bluuebunny/crossref_metadata_2025 huggingface dataset:
The Grebes: Podicipedidae
Authors: Nuechterlein Gary L.
Published: September 2019

The following critiques express the opinions of the individual evaluators regarding the strengths, weaknesses, and value of the books they review. As such, the appraisals are subjective assessments and do not necessarily reflect the opinions of the editors or any official policy of the American Ornithologists’ Union.
The Birds of Morocco
Authors: Urban Emil K.
Published: September 2019

The following critiques express the opinions of the individual evaluators regarding the strengths, weaknesses, and value of the books they review. As such, the appraisals are subjective assessments and do not necessarily reflect the opinions of the editors or any official policy of the American Ornithologists’ Union.
Elevational Zonation and the Phylogenetic Relationships of the Henicorhina Wood-Wrens
Authors: Dingle Caroline , Lovette Irby J. , Canaday Chris , Smith Thomas B.
Published: September 2019

The Henicorhina wood-wren complex consists of three taxonomic species. Two of these, the Gray-breasted Wood-Wren (Henicorhina leucophrys) and the White-breasted Wood-Wren (H. leucosticta), are widespread throughout Central America and northern South America, with leucophrys occurring at higher elevations in regions where both occur. A third, recently described, species—the Bar-winged Wood-Wren (H. leucoptera)—occurs only in several isolated cordilleras in southeastern Ecuador and northeastern Peru, where it replaces the Gray-breasted Wood-Wren at the highest elevations. We used mitochondrial DNA sequences to explore the phylo-genetic relationships among populations of these taxa and to draw inferences about the evolutionary origins of elevational zonation. We found substantial mitochondrial diversity within both leucophrys and leucosticta. Differentiation across the Andes in leucophrys was negligible, but populations from Central America and from northwestern Ecuador showed substantial differentiation. Three highly differentiated haplotype groups were also present in leucosticta, corresponding to populations in the eastern Andean lowlands, Central America, and the Chocó region of northwestern Ecuador; these populations may each warrant taxonomic species status. Bar-winged haplo-types nested within the mitochondrially diverse leucosticta group, where they were most closely allied to the geographically distant Chocó haplotypes. This leucoptera-leucosticta affinity is not consistent with previous inferences, based on plumage and behavioral similarities, that grouped leucoptera and leucophrys as sister species. These reconstructions refute the hypothesis that elevational zonation in this clade originated from in situ speciation along an elevational gradient, and instead highlight the role of complex changes in geographic distributions in fostering phylogenetic and ecological diversification.

Reemplazos Altitudinales y Relaciones Filogenéticas en el Género Henicorhina (Troglodytidae)
Foraging Behavior and Predation Risk in Male and Female Eurasian Blackbirds (Turdus Merula) During the Breeding Season
Authors: Post Peter , Götmark Frank
Published: September 2019

In many birds, breeding males display bright colors, sing, and engage in active territory defense; whereas females are less conspicuous. Therefore, it is sometimes assumed that in the breeding season males suffer higher predation than females. Several studies have reported, however, higher female predation rates, which suggests that traits other than coloration and mate-acquisition behaviors are important in determining predation rates for the sexes. Theoretical and empirical work suggests that foraging behavior and foraging rate are major determinants of predation risk. Here, we examine this possibility in a study of breeding Eurasian Blackbirds (Turdus merula) and predation on them by Eurasian Sparrowhawks (Accipiter nisus). Female Eurasian Blackbirds foraged more than males and foraged closer to the ground, both early and late in the breeding season. On the basis of this observation, we predicted that females should suffer higher predation than males. Of 98 Eurasian Blackbirds taken in 33 Eurasian Sparrowhawk territories during four years, 56 were females and 42 males. On the basis of the male-biased sex ratio in the population, female Eurasian Blackbirds suffered higher predation risk than males. For breeding birds, these results indicate a trade-off between foraging effort and predation rate, which is of importance for sexual dichromatism (selection for female crypsis), population sex ratio, and behaviors of the sexes.

Le Comportement de Quête Alimentaire et les Risques de Prédation chez Turdus merula au Cours de la Saison de Reproduction
Effects of Invasive Exotic Grasses on South Texas Rangeland Breeding Birds
Authors: Flanders Aron A. , Kuvlesky William P. , Ruthven Donald C. , Zaiglin Robert E. , Bingham Ralph L. , Fulbright Timothy E. , Hernández Fidel , Brennan Leonard A.
Published: September 2019

Invasive exotic plants are a major threat to many species of wild birds. When these plants become established and widespread, the floristic composition of native plant communities becomes simplified, which can result in long-term and often irreversible habitat degradation for birds and other animals. Until recently, few studies have focused on the effect of invasive exotic grasses on breeding birds in southwestern rangelands. During the 2001 and 2002 breeding seasons (May-June), we compared the abundance and species richness of breeding birds, native flora, and arthropods on South Texas rangeland plots dominated by native grasses and plots dominated by two invasive exotic grasses, Lehmann lovegrass (Eragrostis lehmanniana) and buffelgrass (Cenchrus ciliaris). Native-grass cover was >400% greater on native-grass sites than on exotic-grass sites. Forb and grass species-richness were higher on native-grass sites. Shrub canopy cover, bare ground, and vegetation height measurements were similar on native-grass and exotic-grass sites. Overall bird abundance was 32% greater on native-grass sites than on exotic-grass sites. Lark Sparrows (Chondestes grammacus) were 73% more abundant on native-grass sites. Four other species—Black-throated Sparrow (Amphispiza bilineata), Northern Mockingbird (Mimus polyglottos), Northern Bobwhite (Colinus virginianus), and Cassin’s Sparrow (Aimophilla cassini)— were 26–70% more abundant on native-grass sites. The guild of birds that foraged on the ground under open brush canopies was almost twice as abundant on native-grass sites. Arthropod abundance was 60% greater on the native-grass site we sampled. Specifically, spiders, beetles, and ants were 42–83% more abundant on a native-grass site than on a buffelgrass site. Compared with rangelands dominated by native vegetation, areas dominated by Lehmann lovegrass and buffelgrass in South Texas appear to provide less suitable habitat for breeding birds, especially for bird species that forage on or near the ground.

Efectos de Pastos Invasores Exóticos en las Aves que Nidifican en los Campos de Pastoreo del Sur de Texas
Foraging Behavior of Eurasian Three-Toed Woodpeckers (Picoides Tridactylus Alpinus) in Relation to Sex and Season in Germany
Authors: Pechacek Peter
Published: September 2019

I studied year-round foraging behavior of 28 color-banded Eurasian Three-toed Woodpeckers (Picoides tridactylus alpinus) from 1995 to 1999 in Berchtesgaden National Park, Germany. My research focused on how foraging time was divided among various substrates and foraging techniques. Foraging behavior was recorded by instantaneous sampling during independent observation sessions (i.e. foraging bouts). A combination of tapping and pecking was the most important foraging technique used during breeding (>43%) and nonbreeding (>59%). Both mean and maximum foraging bouts (mean ± SD) lasted longer during nonbreeding periods (mean: 17.0 ± 3.7 min, maximum: 61.9 ± 30.2 min) than during breeding periods (4.3 ± 3.0 min, 15.5 ± 16.1 min). Sap-sucking was observed rarely during breeding. Males spent less time foraging on branches, whereas females spent less time in the lower third of trees on which they foraged. Males also manipulated foraging substrates more by pecking and digging (probing), whereas females did more climbing and position-changing on foraging trees. I concluded that Eurasian Threetoed Woodpeckers changed their foraging techniques according to seasonal changes in diet and that, during breeding, males used better foraging grounds than females.

Le Comportement de Quête Alimentaire chez Picoides tridactylus alpinus en Relation avec le Sexe et la Saison en Allemagne
A Test of the Environmental Hotspot Hypothesis for Lek Placement in Three Species of Manakins (Pipridae) in Ecuador
Authors: Ryder Thomas B. , Blake John G. , Loiselle Bette A.
Published: September 2019

Lekking is classified as a form of male-dominance polygyny in which males lack control of resources essential for the acquisition of females. Of particular interest to behavioral ecologists has been the mechanistic basis of male spatial aggregation and the maintenance of site fidelity over time. The “hotspot” hypothesis has been proposed as both an ultimate and proximate mechanism by which males aggregate in locations where females are likely to be encountered. The hypothesis has been extended to include areas of the environment that act to constrain females’ use of space. Here, we test a prediction of this hypothesis for three species of manakins (Pipridae): that leks are located in places where fruit, the main food for these frugivorous birds, is plentiful. We compared four lek sites with four non-lek control sites of Golden-headed (Pipra erythrocephala), Wire-tailed (P. filicauda), and White-crowned (P. pipra) manakins in an Amazonian forest in Ecuador. Our results show that lek sites had higher fruit biomass than control sites. Moreover, lek sites had more plants bearing ripe fruit as well as a higher fruit biomass per plant than control sites. Thus, our results support the environmental hotspot hypothesis as an explanation for current lek site occupancy and suggest that fruit availability may also explain the placement of traditional manakin lekking sites. We also discuss a potential direct benefit for subordinate male manakins derived from the notion of central-place foraging and public information-sharing.

Una Prueba de la Hipótesis de que Puntos que Concentran Recursos Explican la Ubicación de las Asambleas de Cortejo en Tres Especies de Saltarines (Pipridae) en Ecuador
Responses of Parasitized And Unparasitized Common Redstart (Phoenicurus Phoenicurus) Populations Against Artificial Cuckoo Parasitism
Authors: Rutila Jarkko , Jokimäki Jukka , Avilés Jesús M. , Kaisanlahti-Jokimäki Marja-Liisa
Published: September 2019

Brood parasitism selects for defensive mechanisms that enhance host fitness. Therefore, host populations under different parasitism pressures may express different levels of defense against brood parasites. We tested the rejection responses of currently parasitized and unparasitized Common Redstart (Phoenicurus phoenicurus) populations in Finland to artificial Common Cuckoo (Cuculus canorus) eggs. We predicted a higher level of defense in the parasitized population, but in fact the rejection rate was higher in the nonparasitized population. Nonmimetic artificial eggs were rejected more often than mimetic ones. Desertion probability was higher in the nonparasitized population and was independent of artificial egg type. Common Redstarts in the parasitized population rejected the artificial eggs mostly through ejection, whereas desertion was a more frequent rejection method in the nonparasitized population. Our results suggest that current selection pressures from brood parasites do not always explain the current levels of defense.

Respuestas de Poblaciones Parasitadas y No Parasitadas de Phoenicurus phoenicurus Contra el Parasitismo Artificial de Cuculus canorus
Abundance and Habitat Preferences of Gray Vireos (Vireo Vicinior) on the Colorado Plateau
Authors: Schlossberg Scott
Published: September 2019

The Gray Vireo (Vireo vicinior; hereafter “vireo”) is a little-studied songbird with small breeding and wintering ranges. Because of uncertainty about vireo populations, conservationists are concerned about the future of this species. The goal of the present study was to provide new data on the ecology of the vireo to help determine its conservation status. During May and June 2001, I studied breeding habitat selection by vireos on the Colorado Plateau in northern Arizona and southern Utah. I surveyed for vireos and collected vegetation data on 31 transects in pinyon-juniper (Pinus edulis-Juniperus spp.) woodlands throughout this region. Estimated density of vireos was 0.064 ± 0.011 (mean ± SE) birds ha−1. Analysis at two scales showed that the vireo’s primary habitat preference was for areas where junipers predominate over pinyon pine. Vireos also preferred areas with some shrub cover, and they increased with the prevalence of sagebrush (Artemisia tridentata) among shrubs. Additionally, vireos were more common at lower elevations, an effect that was largely independent of vegetation characters. Habitats preferred by vireos are widespread in the southwestern United States and may be increasing in extent as woodlands expand into grasslands and shrublands. On the basis of these results, I suggest that vireo populations are relatively safe, at least for the short term. Additional data on vireo demography are needed to ensure the long-term conservation of this species.

Abundancia y Preferencias de Hábitat de Vireo vicinior en la Planicie de Colorado
Effects of Predation, Flooding, and Contamination on Reproductive Success of California Clapper Rails (Rallus Longirostris Obsoletus) in San Francisco Bay
Authors: Schwarzbach Steven E. , Albertson Joy D. , Thomas Carmen M.
Published: September 2019

We assessed the reproductive success of the California Clapper Rail (Rallus longirostris obsoletus), an endangered subspecies restricted to San Francisco Bay, and the relative importance of predation, flooding, and contaminants as factors affecting that success. Our study was conducted in six tidal marshes in the northern and southern reaches of San Francisco Bay. This assessment, conducted in four breeding seasons (1991, 1992, 1998, 1999), determined that productivity of California Clapper Rails was much reduced over the natural potential. Only 69% of clapper rail eggs whose viability could be assessed were viable. Hatchability of eggs in North Bay and South Bay marshes was 65% and 70%, respectively. Only 45% of the nests successfully hatched at least one egg. Despite mean clutch sizes of 6.7 and 6.9 in the North and South bays, respectively, clapper rails produced only 1.9 and 2.5 young per nesting attempt. Flooding was a minor factor, reducing the number of eggs available to hatch by only 2.3%. Predation on eggs was a major factor affecting nest success, reducing productivity by a third. Failed eggs were examined for abnormal development and contaminant concentrations. Contamination appeared to adversely influence California Clapper Rail reproductive success, as evidenced by deformities; embryo hemorrhaging; embryo malpositions; a depressed rate of hatchability; excess concentrations of mercury, barium, and chromium over known avian embryotoxic thresholds; and a correlation of deformities with elevated concentrations of some trace elements in eggs that failed to hatch. Mercury was the only significant contaminant common to all marshes.

Efectos de la Depredación, las Inundaciones y la Contaminación sobre el Éxito Reproductivo de Rallus longirostris obsoletus en la Bahía de San Francisco
Effects of Intrinsic and Extrinsic Factors on Survival of White-Winged Scoter (Melanitta Fusca Deglandi) Ducklings
Authors: Traylor Joshua J. , Alisauskas Ray T.
Published: September 2019

In waterfowl, offspring survival and the effects of extrinsic (i.e. weather, hatching date) and intrinsic (i.e. physical and nutritional traits of individual females and ducklings, brood sizes) factors on it are poorly understood. In 2000 and 2001, we estimated duckling and brood survival of White-winged Scoters (Melanitta fusca deglandi) at Redberry Lake, Saskatchewan, Canada, to 30 days of age to examine relationships between duckling survival and (1) hatch date, (2) initial brood size at hatch, (3) duckling size and body condition at hatch, (4) offspring sex, (5) maternal female size and body condition at hatch, and (6) weather. We estimated survival with Cormack-Jolly-Seber models, in program MARK, from observations of individually marked adult females (n = 94) and ducklings (n = 664). Most mortality (i.e. 0.80 and 0.95 for each year, respectively) occurred within six days of hatch in both years. Duckling survival probability decreased with advancing hatch date; increased with larger initial brood sizes; was higher for larger, better-conditioned ducklings; and increased with favorable weather. Brood survival decreased with advancing hatch date, increased with larger initial brood sizes, and increased with favorable weather. For 2000 and 2001, our models predict survival probabilities of ducklings (0.0061 and 0.0027, respectively) and broods (0.015 and 0.00048, respectively) that are lower than any previously reported. We suspect that intense gull (Larus spp.) predation shortly after hatch had the largest influence on duckling survival, though results also underscore the significance of intrinsic factors.

Effets des Facteurs Intrinsèques et Extrinsèques sur la Survie les Jeunes de Melanitta fusca deglandi
Factors Influencing Predation on Ovenbird (Seiurus Aurocapilla) Nests in Northern Hardwoods: Interactions Across Spatial Scales
Authors: Mattsson Brady J. , Niemi Gerald J.
Published: September 2019

Microsite, patch, and landscape conditions may interact to influence nest predation. In northern Minnesota, silvicultural and agricultural practices may be involved in recent increases in nest predators and regional declines in several ground-nesting songbirds. To examine this problem, we evaluated 17 hierarchical models of predation on Ovenbird (Seiurus aurocapilla) nests that included microsite variables, distances to edges, and amount of core forest within a 2-km radius surrounding six study plots. During 2000 and 2001, 157 Ovenbird nests were monitored to estimate nest predation rates. A model that included the main effects of litter depth and core forest area and an interaction term between the two best described variation in predation on Ovenbird nests (AICc weight = 0.83). The nest predation rate from this model was 0.51 ± 0.01 (mean ± SE), assuming mean values of litter depth and amount of core forest. Shallow litter was associated with higher nest predation in three plots surrounded by less core habitat (40–60 ha), whereas there was no relationship in three plots surrounded by more core area (100–150 ha). Management that promotes deep leaf litter and the maintenance of large, intact forest tracts will likely benefit Ovenbirds and other forest songbirds.

Factores que Influencian la Depredación de Nidos de Seiurus aurocapilla en los Bosques del Norte: Interacciones a través de las Escalas Espaciales
Food Limitation During Breeding in a Heterogeneous Landscape
Authors: Granbom Martin , Smith Henrik G.
Published: September 2019

Breeding success in birds may be determined by the availability of food that parents can provide to growing nestlings. A standard method for testing the occurrence of food limitation is to provide supplemental food during different parts of the breeding period. If there is spatial variation in the strength of food limitation, the effect of such an experiment should also vary spatially. We investigated whether the strength of food limitation during nestling rearing in the European Starling (Sturnus vulgaris) was related to the management intensity of agricultural landscapes. We fed birds mealworms during the nestling period in landscapes with high or low local availability of pasture, the preferred foraging habitat. Both habitat and food supplementation affected growth and survival of nestlings; the effects of the food-supplementation experiment were generally stronger than those of habitat. Mortality mainly struck the last-hatched chick. Both habitat and food supplementation positively affected nestling growth, measured as nestling tarsus length. In addition, food supplementation positively affected feather growth and asymptotic mass. Contrary to expectation, no interactions existed between effects of habitat and food supplementation, which suggests that breeding success was limited by food availability in both landscapes. Potential reasons for this lack of effect are parental compensation and low statistical power. Also, breeding densities were higher in landscapes with more pastures, possibly equalizing the per-capita availability of food. Thus, our results demonstrate that reproductive success was limited by availability of food when local availability of preferred foraging habitat was either low or high, but fail to demonstrate spatial variation in the strength of food limitation.

Escasez de Alimentos durante el Período Reproductivo en un Paisaje Heterogéneo
Seed Preferences in Sparrow Species of the Monte Desert, Argentina: Implications for Seed-Granivore Interactions
Authors: Cueto Víctor R. , Marone Luis , de Casenave Javier Lopez
Published: September 2019

We assessed seed preference in four species of sparrows that are common to the central Monte desert of Argentina. Our hypotheses are that (1) sparrows always prefer grass over forb seeds and (2) different species of sparrows show the same preferences when consuming seeds. We presented seeds from eight species of plants (four grasses and four forbs) in both choice and nonchoice experiments. In general, sparrow species preferred grass over forb seeds, though one of them (Rufous-collared Sparrow [Zonotrichia capensis]) included one forb species (Parthenium hysterophorus) among its preferred seed items. Among grass seeds, sparrows avoided or showed less preference for the tiny seeds of Sporobolus cryptandrus, which suggests that seed weight may affect seed choice among grasses. Avoidance of most forb species, by contrast, could not be associated with seed size, probably because of the presence of unpalatable or toxic compounds in forb seeds. Experimental evidence suggests that the main feeding pressure of sparrows is clearly directed to grass seeds, which coincides with reported information on bird diet. Results support assertions that sparrows can cause a negative effect on the composition and abundance of grass seeds in the soil seed-bank, a necessary condition for birds in playing a significant role on grass population dynamics in the central Monte desert of Argentina.

Preferencias por Semillas de los Emberízidos del Desierto del Monte, Argentina: Implicancias para la Interacción Semillas-granívoros
Scale-Dependent Habitat use of Acadian FlyCatcher (Empidonax Virescens) in Central Ohio
Authors: Bakermans Marja H. , Rodewald Amanda D.
Published: September 2019

We used a multiscale approach to examine use of riparian forests by Acadian Flycatchers (Empidonax virescens) at three distinct scales: microsite (nest or territory), local stand (3-ha patch of forest), and landscape (1-km-radius area). We examined the extent to which understory arthropod biomass, vegetation structure, and breeding productivity affected habitat use by Acadian Flycatchers across 36 mature riparian forests along an urbanization gradient in central Ohio, 2001–2002. Using an information-theoretic approach, we found that although vegetation structure and understory arthropod biomass were associated with nest and territory location at small spatial scales, they failed to explain habitat use across stands. Instead, percentage of urban cover in the landscape best explained variation in the abundance of Acadian Flycatchers among stands. In fact, Acadian Flycatchers were >3× more abundant in the most rural (≤1% urban) riparian forests than in the more urban (≥10% urban) riparian forests. Nest survival and productivity also declined as urban development increased within the landscape. We suggest that increased nest predation in urban riparian forests, coupled with either reduced productivity or site fidelity or both, may be an underlying mechanism of landscape-scale patterns. Results suggest that explicit consideration of multiple spatial scales, and especially landscape matrix composition, is critical for understanding habitat use.

Uso del Hábitat Dependiente de la Escala por parte de Empidonax virescens en el Centro de Ohio
Unusual Sperm Morphology in the Eurasian Bullfinch (Pyrrhula Pyrrhula)
Authors: Birkhead Timothy R. , Immler Simone , Pellatt E. Jayne , Freckleton Robert
Published: September 2019

The sperm of the Eurasian Bullfinch (Pyrrhula pyrrhula) differs markedly in gross morphology from that of all other passerines examined to date. In other passerines, the sperm head is pointed and helical, and the midpiece comprises a mitochondrial helix extending along the flagellum; whereas in the Eurasian Bullfinch, the sperm acrosome is rounded, not helical, and the midpiece is extremely short. In a pairwise study, using principal component analysis (PCA), we combined quantitative and qualitative sperm morphology traits and conducted a phylogenetic correlation to compare the sperm morphology of Eurasian Bullfinch and Beavan's Bullfinch (P. erythaca) with nine other pairs of congeneric passerines. The analysis revealed that Eurasian Bullfinch was a dramatic outlier in sperm morphology and that Eurasian and Beavan's bullfinches are more different than any other pair of species. Excluding Eurasian Bullfinch from the analysis showed that most variation in sperm morphology in the other species was attributable to phylogeny. The Eurasian Bullfinch also has extremely small testes for its body size, which indicates that sperm competition is infrequent in this species; we discuss the possibility that relaxed selection, via lack of sperm competition, may have contributed to the species' unusual sperm morphology.

Morfología Espermática Inusual en Pyrrhula pyrrhula
Ecological and Physiological Factors Affecting Brood Patch Area and Prolactin Levels in Arctic-Nesting Geese
Authors: Jónsson Jón Einar , Afton Alan D. , Alisauskas Ray T. , Bluhm Cynthia K. , El Halawani Mohamed E.
Published: September 2019

We investigated effects of ecological and physiological factors on brood patch area and prolactin levels in free-ranging Lesser Snow Geese (Chen caerulescens caerulescens; hereafter “Snow Geese”) and Ross's Geese (C. rossii). On the basis of the body-size hypothesis, we predicted that the relationships between prolactin levels, brood patch area, and body condition would be stronger in Ross's Geese than in the larger Snow Geese. We found that brood patch area was positively related to clutch volume and inversely related to prolactin levels in Ross's Geese, but not in Snow Geese. Nest size, nest habitat, and first egg date did not affect brood patch area in either species. Prolactin levels increased as incubation progressed in female Snow Geese, but this relationship was not significant in Ross's Geese. Prolactin levels and body condition (as indexed by size-adjusted body mass) were inversely related in Ross's Geese, but not in Snow Geese. Our findings are consistent with the prediction that relationships between prolactin levels, brood patch area, and body condition are relatively stronger in Ross's Geese, because they mobilize endogenous reserves at faster rates than Snow Geese.

Factores Ecológicos y Fisiológicos que Afectan el Área del Parche de Incubación y los Niveles de Prolactina en Gansos Nidificantes del Ártico
What Makes a Good Nest? Benefits of Nest Choice to Female Baya Weavers (Ploceus Philippinus)
Authors: Quader Suhel
Published: September 2019

The nests of some birds are built exclusively by males and then displayed to females. In such species, one expects females to choose those nests that provide maximum safety to themselves and their offspring. What attributes of a nest should females use in making these choices? Here, I examine the correlates of nesting success in the Baya Weaver (Ploceus philippinus), a species in which males provide nests and little else. In particular, I examine which of two suites of nest attributes best predicts nesting success: nest location (which reflects male competitive ability) or nest architecture (which reflects male building skill). Because whether a nest has successfully fledged young is sometimes uncertain, I supplement generalized linear model analyses with survival analyses, which can incorporate ambiguity in nest fate. Together, these analyses reveal that nests built in thorny trees and woven with fine fiber have high success. Nesting success also increases with nest height and with thickness of the supporting branch. Overall, nest location is a slightly better predictor of success than nest architecture; this is consistent with previous findings that female choice of nests is influenced more by location than by architecture.

¿Qué Hace a un Nido un Buen Nido? Beneficios de la Selección de Nidos para las Hembras en Ploceus philippinus
A Molecular Phylogeny of Kingfishers (Alcedinidae) With Insights Into Early Biogeographic History
Authors: Moyle Robert G.
Published: September 2019

The phylogeny of kingfishers was reconstructed by comparing mitochondrial and nuclear DNA sequences representing 38 ingroup species. Analysis of the combined data and the nuclear data alone recovered the Alcedininae as the basal lineage in the family. This basal arrangement, and support for many relationships within the three subfamilies, allows discussion of biogeographic issues. The Australian region and Pacific islands display the highest diversity of kingfishers, but this diversity is not a reflection of a long history in the region. Rather, high diversity and endemism in the Australian region is inferred to result from relatively recent radiations from southern Asia. The most parsimonious explanation for the origin of New World taxa is two dispersal events from the Old World. Within the large Halcyon radiation, the phylogeny is well resolved and allows evaluation of generic assignments. The phylogeny supports splitting Todiramphus from Halcyon. Todiramphus and Syma are sister taxa, as are Halcyon and Pelargopsis. Thus, merging or retaining those genera is a more subjective decision. Although not fully resolved, relationships within the alcedinines indicate that Ceyx and Alcedo, as currently delimited, are not natural groups.

Phylogénie Moléculaire des Alcedinidae avec un Aperçu de l'Histoire Biogéographique Ancienne
Tracking Dispersal in Birds: Assessing the Potential of Elemental Markers
Authors: Donovan Therese , Buzas Jeffrey , Jones Peter , Lisle Gibbs H.
Published: September 2019

Natal dispersal in vagile species such as songbirds can shape a population's range and structure. Although effective conservation practices depend on knowledge of the scale and frequency of natal dispersal, these issues remain poorly understood because of methodological gaps. In this exploratory study, we assessed whether element signatures within natal feathers might be used to identify the geographic birth site of first-year breeders. We used two related techniques, inductively coupled plasma mass spectrometry (ICP-MS) and inductively coupled plasma with optical emission spectrometry (ICP-AES), to quantify element levels in natal feather samples from 7 species at 27 sites across the eastern United States. The techniques differed in the manner in which elements were quantified and in their detection limits. Our goal was to determine whether element analyses of feathers could discriminate (1) different species within a site and (2) different sites within a species. Additionally, because spatial autocorrelation of element levels is needed for element analysis to be an effective tool in assessing natal dispersal, we also evaluated the spatial autocorrelation of ICP-AES samples at 18 sites across the eastern United States.

Both ICP-MS and ICP-AES analyses separated species within a site with fairly high accuracy, though the discriminating elements varied with site. However, within a species, natal feather locations were not identified with high accuracy on the basis of feather elements. We were not able to determine whether there is spatial correlation among individual elements or a principal component analysis (PCA) score that described the elemental makeup of a feather. A kriging model was fit to the semivariogram of PCA scores to produce a base-map of element signatures across the eastern United States. This map was ineffective at predicting feather-element values at sample sites. Whether elemental analyses can identify natal dispersal distances requires further study. We suggest that future studies evaluate elements with ICP-MS methodologies on a single, box-nesting species that is sampled more intensively at smaller geographic scale, or on species that occur in very discrete populations. Additionally, this methodology should be evaluated in concert with stable-isotope analyses of feathers and, potentially, genetic analyses.

Suivre la Dispersion chez les Oiseaux: Évaluer le Potentiel de Marqueurs Élémentaires
Do Partial and Regular Migrants Differ in Their Responses to Weather?
Authors: Nilsson Anna L. K. , Alerstam Thomas , Nilsson Jan-Åke
Published: September 2019

Partial migration is often considered a transitory stage between migration and residency, and whether partial migrants take weather conditions into account during migration is largely unknown. To assess whether partial migrants differ from regular migrants in their responses to weather, we compared the migratory intensity of a partial migrant, the Blue Tit (Cyanistes caeruleus), with more regular migrants in relation to weather at a migratory passage site in southern Sweden (Falsterbo) during the years 1993–2002. The regular migrants in the study were Linnet (Carduelis cannabina), Common Chaffinch (Fringilla coelebs), Brambling (F. montifringilla), and European Robin (Erithacus rubecula). The Blue Tit differed from the regular migrants mainly in showing a striking negative correlation between migratory activity and cloud cover. Also, weather had the highest explanatory power for migratory intensity in the Blue Tit. This suggests that the Blue Tit is more sensitive to weather conditions on migration than the regular migrants and that it preferably awaits days with wholly or partly clear skies before migrating past Falsterbo. As a consequence, Blue Tits usually restrict their migratory flights to the safest occasions, with relatively calm weather, good visibility, and all orientation cues (solar as well as magnetic) available.

¿Difieren los Migrantes Parciales y Regulares en sus Respuestas al Clima?
Testosterone Treatment to Free-Ranging Male Dark-Eyed Juncos (Junco Hyemalis) Exacerbates Hemoparasitic Infection
Authors: Deviche Pierre , Parris Jennifer
Published: September 2019

The “immunocompetence handicap” hypothesis predicts that reproductive hormones, in particular testosterone (T), are immunosuppressive and consequently increase susceptibility to diseases and parasite infections, but this prediction has not been evaluated in free-living birds and the factors mediating the immunosuppressive influence of T remain poorly known. To address these issues, we administered supplemental T via implants to free-ranging adult male Dark-eyed Juncos (Junco hyemalis) and characterized the effects of this treatment on infection with the two most prevalent hematozoan parasites in this species, Leucocytozoon fringillinarum and Trypanosoma avium. Males caught at the beginning of their breeding season (May) received T-filled, empty (control), or no Silastic capsules, and were recaptured five weeks later. Capsule implantation had, by itself, no effect on parasite infections, body mass, or size of an androgen-dependent secondary sexual characteristic, the cloacal protuberance. Testosterone treatment maintained physiologically high plasma levels of the steroid for the duration of the study, thus preventing the seasonal decline in these levels that occurred in control males. As predicted by the immunocompetence handicap hypothesis, the hormone treatment increased blood L. fringillinarum abundance. This increase was specific, in that implanted T did not affect (1) either the prevalence or the incidence of L. fringillinarum, (2) body mass, or (3) size of the cloacal protuberance. Trypanosoma avium prevalence was not influenced by T treatment either, but it increased between May and June, which suggests that it is regulated by factors other than the activity of the reproductive system. These findings provide the first demonstration in free-ranging birds that experimentally elevated physiological T levels increase hematozoan infection.

El Tratamiento de Testosterona en Machos Silvestres de Junco hyemalis Exacerba la Infección de Hemoparásitos
Landscape-Scale Physiology: Site Differences in Refueling Rates Indicated by Plasma Metabolite Analysis in Free-Living Migratory Sandpipers
Authors: Seaman Dana A. Acevedo , Guglielmo Christopher G. , Elner Robert W. , Williams Tony D.
Published: September 2019

Variation in plasma metabolite profiles can provide information on physiological state and relative rates of mass change in free-living birds caught only once, and this technique could be used to compare rates of mass change (fattening) among populations or sites in relation to habitat quality. We compared plasma metabolite levels, as an index of relative refueling rates, in migratory Arctic-nesting Western Sandpipers (Calidris mauri), on a landscape scale at as many as nine sites over two years and during three different migratory stages within the Georgia Basin-Puget Sound region of British Columbia and Washington. There was significant intersite variation in plasma triglyceride levels in both years, but only for the northward migration. By contrast, there was little evidence of intrasite variability (i.e. metabolite profiles of birds using the same site were consistent between years and migratory stages), though we documented intrasite variation resulting from birds' use of different microhabitats at the same site. Plasma glycerol levels did not vary systematically among sites, though they varied among years; on average, birds had higher glycerol levels during northward migration than during southward migration. For the northward migration only, there was a positive relationship between plasma triglyceride levels and total macrofaunal prey abundance among sites. Birds using smaller sites with a lower index of mudflat exposure (mean number of kilometer-hours of mudflat exposed in a 24-h period, reflecting the opportunity to forage at each site) tended to have lower triglyceride levels.

Fisiología a Escala de Paisaje: Diferencias entre Sitios en las Tasas de Reabastecimiento Indicadas por Análisis de Metabolitos del Plasma en Chorlos Migratorios Silvestres
Curassows and Related Birds.
Authors: Collar Nigel J.
Published: September 2019

The following critiques express the opinions of the individual evaluators regarding the strengths, weaknesses, and value of the books they review. As such, the appraisals are subjective assessments and do not necessarily reflect the opinions of the editors or any official policy of the American Ornithologists' Union.
Antipredator Defenses in Birds and Mammals.
Authors: Grubb Thomas C.
Published: September 2019

The following critiques express the opinions of the individual evaluators regarding the strengths, weaknesses, and value of the books they review. As such, the appraisals are subjective assessments and do not necessarily reflect the opinions of the editors or any official policy of the American Ornithologists' Union.
Peregrine Falcon: Stories of the Blue Meanie
Authors: Clement Roland C.
Published: September 2019

The following critiques express the opinions of the individual evaluators regarding the strengths, weaknesses, and value of the books they review. As such, the appraisals are subjective assessments and do not necessarily reflect the opinions of the editors or any official policy of the American Ornithologists' Union.
Estimating Detection Probablities of River Birds using Double Surveys
Authors: Fletcher Robert J. , Hutto Richard L.
Published: September 2019

We describe a method for surveying birds in river habitats that allows for rapid assessment across broad spatial scales and estimation of detection probabilities. Our river survey approach incorporates a double-survey technique, whereby observers in two canoes simultaneously survey birds along a river reach. Data are in the form of a two-sample mark-recapture history, and covariates suspected of influencing detection probabilities can be included in the modeling process and evaluated using information-theoretic approaches. We provide an example using the method along the Madison and upper Missouri rivers in Montana. Overall, detection probabilities for each observer ranged from 57% to 89%, and combined detection probabilities (the likelihood of at least one observer detecting an individual) were consistently high (88% across all species). Detection probabilities across species were positively correlated with body mass. Detection probabilities for some species were influenced by observer, river conditions, and whether species were in groups or alone; groups were more detectable, and individuals in slow-flowing and wide sections of river were more detectable. Boat-based double surveys are a viable method for estimating detection probabilities of birds in river habitats, and double surveys should be considered in other aquatic

Estimaciones de Probabilidades de Detección de Aves de Río Utilizando Muestreos Dobles systems.
Growth and Allocation in Captive Common Murre (Uria Aalge) Chicks
Authors: Benowitz-Fredericks Z Morgan , Kitaysky Alexander S. , Thompson Christopher W.
Published: September 2019

In birds, relative growth rates of morphological characters change in response to restricted food intake during development. Differential allocation of limited resources is hypothesized to reflect functional priorities for developing chicks. Body mass, wing, and flight feathers have been identified as potential priorities for seabird chicks. We used allometry to examine allocation in captive Common Murre chicks fed within a range of natural provisioning. During days 10–45 post-hatch, chicks were fed one of four diets that varied in biomass, energy content, and composition. Energy intake had a more profound effect on growth and development than diet composition; it significantly reduced absolute growth of body mass, manus, and tarsus. Between day 15 and day 20, allocation changed in all treatments: growth of manus was maintained at the expense of body mass. Chicks in more restricted treatments shifted allocation to manus at a lower body mass than those in less restricted groups, but subsequently allocated similarly. Wing loading was higher for chicks than for adult alcids, but scaled similarly. Growth of primary feathers was the most sensitive to small differences in diet composition. Our data also suggest that some changes in allocation may be ontogenetically determined rather than part of an adaptive response to reduced food intake.

Croissance et Allocation chez des Oisillons Uria aalge
Breeding Biology and Success of a Reintroduced Population of the Critically Endangered Puaiohi (Myadestes Palmeri)
Authors: Tweed Erik J. , Foster Jeffrey T. , Woodworth Bethany L. , Monahan William B. , Kellerman Jherime L. , Lieberman Alan
Published: September 2019

The ultimate success of reintroduction programs for endangered species depends on the ability of reintroduced animals to breed in the wild. We studied the nesting success and breeding biology of a reintroduced population of Puaiohi (Myadestes palmeri) on the island of Kaua'i, Hawaii. Thirty-four captive-bred Puaiohi were released into the Alaka'i Swamp in 1999-2001 and monitored using radiotelemetry. Ten females and two males paired with wild and other released birds, including one polygynous trio. From March to September, 31 nests were built. Mean clutch size was 2.0 eggs, daily nest survival was 0.97 ± 0.01 (mean ± SE) and overall nest success was 0.40 ± 0.02. We confirmed predation, most probably by rats (Rattus spp.), as the greatest cause of nest failure, occurring at 38% of active nests with known fates, and causing the death of two nesting adult females. Ground-based rodent control proved ineffective at protecting nest attempts. Successful nests fledged an average of 1.4 young each (n = 10), and 85% of fledglings survived at least two weeks. Importantly, breeding behavior and success were comparable to those of wild Puaiohi. This is the first record of breeding in the wild from captive-bred endangered Hawaiian passerines. The ability of captive-bred Puaiohi to survive and breed successfully in the wild bodes well for future releases of this and other endangered passerines, but high predation rates on nests and nesting females highlights the importance of maintaining and restoring safe habitat for recovery.

Biología y Éxito Reproductivo de una Población Reintroducida de Myadestes palmeri, una Especie en Peligro Crítico
Nest Depredation, Brood Parasitism, and Reproductive Variation in Island Populations of Song Sparrows (Melospiza Melodia)
Authors: Wilson Scott , Arcese Peter
Published: September 2019

Theory suggests that the persistence of metapopulations will be influenced by the degree of synchrony in the dynamics of their component populations. Various studies have shown that climate can promote synchrony in the size of adjacent populations linked by dispersal, but fewer studies have examined the effects of climate on underlying demographic rates. We studied annual variation in the timing of breeding and reproductive rates in Song Sparrow (Melospiza melodia) on islands linked by dispersal to determine whether biotic factors acting at local scales or climatic factors acting at a regional scale were more influential of variation in demography. The onset of egg laying varied markedly among years but was roughly synchronous across islands within years. Despite this synchrony, island populations varied markedly in reproductive rate, mainly from spatial variation in nest depredation and brood parasitism. In general, populations farther from Vancouver Island and with fewer resident predators experienced less nest depredation and brood parasitism, and higher reproductive rates, than populations closer to Vancouver Island. Our results show that even when climate acts regionally to synchronize reproductive timing in adjacent populations, its effects on reproductive rate may be overridden by biotic factors that vary among populations.

Depredación de Nidos, Parasitismo de Cría y Variación Reproductiva en Poblaciones Isleñas de Melospiza melodia