Evening Grosbeak Research Articles

Flight calls and trills of Evening Grosbeaks can be used to map movements and ranges of call types 1 and 2

Evening Grosbeak (Coccothraustes vespertinus) is a species of North American Fringillid finch thought to be one of the fastest declining songbirds across North America. It has been divided into five groups, potentially distinct lineages, based in part on structure of their flight calls. The primary flight calls of each type exhibit structural variation that has not been described and the degree to which that variation might lead to identification errors has not been quantified. We describe the variation in call structure of type 1 Evening Grosbeaks recorded at a spring migratory stopover site (Corvallis, Oregon) and nearby areas in the Pacific Northwest, USA. We recorded grosbeaks weekly from April through early June 2023. We reviewed more than 10,000 recorded call notes to characterize the variety of calls and their configurations. We found a high diversity of call notes including at least 11 recurring readily identifiable variants of the primary flight calls, all of which were attributed to individuals thought to be type 1 birds. Geographically, the nearest neighbors of type 1 Evening Grosbeaks are type 2s, which have uncommonly been recorded in our study area but whose breeding range appears to overlap that of type 1 in southern Oregon. We quantified recordings of type 2 flight calls and compared them with type 1 flight calls, finding that linear discriminant function analyses correctly identified >95% of recordings to type. Inclusion of a metric of asymmetry in call shape improved correct classification to 98.5%. We also found that the other dominant calls given by both types, buzzy trills, could be identified correctly to type with a high level of confidence. The sufficiently different characteristics of flight calls and trills indicate that types 1 and 2 are identifiable spectrographically in most cases, providing confidence that the geographic distribution and migratory movements of call-type populations, despite being essentially identical in plumage, can be documented effectively by characteristics of call notes.

AN EVENING GROSBEAK WITH UNIQUE CROWN COLORATION

Reported herein is the description of atypical head coloration on a male Evening Grosbeak (Coccothraustes vespertinus). This coloration is unique in that feathers on the posterior of the crown lack the typical dark melanin pigmentation, allowing the underlying vivid yellow (carotenoid) pigmentation that is usually revealed on the male's eyebrow stripe to also be revealed here. The non-melanic form of melano-carotenoid schizochroism is a likely explanation for this crown color variation. Given the importance of crowns and their coloration during mate selection among various avian species, their importance for Evening Grosbeaks is worth further investigation.

Dramatic Declines of Evening Grosbeak Numbers at a Spring Migration Stop-Over Site

Evening Grosbeak (Coccothraustes vespertinus) populations have been hypothesized to be in steep decline across North America. Data characterizing long-term changes are needed to quantify the magnitude of the declines. We surveyed grosbeaks at a spring migratory stop-over site in Corvallis, Oregon, USA, where birds gather annually during April and May to feast on elm (Ulmus spp.) seeds before departing to breeding sites. An estimate produced by a statistics professor in the 1970s indicated peak numbers were 150,000 to 250,000 birds. Our surveys in 2013–2015 found annually variable numbers, from a few hundred grosbeaks in the lowest year to less than five thousand birds in the highest year. If the original estimate is approximately true, Evening Grosbeak numbers have experienced dramatic declines, averaging −2.6%/year, over the last four decades. Our local observation of declines during spring aligns with declines documented in winter across North America by bird feeder studies and in summer by the Breeding Bird Survey. We explore potential explanations for the changes in population size, such as influences of spruce budworm outbreaks, disease, and decreased structural diversity of forests owing to harvest practices. We also consider the challenges of interpreting changes in abundance of species with exceptionally variable populations, especially if population fluctuations or cycles may have long periodicities. Finally, we call for additional planned surveys to track the numbers of this enigmatic and charismatic species.

On the incubation behavior of Evening Grosbeaks (Coccothraustes vespertinus)

Knowledge of the breeding behavior of Evening Grosbeaks (Coccothraustes vespertinus) is based largely on a multiyear study in Colorado during the 1980s. In Colorado, the duration of full incubation bouts by female grosbeaks had a mean of 26.6 min, a value repeated since then in the literature. For one nesting pair of grosbeaks I studied in Montana, full incubation bouts (n = 5) by the undisturbed female during 22 h of direct nest watches on 7 d in June 2018 had a mean of 112.6 min (range = 45–202 min), much longer than the value reported in the Colorado study. Incomplete incubation bouts (female already incubating on my arrival or at my departure) by the undisturbed Montana female (n = 11) during the same observation period had a mean of 56.2 min, 4 of which were a minimum of 94–146 min, further suggesting that longer duration incubation bouts may be the norm for this species. Duration of incubation bouts for Evening Grosbeak in the Colorado study appear to be brief relative to other North American fringillids, but my limited data suggest that Evening Grosbeaks are typical in this regard. Mean duration of 10 nest absences by the undisturbed Montana incubating female was 9.7 ± 7.6 min (range = 3–26 min), similar to the Colorado study (10.1 ± 10.7 min). Male behavior during incubation also appeared similar to results from Colorado (no attending the eggs, frequent exchange of vocalizations with the nesting female, escorting and feeding the female only when off the nest). I conclude that the duration of nest watches (60–80 min) in the Colorado study was inadequate to determine the length of many longer incubation bouts by female Evening Grosbeaks.

Birds of a feather don’t always flock together: variation in molt origins and movement patterns of winter finches in Ontario

For irruptive or facultative migrants in the subfamily Carduelinae, the winter finches, seasonal movements are extensive but have been poorly described in North America. We used stable hydrogen isotope measurements of feathers (δ2Hf) collected in three regions in Ontario, Canada, during the winters of 2014–15 and 2015–16 to infer potential breeding origins of four species. We also deployed color bands to better understand migratory movements within and across winters. Values of δ2Hf differed by age, sex, and capture location both within and among species. Predicted breeding origins of wintering evening grosbeaks (Coccothraustes vespertinus) and pine grosbeaks (Pinicola enucleator) were largely from northwestern North America, suggesting a predominately west–east pattern of seasonal movements. Common redpolls (Acanthis flammea) and hoary redpolls (A. hornemanni) largely originated from the High Arctic or western Canada, suggesting predominantly north–south seasonal movements. Grosbeaks were most often recaptured or re-sighted at the same capture location between winters. Recaptures and observations of color-banded redpolls only occurred within a winter and mostly at the same capture location. Our results document the first linkages between potential breeding and wintering sites for a large number of individual winter finches during two successive winters. Observed variation in breeding origins and movement patterns suggests each species employs a different migration strategy; therefore, future research and conservation efforts might be more beneficial if directed at individual species of winter finch.

Evening Grosbeaks Feeding on Pupae of the Forest Tent Caterpillar in the Dune- Ridge Forest, Delta Marsh, Manitoba, Spring 1976

Evening Grosbeaks Feeding on Pupae of the Forest Tent Caterpillar in the Dune- Ridge Forest, Delta Marsh, Manitoba, Spring 1976

HOUSE FINCH ( HAEMORHOUS MEXICANUS)-ASSOCIATED MYCOPLASMA GALLISEPTICUM IDENTIFIED IN LESSER GOLDFINCH ( SPINUS PSALTRIA) AND WESTERN SCRUB JAY ( APHELOCOMA CALIFORNICA) USING STRAIN-SPECIFIC QUANTITATIVE PCR.

: In 1994 Mycoplasma gallisepticum was found to be the etiologic agent of House Finch ( Haemorhous mexicanus) conjunctivitis, a rapidly expanding epidemic caused by a genetically discrete, House Finch-associated strain of M. gallisepticum (HFMG). While most prominent in House Finches, HFMG has been reported in other members of the family Fringillidae, including American Goldfinches ( Spinus tristis), Purple Finches ( Haemorhous purpureus), Pine Grosbeaks ( Pinicola enucleator), and Evening Grosbeaks ( Coccothraustes vespertinus). Herein we report two new potential host species of HFMG strain, the Lesser Goldfinch ( Spinus psaltria), belonging to the Fringillidae family, and the Western (California) Scrub Jay ( Aphelocoma californica), belonging to the Corvidae family. The latter is one of only two reports of HFMG being found outside the Fringillidae family, and of these is the only one reported outside of captivity. Furthermore, non-HFMG M. gallisepticum was identified in an American Crow ( Corvus brachyrhynchos), indicating presence of additional strains in wild birds. Strain typing of M. gallisepticum isolates was done via HFMG-specific quantitative PCR analysis and validated using random amplified polymorphic DNA analysis. Our results suggested an expanded host range of HFMG strain, and further suggested that the host range of HFMG was not limited to members of the family Fringillidae.

Structure and variation of the Fringillidae (Aves: Passeriformes) mitochondrial DNA control region and their phylogenetic relationship

The control region is the major noncoding segment of animal mitochondrial DNA. To infer the structure and variation of Fringillidae mitochondrial DNA control region, the entire control region sequences of 25 species were analyzed. The length of the control region sequences was very conserved (1230 ± 18) and can be separated into three domains. The frequency of both substitutions and gaps was highest in the third domain and lowest in the central region. The control region has the same flanking gene order from tRNAGlu to tRNAPhe. Genetic distances between species ranged from 1.80% (between Carduelis pinus and Carduelis spinus) to 25.34% (between Carduelis sinica and Coccothraustes vespertinus). The average genetic distances among the species within the genera varied from 5.11% (Leucosticte) to 14.31% (Carpodacus). The average genetic distances showed insignificantly negative correlation with ts/tv. Domain III is the most variable of the three domains among all the genera. The control region of Fringillidae contains a putative TAS element and the highly conserved CSB-1, and F, E, D, C boxes. However, neither CSB-2 nor CSB-3 could be unambiguously identified in the Fringillidae. The maximum likelihood method was used to construct a phylogenetic tree. Control region analysis demonstrated that some currently recognized genera may be polyphyletic, including Carpodacus, Carduelis and Serinus.

House Finch (Haemorhous mexicanus) Conjunctivitis, and Mycoplasma spp. Isolated from North American Wild Birds, 1994-2015.

Sampling wild birds for mycoplasma culture has been key to the study of House Finch (Haemorhous mexicanus) conjunctivitis, yielding isolates of Mycoplasma gallisepticum spanning the temporal and geographic ranges of disease from emergence to endemicity. Faced with the challenges and costs of sample collection over time and from remote locations for submission to our laboratory for mycoplasma culture, protocols evolved to achieve a practical optimum. Herein we report making M. gallisepticum isolates from House Finches almost every year since the disease emerged in 1994, and we now have 227 isolates from 17 states. Our wild bird host range for M. gallisepticum isolates includes Blue Jay ( Cyanocitta cristata ), American Goldfinch (Spinus tristis), Lesser Goldfinch (Spinus psaltria), Purple Finch (Haemorhous purpureus), Evening Grosbeak ( Coccothraustes vespertinus ), and herein first reports for Western Scrub-jay ( Aphelocoma californica ), and American Crow ( Corvus brachyrhynchos ). By collecting and identifying isolates from birds with clinical signs similar to those of House Finch conjunctivitis, we also expanded the known host range of Mycoplasma sturni and obtained isolates from additional wild bird species. Accumulating evidence shows that a diverse range of wild bird species may carry or have been exposed to M. gallisepticum in the US, as in Europe and Asia. Therefore, the emergence of a pathogenic M. gallisepticum strain in House Finches may actually be the exception that has allowed us to identify the broader epidemiologic picture.

The Voices of Birds: Call Dialects of the Evening Grosbeak

The Voices of Birds: Call Dialects of the Evening Grosbeak

Analysis of combined data sets yields trend estimates for vulnerable spruce-fir birds in northern United States

Continental-scale monitoring programs with standardized survey protocols play an important role in conservation science by identifying species in decline and prioritizing conservation action. However, rare, inaccessible, or spatially fragmented communities may be underrepresented in continental-scale surveys. Data on these communities often come from decentralized, local monitoring efforts that differ in their goals and survey protocols. We combine 16 point count datasets, controlling for differences in protocol and detection probabilities to estimate regional trends for 14 spruce-fir forest bird species across Northeastern and Midwestern United States, a vulnerable community threatened by numerous anthropogenic stressors and widely considered a priority for conservation. Our analyses indicated that four species considered as ecological indicators for this community, Bicknell’s Thrush (Catharus bicknelli), Magnolia Warbler (Setophaga magnolia), Blackpoll Warbler (Setophaga striata) and Yellow-bellied Flycatcher (Empidonax flaviventris), each exhibited significant declines. Olive-sided Flycatcher (Contopus cooperi), a species of concern in parts of its range, and two additional species for which no previous concern existed, the Evening Grosbeak (Coccothruastes vespertinus) and the Gray Jay (Perisoreus canadensis), each also showed significant overall declines. Five out of nine species with sufficient data for analyses from Northeastern and Midwestern surveys showed significant differences in trends between these regions. Spruce-fir obligate species were more likely to decline significantly than species that use spruce-fir in addition to other habitat types. These results demonstrate the value of combining disparate data sources for analyzing regional patterns of population trends to confirm and extend conservation concern for some species and identify others for which additional attention may be needed.

Redpoll Snow Bathing: Observations and Hypothesis

Abstract - A flock of 100–150 Carduelis flammea (Common Redpolls) made at least 252 cavities and short tunnels in fluffy snow over 5 consecutive days in western Maine at temperatures from -26 °C to -14 °C. They produced neither structure during 4 days when temperatures were above freezing and the snow was wet, nor during a month of other variable weather. In the same area during two winters, Carduelis tristis (American Goldfinches), Carpodacus purpureus (Purple Finches), Pinicola enuncleator (Pine Grosbeaks), and Coccothraustes vespertinus (Evening Grosbeaks) exhibited no snow tunneling behavior at any time even though, excluding the Pine Grosbeaks and Goldfinches, I observed them throughout the entirety of 2 winters. Common Redpolls did not use the observed snow cavities as shelters, nor did the structures appear to be related to foraging. Social stimulation and play are likely proximate stimuli for the behavioral release of the Common Redpolls' snow-manipulating behavior.

A review of the zumpti species group of the genus Harpyrhynchoides (Acariformes: Harpirhynchidae)--ectoparasites of passerines.

The zumpti species group of the genus Harpyrhynchoides (Harpirhynchidae), parasites of passerines, is revised. A key to the species of this group is provided and data on host associations and geographic distribution of its constituent species are summarized. This group includes six previously recognized species: Harpyrhynchoides alaudinus Bochkov, 2000, H. brevis (Ewing, 1911) comb. nov., H. heatherae Bochkov and Galloway, 2013, H. rubeculinus (Cherny and Sixl, 1971), H. vulgaris Bochkov and Galloway, 2004, and H. zumpti (Fain, 1972). Three species from North American passerines are described as new: H. setophaga sp. nov. from Setophaga ruticilla (Parulidae), H. xanthocephalus sp. nov. from Xanthocephalus xanthocephalus (Icteridae), and H. spizella sp. nov. from Spizella passerina (Emberizidae). Additionally, H. brevis is redescribed based on samples from Coccothraustes vespertinus (type host) and Loxia curvirostra (Passeriformes: Fringillidae) from North America. Harpyrhynchoides kirgizorum Fain et al. 1999 syn. nov. is synonymized with H. zumpti.

Mites of the GenusTorotrogla(Prostigmata: Syringophilidae) From North American Passerines

Five new quill mite species of the genus Torotrogla Kethley, 1970 (Acari: Syringophilidae) are described from North American passerines: T. aphelocoma sp.n. from Aphelocoma californica (Corvidae) and T. cardinalis sp.n. from Cardinalis cardinalis (Cardinalidae) in Texas; and T. coccothraustes sp.n. from Coccothraustes vespertinus (Fringillidae), T. cyanocitta sp.n. from Cyanocitta stelleri (Corvidae), and T. piranga sp.n. from Piranga ludoviciana (Thraupidae) in California. A key to females of all known Torotrogla spp. and a table with their host associations and distributions are given.

WINTER SURVEY DATA REVEAL RANGEWIDE DECLINE IN EVENING GROSBEAK POPULATIONS

Abstract Once one of the most common species seen at bird feeding stations across much of North America in winter, the Evening Grosbeak (Coccothraustes vespertinus), appears to be experiencing a population decline. Like other finches associated with the boreal forest or high elevations, Evening Grosbeaks form flocks in winter, often irrupting out of their breeding range and frequenting supplemental feeding stations where populations may be monitored. We sought to quantify the extent of changes in the abundance and distribution of Evening Grosbeak populations using data gathered in winter by Project FeederWatch, a continent-wide monitoring program that began in 1987. FeederWatch data gathered between 1988 and 2006 indicated a significant surveywide decline in the mean flock size recorded over time. The proportion of sites reporting Evening Grosbeaks plummeted by 50% in 18 years. At locations where the species continued to be seen, mean flock size declined by 27%. Similarly, analysis of data from 391 sites ...

RESPONSE OF BIRDS TO THINNING YOUNG DOUGLAS‐FIR FORESTS

Silvicultural practices, such as thinning, are increasingly performed both for commodity production and to help achieve biodiversity goals and promote ecological restoration. However, relatively little research has examined effects of thinning conifer forests on vertebrates. We experimentally manipulated stands using a randomized block design to evaluate influences of two thinning intensities on populations of diurnal breeding birds in western Oregon. We conducted point counts of birds seven times each year in 1994 (prior to treatment) and from 1995 through 2000 (subsequent to treatment). We analyzed data using multiple linear regression and information‐theoretic approaches to model selection. Of the 22 species for which we had sufficient data for analysis, detections of nine species decreased and eight species increased in thinned stands relative to controls, and there was no strong evidence that thinning influenced numbers of five species. Of the 17 species that responded to thinning, the magnitude of response of eight species varied with thinning intensity; for each of these species, response was greatest in the more heavily thinned stands. Although no species was extirpated from stands following thinning, detections of Hutton's Vireos (Vireo huttoni), Golden‐crowned Kinglets (Regulus satrapa), Brown Creepers (Certhia americana), Black‐throated Gray Warblers (Dendroica nigrescens), and Varied Thrushes (Ixoreus naevius) decreased to less than half of the detections in controls in one or more treatment types, suggesting thinning significantly reduces their numbers. In contrast, American Robins (Turdus migratorius), Townsend's Solitaires (Myadestes townsendi), and Hammond's Flycatchers (Empidonax hammondii) were rare or absent in controls but regularly present in thinned stands, and detections of Western Tanagers (Piranga ludoviciana), Evening Grosbeaks (Coccothraustes vespertinus), and Hairy Woodpeckers (Picoides villosus) increased by threefold or more in thinned stands relative to controls. Only Pacific‐slope Flycatchers (Empidonax difficilis), Warbling Vireos (Vireo gilvus), and Western Tanagers showed strong evidence of temporal trends in response. For these species, differences between numbers in controls and treated stands became more extreme through time. Our findings suggest that thinning densely stocked conifer stands in landscapes dominated by younger stands enhances habitat suitability for several species of birds, but that some unthinned patches and stands should be retained to provide refugia for species that are impacted by thinning.

Lutein-based plumage coloration in songbirds is a consequence of selective pigment incorporation into feathers

Many birds obtain colorful carotenoid pigments from the diet and deposit them into growing tissues to develop extravagant red, orange or yellow sexual ornaments. In these instances, it is often unclear whether all dietary pigments are used as integumentary colorants or whether certain carotenoids are preferentially excluded or incorporated into tissues. We examined the carotenoid profiles of three New World passerines that display yellow plumage coloration—the yellow warbler ( Dendroica petechia), common yellowthroat ( Geothlypis trichas) and evening grosbeak ( Coccothraustes vespertinus). Using high-performance liquid chromatography, we found that all species used only one carotenoid—lutein—to color their plumage yellow. Analyses of blood carotenoids (which document those pigments taken up from the diet) in two of the species, however, revealed the presence of two dietary xanthophylls—lutein and zeaxanthin—that commonly co-occur in plants and animals. These findings demonstrate post-absorptive selectivity of carotenoid deposition in bird feathers. To learn more about the site of pigment discrimination, we also analyzed the carotenoid composition of lipid fractions from the follicles of immature yellow-pigmented feathers in G. trichas and D. petechia and again detected both lutein and zeaxanthin. This suggests that selective lutein incorporation in feathers is under local control at the maturing feather follicle.

Seed‐crop size and eruptions of North American boreal seed‐eating birds

Summary Eruptions occur when a species appears in unusually high densities within and often outside of its normal range. We used 30 years of Christmas Bird Counts combined with cone/seed‐crop data on boreal coniferous trees, breeding bird surveys, and weather records to test correlates of winter eruptions by 11 species of primarily boreal North American seed‐eating birds. Eruptions of six species in eastern (red‐breasted nuthatch Sitta canadensis L., black‐capped chickadee Parus atricapillus L., evening grosbeak Hesperiphona vespertina Cooper, pine grosbeak Pinicola enucleator L., red crossbill Loxia curvirostra L. and bohemian waxwing Bombycilla garrulus L.) and five species in western North America (pine grosbeak, pine siskin Carduelis pinus Wilson, evening grosbeak, bohemian waxwing and red‐breasted nuthatch) correlated with a combination of large coniferous seed crops in the previous year followed by a poor crop. Breeding population size in the year of the eruption was also correlated positively with the event in two of the species. Eruptions in these species apparently occur when large boreal seed crops resulting in high population densities (via high overwinter survivorship and/or high reproductive success) are confronted with a relatively poor seed crop the next autumn. Eruptions of common redpolls Carduelis flammea L. and black‐capped chickadees in the west followed only large seed crops the previous year, suggesting that high density is a more important factor leading to eruptions than seed crop failure. The opposite was true for white‐winged crossbills (Loxia leucoptera Gmelin) in the east, where eruptions correlated only with poor current year seed crops. This was the only species supporting the ‘seed‐crop failure’ hypothesis as the sole cause of eruptions. Purple finches Carpodacus purpureus Gmelin erupted following years when breeding population densities were high for reasons apparently unrelated to the seed crop. Eruptions of three species in both regions were uncorrelated with any of the variables tested. We conclude that seed crops of boreal trees play a pivotal role in causing eruptions for a majority of boreal species, usually through a combination of a large seed crop resulting in high population densities followed by a poor seed crop rather than seed‐crop failure alone. Weather conditions were not a significant factor correlating with eruptions in any of the species.

Non-melanic shizochroism in Alberta Evening Grosbeaks, Coccothraustes vespertinus

Non-melanic shizochroism in Alberta Evening Grosbeaks, Coccothraustes vespertinus

Cognitive ethology, vigilance, information gathering, and representation: Who might know what and why?

Cognitive ethology, a relatively new interdisciplinary and integrative science, is under attack with respect to its scientific status. However, there also are strong supporters of research in this area. In this paper I consider 1. (1) some of the topics in which cognitive ethologists are interested, 2. (2) possible connections between cognitive analyses of social behavior and philosophical concepts including intentionality and representation, 3. (3) recent work on vigilance or scanning behavior in highly social birds, Evening Grosbeaks ( Coccothraustes vespertinus), that benefits from taking a cognitive perspective, 4. (4) what may be gained by taking a cognitive approach to the study of social behavior and what may be lost by not doing so. My study of vigilance indicates that the way in which individuals are positioned with respect to one another influences their behavior, and that when a flock contains four or more birds there are large changes in scanning and other patterns of behavior that may be related to how grosbeaks attempt to gather information about other flock members. When birds are arranged in a circular array so that they can see one another easily compared to when they are arranged in a line that makes visual monitoring of flock members more difficult, birds who have difficulty seeing one another are 1. (i) more vigilant, 2. (ii) change their head and body positions more often, 3. (iii) react to changes in group size more slowly, 4. (iv) show less coordination in head movements, 5. (v) show more variability in all measures. These differences in behavior argue against the pooling of data collected on individuals feeding in different geometric arrays. The variations in behavior also may say something about if and how individuals attempt visually to represent their group to themselves-how they form, store, and use records of the behavior of others to inform their own future behavior.