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Highlights • Canyon towhees time to avoid conspecific song but do not avoid anthropogenic noise. • Four species with variable singing style do not adjust spectrum or timing to noise. • Singing style in general does not appear to correlate with noise-dependent flexibility. • Song consistency may have signal value and therefore persist under noisy conditions. Abstract Many bird species adjust their songs to noisy urban conditions by which they reduce masking and counteract the detrimental impact on signal efficiency. Different species vary in their response to level fluctuations of ambient noise, but it remains unclear why they vary. Here, we investigated whether noise-dependent flexibility may relate to singing style and signal function of the flexible acoustic trait. Species with highly variable songs may generally be more flexible and strongly repetitive singers may be more limited to stray from their stringent patterns. We exposed males of four passerine species with contrasting singing styles (repertoire size, immediate or eventual variety singing and syllable diversity) to three experimental sound conditions: 1) continuous urban noise; 2) intermittent white noise and 3) conspecific song playback. We found no spectral or temporal changes in response to experimental noise exposure in any of the four species, but significant temporal adjustment to conspecific playback in one of them. We argue that the consistency in song frequency and timing may have signal value, independent of singing style, and therefore be an explanation for the general lack of noise-dependent flexibility in the four species of the current study. [ABSTRACT FROM AUTHOR]

The maintenance or breakdown of reproductive isolation is an observable outcome of secondary contact between species. In cases where hybrids beyond the F1 are formed, the representation of each species' ancestry can vary dramatically among genomic regions. This genomic heterogeneity in ancestry and introgression can offer insight into evolutionary processes, particularly if introgression is compared in multiple hybrid zones. Similarly, considerable heterogeneity exists across the genome in the extent to which populations and species have diverged, reflecting the combined effects of different evolutionary processes on genetic variation. We studied hybridization across two hybrid zones of two phenotypically well-differentiated bird species in Mexico ( Pipilo maculatus and P. ocai), to investigate genomic heterogeneity in differentiation and introgression. Using genotyping-by-sequencing ( GBS) and hierarchical Bayesian models, we genotyped 460 birds at over 41 000 single nucleotide polymorphism ( SNP) loci. We identified loci exhibiting extreme introgression relative to the genome-wide expectation using a Bayesian genomic cline model. We also estimated locus-specific FST and identified loci with exceptionally high genetic divergence between the parental species. We found some concordance of locus-specific introgression in the two independent hybrid zones (6-20% of extreme loci shared across zones), reflecting areas of the genome that experience similar gene flow when the species interact. Additionally, heterogeneity in introgression and divergence across the genome revealed another subset of loci under the influence of locally specific factors. These results are consistent with a history in which reproductive isolation has been influenced by a common set of loci in both hybrid zones, but where local environmental and stochastic factors also lead to genomic differentiation. [ABSTRACT FROM AUTHOR]

Urban animals inhabit an environment considerably different than do their non-urban conspecifics, and to persist urban animals must adjust to these novel environments. The timing of seasonal reproductive development (i.e., growth of gonads and secondary sex organs) is a fundamental determinant of the breeding period and is frequently advanced in urban bird populations. However, the underlying mechanism(s) by which birds adjust the timing of reproductive development to urban areas remain(s) largely unknown. Here, we compared the timing of vernal reproductive development in free-ranging urban and non-urban male Abert’s Towhees, Melozone aberti , in Phoenix, Arizona, USA, and tested the non-mutually exclusive hypotheses that earlier reproductive development is due to improved energetic status and/or earlier increase in endocrine activity of the reproductive system. We found that urban birds initiated testicular development earlier than non-urban birds, but this disparity was not associated with differences in body condition, fat stores, or innate immune performance. These results provide no support for the hypothesis that energetic constraints are responsible for delayed reproductive development of non-urban relative to urban male Abert’s Towhees. Urban birds did, however, increase their plasma luteinizing hormone, but not plasma testosterone, earlier than non-urban birds. These findings suggest that adjustment to urban areas by Abert’s Towhees involves increases in the endocrine activity of the anterior pituitary gland and/or hypothalamus earlier than non-urban towhees. [ABSTRACT FROM AUTHOR]

We describe an encounter of eight territorial California towhees (Melozone crissalis), alternately engaged in mobbing a western scrub-jay (Aphelocoma californica) and vigorous conspecific attack and display. We additionally characterize a previously unreported crouching posture adopted by the towhees while surrounding the scrub-jay and hypothesize that this posture communicates submissiveness to conspecific owners of a territory. We suggest that this behavioral sequence resulted from a conflict between cooperation among pairs and defense of resources among pairs, wherein behaviors consistent with both were exhibited nearly simultaneously. [ABSTRACT FROM AUTHOR]

The history of the Monte Carlo for complex chemical systems Towhee open source Monte Carlo molecular simulation tool is discussed. A proof is given that the Widom insertion method for computing the chemical potential is formally correct even when combined with the most general version of arbitrary trial distribution configurational-bias Monte Carlo. A simulation strategy for computing single component vapour–liquid phase coexistence curves is presented as a guide for inexperienced practitioners of Monte Carlo simulations. A review of papers that cite the Towhee code is presented. The paper concludes with a discussion about releasing and sustaining a simulation package that uses an open source software license. [ABSTRACT FROM PUBLISHER]

We employed a chronosequence approach to evaluate patterns of bird abundance in relation to post-fire vegetation recovery in mountain big sagebrush ( Artemisia tridentata vaseyana). We estimated population density for 12 species of birds within the perimeters of 4 fires that had undergone 8-20 years of vegetation recovery and on adjacent unburned areas in the northwestern Great Basin, USA. Six species showed negative responses to fire persisting up to 20 years. Two species showed positive responses with effects persisting for <20 years. Understory vegetation was similar between burned and unburned areas irrespective of recovery time, and shrub canopy cover was similar between burned and unburned sites after 20 years of recovery. Persistent reductions in bird densities lead us to conclude that shrub canopy cover alone is not a sufficient metric for predicting recovery of songbird abundances following disturbance in mountain big sagebrush. © 2013 The Wildlife Society. [ABSTRACT FROM AUTHOR]

The article presents a study which investigates the stress of birds in an urbanizing landscape. The study has measure the physiological traits of Canyon Towhee and Inca Dove birds, such as the levels of immunoglobulin and corticosterone, that occupy three habitat alteration levels. Results show that 30% of the capture towhees in urban areas are suffering chronic stress. Study also reveals the appropriate physiological response of Inca Dove in urban areas.

Pipilo naufragus, new species, is described from Middle and Late Pleistocene to Holocene cave and pond deposits on the island of Bermuda. It is most similar to the Eastern Towhee P. erythrophthalmus but differs in having a heavier bill, more robust hindlimbs, and reduced wing and pectoral girdle, with the sternum in particular being shorter, wider, and with a much smaller carina. At least one early historical account (1610) contains a description of a large bunting-like bird that almost certainly refers to this species, which would have been exterminated by introduced pigs, rats, and cats following human settlement of Bermuda in 1612. [ABSTRACT FROM AUTHOR]

We used mist nets to survey small migrant and resident birds of scrub habitats in arroyos and adjacent uplands of the northern Chihuahuan Desert during late February-early May 1993-1997. We captured 723 individuals of 49 species. Species diversity was greater in arroyos than in adjacent uplands. Black-throated sparrows (Amphispiza bilineata), white-crowned sparrows (Zonotrichia leucophrys), and green-tailed towhees (Pipilo chlorurus) were captured most frequently. Rates of capture for residents, short-distance migrants, and Neotropical migrants were higher in arroyos than in adjacent shrubland and showed an increase after mid- April caused by an influx of Neotropical migrants heading north to their breeding grounds. Our results suggest that arroyos are important as stopover sites during spring for many migrants, especially Neotropical migrants, as they cross the northern Chihuahuan Desert. [ABSTRACT FROM AUTHOR]

We attempted to collect diet samples using throat ligatures from nestlings of three songbird species in a riparian woodland in southeastern Arizona from May to August 2009. We had success with Song Sparrows (Melospiza melodia), observed adult Yellow-breasted Chats (Icteria virens) reclaim food from nestlings, and discontinued the use of throat ligatures when we observed an adult Abert's Towhee (Pipilo aberti) remove two, 3-4-day-old ligatured nestlings from its nest. Previous studies have reported problems (e.g., aggression toward nestlings by adults) with throat ligatures, but we are the first to document removal (and subsequent nestling mortality) in response to this technique. We urge investigators to exercise caution when using throat ligatures on species for which evidence of the safety and efficacy of this method are lacking, especially when nestlings are small in size relative to adults. [ABSTRACT FROM AUTHOR]

Two mixed pairs of towhees were found in irrigated desert yards near Tucson, Arizona. The first known towhee Ft hybrids, from a female Pipilo aberti (Abert's Towhee) and male P. fuscus (Canyon Towhee) were studied from winter of 1998-1999 through summer 2000. This mixed pair raised at least eight young in three broods during the two breeding seasons. Young were so similar to P. fuscus that, if seen outside this context, they would probably not be identified as hybrids. A second mixed pair, also near Tucson, suggests that hybridization between P. aberti and P. fuscus may be more common than originally thought. Lack of previously reported hybridization between P. aberti and P. fuscus may be either due to internal or external isolating mechanisms, limited survival and longevity, or human failure to recognize hybrids. [ABSTRACT FROM AUTHOR]

California towhees (Pipilo crissalis) defend all-purpose, type-A territories throughout the year and are believed to remain on home ranges for successive breeding seasons. I present the first data regarding use of space by California towhees from a long-term study of a color-banded population. I examined individual site-fidelity to home ranges over 5 breeding seasons and combined this information with radiotelemetry data to assess sizes of home ranges and use of habitats. California towhees exhibited strong site-fidelity to breeding territories. All (n = 31) individuals located >10 times in a season were site-faithful across years for up to 4 years. Average size of home range was 0.83 ± 0.31 ha. Size of home range did not differ by sex, and paired birds occupied similar home ranges. All home ranges were composed of a variety of habitats, including open field, dense forest, and riparian areas. California towhees used habitat types differentially throughout the breeding season, and nested in a variety of plants. Prior to and following nesting, they were most often in open areas that provided good forage. While nesting, males and females were most often in dense vegetation. Because they defend type-A territories year-round, potentially for their entire lives, California towhees may benefit from settling on home ranges with high diversity of habitats that can meet fluctuating needs for resources. [ABSTRACT FROM AUTHOR]

The article presents a study on the used of hypothetico-deductive approach to test two hypotheses' ability to describe fecal-sac ingestion of the Spotted Towhee. The study shows that predictions on parental-nutrition hypothesis confirmed that more fecal sacs should be ingested while the economic-disposal hypothesis is rejected. It concludes that fecal sac ingestion of the species is understood as a resource supplement to parents or as a mechanism to fill hunger so they can feed their offsprings.

We used Polymerase Chain Reaction (PCR) amplification of 16S rRNA genes and Denaturing Gradient Gel Electrophoresis (DGGE) to describe the microbial communities present in the cloacae of spotted towhees Pipilo maculatus. Our goals were to quantify bacterial diversity of breeding females, describe microgeographic variation of cloacal communities in a network of four urban parks in Portland, OR, and evaluate the degree to which microbial species richness varied with individual female characteristics (age, size, and condition). We detected 57 Operational Taxonomic Units (OTUs) in 46 towhees, but most OTUs showed a relatively low prevalence. Discriminant function analysis correctly classified 69.6% of towhees to their park of origin based on the presence or absence of five OTUs. Parks thus had unique “microbial signatures”. The presence or absence of specific OTUs was not associated with a female's age, but a general linear models analysis established that OTU richness was greatest among females with short tails, narrow bills, and with the exception of one individual, among relatively heavy birds. We speculate that the microgeographic differences in cloacal microbial community structure may exist due to differences in anthropogenic influences among parks. The explanations for the negative relationship between microbial richness and flight feather length, but positive relationship between microbial richness and body condition are unclear, but may reflect the different time frames over which feather growth and body mass are determined. [ABSTRACT FROM AUTHOR]

We investigated factors at multiple scales that might influence nest predation risk for Spotted Towhees (Pipilo maculatus) along the Sacramento River, California, within the context of large-scale riparian habitat restoration. We used the logistic-exposure method and Akaike's information criterion (AIC) for model selection to compare predator search, predator abundance, restoration, and temporal effects hypotheses. Our candidate models represented restoration, temporal, nest activity, nest concealment, agriculture, and flood effects. Restoration sites did function as breeding habitat, with nest survival comparable to mature forest sites and some young being produced. The best-supported models contained the covariates cowbird young in host nest and calendar date. All supported models contained the covariate cowbird young, the only variable with a strong effect. In contrast to our prediction, nest survival increased with cowbird young in the nest, implicating adult cowbirds in nest predation events. Nest survival declined throughout the breeding season and increased marginally with nest concealment. We calculated the finite rate of population increase (λ), using a model that incorporated nest success estimates for parasitized and unparasitized nests, double brooding, the locally observed cowbird parasitism rate for Spotted Towhees, number of young fledged from successful parasitized and unparasitized nests, adult survival and a range of juvenile survival values, estimated as percentages of adult survival. Values of λ did not approach the replacement level of one, indicating that this population is not self-sustaining. We recommend extensive habitat restoration in the floodplain landscape, ideally in conjunction with cowbird control, to reduce nest predation and parasitism pressures. [ABSTRACT FROM AUTHOR]

Fire alters the structure and composition of shrublands and affects habitat quality for the associated avifauna. Because shrubland ecosystems have been greatly reduced from their original extent in western North America and fire is increasingly being used to manage these landscapes, a better understanding of how fire affects the associated vegetation and wildlife is imperative. We evaluated the response of Green-tailed Towhees (Pipilo chlorurus) to prescribed fire in the montane shrublands of Rocky Mountain National Park, Colorado during 2002 and 2003. Three to five years following prescribed burning, Green-tailed Towhee density and shrub cover were generally higher in unburned areas. Nests (n = 179) were located in unburned vegetation; within burned sites, all nests were in remnant patches. Green-tailed Towhee nest survival was 57% (95% Cl = 65%) across the two years of the study. More than half of the nests were in common juniper (Juniperus communis) shrubs, and nest survival was higher for nests in junipers than those in other shrub species. Daily nest survival rates were lower at the site with the highest density of towhees and declined over the breeding season. With regard to shrub cover, opposite trends were observed for nest-site selection and nest survival: nest plots had greater shrub cover than non-nest plots, but nest survival decreased with increasing shrub cover. Because shrub cover affects towhee density and nest survival in conflicting ways, fire management at Rocky Mountain National Park alters both habitat availability and suitability for Green-tailed Towhees. [ABSTRACT FROM AUTHOR]

The article provides information on the 12th Report of the Avian Records Committee of Connecticut of the Connecticut Ornithological Association. Among the bird species added to the Connecticut State Checklist are cackling goose, snowy plover, Eurasian collared dove and spotted towhee. The members of the committee who evaluated and voted on the reports were Buzz Devine and Janet Mehmel. The aim of the revisions made to the Review List is to reflect latest information on birds in the state.

We estimated apparent annual survival and recapture probabilities for adult Black-headed Grosbeaks (Pheucticus melanocephalus) and Spotted Towhees (Pipilo maculatus) at four sites along the Sacramento River, California. To calculate our estimates, we used capture-recapture mist-net data collected over two time periods at four study sites: from 1993 to 1995 at Flynn, Ohm, and Sul Norte, and from 1995 to 2000 at Ohm and Phelan Island. Our primary objective was to determine whether there were site-specific differences in adult survival and recapture probabilities for each species. Such differences are rarely investigated, yet, if present, suggest site-specific differences in habitat quality, with important implications for source/sink dynamics. We found site-specific variation in Black-headed Grosbeak survival within both the 1993-1995 dataset (Flynn = 0.797 ± 0.496, Ohm = 0.158 ± 0.191. Sul Norte = 0.773 ± 0.131) and the 1995-2000 dataset (Ohm = 0.088 ± 0.090, Phelan Island = 0.664 ± 0.111). For Spotted Towhees (1993-1995 data), the most supported model assumed constant survival across sites (0.602 ± 0.240), but there was some support for site variation in survival. as well (Flynn = 0.653 ± 0.365, Ohm = 0.214 ± 0.253, Sul Norte = 0.632 ± 0.258). These results clearly suggest site variation for Black-headed Grosbeaks, and weak evidence of site variation for Spotted Towhees. For both species, the general pattern was low survival at Ohm, suggesting low-quality habitat there and/or reduced site fidelity. The magnitude of site-to-site variation in survival observed in the Black-headed Grosbeak, and suggested for Spotted Towhee, has strong implications for determining source versus sink population status. To determine source versus sink status, we conclude that investigators must not only take into account site variation in reproductive success, but also consider site-specific estimation of adult survival. [ABSTRACT FROM AUTHOR]

Sound localization is critical to communication when signalers are distributed widely in space and when reverberations that accumulate over distance might otherwise degrade temporal patterns in vocalizations. We readdress the accuracy with which a small passerine bird, the eastern towhee, Pipilo erythrophthalmus L., is able to resolve azimuth in the field. We then report results from two-alternative forced-choice (2AFC) experiments in which three of four subjects were able to discriminate an estimated speaker separation angle of approximately 7°. Subjects oriented laterally when discriminating azimuth in the 2AFC task and each subject preferred a different head orientation. Side biases occurred as a function of head orientation and, as a consequence, we conducted a second 2AFC experiment in which subjects were required to discriminate between two closely spaced lights. Subjects oriented similarly in this visual task, however, side biases did not occur as a function of head orientation. Despite side biases in the auditory task, performance generally declined when subjects were played tones with frequencies near ∼3 kHz. [ABSTRACT FROM AUTHOR]

Eastern towhees, Pipilo erythrophthalmus (Emberizidae, Passeriformes), appear to estimate source-SPL using spectral or temporal variables. Nevertheless, vocalizations are dynamic by nature and it remains unclear whether subjects pay attention to correlations between discrete variables or pay attention to the dynamics that these variables summarize. Sine functions are used to describe coarse (slow, <10 Hz) frequency and amplitude modulations in towhee calls and correlations between variables are identified. Towhee calls are also finely (rapidly, >400 Hz) modulated in both amplitude and frequency. Fine amplitude and frequency modulations correlate well (occur in phase) over relatively low fundamental frequencies (<~3.5 kHz) and tend to have greater amplitudes and frequencies over these same frequencies. Modulations and correlations between modulations might exist due to stable dynamic interactions that occur within and between the physical forces that function to produce modulations in vocalizations. Results support the hypothesis that towhees communicate within separate sound frequency channels defined to each side of ~3.5 kHz. [ABSTRACT FROM AUTHOR]

Focuses on Eastern towhees, Pipilo erythrophthalmus, in Florida, which estimates source sound-pressure level (SPL) and often misjudges speaker distance in the field when vocalization source SPL is varied experimentally. Details of a study focusing on SPL as an auditory distance cue in towhees; Discussion of the possibility that towhees employ a duplex sound localization strategy.

Provides information on a study which examined the breeding season survival rates, nest success rates, breeding densities, and daily movements of the Eastern Towhees at the Savannah River site, South Carolina, from 1995 to 1996. Study area and methods; Results; Discussion.

Presents a study which looked at instances where Eastern Towhee birds mimicked calls of other species. Definition of the term `vocal mincry'; Methodology used to conduct the study; Results of the study.

Misdirected parental care, or care directed toward unrelated young, has been recorded for many bird species. The Wood Thrush (Hylocichla mustelina) is not known to practice this behavior or allow other species to attend to its young. We observed a Wood Thrush nest with three Wood Thrush nestlings and one Brown-headed Cowbird (Molothrus ater) nestling being attended by a male Eastern Towhee (Pipilo erythrophthalmus). The towhee fed the young of both species in the nest for at least 5 days and was subsequently observed feeding a Wood Thrush fledgling. The towhee also participated in nest maintenance and defense. The proximate cause of towhee attendance at the Wood Thrush nest remains unknown, but begging calls from the nestlings may have stimulated the behavior. [ABSTRACT FROM AUTHOR]

The article reports on the observation of the bird Towhees, in Sioux County, Nebraska on May 20, 2018. Topics discussed include the breeding of Towhees in the white irides at the Gilbert-Baker Wildlife in extreme northwest of the Nebraska Panhandle, mentions the identification of male bird through deep saturated black head with juvenile feathers and female with her soft-part colors; and information on the eye color of juvenile male Towhees.

The article describes the author's experience of accidentally photographing Willard, a medium, streaky brown bird scratching below the bird feeder he set up. The author discusses the identification of the bird as a Red-winged Blackbird, the physical features of the birds, and the decreasing number of Eastern Towhee in Connecticut.

Provides information on a ground nest of Canyon Towhees or Pipilo fuscus found in Santa Fe County, New Mexico on May 14, 2001. Typical nests of Canyon Towhees; Characteristics of Canyon Towhees.

Models of habitat selection commonly asume that higher-quality source habitats will be occupied at higher densities than sink habitats. We examined an apparent sink habitat for California Towhees (Pipilo crissalis) in which densities are greater than in nearby source habitats. We estimated territory density using spot-mapping and monitored nests of towhees in grazed and ungrazed oak-pine woodland habitat. Breeding density of California Towhees was higher in ungrazed oak-pine woodlands than in grazed areas, yet birds in the ungrazed site experienced lower reproductive success. Predation during the nestling period was primarily responsible for the lower nest success. Clutch size and the number of young fledged were also lower in the ungrazed site. Towhees selected nest sites with high foliage density and cover of live oaks (Quercus wislizenii) in the understory. Grazed sites had greater cover of live oak than ungrazed sites, and successful nests were more often built in live oak than in other plant species. This pattern could not be explained by dominant birds settling in grazed sites and excluding subdominant individuals because a large proportion of adults continued to settle in the ungrazed area. Towhees may have perceived the dense foliage of the ungrazed area as suitable due to abundant nest sites, cover, and food, resulting in an "ecological trap." The resulting high density of birds there may have contributed to density-dependent predation. Alternatively, towhees are not ideally adapted to their habitats because of their sedentary habits and site tenacity that is not affected by persistent nest loss. We stress the need to examine the reproductive success and productivity of individual species within specific habitat types. [ABSTRACT FROM AUTHOR]

The article reports on several visiting and transient birds during winter. The first bird featured is the cardinal which is also known as Kentucky cardinal, cardinal grosbeak, and Virginia nightingale. The second bird has many titles including towhee, bunting, ground-robin, marsh-robin, chewink, and joree. The other birds are the crested titmouse and the wee chickadee.