Rufous-collared Sparrow Zonotrichia Capensis Research Articles

Importance of Algarrobo Trees Prosopis flexuosa for Territory Establishment of Three Seed-Eating Passerine Species in the Central Monte Desert

In the central Monte desert in Argentina, feeding site selection by seed-eating birds and their high abundance associated with the presence of trees (particularly Algarrobos Prosopis flexuosa) are well known patterns during the breeding season, but these associations disappear during autumn and winter. In order to understand habitat selection by these bird species, we assessed the importance of Algarrobos during the defence and establishment of breeding territories in the open Algarrobo woodland of the central Monte desert for the three most common resident seed-eating birds: Ringed Warbling-finch Microspingus torquatus, Many-coloured Chaco Finch Saltatricula multicolor and Rufous-collared Sparrow Zonotrichia capensis. Despite some ecological differences between the species (e.g. nest site selection, feeding behaviour) all of them selected Algarrobos as song posts. Height, density and spatial configuration of these trees were features associated with the selection of territories. The patterns of selection we found at previously unexplored spatial scales (territory and within-territory) and associated with territorial defence, provided plausible explanations to seasonal shifts in the space use reported for central Monte desert seed-eating birds and highlight the close link between central Monte desert avifauna and Algarrobos. As in many arid regions, tall scattered trees are keystone features of the central Monte desert and management plans should be implemented in order to stop the current degradation and loss of these arid woodlands.

Two new feather mites of the genus Proctophyllodes Robin (Acari formes: Proctophyllodinae) from passerines in Brazil

Proctophyllodes Robin (Proctophyllodidae: Proctophyllodinae) is a widely distributed feather mite genus, which most species show high level of specificity to their bird hosts. We describe two new species of this genus from passerines commonly found in urban environments in Brazil: Proctophyllodes molothrus sp. nov. from the Shiny Cowbird Molothrus bonariensis (Gmelin) (Icteridae), and P. carmenmirandae sp. nov. from the Rufous-collared Sparrow Zonotrichia capensis (Statius Müller) (Passerellidae). The former is similar to P. egglestoni Spory and differs from it in having a unique shape of opisthosomal lobes in females; P. carmenmirandae is closer to P. tiaris Atyeo & Braasch and differs in having a relatively longer adeagus in males and setae h1 situated on soft tegument between hysteronotal and lobar shields in females.

Differences in circulating corticosterone levels associated with elevation of breeding sites in Rufous-collared Sparrows Zonotrichia capensis

To facilitate breeding and any energetically costly activity, individuals of the same species can substantially vary their circulating corticosterone (CORT) levels to cope with local environmental conditions at different elevations. We compared baseline and the stress-induced plasma CORT levels during the parental care stage between free-living Rufous-collared Sparrows (Zonotrichia capensis) that breed at high (~ 2500 m) and low (~ 500 m) elevations in central Chile. We found that baseline CORT levels at different elevations were similar and that stress-induced levels were significantly lower in birds breeding at high elevation; however, we detected no sexual dimorphism in CORT levels related to elevation. We found that larger individuals had higher stress-induced CORT levels at low elevation regardless of sex. Our results show that environmental conditions at high elevation seem to be not severe enough to promote more elevated baseline CORT levels. However, breeding Rufous-collared Sparrow must still deal with both shorter breeding seasons and increased exposure to unpredictable events. Thus, a reduced stress response during the parental care stage would be more favorable for supporting breeding activities at high elevations. Future studies should focus on describing the life-history traits of these populations and the effects that other stressors, such as predation pressure and food availability, may have on the adrenocortical response in these environments to evaluate the consequences for survival and reproductive success. This information is important for enhancing our understanding of the ecological and evolutionary mechanisms that modulate variation in the adrenocortical response among populations of the same species.

Winter Flock Structure in the Central Monte Desert, Argentina

Flocking behaviour has been studied for decades around the world, but there is little knowledge of this subject in desert bird communities. We investigate winter flock structure in open woodlands of the central Monte desert, Argentina, during two consecutive years. Of the 22 bird species that were recorded in flocks, most were granivorous. There were differences in flock density between years, probably due to fluctuation in seed abundance. More than half of the observed flocks were composed of different species (i.e. mixed-species flocks). We detected only two regular species (found in more than 75% of flocks): Rufous-collared Sparrow Zonotrichia capensis and Ringed Warbling Finch Poospiza torquata, both granivorous birds. Ringed Warbling Finch and Cinnamon Warbling Finch Poospiza ornata co-occurred at a higher frequency than expected by chance, and formed subgroups within flocks. Many-colored Chaco Finch Saltatricula multicolor, Greater Wagtail-tyrant Stigmatura budytoides, Brown Cacholote Pseudoseisura ...

FORRAJEO DE Zonotrichia capensis (Passeriformes: Emberizidae) Y VALOR DEL PARCHE EN CERCAS VIVAS JÓVENES DE LA SABANA DE BOGOTÁ

<p>El copetón Zonotrichia capensis tiene una amplia distribución en América neotropical, es un ave tolerante a las intervenciones humanas, pero sabemos poco sobre su comportamiento de forrajeo en los Andes colombianos. Por ello, estudiamos la estrategia de forrajeo del copetón y, adicionalmente, el valor de parches alimentarios a lo largo de dos cercas vivas jóvenes (plantación < 2 años), en relación con la distancia a una zona de ronda del río Bogotá, en Cajicá, Sabana de Bogotá, Colombia. El río es un área dominada por árboles en una matriz rural a urbana. Utilizamos parches artificiales hechos de bandejas de aluminio con semillas mezcladas con arena. Determinamos la proporción de consumo entre tres parches con diferentes densidades de alimento inicial, para determinar si los copetones obtienen información del parche. Usamos también parches artificiales para determinar si la distancia al río a lo largo de dos cercas vivas jóvenes afectaba el forrajeo. Nuestros resultados indican que Z. capensis no obtuvo información del parche y no reconoció diferencias en parches con diferente densidad inicial de alimento. Adicionalmente, la distancia al río afectó el valor de los parches de forrajeo en solo una de las cercas vivas examinadas donde hubo mayor consumo cerca al río. Al parecer, la densidad inicial de alimento no afectó el nivel de explotación del parche por parte de los copetones, mientras que el valor del parche en las cercas vivas jóvenes puede estar influido por la distancia al río.</p><p><strong>Foraging Behavior of Zonotrichia capensis (Passeriformes: Emberizidae) and Patch Value in Young Live Fences in the Bogotá High Plateau</strong></p><p>The Rufous-collared Sparrow Zonotrichia capensis is a widely distributed species in neotropical America, it is tolerant to human interventions, but we know little about its foraging ecology on the Colombian Andes. Therefore, we studied the foraging strategy and, additionally, the value of foraging patches along two young live fences (< 2 year planted) in relation to the Bogota River in Cajica, in an Andean highland plateau in Colombia. The Bogota River is one of few areas dominated by arboreal vegetation in an urban- rural matrix at the study site. We used artificial food patches made of aluminum trays with seeds mixed with sand. We measured the proportion of food consumed in patches with different initial food density to determine whether sparrows obtain information from the patch. We also used artificial patches to determine whether distance to the river affected the sparrow’s foraging in two young live fences. Our results indicate that Z. capensis did not gather any information from the patch and did not differentiate patches with different amounts of food. Furthermore, the distance to the river affected the value of food patches, but only in one of the live fences, where there was higher food consumption close to the river. Apparently, the food initial-density did not affect the patch exploitation level by sparrows, but the patch value in young live fences could be influenced by distance to the river.</p>

Alteraciones de coloración en el plumaje de aves silvestres del Ecuador

Este artículo analiza 61 casos de aberraciones cromáticas del plumaje (ausencia total o parcial de pigmentos en algunas o en todas las plumas) en 43 especies de aves silvestres ecuatorianas, agrupadas en 21 familias, incluyendo 51 nuevos registros y siendo este el primer reporte de aberraciones en Ecuador para 14 familias. Esta compilación incluye datos colectados por los autores, comunicaciones personales de expertos observadores de aves y visitas a colecciones ornitológicas de museos en Quito, Ecuador. La alteración más común fue el leucismo y las especies con mayor número de reportes fueron el Mirlo Grande Turdus fuscater y el Gorrió Ruficollarejo Zonotrichia capensis. La mayoría de registros proviene de áreas rurales en la zona altoandina, siendo Pichincha la provincia con más registros. La documentación de la distribución y frecuencia de estas aberraciones de coloración de plumaje tiene importantes implicaciones de conservación y monitoreo, permitiendo evidenciar las posibles causas que inducen estas alteraciones en las poblaciones de aves; por ello también presentamos definiciones de los principales tipos de aberraciones cromáticas con el fin de familiarizar a los observadores de aves y estimular la difusión de sus registros.

Seasonal Space use and Territory Size of Resident Sparrows in the Central Monte Desert, Argentina

Knowledge of space use and territoriality of New World birds largely derives from studies in temperate North America and the tropics, whereas it remains poorly studied in temperate South America, particularly in arid environments. Here we studied the seasonal space use and territory size among resident individuals of three sparrows in a temperate semi-desert of Argentina: the ringed warbling-finch Poospiza torquata, the rufous-collared sparrow Zonotrichia capensis and the manycoloured Chaco-finch Saltatricula multicolor. Both territorial behaviour and use of space of the three species showed seasonal changes. The ringed warbling-finch and the rufous-collared sparrow used larger areas during the non-breeding season than during the breeding season, while the many-coloured Chaco-finch used areas of similar size in the two periods. Defence activities were absent for all three species during the non-breeding season. During the breeding season, each species defended territories that were smaller for the rufous-collared sparrow (0.79 ± 0.04 ha) than for the ringed warbling-finch (1.35 ± 0.04 ha) and the many-coloured Chaco-finch (1.21 ± 0.07 ha). Seasonal territoriality and territory size reported for resident individuals were similar to those reported for north-temperate sparrows in xeric environments.

Seasonal Modulation of Testosterone during Breeding of the Rufous-Collared Sparrow (Zonotrichia capensis australis) in Southern Patagonia

The roles of testosterone (T) during reproduction are often complex and vary among and within vertebrate taxa and locations, making general hypotheses relating T to breeding behavior and success difficult to integrate. In birds, T is thought to influence degrees of territoriality and associated aggression in males to maximize breeding success. Importantly, most work supporting these ideas has been conducted in the Northern Hemisphere. However, accumulating work on tropical species has shown divergent patterns of T in association with breeding behavior. The compilation of work from northern temperate and tropical species suggests that the function of T in relation to breeding behavior varies across latitude and environmental conditions. We investigate the patterns of T in relation to breeding behavior in a subspecies of the rufous-collared sparrow Zonotrichia capensis australis breeding at high latitude in the Southern Hemisphere (55°S). We then compare the T profiles and breeding behaviors of male Z. c. australis to conspecifics breeding in the tropics and congeners in North America to test the hypothesis that environments with breeding seasons of similar lengths will drive similar patterns of T in relation to breeding behavior. We found that Z. c. australis have high levels of T during the early-breeding periods when territories are being established and low levels of T during the parental phase of breeding, similar to temperate and Arctic birds in the Northern Hemisphere but unlike tropical Zonotrichia capensis costaricensis. In contrast, we found that Z. c. australis also exhibit similar aggressive behaviors in early breeding and midbreeding, unlike many birds in the Northern Hemisphere.

Osmoregulatory and metabolic costs of salt excretion in the Rufous-collared sparrow Zonotrichia capensis

Recent experiments on shorebirds have demonstrated that maintaining an active osmoregulatory machinery is energetically expensive. This may, in part, explain diet and habitat selection in birds with salt glands. However little is known about the osmoregulatory costs in birds lacking functional salt glands. In these birds, osmotic work is done almost exclusively by the kidneys. We investigated the osmoregulatory cost in a bird species lacking functional salt glands, the passerine Zonotrichia capensis. After 20days of acclimation to fresh water (FW) and salt water (200mM NaCl, SW), SW birds tended to be heavier than FW birds. However, this difference was not statistically significant. Total basal metabolic rate was higher in SW birds as compared with FW birds. Renal and heart masses were also higher in the SW group. We also found greater medullary development and an increase in urine osmolality in the SW group. In spite of Z. capensis' ability to tolerate a moderate salt load in the laboratory, we hypothesize that increased cost of maintenance produced by salt consumption may significantly affect energy budget, dietary, and habitat choices in the field.

Partial host fidelity in nest selection by the shiny cowbird (Molothrus bonariensis), a highly generalist avian brood parasite

Obligate avian brood parasites can be host specialists or host generalists. In turn, individual females within generalist brood parasites may themselves be host specialists or generalists. The shiny cowbird Molothrus bonariensis is an extreme generalist, but little is known about individual female host fidelity. We examined variation in mitochondrial control region sequences from cowbird chicks found in nests of four common Argentinean hosts. Haplotype frequency distributions differed among cowbird chicks from nests of these hosts, primarily because eggs laid in nests of house wrens Troglodytes aedon differed genetically from those laid in nests of the other three hosts (chalk-browed mockingbird Mimus saturninus, brown-and-yellow marshbird Pseudoleistes virescens, and rufous-collared sparrow Zonotrichia capensis). These differences in a maternally inherited marker indicate the presence of a nonrandom laying behaviour in the females of this otherwise generalist brood parasite, which may be guided by choice for nest type, as house wrens nest in cavities whereas the other three species are open cup nesters.

Seasonal Changes in Diet, Digestive Morphology and Digestive Efficiency in the Rufous-Collared Sparrow (Zonotrichia capensis) in Central Chile

Seasonal changes in birds' energy requirements as well as in environmental food availability and quality, influence birds' capability to obtain and digest food (Karasov 1990). Increased metabolic rates, hypertrophy of the gastrointestinal tract, and increased absorption of nutrients may be viewed as responses ofwintering birds to physical and biotic seasonal habitats (Sibly 1981, Dykstra and Karasov 1992). In central Chile, the climate is seasonal with warm, dry summers and cool rainy winters; mean annual temperature is 22.1C and mean annual minimum temperature is 7.7C (di Castri and Hajek 1976). One of the most conspicuous resident birds of the mediterranean environments in central Chile is the Rufouscollared Sparrow Zonotrichia capensis (Emberizidae). This species is opportunistic, feeding on seeds and insects and showing seasonal dietary shifts according to food availability (L6pez-Calleja 1995). Individuals of this species also exhibit seasonal changes in metabolic rates and thermal insulation (Novoa 1993). Consequently, Z. capensis lives under marked seasonal variations in energy availability and requirements. Specifically, when nutritional demands increase during winter, birds may respond to the seasonal environment through behavioral, anatomical and physiological changes that allow the maintenance of a positive energy budget and consequently permit survival. The aim of this work is to examine the relationship between seasonal changes in diet, digestive tract morphology, and digestive efficiency ofRufous-collared Sparrows in central Chile.