasas de alimentación sobre polluelos parasitados por ácaros y larvas de moscas hematófagas. No observamos diferencias significativas en la tasa a la cual las parejas alimentaron a los polluelos entre nidos altamente infectados naturalmente por la larva de la mosca (6–19 larvas por polluelo) y nidos en que la exposición a las larvas fue eliminada o severamente reducida experimentalmente (0–2 larvas por polluelo). En parte, la aparente falta de compensación por parte de los padres sobre la pérdida de recursos de los polluelos infectados puede explicar sus bajas tasas de ganancia de peso y los niveles reducidos de hemoglobina documentados en un estudio asociado al presente. Los polluelos parasitados probablemente se encuentran muy débiles o anémicos como para intensificar la actividad de reclamo lo que alertaría a los padres sobre su mayor necesidad de alimento.

scholarly journals Calcium Availability Limits Reproductive Output of Tree Swallows (Tachycineta Bicolor) in a Nonacidified Landscape

The Auk ◽  
2005 ◽  
Vol 122 (1) ◽  
pp. 246-254
Author(s):  
Mark T. Bidwell ◽  
Russell D. Dawson
Keyword(s):  
Reproductive Output ◽  
Oyster Shell ◽  
Tachycineta Bicolor ◽  
Tree Swallows ◽  
Avian Reproduction ◽  
Good Body Condition ◽  
Supplemental Calcium ◽  
Clutch Initiation ◽  
Calcium Availability ◽  
Free Ranging

Abstract Breeding birds require high levels of energy and certain nutrients, such as calcium. The extent to which calcium limits reproduction in wild birds is unclear. We performed a supplementation experiment to determine whether calcium limits the reproductive output of free-ranging insectivorous Tree Swallows (Tachycineta bicolor), a species whose usual diet contains little calcium. Providing supplemental calcium in the form of crushed oyster shell did not affect clutch initiation date, but it caused birds that had not started constructing a nest when we first detected them on the study area to begin laying sooner, which suggests that calcium reduced the length of the prelaying period. Supplemented females produced larger eggs, and that effect was most pronounced among females in good body condition. There was a trend for supplemented birds to produce larger clutches, and their clutches had significantly greater total mass than those of control birds. Supplemented birds, in particular those breeding late in the season, also hatched significantly more eggs. Our results suggest that calcium availability may limit some aspects of avian reproduction, even in nonacidified landscapes like our study area, where levels of calcium in the soil are high. La Disponibilidad de Calcio Limita el Rendimiento Reproductivo de Tachycineta bicolor en un Paisaje no Acidificado

The shape of eggs in different-sized clutches of the house wren (Troglodytes aedon)

2001 ◽  
Vol 79 (8) ◽  
pp. 1527-1531 ◽  
Author(s):  
L Scott Johnson ◽  
Jennifer E Leyhe ◽  
Caryn Werner
Keyword(s):  
Clutch Size ◽  
Large Set ◽  
Troglodytes Aedon ◽  
House Wren ◽  
House Wrens ◽  
Female Body Size ◽  
Tree Cavities ◽  
Cavity Nesting ◽  
Egg Shape ◽  
Specific Variation

The substantial inter- and intra-specific variation that occurs in the shape of birds' eggs remains largely unexplained. Several researchers have hypothesized that selection will favour a shape that results in the most compact fit of eggs under the incubating parent. Mathematical modeling has suggested that optimal egg shape depends on the number of eggs laid. We tested predictions of one previously published model by comparing the shape of eggs in clutches of 4, 5, 6, 7, and 8 eggs in a Wyoming, U.S.A., population of the house wren (Troglodytes aedon), a small, cavity-nesting songbird whose eggs vary considerably in shape. Contrary to predictions of the model, the typical shapes of eggs from different-sized clutches were very similar. Moreover, slight differences in shape detected were not in directions predicted by the model. There may be less selection on house wrens to adjust egg shape to clutch size because they lay eggs that are small relative to female body size, because eggs are placed in a deep spherical cup that conforms to the shape of the female's abdomen and because nests are to some degree insulated, being located in tree cavities. Full evaluation of the model will require comparisons of egg shape and clutch size in a large set of species that differ in natural-history characteristics such as egg size, nest shape, and nest placement.

Condition-dependent sex difference in nestling House Wren (Troglodytes aedon) response to phytohaemagglutinin injection

2014 ◽  
Vol 92 (1) ◽  
pp. 1-7 ◽  
Author(s):  
C.F. Thompson ◽  
S.K. Sakaluk ◽  
B.S. Masters ◽  
B.G.P. Johnson ◽  
L.A. Vogel ◽  
...  
Keyword(s):  
Immune System ◽  
Health State ◽  
Immune Responsiveness ◽  
Troglodytes Aedon ◽  
House Wren ◽  
Male And Female ◽  
House Wrens ◽  
Bacteria Killing ◽  
The One ◽  
Breeding Seasons

Adult male and female birds typically respond differently to immunological challenges, but whether this difference is present in altricial nestlings is not well-documented. Furthermore, the timing of the development of different axes of the immune system might vary in nestlings and also be affected by differences in condition and health state. We tested for sex-related differences in the immune response of nestling House Wrens (Troglodytes aedon Vieillot, 1809) to the injection of phytohaemagglutinin (PHA) and in the bacteria-killing capacity of their plasma. Based on prior work, we predicted that if there were sex-related differences in immune responsiveness, they would most likely occur when the sexes differed in some measure of condition or health state. Female nestlings had a stronger response to the injection of PHA than males in the one of three breeding seasons in which the condition of nestling females exceeded that of males, suggesting that the response to PHA injection is condition-dependent rather than sex-dependent. The sexes, however, did not differ in bactericidal activity, suggesting that different axes of the immune system may not be affected to the same degree by differences in sex or in condition.

Female house wrens value the nest cavity more than exclusive access to males during conflicts with female intruders

Behaviour ◽  
2018 ◽  
Vol 155 (2-3) ◽  
pp. 151-180 ◽  
Author(s):  
Cara A. Krieg ◽  
Thomas Getty
Keyword(s):  
Female Aggression ◽  
Troglodytes Aedon ◽  
High Quality ◽  
House Wren ◽  
Nest Cavity ◽  
House Wrens ◽  
Nest Boxes ◽  
Male Care ◽  
To Receive ◽  
Male House

Abstract Individuals should fight hardest when they stand to lose the most. Whereas males frequently compete for fertile females, females more often compete for high quality males, male care, or resources required to breed. We asked whether established, territorial female house wrens (Troglodytes aedon) challenged by simulated female intruders fight as if they place more value on retaining (1) their nesting cavity or (2) exclusive access to other benefits offered by males. We randomly assigned house wren pairs to receive one or three nest boxes and then assayed female aggression. The relative costs to losing differed between box treatments. For one-box females, the risk of losing the cavity and territory was higher. For three-box females, the risk of losing the cavity may be lower because intruders may be able to settle as secondary females in the supplemental boxes. In this situation, females would lose exclusive access to males and their territories but would still retain the male’s assistance rearing offspring since male house wrens favour their oldest brood. We found that one-box females were significantly more aggressive. This response may be adaptive, as females that switched territories between broods were significantly more likely to lose their entire nest prior to hatching than females that retained the same territory. We interpret our results to mean that female house wrens value the nest cavity more than other benefits from exclusive access to males and their territories. This work contributes to a body of evidence that females often compete for resources required to breed.

Alarm calls of house wrens (Troglodytes aedon bonariae) elicit responses of conspecific and heterospecific species

Behaviour ◽  
2021 ◽  
pp. 1-19
Author(s):  
Mariana E. Carro ◽  
Gustavo J. Fernández
Keyword(s):  
Alarm Calls ◽  
Type I ◽  
Type Ii ◽  
Troglodytes Aedon ◽  
House Wren ◽  
Multiple Functions ◽  
House Wrens

Abstract Nesting house wrens (Troglodytes aedon bonariae) use two basic alarm calls (Type I and Type II) when detect a threat near the nest. We experimentally analysed if calls distract predators or serve to recruit other birds to create a mobbing flock to deter predators. The results show that individuals preferentially position themselves in front of the threat, disclosing the location of the nest. Also, using playbacks of house wren alarm calls we found that these calls recruited both conspecific and heterospecific individuals to create a mobbing response. The alarm calls of house wrens seem to fulfil multiple functions, not only conveying information about the threat to their mates and nestling as revealed in previous studies, but also as a signal that attracts the attention of other conspecific and heterospecific individuals and can trigger a mobbing response to deter the predator.

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