Plumage Differences Research Articles

Morphotypes or distinct species? A multilocus assessment of two East Asian scimitar babblers (Aves, Timaliidae)

AbstractIn birds, widespread species complexes often exhibit dramatic plumage differences across their distribution, which can give rise to discordance between morphotypes and phylogroups. Accurate identification of species diversity may require an integrated approach in which multilocus genetic data are used for inference and further corroborated by ecological, morphometric or behavioural data. Pomatorhinus gravivox and P. swinhoei, which were formerly considered component races of P. erythrogenys, were recently split using a delimitation system that mainly relied on the quantification of differences in phenotypic traits. We therefore carried out a reassessment of this taxonomic recommendation by conducting phylogenetic and population genetic analyses with multilocus genetic data. A deep mitochondrial split with a Kimura 2‐parameter distance of 0.061 was observed, mainly corresponding to the two morphologically defined species. However, one individual from P. swinhoei harboured a haplotype of P. gravivox. Individual‐based analyses of nuclear loci identified two distinct clusters that were exactly congruent with the two species. BPP delimitation also provided support for the separation. These congruencies support the notion that these two taxa are best regarded as two separate species. The presence of the P. gravivox mitochondrial haplotype in P. swinhoei was most likely a result of hybridization, due to the clear separation of nuclear loci. The speciation might be attributed to paleoclimatic changes but requires further evaluation due to the likelihood of ecological speciation. This study was in accordance with the results inferred from the quantitative system but highlighted the importance of sampling various data, especially in contact zones, in the study of taxonomy and speciation history.

Untangling cryptic diversity in the High Andes: Revision of the Scytalopus [magellanicus] complex (Rhinocryptidae) in Peru reveals three new species

AbstractTropical mountains feature marked species turnover along elevational gradients and across complex topography, resulting in great concentrations of avian biodiversity. In these landscapes, particularly among morphologically conserved and difficult to observe avian groups, species limits still require clarification. One such lineage is Scytalopus tapaculos, which are among the morphologically most conserved birds. Attention to their distinctive vocal repertoires and phylogenetic relationships has resulted in a proliferation of newly identified species, many of which are restricted range endemics. Here, we present a revised taxonomy and identify species limits among high-elevation populations of Scytalopus tapaculos inhabiting the Peruvian Andes. We employ an integrated framework using a combination of vocal information, mitochondrial DNA sequences, and appearance, gathered from our own fieldwork over the past 40 yr and supplemented with community-shared birdsong archives and museum specimens. We describe 3 new species endemic to Peru. Within all 3 of these species there is genetic differentiation, which in 2 species is mirrored by subtle geographic plumage and vocal variation. In a fourth species, Scytalopus schulenbergi, we document deep genetic divergence and plumage differences despite overall vocal similarity. We further propose that an extralimital taxon, Scytalopus opacus androstictus, be elevated to species rank, based on a diagnostic vocal character. Our results demonstrate that basic exploration and descriptive work using diverse data sources continues to identify new species of birds, particularly in tropical environs.

Sexing a Monomorphic Plumage Seabird Using Morphometrics and Assortative Mating

This study aimed to establish a reliable method based on morphometrics to sex Long-tailed Jaeger (Stercorarius longicaudus), a species with slight differences in body size between sexes but no plumage differences. The presence of assortative mating based on size was also examined to determine if within-pair differences in size could improve sexing. Seventy-six Long-tailed Jaegers were measured, including 26 breeding pairs, on Bylot Island (Nunavut, Canada) during summers 2014-2018. Bird weight, wing chord, tarsus, head, and tail feathers were measured, and breast feathers were collected to determine sex with DNA extracts. A first discriminant function based on two variables (body mass and wing chord) accurately sexed 83% of birds. Some evidence for positive assortative mating based on size was found, as body mass of pair members was positively related, and 88% of females were heavier than their partner. A second discriminant function that included body mass, wing chord, length of the central tail feather, and partner's body mass accurately sexed 92% of birds. Adding a new morphometric and information from the partner allowed a reduction in sex misclassification by half (17% vs. 8%). In conclusion, external body measurements are useful to sex Long-tailed Jaegers, a slightly dimorphic species, and measurements of both members of a pair considerably improve the accuracy of sexing, likely due to the presence of assortative mating.

The discriminant power of biometrics for sex determination in European Bee-eaters Merops apiaster

ABSTRACT Capsule A combination of several biometric measures enables the reliable sexing of the European Bee-eater Merops apiaster, a species with subtle sex differences in plumage and morphometry. Aims To explore variation in biometrics and their suitability to discriminate sex in adult European Bee-eaters Merops apiaster. Methods We sampled populations of a long-distance migratory species with low sexual size dimorphism, the European Bee-eater Merops apiaster, from colonies in western Iberia (Portugal) and Central Europe (Germany) to investigate body size variation and derive population-specific and general sex discriminant functions. Results Overall, male Bee-eaters were larger than females while Bee-eaters from Germany and Portugal did not differ in size, except for primary length and tail length. The best single measurement to discriminate sex was wing length for Portuguese birds and tail tip length for German birds, as in the combined dataset. Multivariate discriminant functions of head-bill, wing and tail tip lengths provided the highest discriminant accuracy, discriminating sex for 91% of the birds from Portugal, 96% from Germany and 94% when using the combined dataset. Nonetheless, the discriminant accuracy remained high in the functions using only two variables for Portugal (head-bill and tail tip 91%, head-bill and wing 88%, wing and tail tip 88%), Germany (head-bill and tail tip 95%, wing and tail tip 97%) and in the combined dataset (head-bill and tail tip 92%, wing and tail tip 93%). Conclusions Population specific discriminant functions allow sexing of European Bee-eaters by morphometry with high degree of accuracy at least for Iberia and Central European populations. Such discriminant functions can be used to assign the sex of adult Bee-eaters reliably and swiftly while the bird is still in the hand, highlighting the potential of these functions for rapidly sexing species with low degrees of sexual size and plumage dimorphism.

External anatomy, plumages, and historical distribution of the Eskimo Curlew (Numenius borealis)

I sought to distinguish between sexes and age classes of the Eskimo Curlew (Numenius borealis), as well as to clarify the historical migration pathways and breeding distribution of the species. Discriminant function analysis revealed that sexes significantly differed in bill and tail length, with bill length the best predictor of sex. I found no significant seasonal discrimination in measurements among individuals, nor did I find any difference between early and later Northeastern fall migrants (i.e., primarily adults vs. primarily juveniles). Breast marking shape and extent of white on throat were uncorrelated with other plumage characteristics, whereas pale abdomens and wide, paler margins of wing covert feathers correlated with low density of breast markings. Individuals with pale abdomens and heavily spotted backs also had wide margins of wing covert feathers. Back spotting was the only significant plumage character related to sex, with heavy spotting predominating among females and light spotting predominating among males. I found few clear seasonal differences in plumage among specimens, although dorsal ground color may have averaged darker on spring specimens. Moreover, more lightly back-spotted individuals tended to occur in later fall, which suggested that these birds were juveniles. The existence of individuals with few Y-shaped breast markings appeared to represent one end of a range of plumage conditions that exhibited no clear relationship to age, sex, or geographic location. Mapping locations of museum specimens clarified details of migration pathway extent, provided evidence of migratory concentration spots, and provided additional evidence that Alaska once possessed a breeding population. Examining dates of last collection indicated that populations collapsed below levels at which birds were regularly located after the first decade of the 20th century.

Species delimitation within the Glaucidium brodiei owlet complex using bioacoustic tools

BackgroundThe taxonomy of the Collared Owlet (Glaucidium brodiei) species complex is confused owing to great individual variation in plumage colouration seemingly unrelated to their distribution. Although generally recognised as a single species, vocal differences among the subspecies have been noted by field recordists. However, there is no study assessing the vocal differences among these four subspecies.MethodsWe obtained 76 sound recordings of the G. brodiei species complex comprising all four subspecies. We conducted bioacoustic examinations using principal component analysis and the Isler criterion to quantitatively test species boundaries within the G. brodiei complex. In addition, we compared plumage colouration among 13 specimens of the G. brodiei complex deposited at the Natural History Museum at Tring, UK and the Lee Kong Chian Natural History Museum, Singapore to ascertain the presence of plumage differences across taxa.ResultsWe found the Bornean and Sumatran populations vocally similar to each other, but distinctly different from the mainland and Taiwan populations. The vocal pattern seems to corroborate plumage distinctions in the colouration of neck collars: the Bornean and Sumatran taxa share a white neck collar, whereas the continental and Taiwan taxa share a rufous neck collar.ConclusionsWe propose the taxonomic elevation of the Sumatran and Bornean populations to species level as Sunda Owlet G. sylvaticum, with one subspecies on Sumatra (G. s. sylvaticum) and Borneo (G. s. borneense) each. Our study corroborates the importance of bioacoustics in ascertaining species boundaries in non-passerines, and emphasises the significance of incorporating multiple species delimitation approaches when making taxonomic decisions.

Species limits and biogeography of Rhynchospiza sparrows

The genus Rhynchospiza comprises two species, the monotypic Tumbes Sparrow (R. stolzmanni) and the Stripe-crowned Sparrow (R. strigiceps) with subspecies strigiceps and dabbenei. In the study reported here we evaluated the taxonomic status of these taxa and discussed key features involved in speciation. All three taxa exhibited multiple differences in plumage, morphology, and vocalizations, supporting the recognition of three species in Rhynchospiza. The very large-billed R. stolzmanni has a song composed of a succession of faster complex trilled phrases, shows a small black loral line and dark-chestnut head stripes with large dark central-stripe to individual feathers, and is resident in the Tumbes region. The large and heavy dabbenei has a song consisting of a series of simple chirping notes, shows a large black loral crescent and chestnut head stripes with a reduced to absent dark center to feathers, and inhabits the Austral Yungas as a year-round resident. The small and pale strigiceps has a song consisting of a succession of complex trilled phrases, shows a small black loral line and rufous-brown head stripes with large dark central-stripe to feathers, and inhabits Dry and Sierran Chaco where it is a partial migrant. Locality data and ecological niche modeling show that dabbenei and strigiceps are allo-parapatric and use different altitudinally segregated habitats at their zone of parapatry. Molecular phylogenetic analyses (NADH dehydrogenase 2 [ND2] gene) revealed R. stolzmanni to be sister (11.5% divergent) to a recently diverged dabbenei and strigiceps clade (1.6% divergent). We conclude that the genus Rhynchospiza comprises three species-level entities, each restricted to a major biogeographic region, and that vocalizations and facial patterns provide key evidence on species limits in these otherwise similarly plumaged taxa. The evolutionary–cultural differences in songs, with complex phrases in those of R. strigiceps and R. stolzmanni, and single notes in the songs of R. dabbenei, suggest changes in the innate vocal learning template during speciation in the latter.

Phenotypic and genetic introgression across a moving woodpecker hybrid zone.

In hybrid zones in which two divergent taxa come into secondary contact and interbreed, selection can maintain phenotypic diversity despite widespread genetic introgression. Red-breasted (Sphyrapicus ruber) and red-naped (S.nuchalis) sapsuckers meet and hybridize along a narrow contact zone that stretches from northern California to southern British Columbia. We found strong evidence for changes in the structure of this hybrid zone across time, with significant temporal shifts in allele frequencies and in the proportions of parental phenotypes across the landscape. In addition to these shifts, we found that differences in plumage predict genetic differences (R2 =0.80), suggesting that plumage is a useful proxy for assessing ancestry. We also found a significant bimodal distribution of hybrids across the contact zone, suggesting that premating barriers may be driving reproductive isolation, perhaps as a result of assortative mating based on plumage differences. However, despite evidence of selection and strong patterns of population structure between parental samples, we found only weak patterns of genetic divergence. Using museum specimens and genomic data, this study of sapsuckers provides insight into the ways in which phenotypic and genetic structure have changed over a 40-year period, as well as insight into the mechanisms that may contribute to the maintenance of the hybrid zone over time.

On the genetic distinctiveness of tailorbirds (Cisticolidae: Orthotomus) from the South-east Asian mainland with the description of a new subspecies

BackgroundThe Cambodian Tailorbird (Orthotomus chaktomuk) was one of the most recent major ornithological discoveries in South-east Asia as it originated from lowland seasonally flooded scrub within the densely inhabited floodplain around the Tonle Sap, Mekong and Bassac rivers (Cambodia). The Cambodian Tailorbird is sister to the Dark-necked Tailorbird (O. atrogularis) with very limited genetics and biometric differentiation. Between 2004 and 2012, evidences of a new population of Ashy Tailorbird (O. ruficeps) in SE Cambodia/Vietnam accumulated but no museum specimens were ever reported. The Ashy Tailorbird currently consists of eight subspecies among which the closest geographical populations, O. r. cineraceus (SE Burma to Malay Peninsula, Sumatra, Bangka and Belitung) and O. r. borneoensis (Borneo), are allopatric. Subspecific identification of the Cambodian Ashy Tailorbirds individuals was not possible because of the limited differences in plumage among subspecies.MethodsWe inspected the Orthotomus ruficeps specimens housed at the Museum National d’Histoire Naturelle (Paris) and discovered five specimens of O. ruficeps collected by Louis Rodolphe Germain in ‘Cochinchina’ (corresponding to southern Vietnam) during the nineteenth century. We sequenced one mitochondrial locus and gathered biometric data from these specimens and compared them with other Orthotomus lineages.ResultsThe Ashy Tailord population from SE Cambodia and Vietnam is distinct from the two geographically close subspecies O. r. borneoensis (1.7%) and O. r. cineraceus (1.3%). O. chaktomuk is nested within O. atrogularis in the mitochondrial gene tree. The SE Cambodia/Vietnam population of O. ruficeps is distinct from the two other subspecies in bill shape.ConclusionOur study described the biometric and molecular distinctiveness of a recently re-discovered population of Ashy Tailord in SE Cambodia and Vietnam and suggests that this population constitutes an independent evolutionary lineage that we describe here as a new subspecies. The newly described Cambodian Tailorbird is nested within the Dark-necked Tailorbird and the genetic divergence is much lower than initially described (0.4‒0.7% vs 1.1‒1.4%).

A flicker of hope: Genomic data distinguish Northern Flicker taxa despite low levels of divergence

ABSTRACT Next-generation sequencing technologies are increasingly being employed to explore patterns of genomic variation in avian taxa previously characterized using morphology and/or traditional genetic markers. The hybridization dynamics of the Northern Flicker complex have received considerable attention, primarily due to the conspicuous plumage differences among these birds and the geographically extensive hybrid zone between the Red-shafted (Colaptes auratus cafer) and Yellow-shafted (Colaptes auratus auratus) flickers in the Great Plains region of North America. However, no traditional molecular techniques have been able to differentiate these 2 morphologically well-defined taxa from one another, or conclusively from the closely related Gilded Flicker (Colaptes chrysoides). Here, we use a next-generation sequencing approach to assess the genetic diversity and evolutionary history of these 3 taxa. We confirm the overall low levels of differentiation found using traditional molecular markers, but are...

Investigation of the status of the enigmatic White‐chested TinkerbirdPogoniulus makawaiusing molecular analysis of the type specimen

Following the discovery of a uniquely plumagedPogoniulustinkerbird inCryptosepalumforest in northwest Zambia in 1964 and its subsequent description in 1965 as a distinct species, White‐chested TinkerbirdPogoniulus makawai, there has long raged a debate regarding its taxonomic status. The failure to find further individuals in spite of numerous attempts has led several taxonomists to question its status as a distinct species. UsingDNAfrom theP. makawaitype specimen we performed a molecular phylogenetic analysis including samples from other tinkerbird species and, in particular, several subspecies of Yellow‐rumped TinkerbirdPogoniulus bilineatus, of which several observers considered theP. makawaispecimen an aberrant individual. Phylogenetic analyses of both mitochondrial and nuclearDNArecoveredP. makawaias being nested within a clade of Yellow‐rumped Tinkerbirds. Our results suggest that White‐chested Tinkerbird is not a distinct species but either a distinct subspecies or an aberrant form of Yellow‐rumped Tinkerbird; in either case a genetic basis for plumage differences cannot be ruled out. At present our limited nuclearDNAdata do not suggest hybridization with another tinkerbird species. Finally, we suggest that further surveys are needed to determine the extent to which loci that may underpin the ‘makawai phenotype’ may persist in the region, as well as to ascertain the extent to which theP. makawaiform itself, or the entire regional population of Yellow‐rumped Tinkerbirds, warrants subspecific status.

Morphological evidence for the taxonomic status of the Bridge’s Guan, Penelope bridgesi, with comments on the validity of P. obscura bronzina (Aves: Cracidae)

Penelopeobscura Temminck, 1815 is a forest guan found in Brazil, Paraguay, Uruguay, Argentina and Bolivia. Three subspecies are currently recognized: Penelopeo.obscura Temminck, 1815, P.o.bridgesi Gray, 1860, and P.o.bronzina Hellmayr, 1914. The limits between Penelope taxa are poorly understood since few studies have evaluated their differences in plumage, distribution and taxonomy. Based on 104 specimens deposited in ornithological collections we studied the variations in the plumage of P.obscura, including all characters that have been used to describe the included subspecies. Our results show that the plumage of these birds is extremely variable in southern and southeastern Brazil. Without any morphological and morphometric characters to support P.o.bronzina as a valid taxon, we synonymized it with P.obscura. Conversely, P.o.bridgesi, which occurs in the Yungas and the Chaco, is a distinct taxon and should be treated as a separate species from P.obscura.

Isolation by distance, not incipient ecological speciation, explains genetic differentiation in an Andean songbird (Aves: Furnariidae: Cranioleuca antisiensis, Line-cheeked Spinetail) despite near threefold body size change across an environmental gradient.

During the process of ecological speciation, reproductive isolation results from divergent natural selection and leads to a positive correlation between genetic divergence and adaptive phenotypic divergence, that is, isolation by adaptation (IBA). In natural populations, phenotypic differentiation is often autocorrelated with geographic distance, making IBA difficult to distinguish from the neutral expectation of isolation by distance (IBD). We examined these two alternatives in a dramatic case of clinal phenotypic variation in an Andean songbird, the Line-cheeked Spinetail (Cranioleuca antisiensis). At its geographic extremes, this species shows a near threefold difference in body mass (11.5 to 31.0g) with marked plumage differences. We analysed phenotypic, environmental and genetic data (5,154 SNPs) from 172 individuals and 19 populations sampled along its linear distribution in the Andes. We found that body mass was tightly correlated with environmental temperature, consistent with local adaptation as per Bergmann's rule. Using a PST -FST analysis, we found additional support for natural selection driving body mass differentiation, but these results could also be explained by environment-mediated phenotypic plasticity. When we assessed the relative support for patterns of IBA and IBD using variance partitioning, we found that IBD was the best explanation for genetic differentiation along the cline. Adaptive phenotypic or environmental divergence can reduce gene flow, a pattern interpreted as evidence of ecological speciation's role in diversification. Our results provide a counterexample to this interpretation. Despite conditions conducive to ecological speciation, our results suggest that dramatic size and environmental differentiation within C.antisiensis are not limiting gene flow.

Species Rank For the Critically Endangered Atlantic Lesser Frigatebird (Fregata trinitatis)

The Atlantic Lesser Frigatebird (Fregata trinitatis) is elevated to a separate species from Fregata ariel of the Indo-Pacific based on plumage differences and greater robustness of the rostrum and wing bones. The species now occurs only on the remote South Atlantic island of Trindade (South Trinidad) over 1,100 km east of mainland Brazil, although fossils establish that it once also occurred at St. Helena. Fregata trinitatis no longer breeds on the main island of Trindade and is only known to nest with certainty on a small rocky islet on the southern coast, where there may be fewer than 20 breeding pairs.

Admixture mapping in a hybrid zone reveals loci associated with avian feather coloration.

Identifying the genetic bases for colour patterns has provided important insights into the control and expression of pigmentation and how these characteristics influence fitness. However, much more is known about the genetic bases for traits based on melanin pigments than for traits based on another major class of pigments, carotenoids. Here, we use natural admixture in a hybrid zone between Audubon's and myrtle warblers (Setophaga coronata auduboni/S. c. coronata) to identify genomic regions associated with both types of pigmentation. Warblers are known for rapid speciation and dramatic differences in plumage. For each of five plumage coloration traits, we found highly significant associations with multiple single-nucleotide polymorphisms (SNPs) across the genome and these were clustered in discrete regions. Regions near significantly associated SNPs were enriched for genes associated with keratin filaments, fibrils that make up feathers. A carotenoid-based trait that differs between the taxa-throat colour-had more than a dozen genomic regions of association. One cluster of SNPs for this trait overlaps the Scavenger Receptor Class F Member 2 (SCARF2) gene. Other scavenger receptors are presumed to be expressed at target tissues and involved in the selective movement of carotenoids into the target cells, making SCARF2 a plausible new candidate for carotenoid processing. In addition, two melanin-based plumage traits-colours of the eye line and eye spot-show very strong associations with a single genomic region mapping to chromosome 20 in the zebra finch. These findings indicate that only a subset of the genomic regions differentiated between these two warblers are associated with the plumage differences between them and demonstrate the utility of reduced-representation genomic scans in hybrid zones.

Phenotypic variation and vocal divergence reveals a species complex in White-eared Ground-sparrows (Cabanis) (Aves: Passerellidae)

The taxonomy of the genus Melozone has recently been analyzed from genus to subspecies level, leading to a significant revision of our understanding of this group of birds. Previous studies quantified differences in phenotypic traits, behavior, and genotypes, to provide a better understanding of the underappreciated diversity within Melozone and the relationship between species within this genus. Yet the relationship between the subspecies of White-eared Ground-sparrows, Melozone leucotis, has not received thorough taxonomic scrutiny. In this study, we evaluate the taxonomic status of the three recognized subspecies of M. leucotis using multiple morphometric characteristics, plumage color features, and vocalizations. We measured plumage patterns and reflectance from museum specimens, morphometric features from museum specimens and live birds, and vocal characteristics from sound recordings. We observed substantial variation between subspecies in plumage, morphometry, and voice, especially between northern and southern birds. The phenotypic and vocal differences exhibited by M. l. occipitalis (from Chiapas, Mexico; Guatemala; and El Salvador) suggest that its taxonomic relationship with the M. l. leucotis and M. l. nigrior complex (from Costa Rica and Nicaragua, respectively) needs to be reevaluated, because these two groups are highly diagnosable from one another. Additionally, M. l. occipitalis is geographically isolated from the other two subspecies, reducing the probability of contact by natural causes in the near future. Based on the clear differences in voice, plumage, and morphometric features reported here, we propose that M. l. occipitalis be recognized as a distinct species, M. occipitalis (Salvin's Ground-sparrow), diagnosed on the basis of its longer tail, longer bill, duller plumage, and songs with a lower frequency of maximum amplitude.

Identifying Bald Versus Golden Eagle Bones: A Primer for Wildlife Biologists and Law Enforcement Officers

Abstract Remains of bald eagles Haliaeetus leucocephalus and golden eagles Aquila chrysaetos are regularly encountered in avian mortality surveys and wildlife crime investigations. These species exhibit well-documented plumage differences, allowing identification in most instances when feathers are present. However, skeletal remains are much more difficult to identify and may be the only material available after mortality events (e.g., decomposed remains associated with power lines or wind turbines). Eagle bones are also sometimes incorporated into crafted items without other associated remains. I describe and illustrate shape-based osteological characters that have been determined to be reliable for distinguishing most major bones of bald versus golden eagles. Using the annotated photographs provided as a guide, nonspecialists will be able to identify eagle skeletal remains with high accuracy. This information will be of interest to wildlife law enforcement officers; state, federal, and tribal wildlife biologists documenting avian mortality; and anthropologists and archaeologists.

Morphometric Differences Between Sexes In the White-Faced Ibis (Plegadis chihi)

ABSTRACT Sexual dimorphism in birds may express itself as differences in body size, plumage, color and/or behavior. Many species are monomorphic in color, which makes sex determination difficult in the field. In order to develop a tool to distinguish between male and female specimens of the White-faced Ibis, Plegadis chihi, by using external body measurements, the objective of this work was to quantify morphometric differences between sexes in adults of this species. The following variables were measured: culmen length, bill height and width, tarsus length, middle toe (with claw) length, wing chord, tail length and body mass. Males were larger than females in all of these variables, and presented statistically significant differences for six out of eight parameters. Three discriminant classification functions were obtained with an accurate total classification rate in >85% of the cases. The length of the culmen, tarsus, middle toe with claw, and wing chord, were among the most useful variables to discrimi...

A new species of tapaculo (Rhinocryptidae: Scytalopus) from the Western Andes of Colombia

We describe Scytalopus alvarezlopezi from the Western Andes of Colombia. The new species forms part of a distinctive clade of Scytalopus tapaculos (Rhinocryptidae) that also includes S. robbinsi from Ecuador and S. stilesi and S. rodriguezi, which occur on the Central and Eastern Andes of Colombia. S. alvarezlopezi is easily diagnosable from its near relatives by its song and mitochondrial DNA; differences in plumage exist but are more subtle. The species inhabits dense understory vegetation on the floors and lower slopes of ravines in cloud forest at elevations of 1,300 to 2,100 m. On the Pacific slope, its altitudinal distribution is sandwiched between those of S. chocoensis (below) and S. vicinior (above); the latter in turn is replaced higher up by S. spillmanni and S. latrans, but S. alvarezlopezi also occurs at ∼2,000–2,100 m on eastern slopes just below the low ridgeline. All of the latter species are distinguished by vocal and plumage characters. Marked sexual differences in plumage exist in stilesi, but females have yet to be collected for alvarezlopezi and rodriguezi. We consider that S. alvarezlopezi is not threatened at present, but could be potentially vulnerable due to its restricted distribution; it is endemic to Colombia.

Molecular Ecology of New World Quails: Messages for Managers

Recent genetic studies of New World quails (Odontophoridae) have yielded important, and sometimes, counter-intuitive insights regarding their evolutionary relationships, genetic diversity, population structure, and biogeographic history. Many of these new insights have important implications for managers. New World quails are a distinct family within galliforms, most closely related to guineafowl (Numididae) and pheasants (Phasianidae) rather than guans and chachalacas (Cracidae). The African stone partridges (Ptilopachus spp.) are the closest living relatives of the New World quails. The combination of phylogeographic studies with ecological niche modeling has revealed the biogeographic history of several species of New World quails, including Pleistocene refugia and post-Pleistocene range expansions, contractions, or stasis. Divergence times within and among genera often date to climactic or geologic events 1–5 million years ago. The many subspecies of quail described over the past 100 years were based on minor differences in plumage and probably represent artificial sectioning of latitudinal clines rather than historically isolated and evolutionary distinct units. Subspecies are often used as proxies for management units, but conservation efforts directed at the northern bobwhite (Colinus virginianus) and scaled (Callipepla squamata), California (C. californica), and Gambel’s (C. gambelii) quails may not benefit from such an approach. Ecological regions, rather than subspecies, are probably more appropriate as a ‘‘management unit.’’ The overall lack of population structure, evidence of long-distance dispersal and historical gene flow among populations, and the cyclical population dynamics of these species suggest that there is a biological basis for conserving large blocks of interconnected habitat. Focal areas of restoration projects should be spatially extensive and interconnected to facilitate dispersal and recolonization. With a better understanding of how quail populations responded to past climactic conditions, we are better able to predict how quail may respond to future conditions and ensure the conservation of these iconic New World birds.