Troglodytes Aedon Research Articles

Female Attraction To Male Song in House Wrens (Troglodytes Aedon)

Abstract This study tested the hypothesis that the song of male birds can function to attract mates. At 11 different locations on our Wyoming study area, we broadcast the song of male house wrens (Troglodytes aedon) from a loudspeaker mounted next to an empty nest box in an unoccupied wren territory. The number of female wrens attracted to the 'speaker box' was compared to the number visiting a silent, control box on another, unoccupied territory nearby. Females visited speaker boxes at a significantly higher rate than they visited control boxes. Ten females visited speaker boxes in six different trials during periods when no male was associated with either the speaker or control box (total time = 45.5 h; visit rate = 0.22/h). In contrast, only one female visited a control box during these same periods (= 0.02 visits/h), and she did so after first visiting the speaker box. Two females visited the speaker box simultaneously in some trials and chasing or fighting always ensued. Many females showed signs of settling permanently at speaker boxes, remaining at speaker boxes from their arrival to the end of the trial (> 5 h in two cases), and most began constructing nests in boxes, despite the absence of a male. In summary, this study provides strong experimental evidence that the song of male house wrens can function to attract mates for breeding.

Use of ELISA for Determination of Plasma Prolactin Levels in the House Wren

Prolactin concentrations in avian plasma have been traditionally quantified using a radioimmunoassay (RIA) procedure. RIA is useful for such studies due to its sensitivity and specificity (e.g., Follett et al. 1972, Wingfield and Farner 1975, McNeilly et al. 1978, Burke and Papkoff 1980, Schwabl 1993). For example, the heterologous RIA for detecting prolactin in turkeys, developed by McNeilly et al. (1978), recovered 98% of a prolactin standard added to a turkey plasma sample and exhibited less than 0.1% cross reactivity with other plasma hormones. In an homologous RIA developed by Burke and Papkoff(1980), detection limits of approximately 0.42 ? 0.13 ng were reported. Despite these advantages, RIA has drawbacks for field ecologists, including the high cost of isotope and the necessity of working with radioactive ligands. We report here a non-radioactive alternative to RIA for measurement of plasma prolactin levels in the House Wren (Troglodytes aedon L.), namely, a commercially-available (Leinco Technologies Inc.) enzyme-linked immunosorbant assay (ELISA) kit. The ELISA kit used was based on capturing avian plasma prolactin with a murine monoclonal antibody (mAb) specific for prolactin, followed by detection of the captured prolactin with a polyclonal antibody directed against prolactin. The test may be ideal for usage by field ecologists since it is non-isotopic, portable, does not rely on specificity of the detection antibody, quick, involves little sample or standard preparation, can be used on small sample volumes and requires little specialized equipment.

Nest-Site Relationships among Cavity-Nesting Birds of Riparian and Snowpocket Aspen Woodlands in the Northwestern Great Basin

We examined nest-site and nest-cavity characteristics for six species of cavity-nesting birds in montane riparian and snowpocket aspen (Populus tremuloides) woodlands in the northwestern Great Basin. Live trees and snags with DBH >24 cm were favored as nest sites by all species. Red-naped Sapsuckers (Sphyrapicus nuchalis) and Northern Flickers (Colaptes auratus) provided different sizes of nest cavities for a suite ofnonexcavator species. Flickers preferentially nested in snags; sapsuckers nested primarily in live trees, but used live trees and snags in proportion to their availabilities. Relative abundances of excavators and nonexcavators were associated positively with numbers of cavities. Nest-site variables overlapped extensively among species; Tree Swallows (Tachycineta bicolor) relied heavily on sapsuckers for provision of nest cavities, European Starlings (Sturnus vulgaris) and Mountain Bluebirds (Sialia currucoides) primarily used flicker-excavated cavities, and House Wrens (Troglodytes aedon) used nest cavities across the broadest range of nest-site characteristics. Compass orientation of nest-cavity entrances was strongly bimodal, with most facing east or southwest. Cavity entrances of species that foraged largely outside of riparian woodlands were oriented toward woodland edge, in contrast to nest cavities used by species that foraged largely within riparian woodlands. Snowpocket woodlands were much more extensive than riparian aspen, but birds strongly preferred riparian aspen stands as nesting habitats, presumably due to the scarcity of large aspen in snowpockets. Nest cavities appear to be a limiting resource with high potential for interspecific nest-site competition in these woodlands. Decades of livestock overuse and fire suppression have greatly diminished the availability of large aspen in riparian habitats throughout the region.

Ticks (Acari: Ixodidae) Infesting Wild Birds (Aves) and White-Footed Mice in Lyme, CT

Birds were captured and recaptured (20.8% of 5,297) with Japanese mist nets, and white-footed mice, Peromyscus leucopus (Rafinesque), were caught and recaught (69.1% of 355) with Sherman box traps during the late spring, summer, and early fall from July 1989 through October 1991 to study tick-host relationships in Lyme, CT. Ixodes scapularis Say, a vector of Lyme disease spirochetes, Borrelia burgdorferi sensu stricto Johnson, Schmid, Hye, Steigerwalt & Brenner, infested 803 birds (15.2%) in 36 species and 148 (40.3%) of the mice. This tick dominated both birds (94.4% of 4,065 ticks) and mice (82.6% of 529 ticks). Other ticks that were recovered from birds were Haemaphysalis leporispaustris (Packard) (23 birds in seven species), I. dentatus Marx (34 birds in 14 species), and Dermacentor variabilis (Say) (two birds in two species). The latter was also collected from 12.7% of the 355 mice (n = 92 ticks). Infestations of I. scapularis were high for worm-eating warblers (30.6% of 111), ovenbirds (44.4% of 286), common yellowthroats (27.1% of 188), hooded warblers (35% of 80), Carolina wrens (50.9% of 110), house wrens (21.6% of 102), wood thrushes (23.0% of 867), veeries (32.5% of 246), and American robins (36.2% of 69). Coinfestation by larvae and nymphs of I. scapularis was significantly high for Carolina wrens (35.7% of 56 infested individuals), veeries (27.2% of 80), American robins (29.4% of 25), and common grackle (19.0% of 5), possibly enhancing transmission of B. burgdorferi. Mean crowding on larvae by nymphs, measured by Lloyd's index (1967), was highest for these four species (range 1.19-5.76). Seasonal patterns of infestation for each species of bird can account for much of the differences in degree of coinfestation. High infection rates by B. burgdorferi in larvae removed from some of these birds (14.9-20.0%) were found on those birds with both high numbers of larvae and nymphs. Spirochetemia in most avian hosts may be short and only certain species with concurrent infestations of nymphs and larvae may function effectively as reservoirs.

History of Shiny Cowbird Molothrus bonariensis brood parasitism in Trinidad and Tobago

In attempting to evaluate the evolutionary stability of the reproductive strategies of an avian brood parasite, it is important to know whether or not the observed levels of parasitism on host species have changed through time and whether or not new host species are being used in the region under study. In this regard, the islands of Trinidad and Tobago provide an excellent opportunity because they are ornithologically well known and the expansion of the parasitic Shiny Cowbird Molothrus bonariensis into the West Indian region is thought to have originated from Trinidad and Tobago. On the whole, host choice has remained remarkably stable over the past 50–60 years. The three hosts (House Wren Troglodytes aedon, Red‐breasted Blackbird Leistes militaris and Yellow‐hooded Blackbird Agelaius icterocephalus) known to be heavily parasitized historically remain heavily parasitized today. Only one instance of parasitism of a new host (Tropical Kingbird Tyrannus melancholicus) is recorded. In the case of one intensively studied host, the Yellow‐hooded Blackbird, cowbird parasitism had a minimal negative effect on the host's reproductive success. Reproductive equilibrium in this study seemed to be maintained by behavioural adaptations of host and parasite to each other. The stable pattern of host choice by Shiny Cowbirds in Trinidad and Tobago may not develop elsewhere in the West Indian region. Before the cowbird's expansion in the West Indies, potential hosts had no prior experience of brood parasites. Consequently, the island bird populations are unlikely to have evolved defensive strategies and thus may be more vulnerable to reproductive failure as a result of cowbird parasitism, precluding the development of a stable system at this point in time.

GEOGRAPHIC AND SEASONAL PATTERNS OF CLUTCH-SIZE VARIATION IN HOUSE WRENS

ABsTRAcr.-I report on geographic variation and seasonal decline in clutch size in House Wrens (Troglodytes aedon), a species that breeds throughout much of the New World. Nest records from British Columbia to Tierra del Fuego (n = 3,246 clutches) show that clutch size increases with latitude in both the Northern and Southern hemispheres. Seasonality of food resources, as measured by actual evapotranspiration (AE), does not explain much of the variation in clutch size, especially when controlling for latitude. This result shows that either seasonality is unimportant or that AE is a poor indicator of the food available to House Wrens. Seasonal decline in clutch size varies geographically such that in northern populations, clutch size declines much more rapidly during the breeding season than in low latitude populations. A model explaining this pattern, the offspring-survivorship hypothesis, predicts that the rate of seasonal decline in clutch size is related to the difference in survivorship between earlyand late-fledged young. Field study in Monteverde, Costa Rica, showed that clutch size did not change seasonally and that late-fledged young were at least as likely to survive to the following breeding season as early-fledged young. This pattern is in contrast to North Temperate areas where clutch size declines sharply during the breeding season and late-fledged young are much less likely to survive to the following year than early-fledged young. Received

The Effects of Food, Nest Predation and Weather on the Timing of Breeding in Tropical House Wrens

I tested three hypotheses that could explain variation in the timing of breeding in populations of House Wrens (Troglodytes aedon) at four sites in Costa Rica. The sites were located at 200-1,500 m elevation on both sides and on top of the central mountain range, and had climates differing in temperature, the severity of the dry season, and total rainfall. For the first hypothesis, that breeding is timed to coincide with peaks in food availability, I monitored the monthly abundance of arthropod prey and wren clutch initiations at the four sites. Cross-correlation analysis showed that at three sites, wrens initiated clutches several months prior to when prey levels were high. Indeed, breeding began when prey levels were at their annual low. At the fourth site, prey levels varied little throughout the year and House Wrens nested nearly year round. These results indicate that sufficient food to produce eggs or feed nestlings may have been available throughout the year. Breeding appeared to be timed so that juvenile dispersal and molt occurred when food was most plentiful. The second hypothesis, that breeding is timed to avoid seasons when nest predation is high, was not supported because the rate of nest predation did not vary temporally. The third hypothesis, that breeding is timed to avoid climatic events that can increase the physiological costs of reproduction, was not supported at the three lower elevation sites. Clutch initiation at the highest site, however, did not commence until the early dry season wind and mist subsided. The termination of breeding was not correlated with climatic changes at -any of the sites. Thus reproduction in tropical House Wrens seems generally to be timed to facilitate post-breeding activities, not activities associated with nesting itself.

Organochlorines and reproductive success of birds in orchard and non-orchard areas of central British Columbia, Canada, 1990?91

Most orchards in British Columbia, Canada and the northwestern United States received substantial applications of DDT in the mid-1940s through the early 1970s. Bird eggs were collected from orchard and non-orchard areas in the Okanagan Valley fruit-growing region of central British Columbia during 1990 and 1991 to determine levels of DDT, DDE, and other organochlorines. American robin (Turdus migratorius) eggs from orchard areas contained extremely high levels of both DDE (up to 103 mg/kg) and DDT (up to 26 mg/kg). For robins, tree swallows (Tachycineta bicolor), and house wrens (Troglodytes aedon), levels of DDT and DDE in eggs were significantly higher in orchard habitats than in non-orchard habitats. These data suggest that Okanagan Valley birds were acquiring DDT and DDE burdens locally, and not on their Latin American wintering grounds, as has been previously hypothesized. Ratios of DDE to DDT in robin eggs were quite low (<10), implying that DDT is not breaking down readily in orchard soils and/or that orchards have been receiving recent illicit applications of DDT. There was no evidence of lower reproductive success among tree swallows, house wrens, and bluebirds that nested in orchard versus non-orchard habitats, so the levels of DDT and DDE contained in their eggs (⩽0.1 and ⩽5 mg/kg, respectively) were probably not deleterious. There was no difference in reproductive success of robins nesting in conventional versus organic orchards. Although we did not have a sufficient sample of non-orchard robin nests, comparisons with data on reproductive success in the literature indicates that despite exceedingly high DDT and DDE concentrations, reproduction was not affected. Levels of other organochlorines (dieldrin, heptachlor epoxide, PCBs) in eggs were low, and usually below the minimum detectable threshold. The high DDE concentrations in these eggs from the Okanagan valley indicate that DDE body burdens of passerines nesting there would probably present a considerable toxic hazard to predators, particularly birds of prey.

That's Great!

Last week I read an article about the digestive tracts of birds. I was fascinated to learn that the house wren's intestine grows longer in winter to accommodate the increased food supply needed to maintain body temperature at low environmental temperatures (Karasov 1993). Not only does the intestine grow over 20% longer, it also becomes more efficient at absorbing nutrients. Several other species, including the rock ptarmigan and the spruce grouse, also grow longer guts at times when they eat more food. Other bird species have different digestive adaptations to seasonal changes in food supplies. The robin is not good at absorbing sugars from the intestine, but during the fall and winter when insects are scarce, this bird relies more heavily on fruits. With a change from a high-insect to a highfruit diet, the speed at which food moves through the robin's digestive tract increases. Since absorption is inefficient, the only way the bird can obtain enough nutrients is to move a lot of food through the digestive tract as rapidly as possible. While I knew that the digestive tracts of humans and other animals respond to changes in diet, I didn't know that the response could be as striking as a 20% increase in intestinal length or a 100% increase in the transport rate. Reading articles that describe fascinating adaptations such as these is one of the joys of being a biologist. After finishing an article like this, I just sit back and say, That's great! Because the living world is so rich, there are many articles that elicit this response, and I'd like to discuss a few of them in this column.

Experiência de manejo de aves em áreas antrópicas, com a utilização de caixas de madeira como locais para nidificação

Use of nest-boxes for management of cavity nesting birds in anthropic areas can give good results. In November 1987, data collection begun in UNICAMP, Campinas (Sao Paulo), with the objective of favouring establishment and increase in urban bird communities. The House Wren (Troglodytes aedon Viellot. 1807) and House Sparrow (Passer domesticus Linnaeus, 1758) used the nest boxes for reproduction. Nests were collected and analysed (weight, used materials, incubation chamber materials, nest form). House Sparrow used thin materials, like straw, paper and plastic, while house wren used heavy materials, like sticks, wire and tabs of soff drink cans. The nest-boxes offered favorable conditions to bird reproduction and protection in disturbed areas, and showed signs of leading to increase in diversity of species, that might use this nest-boxes for reproduction in the future.

Territorial polygyny in house wrens: are females sufficiently compensated for the cost of mate sharing?

Territorial polygyny in house wrens: are females sufficiently compensated for the cost of mate sharing?

Why is reduced male parental assistance detrimental to the reproductive success of secondary female house wrens?

Abstract. Polygynous male house wrens, Troglodytes aedon, usually provide their second of two mates with little or no aid in feeding nestlings. Most 'poorly aided' secondary females raise fewer and lower 'quality' offspring than 'fully aided' females. The parental behaviour of poorly aided secondary females was examined to determine why reduced male parental assistance so often lowers their reproductive success. Compared with fully aided first-mated females, poorly aided secondary females spent less time in nests brooding nestlings (∼3 min/h), and increased their rate of prey delivery to nestlings. However, nestlings of poorly aided secondary females still received significantly fewer prey than nestlings of fully aided first-mated females during the first half of the nestling stage. To match the per caput rate at which pairs delivered prey at nests of fully aided first-mated females during this period, it was estimated that poorly aided secondary females would have to reduce time spent brooding nestlings to less than 50% of that shown by fully aided females. Mean metabolic rate of nestlings may be so reduced at this level of brooding that they could not ingest and metabolize all food received. Nevertheless, a review of the literature indicates that poorly aided secondary female house wrens clearly shift relatively less time from brooding to foraging than do poorly aided females in other small passerine bird species. In this paper, it is argued that maintenance of extensive brooding by poorly aided female wrens cannot be explained by a high risk of nestling death from hypothermia. Rather, females in this species may stay in nests to prevent removal of offspring from nests by conspecific intruders.

Daily Energy Expenditure by Nestling House Wrens

Journal Article Daily Energy Expenditure by Nestling House Wrens Get access Cheryl R. Dykstra, Cheryl R. Dykstra Department of Wildlife Ecology, University of Wisconsin, Madison, WI 53706 Search for other works by this author on: Oxford Academic Google Scholar William H. Karasov William H. Karasov Department of Wildlife Ecology, University of Wisconsin, Madison, WI 53706 Search for other works by this author on: Oxford Academic Google Scholar The Condor, Volume 95, Issue 4, 1 November 1993, Pages 1028–1030, https://doi.org/10.2307/1369439 Published: 01 November 1993 Article history Received: 03 December 1992 Accepted: 21 April 1993 Published: 01 November 1993

Avian Hatching Asynchrony: Brood Classification Based on Discriminant Function Analysis of Nestling Masses

Studies of hatching asynchrony in altricial birds have used several methods to determine if a brood hatches synchronously or asynchronously. The most commonly used methods include making frequent nest visits during the time of hatching and using nestling mass or other measures of size on a given day to estimate nestling age or to describe the extent of the size hierarchy within broods. We made daily nest visits to determine if House Wren (Troglodytes aedon) broods hatched synchronously or asynchronously, and then compared classification of these broods based on discriminant function analysis with that based on mass differences of nestlings. The best misclassification rate based on dis? criminant function analysis was 17.5%, whereas the rates based on mass differences (23.1%) and estimates of nestling age (27.5%) were higher, but not significantly higher. The most frequent error occurring in discriminant function analysis was misclassifying asynchronous broods as synchronous broods, whereas the most frequent error based on mass differences of nestlings was misclassifying synchronous broods as asynchronous ones. Discriminant function analysis based on coefficient of variation of nestling mass and number of nestlings was about as effective (error rate = 17.5%) as was classification using individual masses. We recommend that investigators who wish to categorize broods objectively as synchronous or asynchronous based on nestling masses or other measures of size should use a discrim? inant function analysis.

The Cost of Polygyny in the House Wren Troglodytes aedon

Our objective was to determine why territorial polygyny occurs in the house wren Troglodytes aedon, a small, insectivorous, cavity-nesting songbird. In this paper, we present evidence that choosing a mated male in our Wyoming (USA) study population is inherently costly to female fitness. In each of three breeding seasons, females who chose mated males (i.e. «secondary» = 2° females) produced significantly fewer fledglings per breeding attempt than females who chose unmated males (monogamous (M°) and primary (1°) females). Secondary females were less likely than M°/1° females to complete nesting attempts, primarily because they lost more broods to starvation, and had more clutches and broods destroyed by conspecifics intruding onto territories

Does the cost of polygyny in house wrens include reduced male assistance in defending offspring?

This study investigated whether reduced male aid in defending offspring potentially reduces the fitness of females choosing already-mated males in the house wren (Troglodytes aedon), a small, territorial songbird. Frozen snakes were placed at 23 nests of monogamously mated males and 12 “secondary” nests of bigamously mated males. All presentations were made during incubation stages of females attending focal nests. Snakes were placed at nests of secondary females when nests of their primary counterparts contained young 5–9 days old. Males are most attentive to primary nests during this period and should therefore be relatively inattentive to secondary mates and nests. Nevertheless, an equal proportion of monogamous and bigamous males discovered snakes within 15 min, and mean time to discovery, when discovery occurred, did not differ with nest status. Monogamous and bigamous males were also equally likely to attack snakes physically once discovered. Monogamous males appeared no more likely to discover snakes than bigamous males for two main reasons. First, although monogamous males were near focal nests (i.e., < 10 m) more often than bigamous males, monogamous males tended to stay out of view of nests for long periods. In contrast, bigamous males always went immediately to focal nests upon arriving in their vicinity. Second, about one-third of monogamous males in this study spent much of their time during trials at the far edges of their territories advertising for secondary mates. Our experiment suggests that reduced male aid in defending nests against small, diurnal predators probably does not contribute to the cost of polygyny in house wrens.

Relative Importance of Bird Species as Hosts for Immature Ixodes dammini (Acari: Ixodidae) in a Suburban Residential Landscape of Southern New York State

Abundance of birds and their tick parasites were estimated in a residential community located in Westchester County, NY, where Lyme disease is endemic. In total, 36 bird species (416 captures) were collected, of which 25 species (69%) were parasitized by ticks. Ixodes dammini Spielman, Clifford, Piesman & Corwin composed 96.4% of the 1,067 ticks found on birds. The bird species most heavily parasitized was house wren, Troglodytes aedon Vieillot (11.1 Ixodes dammini per bird). Relative density estimates of birds, using fixed circle radius counts, revealed dominance by the American robin, Turdus migratorius L. (29.3%), followed by the common grackle, Quiscalus quiscula (L.) (9.3%). Bird density estimates were combined with tick abundance data to calculate an importance value for each bird species as a host for immature I. dammini. The American robin was most important, accounting for 72.7% of all larval I dammini found on birds, followed by the common grackle (8.2%) and the house wren (5.9%). Both the American robin and house wren are reservoir competent for the Lyme disease spirochete Borrelia burgdorferi Johnson, Schmid, Hyde, Steigerwalt & Brenner and therefore may contribute to the risk of Lyme disease for humans. During August when larvae were most prevalent, 39% of the American robins and 70% of the common grackles were observed on lawns. These species are probable contributors to nymphal I. dammini populations found on lawns.

Nesting Energetics of House Wrens (Troglodytes aedon) in Relation to Maximal Rates of Energy Flow

We tested the hypothesis that brood size in House Wrens (Troglodytes aedon), which have a mean mass of 10.6 g, is confined by digestive limits to maximal rate of energy flow in parents feeding nestlings. Using doubly-labeled water (DLW), we measured field metabolic rate during feeding of nestlings (FMR,), tested whether it increased with brood size, and compared it with the wrens' near-maximal rate of intake, digestion, and assimilation measured in the laboratory. To expand the range of House Wrens' effective brood sizes (i.e. brood size/parent), we manipulated some brood sizes by removal of the male parent or by addition of extra chicks or eggs. The rate of nest visits by parent wrens was positively correlated with mass of chicks (P < 0.001). Various measures of brood size were regressed against FMR,. However, when brood size and overnight minimum air temperature were entered together in a stepwise multiple-regression model, only minimum air temperature was significantly related to FMR, (P = 0.013, r2 = 0.201). Mean FMR, (60.8 3;2;± 2.0 kJ /day) was lower than the near-maximal rate of intake, digestion and assimilation measured in the laboratory (92.7 kJ I day). Therefore, we reject the hypothesis that brood size is limited by digestive constraints on maximum metabolic rate in House Wrens.

Effects of the parasitic botfly Philornis carinatus on nestling house wrens, Troglodytes aedon, in Costa Rica.

I studied the life cycle of a botfly (Diptera: Muscidae: Philornis carinatus) and examined the effects of botfly ectoparasitism on nestling house wrens (Passeriformes: Troglodytidae: Troglodytes aedon) during three years in Costa Rica. At three study sites, I found that nestlings were relatively unaffected by botflies, in contrast to all other studies of birds infected with philornid botflies. At Monteverde, the main study site, infected chicks grew slightly slower and had slightly shorter tarsi and wing chords than uninfected chicks, but both groups fledged at similar weights. Since weight at fledging is the only growth character associated with post-fledging survivorship, botfly infections likely cost wrens little in terms of fitness. At all sites, fledging success did not differ between infected and uninfected nests. Botfly infections were more prevalent at two lower elevation sites than at the high elevation Monteverde side. Infection prevalence increased during the nesting season at all study sites, which suggests a botfly life cycle in which adult population levels increase during the wren breeding season and then decline during a dormant period when wrens are not nesting. Finally, botflies may attack chicks throughout the period before fledging, but there is no indication they locate nests before hatching. In sum, botfly parasitism on wrens appears to be benign, perhaps because the study sites are at the edge of the botfly's range or because wrens are not a preferred host.

Effects of Haematophagous Ectoparasites on Nestling House Wrens, Troglodytes aedon: Who Pays the Cost of Parasitism?

We experimentally investigated the effects of two haematophagous ectoparasites, larvae of the blow fly Protocalliphora parorum (Diptera: Calliphoridae) and the mite Dermanyssus hirundinis (Mesostigmata: Dermanyssidae), on the survival, health and growth of nestling house wrens Troglodytes aedon. Nestlings in broods with relatively heavy infestations (> 10 larvae, and hundreds to thousands of mites, per nestling) did not have higher mortality, reduced growth of tarsi and primary feathers, or lower pre-fledging hematocrits than nestlings occupying nests in which parasites were killed with heat