Mountain Bluebirds Research Articles

Energy allocation to reproduction and maintenance in mountain bluebirds (Sialia currucoides): a food supplementation experiment

Mountain bluebirds (Sialia currucoides) were supplemented with food during the nestling period to assess the trade-off between allocation of energy to parental self-maintenance and investment in offspring. Three treatment groups were established, with pairs of birds receiving 0 (control), 9 (small), or 18% (large) of the estimated daily energy requirements of both parents and their brood. Unsupplemented adult females lost an average of 3 g during the nestling period, while both supplemented groups maintained their body mass at approximately 33 g. Adult males in all three groups maintained their mass at approximately 30.5 g. Nestlings in both supplemented groups fledged with heavier masses than did those in the control group. Those receiving the large supplement also grew faster. Food appears to limit the lifetime reproductive success of mountain bluebirds. Adult females allocated additional energy to self-maintenance rather than to increased investment in current offspring. This result was not seen in males. We conclude that our results demonstrate a trade-off between investment in current versus future components of reproductive success.

Mountain Bluebird Nests in Clothes Dryer Vent

Mountain Bluebird Nests in Clothes Dryer Vent

Ash-Throated Flycatchers (Myiarchus cinerascens) Raise Mountain Bluebird (Sialia currucoides) Young

Ash-throated Flycatchers (Myiarchus cinerascens) and Mountain Bluebirds (Sialia currucoides) are secondary cavity-nesters that are sympatric in juniper woodlands of northern Nevada. While conducting a study of Mountain Bluebird reproductive strategies during the 1988-1989 breeding seasons, we observed two instances of Ash-throated Flycatchers raising bluebird nestlings in addition to their own young. Our study area is located in partially burned juniper woodlands north of Reno, Nevada, and contains 68 nestboxes. These boxes have been used since 1985 by Mountain Bluebirds and are also used occasionally by Ash-throated Flycatchers. In the first incident, a nestbox which contained two bluebird eggs on 30 May 1989 was taken over by Ashthroated Flycatchers. The adult bluebirds were unbanded, so we are not sure what happened to them after losing the nestbox; they did not use the nestbox again that season. The female flycatcher did little additional nestbuilding (flycatchers in this area use clumps of fur for nest material whereas bluebirds mainly use strips of bark), but laid her clutch of five eggs alongside the two bluebird eggs by 6 June. She incubated the mixed clutch, and all seven eggs hatched on approximately 19 June. In the four times we checked the nest between hatching and 3 July, the rate of nestling development appeared to be equal for both species. Only flycatchers were seen feeding the young. All nestlings presumably fledged on 11 July, except for one almost completely feathered bluebird nestling found mummified in the nestbox on 12 July (cause of death unknown). Despite repeated searches, we did not see the young after fledging. In the second incident, an Ash-throated Flycatcher laid two eggs by 22 June 1989 in a nestbox in which a bluebird pair had previously fledged a clutch of four young. On 5 July there was one Mountain Bluebird egg in the nest, along with two additional Ash-throated Flycatcher eggs. The flycatcher incubated all five eggs. On 12 July, we found one bluebird and two flycatcher young along with a dead flycatcher nestling and an unhatched egg. The young were approximately two days old. Again, only flycatchers were seen caring for the young. On 15 July (five days after hatching), the nest contained only two dead young (one flycatcher and one bluebird). The other nestling and the unhatched egg were missing. The adults were not in the area and were not seen again. Since predation is a major cause of bluebird egg and nestling mortality in our study area (unpubl. data), we assume this was the cause of nest failure, though nest abandonment cannot be completely ruled out. To our knowledge, this is the first report of Ashthroated Flycatchers raising the young of any other species. These two cases are qualitatively different, and we consider two possible explanations for them: 1. competition for suitable nest sites, and 2. facultative brood parasitism. Nest site competition. Two lines of evidence suggest that Mountain Bluebirds and Ash-throated Flycatchers compete for suitable nest sites in this study area. First, we know of four takeovers of bluebird nests by flycatchers since 1985 (two in 1986, one in 1987, one in 1989). There have been no reciprocal takeovers by bluebirds, presumably because flycatchers are much ' Received 15 October 1990. Final acceptance 7 December 1990. SHORT COMMUNICATIONS 461

A Natural Occurrence of Foster Parenting by a Female Mountain Bluebird

A Natural Occurrence of Foster Parenting by a Female Mountain Bluebird

Errata: Food of Adult and Nestling Western and Mountain Bluebirds

Errata: Food of Adult and Nestling Western and Mountain Bluebirds

Effects of a Late May Snowstorm on Mountain Bluebird and Treeswallow Nesting

Effects of a Late May Snowstorm on Mountain Bluebird and Treeswallow Nesting

Food of Adult and Nestling Western and Mountain Bluebirds

Food of Adult and Nestling Western and Mountain Bluebirds

Nest Site Selection in Mountain Bluebirds

-Nest site selection was analyzed for a Mountain Bluebird (Sialia currucoides) population using two different types of nest box in southcentral Washington. The majority of adult females successful in fledging young during the previous year either returned to the same territory and nest box or selected the same type of nest box if they changed territories. If they were unsuccessful, adult females tended to change territories and box types. Most male and female bluebirds breeding for the first time selected the same type of box as housed their natal nest even though none of these birds returned to its natal territory. Nest site selection and breeding area fidelity were influenced by age, sex, previous breeding experience, and natal nest type. Recently, Cink (1976) examined the degree to which nestling House Sparrows (Passer domesticus) imprinted on the type of structure housing their natal nest. Although he found no evidence that early learning or imprinting had any effect on nest site selection, females tended to choose hole-type nests over open nests. Other studies have shown that some species prefer a larger to a smaller nest box (Jiirvinen 1978) and that floor dimensions of a box can influence clutch size (Karlsson and Nilsson 1977). Jackson and Tate (1974) analyzed selection of artificial nest sites by Purple Martins (Progne subis), House Sparrows, and Starlings (Sturnus vulgaris) and found only slight differences related to interior and exterior colors, location, and materials from which the boxes were constructed. Lumsden (1976) reported that Starlings preferred small entrance holes and dark interiors. Bluebirds, like all cavity-nesting species, are limited by availability of suitable nest sites. Many studies (e.g., Miller 1970, Power 1974) have shown that bluebird populations can be increased by placement of nest boxes in suitable habitat. Although much is known about the reproductive biology of bluebird populations (Power 1966, Peakall 1970, White and Woolfenden 1973, Pinkowski 1977a, 1979a), little has been published concerning nest box selection and breeding area fidelity (the tendency for birds to return to the territory used the previous breeding season). Pinkowski (1979b) analyzed breeding data for Eastern Bluebirds (Sialia sialis) using artificial and natural nest cavities and found that age and nesting success seemed to be the most important factors influencing nest site selection. Additionally, he concluded that imprinting on the natal type of nest site was not important. I theorized that imprinting on the natal type of nest site would be important for secondary cavity-nesting species because of the scarcity of natural cavities and that species-specific differences could influence nest site selection. To test these theories, I examined breeding data for a Mountain Bluebird (Sialia currucoides) population using two different types of nest box and analyzed the influences of age, sex, previous breeding experience, and natal nest type on nest site selection. STUDY AREA AND METHODS The study area was located south of Bickleton and Cleveland, Klickitat County, Washington. Elevation ranges from 915 m near Bickleton on the north to 701 m in valleys running north-south. The northern edge of the study area is on the ecotone between ponderosa pine-Oregon white oak (Pinus ponderosa-Quercus garryana) forest and big sagebrush-bluebunch wheatgrass (Artemisia tridentata-Agropyron spicatum) steppe. Much of the land south of Bickleton and Cleveland is farmed with winter and spring wheat and with barley. Areas not cultivated are moderately grazed by cattle. The two types of nest box were designated as either old or indicating how long they had been present on the study area. The old boxes were first erected in 1966 and new boxes were added each year (J. Brinkerhoff, pers. comm.). These boxes resembled a small house with a peaked roof. The inside dimensions of the floor were 30 x 15 cm with an entrance hole diameter of 4.4 cm; the entrance hole was approximately 10 cm above the floor. The outside of these boxes had a blue roof and white sides; the interiors were not painted. All of the boxes had inside floor dimensions of 12.7 x 12.7 cm with a 3.8-cm diameter entrance hole, the bottom of which was 14 cm from the floor. The boxes were not painted. Both old and boxes were made of wood. The number of old box types available was usually 50 (except for 41 in 1976) and box types numbered 30-31. Old type boxes were placed on top of wooden fence posts and type boxes were nailed to the

Winter Abundance Patterns of Some Songbirds near the 100th Meridian in the Southern United States

-This study examines winter abundance patterns of three groups of song birds across the south-central United States-the phoebes (Sayornis), thrashers (Toxostoma and Oreoscoptes), and bluebirds (Sialia). The analysis was done on 15 years of National Audubon Society Christmas Bird Count data that were collected in an area encompassing most of Texas, Oklahoma, and part of New Mexico. There was no statistically significant east-west variation in group abundances, but a transition from to forms within each group occurred between the 98th and 102nd meridians, and the transition was abrupt. A significant biogeographic boundary appears to exist within two degrees on either side of the 100th meridian. Biogeography traditionally has involved the study of species' distributions over the surface of the earth. Data usually are not available to determine more than simple outline maps of species' ranges (Udvardy, 1969; Rotramel, 1973). A great wealth of avian biogeographic data has been accumulating since 1901 in the form of National Audubon Society Christmas Bird Counts. These data have been used infrequently until recently. Bock et al. (1977) used 10 years of data, which they grouped into five-degree latitude by fivedegree longitude blocks, to add the dimension of geographic variation in winter abundances for some North American bird They found that these abundance patterns showed a major biogeographic boundary in the Southern Great Plains near the 100th meridian. The purpose of our study was to use Christmas Count data on a finer spatial scale to examine changes in winter bird abundance patterns across Texas and Oklahoma, near the 100th meridian. The groups studied were the phoebes (Eastern Phoebe-Sayornis phoebe, Black Phoebe-S. nigricans, and Say's Phoebe-S. saya), the thrashers (Brown Thrasher-Toxostoma rufum, Curve-billed Thrasher-T. curvirostre, Crissal Thrasher-T. dorsale, and Sage Thrasher-Oreoscoptes montanus), and the bluebirds (Eastern Bluebird-Sialia sialis, Western Bluebird-S. mexicana, and Mountain Bluebird-S. currucoides). Each group consists of which are common in our study area, and each group is composed of and counterparts. For the purpose of our analysis we refer to the Eastern Phoebe, the Brown Thrasher, and the Eastern Bluebird as eastern species and all other as western species. The Long-billed Thrasher (T. longirostre), which occurs in our study area, was not included because the majority of its range is in Mexico (A.O.U. Checklist, 1957). We examined Christmas Count data collected in our study area over a 15year period for the above to test the hypotheses that 1) abundance patterns of the three groups show no significant east-west variation; 2) a E SOUTHWESTERN ATURALIST 26(2):95-100 MAY 2 , 1981 This content downloaded from 207.46.13.169 on Sat, 01 Oct 2016 06:07:34 UTC All use subject to http://about.jstor.org/terms The Southwestern Naturalist

Fertility of Albinistic Eggs of Mountain Bluebirds

Fertility of Albinistic Eggs of Mountain Bluebirds

Experiments on Cuckoldry in the Mountain Bluebird

Cuckoldry produces both genetic polygyny within otherwise socially monogamous species and cryptic altruism by cuckolds themselves, thus the genetic effects of cuckoldry are extremely severe, and should result in the evolution of both anticuckoldry behaviors and means of evading them in socially monogamous birds. Nonexperimental observations of mountain bluebirds revealed that (1) nesting males usually follow nest-building and foraging females, and escort them in and out of their nest cavities prior to hatching, thereby apprising themselves of their mates' whereabouts and companions at all times and preventing their own cuckoldry; (2) intruder males without adjacent territories proceed directly to nest sites when invading others' territories and sometimes display there before being evicted, thereby stationing themselves at the place where most copulations occur and giving themselves the opportunity to cuckold the males that occupy the nest sites; and (3) resident bluebirds defend their nest sites and terri...

Reproductive Efficiency and Site Attachment of Tree Swallows and Mountain Bluebirds

Reproductive Efficiency and Site Attachment of Tree Swallows and Mountain Bluebirds

The Foraging Behavior of Mountain Bluebirds: With Emphasis on Sexual Foraging Differences

The Foraging Behavior of Mountain Bluebirds: With Emphasis on Sexual Foraging Differences

Residues in common flicker and mountain bluebird eggs one year after a DDT application.

Common flicker (Colaptes auratus) and mountain bluebird (Sialia currucoides) eggs were examined 1 year after DDT application and showed a marked difference. Residue levels in mountain bluebird eggs were approximately 10 times higher than in common flicker eggs (5.29 to 0.58 ppm wet weight). These differences can be explained by disparate dietary habits. The mean level in American kestrel (Falco sparverius) eggs collected in the spray area at the same time was 6.42 ppm wet weight.

Male Response to Apparent Female Adultery in the Mountain Bluebird (Sialia currucoides): An Evolutionary Interpretation

Male Response to Apparent Female Adultery in the Mountain Bluebird (Sialia currucoides): An Evolutionary Interpretation

Response : Altruism in Mountain Bluebirds?

<i>Response</i> : Altruism in Mountain Bluebirds?

Altruism in Mountain Bluebirds?

Altruism in Mountain Bluebirds?

Male Eastern Bluebird Assists Female Mountain Bluebird in Raising Young

Male Eastern Bluebird Assists Female Mountain Bluebird in Raising Young

Enemies and Other Perils of the Mountain Bluebird in Southwestern Manitoba.

Enemies and Other Perils of the Mountain Bluebird in Southwestern Manitoba.

Use of Dipper Nest by Mountain Bluebird

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