Buteo Species Research Articles

Taxonomic status of Harlan's Hawk Buteo jamaicensis harlani (Aves: Accipitriformes).

Since its description in 1830 by Audubon, Harlan's Hawk (taxon harlani) has been considered both as a species (Buteo harlani) (1830-1891 and 1944-1972) and as a subspecies of Red-tailed Hawk (B. jamaicensis harlani) (1891-1944 and 1973 to present). Both decisions making it a subspecies lacked sufficient taxonomic justification, whereas the 1944 decision to consider it a species was supported by convincing arguments. I conducted field and museum work over many years to better understand the morphology and taxonomic status of harlani and how this taxon differs from other taxa currently included in B. jamaicensis. Some hybridization between these taxa has been reported, as has been between many other species of Buteo. The taxon harlani is distinguished from all subspecies of B. jamaicensis in plumage, including the extent of feathering on the tarsus. The species occupies a breeding range parapatric, but with some overlap, to that of B. jamaicensis but occasionally breeds within a large area of the range of the latter in western Canada. It should be considered a full species based on lack of justification for considering it a subspecies, and the many differences between it and B. jamaicensis, which are greater than differences between any two subspecies of diurnal raptor.

ATYPICAL CHLAMYDIACEAE IN WILD POPULATIONS OF HAWKS ( BUTEO SPP.) IN CALIFORNIA.

Chlamydiaceae bacteria infect many vertebrate hosts, and previous reports based on polymerase chain reaction (PCR) assays and serologic assays that are prone to cross-reaction among chlamydial organisms have been used to describe the prevalence of either DNA fragments or antibodies to Chlamydia spp. in wild raptorial populations. This study reports the PCR-based prevalence of Chlamydiaceae DNA that does not 100% match any avian or mammalian Chlamydiaceae in wild populations of hawks in California Buteo species. In this study, multimucosal swab samples ( n = 291) for quantitative PCR (qPCR) and plasma ( n = 78) for serology were collected from wild hawks. All available plasma samples were negative for antibodies using a C. psittaci-specific elementary body agglutination test (EBA; n = 78). For IgY antibodies all 51 available samples were negative using the indirect immunofluorescent assay. The overall prevalence of Chlamydiaceae DNA detection in wild Buteo species sampled was 1.37% (4/291) via qPCR-based analysis. Two fledgling Swainson's hawks ( Buteo swainsoni) and two juvenile red-tailed hawks ( Buteo jamaicensis) were positive by qPCR-based assay for an atypical chlamydial sequence that did not 100% match any known C. psittaci genotype. Positive swab samples from these four birds were sequenced based on the ompA gene and compared by high-resolution melt analysis with all known avian and mammalian Chlamydiaceae. The amplicon sequence did not 100% match any known avian chlamydial sequence; however, it was most similar (98.6%) to C. psittaci M56, a genotype that is typically found in muskrats and hares. Culture and full genome sequence analysis of Chlamydia spp. isolated from diseased hawks will be necessary to classify this organism and to better understand its epizootiology and potential health impact on wild Buteo populations in California.

Discovery and preliminary multi-species evaluation of single nucleotide polymorphism resources for genus Buteo developed from restriction site-associated DNA paired-end data

Just a few years ago, genomic studies of non-model organisms were extremely time and cost prohibitive, but recent advances in next-generation sequencing have made it possible to generate hundreds to thousands of informative single nucleotide polymorphisms (SNPs) for non-model organisms. We generated a SNP panel using restriction site-associated DNA (RAD) sequencing for species of the genus Buteo (Falconiformes: Accipitridae) with the aim of creating genomic resources in the absence of a reference genome. Using blood and feather samples from three different Buteo species, we used HiSeq Illumina sequencing to generate raw reads. We built 29 162 contigs and discovered 89 921 SNPs using paired-end single-digest RAD data. Using Bayesian clustering and principal componenets analysis, this SNP panel successfully assigned individuals of three Buteo (B. swainsoni, B. jamaicensis, B. lagopus) species correctly to species. We then scanned the SNPs for association with variation in coloration within the three species. This de novo reference will have broad application to the study of Buteo genomic diversity, analysis of population structure within species, identification of hybrids, and other applied studies of the avian genome.

Complete mitochondrial genome of Himalayan buzzard (Buteo buteo burmanicus)

In this study, the complete sequence of the mitochondrial (mt) genome of Buteo buteo burmanicus was determined. This mitogenome was 18,231 bp in length, containing 13 protein-coding genes, 2 rRNA genes, 22 tRNA genes, a control region (CR) and a pseudo-control region (ψCR). The overall base composition of the heavy strand was A, 30.8%; G, 13.2%; C, 31.8%; and T, 24.2%, with a slight AT bias of 65.1%. The complete mitogenomic data may provide more informative for phylogenetic approach for soft corals phylogeny especially for Buteo species.

Distribution and nesting success of ferruginous hawks and Swainson's hawks on an agricultural landscape in the Great Plains

We studied land-cover associations at nest sites and reproductive success of two Buteo species of conservation concern on the southern Great Plains, USA. The study area was in Cimarron County, Oklahoma, where land use is dominated by row-crop agriculture, livestock grazing, and grasslands enrolled in the Conservation Reserve Program (CRP). Ferruginous hawks (B. regalis) were uncommon and nested primarily in and around the Rita Blanca National Grassland. Swainson's hawks (B. swainsoni) were common and nested throughout the study area. Territories of ferruginous hawks contained more sandsage (Artemisia filifolia) habitat and less cropland and CRP lands than random sites, whereas territories of Swainson's hawks mirrored proportions of available landcover. Our results suggest that proportion of nearby sandsage habitat is an important factor in determining Swainson's hawk reproductive success. In addition, ferruginous hawk nest sites were located in areas that contained significantly more sandsage habitat than randomly selected sites in the study area. Nest-site availability may have constrained the distribution of buteos in our study area and is probably a major factor limiting nesting density of ferruginous hawks. Ferruginous hawks typically nest on man-made platforms (e.g., nest platforms and windmills) that in the study area were most common in and around the Rita Blanca National Grassland. Our results suggest that conversion of native grasslands to cropland may have negative consequences for ferruginous and Swainson's hawks. This relationship has been previously demonstrated in several studies of ferruginous hawks, but not for Swainson's hawks. In particular, loss of sandsage habitat on the southern Great Plains may have contributed to range declines in ferruginous hawks and decreased breeding success for Swainson's hawks.

Landscape alterations influence differential habitat use of nesting buteos and ravens within sagebrush ecosystem: Implications for transmission line development

ABSTRACT A goal in avian ecology is to understand factors that influence differences in nesting habitat and distribution among species, especially within changing landscapes. Over the past 2 decades, humans have altered sagebrush ecosystems as a result of expansion in energy production and transmission. Our primary study objective was to identify differences in the use of landscape characteristics and natural and anthropogenic features by nesting Common Ravens (Corvus corax) and 3 species of buteo (Swainson's Hawk [Buteo swainsoni], Red-tailed Hawk [B. jamaicensis], and Ferruginous Hawk [B. regalis]) within a sagebrush ecosystem in southeastern Idaho. During 2007–2009, we measured multiple environmental factors associated with 212 nest sites using data collected remotely and in the field. We then developed multinomial models to predict nesting probabilities by each species and predictive response curves based on model-averaged estimates. We found differences among species related to nesting substrate (nat...

Variation at phenological candidate genes correlates with timing of dispersal and plumage morph in a sedentary bird of prey

Polymorphic genes involved in the conserved molecular signalling of circadian and circannual clocks may play important roles in governing the timing of breeding and dispersal and thereby affect fitness in vertebrates. However, relatively few studies have explored associations between phenological candidate genes and behaviour, and these are somewhat biased towards particular taxonomic groups such as passerine birds and salmonid fish. Consequently, we assayed microsatellite polymorphisms within the exonic and 3' untranslated regions of the regulatory genes CLOCK, NPAS2, ADCYAP1 and CREB1 in the common buzzard (Buteo buteo), a polymorphic raptor species with three plumage morphs that differ in key life history traits including lifetime reproductive success. In contrast to studies of passerines, CLOCK poly-glutamine (poly-Q) was found to be monomorphic in 976 common buzzard nestlings as well as in three other Buteo species. Moreover, none of the candidate genes were significantly associated with fledging dates, although intermediately melanized females were found to lay earlier on average than light or dark morph individuals, and their offspring carried longer ADCYAP1 alleles. In contrast, all three candidate genes explained significant variation in one or more measures of juvenile buzzard dispersal (resighting probability, timing of dispersal and distance dispersed). Our findings contribute towards a broader body of work on the adaptive significance of CLOCK polymorphism, while also building upon previous studies that have documented links between ADCYAP1 variability and the timing of migration.

Reproductive Ecology of the Upland Buzzard (Buteo hemilasius) on the Mongolian Steppe

The breeding distribution of the Upland Buzzard (Buteo hemilasius) is restricted to the eastern Palearctic. In comparison to other Buteo species, little is known about this species' breeding ecology. The objectives of our study were to describe nest sites and reproductive success of Upland Buzzards in Mongolia. The average clutch size for 304 breeding attempts in 2001–07 was 3.49 eggs (±1.09 SD; range 2–8; total of 1061 eggs laid). For 215 breeding attempts, the average brood size was 1.95 nestlings (±1.53; range 0–6). We found that the nest materials and nest size varied greatly, probably corresponding to the availability of nesting materials within the territory. However, the variation in nest size may also reflect the fact that some of the smaller nests were built on human-made structures, such as electric pylons or roofs of small buildings.

Development of 19 microsatellite loci for Swainson's hawks (Buteo swainsoni) and other buteos

AbstractWe developed 26 Swainson's hawk (Buteo swainsoni) microsatellite primers from CA, AAT, CATC and GAGAA enriched genomic libraries. Primers were tested in 357 Swainson's hawks from western North America as well as seven other Buteo species. These markers will have broad application in investigations of Buteo population structure and genetic diversity.

FIRST KNOWN SPECIMEN OF A HYBRID BUTEO: SWAINSON'S HAWK (BUTEO SWAINSONI) × ROUGH-LEGGED HAWK (B. LAGOPUS) FROM LOUISIANA

Abstract We report a specimen that appears to be a hybrid between Swainson's Hawk (Buteo swainsoni) and Rough-legged Hawk (B. lagopus), which, to our knowledge, is the first hybrid specimen for the genus. There are few reports of hybridization between Buteo species, most of which have been observations of interspecific nesting pairs. The specimen described herein was collected in Louisiana and initially identified as a Rough-legged Hawk because of its feathered tarsi and the dark bellyband and carpals. A DNA sequence from the maternally inherited mitochondrial ND6 gene was identical to a published sequence for Swainson's Hawk. Nuclear DNA sequences from two introns contained only five variable sites among a panel of five potential parental taxa, but the hybrid sequence was most consistent with parentage by Rough-legged and Swainson's hawks. The feathered tarsi of the hybrid strongly suggested that the father was either a Rough-legged or Ferruginous hawk (B. regalis), the only North American raptors other ...

A review of nest heights of three Buteo species in eastern and central North America

A review of nest heights of three Buteo species in eastern and central North America

Resource Partitioning among Three Buteo Species in the Centennial Valley, Montana

Birds most commonly partition resources along habitat dimensions, followed by food, then temporal dimensions (Cody 1974, Schoener 1974). Studies in Alberta (Schmutz et al. 1980), Oregon (Cottrell 1981), and Washington (Bechard et al. 1990) reported partitioning of nesting habitat among Red-tailed (Buteo jamaicensis), Ferruginous (B. regalis), and Swainson's Hawks (B. swainsoni) while broad overlap occurred in prey use and nesting chronology. One species was much less common than the other two in each of those studies. In contrast, these closely related hawks coexist in equal abundance in the Centennial Valley, Montana. Do mechanisms that allowed coexistence in previous studies operate in areas where these hawk species are equally abundant? The objective of this study was to determine if and how these hawks partitioned habitat, food, and temporal resources in the Centennial Valley.

The Avoidance-Image Hypothesis and Color Polymorphism in Buteo hawks

The avoidance-image hypothesis proposes that conspicuous, dark-phased raptors invade populations consisting exclusively of light-phased individuals because prey previously attacked by light individuals more strongly avoid light than dark individuals in subsequent attacks (Rohwer 1983). We extend this hypothesis to predict (1) that migratory species of Buteo are more likely to be color polymorphic than resident species, (2) that, among polymorphic species of Buteo, migrants should occur in more than two morphs and residents in just two, and (3) that pairing preferences should be disassortative in dimorphic species. Without information on the genetic control of color variation in highly polymorphic species, pairing preferences cannot be predicted. Comparative data support predictions (1) and (2); few data relevant to prediction (3) exist. The striking color dimorphism and random pairing of the colonial-breeding Falco eleonorae is argued not to violate predictions of the avoidance-image hypothesis.

Fidelity to Breeding Territory in a Population of Red-Tailed Hawks

-Fidelity to breeding territories was examined on 33 Red-tailed Hawk (Buteo jamaicensis) territories in Oregon from 1973 to 1982 using the incidence of plumage dimorphism and mortality rates. Evidence suggested a high rate of return to previously occupied territories by females. The rate of change in the color morphs within territories among years was consistent with mortality rates alone. Alternative interpretations involving males' choice of mates with respect to female color and females' selection of habitat with respect to their color were explored. The first possibility, coupled with strong site fidelity by males could not be ruled out although it would require a high degree of color morph preference. No evidence for correlation between female territory selection and color was found. Plumage dimorphism among males occurred too seldom to permit evaluation of breeding site fidelity among males at the population level. Several distinctively marked males were seen, however, to return to previously occupied territories. Hawks are commonly assumed to breed repeatedly on the same territory (Newton 1979). Little evidence for such fidelity exists, however, beyond anecdotes involving a few distinctively marked or otherwise unique individuals. The few recent studies involving marked birds suggest varying degrees of fidelity to breeding territory among species and even sexes (see Newton 1979 for a review). Such behavior has been documented by marked birds in at least three Buteo species (B. galapagoensis, de Vries 1975; B. platypterus, Matray 1974; B. regalis, Schmutz and Schmutz 1981). Observations of distinctively marked individuals have disclosed territory fidelity among Red-tailed Hawks (Buteo jamaicensis; Fitch et al. 1946, Craighead and Craighead 1956). The data for these species do not indicate the degree to which territory fidelity occurs in populations because movements between territories are more likely to pass undetected. I report here on breeding territory fidelity in a population of Red-tailed Hawks, identified with the use of plumage dimorphism. STUDY AREA AND POPULATION Thirty-three territories were monitored by me and from one to six assistants between 1973 and 1982 on a 137-km2 study area in southeastern Wasco County, Oregon. The native vegetation is characteristic of the Columbia Basin Province (Franklin and Dyrness 1973) and forms a mosaic of habitats dominated by bunchgrass (Agropyron spicatum and Festuca idahoensis) or sagebrush (Artemisia tridentata). Dryland wheat farming and grazing, however, have altered much of the native vegetation. In many areas introduced annual grasses (Bromus tectorum and Elymus caput-medusa) and certain shrubs (Chrysothamnus nauseosus, C. vicidiflorus, and Gutierrezia sarothrae) are locally dominant. The Red-tailed Hawks in this study area were dimorphic, 18% (64/358) of the bird-years being represented by dark-phase individuals. One bird residing on a territory during a breeding season represents one bird-year. Darkphase birds were mostly dark below with little or no contrast between the breast and the abdominal band; from beneath, the dark winglining contrasted sharply with the much paler remiges. Light-phase birds were predomiantly white or cream-colored beneath, including the wing-lining and remiges, with a contrasting abdominal band of varying extent. Although lightand dark-phase birds varied considerably, I was able to classify all but one individual into one category or the other. The exceptional bird was an erythristic female, present for three breeding seasons, whom I classified as dark-phase.

Habitat usage of two woodland Buteo species in Central Ontario

Habitat usage of two woodland Buteo species in Central Ontario

Geographical Ecology of the Common Species of Buteo and Parabuteo Wintering in North America

North American hawks of the subfamily Buteoninae have received considerable attention, mostly with regard to their food habits and breeding biologies (e.g., Errington and Breckenridge 1938, Fitch et al. 1946, Smith and Murphy 1973). Twelve species occur in the New World north of Mexico but only five are widely distributed in winter (A.O.U. 1957). These are the Harris' Hawk (Parabuteo unicinctus), Ferruginous Hawk (Buteo regalis), Red-shouldered Hawk (B. lineatus), Red-tailed Hawk (B. jamaicensis), and Rough-legged Hawk (B. lagopus). Previously published maps based upon Christmas count data indicate that only the last three of these species are at all common over wide areas (Bystrak 1974). A number of workers have examined the relationships between locally sympatric populations of two or more Buteo species (e.g., Stewart 1949, Orians and Kuhlman 1956, Weller 1964, Schnell 1968). In this study we have compiled data from the 1969-70, 197071, and 1971-72 Christmas counts to determine the overall abundance pattern of this genus in the United States and southern Canada. We could then quantify the contributions made by the individual species to that pattern on different parts of the continent. We compared these calculations with certain environmental variables. Results show the degree to which the species' abundance patterns are complementary, and reveal something about the environmental gradients involved.

Flight Displays in Two American Species of Buteo

CRICHTON, V. 1963. Autumn and winter foods of the Spruce Grouse in central Ontario. J. Wildl. Mgmt. 27:597. DAUBENMIRE, R. F. 1946. The life zone problem in the northern intermountain region. Northwest Sci. 20:28-38. ELLISON, L. 1966. Seasonal foods and chemical analysis of winter diet of Alaskan Spruce Grouse. J. Wildl. Mgmt. 27:729-735. JONKEL, C. J., AND K. R. GREER. 1963. Fall food habits of Spruce Grouse in northwest Montana. J. Wildl. Mgmt. 27:593-596.