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Nesting Behavior (nesting + behavior)
Selected AbstractsNesting behavior and breeding success of HoatzinsJOURNAL OF FIELD ORNITHOLOGY, Issue 4 2007Antje Müllner ABSTRACT Hoatzins (Opisthocomus hoazin) are the only member of the family Opisthocomidae and are found only in forests in the Amazon and Orinoco river basin of South America. Although locally common in riparian habitats, information about their natural history is based almost exclusively on observations from gallery forests in the "llanos" (savannahs) of Venezuela. We investigated the nesting activities of Hoatzins in a primary rainforest in Amazonian Ecuador from 1995 to 2000. At our study site, Hoatzins live and breed in the inundated forests that surround lakes and river channels. Egg laying occurred from February to July and from September to November, but always peaked in April, May, and June. The mean clutch size was 2.4 ± 1.1 eggs (N= 291; range = 1,7), but 51% of all clutches contained two eggs. The mean duration of the incubation period was 32 ± 1.5 d (N= 20) and, overall, 17% of Hoatzin nests fledged at least one young. The main cause of nest failure was predation, with birds and snakes being the most frequent predators. Hoatzin reproduction was closely linked to the rainy season, and such timing may be influenced by increased food availability (high water levels cause leaf fall and the subsequent growth of new leaves coincides with the beginning of the feeding period of the young) and reduced risk of nest predation by mammalian predators when water levels are high. Our results indicate that the breeding biology of Hoatzins in tropical rainforest habitat, including small clutch sizes and low annual reproductive success, is similar to that of tropical passerines and provides further support for the existence of typical life history characteristics for tropical birds. SINOPSIS Las hipótesis relacionadas con la variación altitudinal en los ciclos de vida de aves están basadas en una gran cantidad de datos de aves de zona templada, mientras que para el trópico inclusive se desconoce la biología básica. Esto aplica en particular para aves que no son paserinos. Investigamos las actividades de anidamiento de Hoatzin (Opisthocumus hoazin) en un bosque pluvial primario de la amazonia ecuatorial. En nuestra área de estudio, los hoatzines viven y se reproducen en bosques inundados que bordean lagos y canales. Los intentos reproductivos estuvieron asociados a la época de lluvias y se agruparon en unos meses del año. Normalmente, estas aves anidan una vez al año. El reanidamiento solo ocurrio cuando hubo pérdidas durante la época de puesta. Los nidos fueron construidos en los árboles y arbustos más comunes en el hábitat. El número de huevos por camada vario de uno a siete, aunque el 51% de las camadas consistieron de dos huevos. El tiempo promedio de incubación fue de 32 días. El exito promedio de eclosionamiento (para todos los nidos) fue de 34% y el 50% de los pichones dejaron el nido, lo que dio un éxito de anidamiento en general de 17%. La causa principal de pérdida de nidos lo fue la depredación, en donde otras aves y culebras resultaron ser los principales depredadores. La pequeña ventana de tres meses para reproducirse parece ser el resultado de un fuerte constreñimiento para una reproducción exitosa, debido a una mejor protección de los nidos y mayor abundancia de alimentos durante la época de inundación. El hoatzin exhibe un ciclo de vida similar al de paserinos tropicales. Esto indica la efectividad de las presiones ambientales de selección que deben estar envueltas en la formación de dichos trasos. [source] MUSEUM SPECIMENS AND PHYLOGENIES ELUCIDATE ECOLOGY'S ROLE IN COEVOLUTIONARY ASSOCIATIONS BETWEEN MITES AND THEIR BEE HOSTSEVOLUTION, Issue 6 2007Pavel B. Klimov Coevolutionary associations between hosts and symbionts (or parasites) are often reflected in correlated patterns of divergence as a consequence of limitations on dispersal and establishment on new hosts. Here we show that a phylogenetic correlation is observed between chaetodactylid mites and their hosts, the long-tongued bees; however, this association manifests itself in an atypical fashion. Recently derived mites tend to be associated with basal bee lineages, and vice versa, ruling out a process of cospeciation, and the existence of mites on multiple hosts also suggests ample opportunity for host shifts. An extensive survey of museum collections reveals a pattern of infrequent host shifts at a higher taxonomic level, and yet, frequent shifts at a lower level, which suggests that ecological constraints structure the coevolutionary history of the mites and bees. Certain bee traits, particularly aspects of their nesting behavior, provide a highly predictive framework for the observed pattern of host use, with 82.1% of taxa correctly classified. Thus, the museum survey and phylogenetic analyses provide a unique window into the central role ecology plays in this coevolutionary association. This role is apparent from two different perspectives,as (a) a constraining force evident in the historical processes underlying the significant correlation between the mite and bee phylogenies, as well as (b) by the highly nonrandom composition of bee taxa that serve as hosts to chaetodactylid mites. [source] Reproduction of the Mottled Piculet in southern BrazilJOURNAL OF FIELD ORNITHOLOGY, Issue 3 2006Mauro Pichorim ABSTRACT On 28 October 1996, I found a Mottled Piculet (Picumnus nebulosus) nest on Anhangava Mountain in southern Brazil. The nest cavity (10.6 cm × 5.6 cm) was in the trunk of a dead tree at a height of 85 cm. The circumference of the trunk at cavity height was 37 cm and the cavity entrance (diameter = 2.46 cm) was located near the top of the chamber. The nest was lined with wood fragments and contained four eggs. On average, eggs were 16.3-mm long and 13.0-mm wide and weighed 1.38 g. The parents spent 17 d incubating the eggs. Hatchlings had closed eyes and no feathers. By 20 d posthatching, nestlings were active and had plumage similar to that of adult females. Young fledging 22,25 d after hatching. Nestling weight gain and tarsus growth were fastest at the beginning of the nestling period, while wing, tail, and culmen growth had a linear relationship with nestling age. Both the adult male and female provided parental care during the nestling period. Although, the nesting behavior of Mottled Piculets was similar to that reported for other members of the genus, information on the reproductive biology of species in the genus Picumnus is still limited. SINOPSIS En octubre de 1996, encontré un nido de Picumnus nebulosus en las montañas Anhangava de Brazil. La cavidad de anidamiento (10.6 cm × 5.6 cm) se encontró en el tronco de un árbol muerto a una altura de 85 cm. La circunsferencia del tronco, al nivel del nido, fue de 37 cm y la entrada de la cavidad (con diámetro de 2.46 cm) estaba localizada en la parte superior de la cámara. El fondo del nido estaba cubierto con fragmentos del tronco y en este habían cuatro huevos. El tamaño y peso promedio de estos fue de 16.3 mm × 13 mm de ancho y de 1.38 g, respectivamente. El eclosionamiento fue de 17 días. Los pichones al nacer tenían el cuerpo desnudo y los ojos cerrados. A los 20 días los pichones tenían un plumaje similar al de los adultos y estaban sumamente activos. Estos dejaron el nido entre los 22,25 días de edad. La ganancia en peso de los pichones y el crecimiento del tarso fue más rápido a temprana edad, mientras que el incremento en tamaño del ala, cola y culmen mostró un patrón de crecimiento lineal con respecto a la edad del pichón. Ambos adultos atendieron a los pichones. En general la conducta de anidamiento del ave estudiada resultó similar a la informada para otros miembros del mismo género, aunque la información sobre la biología reproductiva de aves del género Picumnus todavía es limitada. [source] The neuronal apoptotic death in global cerebral ischemia in gerbil: Important role for sodium channel modulator,JOURNAL OF NEUROSCIENCE RESEARCH, Issue 6 2009Manoja Kumar Brahma Abstract Global ischemia was induced in gerbil by bilateral occlusion of the common carotid arteries for 5 min. Sodium ionophore monensin or sodium channel blocker tetrodotoxin (TTX) was administered at doses of 10 ,g/kg, i.p., 30 min before ischemia induction; the dose was repeated after 22 hr. Subsequently, brain infarct occurred, determined at 24 hr after occlusion. Large, well-demarcated infarcts were observed in both hemispheres, an important observation because it critically influences the interpretation of the data. Because nitric oxide (NO) production is thought to be related to ischemic neuronal damage, we examined increases in Ca2+ influx, which lead to the activation of nitric oxide synthase (NOS). Then we evaluated the contributions of neuronal NOS, endothelial NOS, and inducible NOS to NO production in brain cryosections. The cytosolic release of apoptogenic molecules like cytochrome c and p53 were confirmed after 24 hr of reflow. TUNEL (terminal deoxynucleotidyl transferase dUTP nick-end labeling) labeling detected the apoptotic cells, which were confirmed in neuron-rich cell populations. After 24 hr, all the ischemic changes were amplified by monensin and significantly attenuated by TTX treatment. Additionally, the nesting behavior and histological outcomes were examined after 7 day of reflow. The neuronal damage in the hippocampal area and significant decrease in nesting scores were observed with monensin treatment and reduced by TTX pretreatment after day 7 of reflow. To our knowledge, this report is the first to highlight the involvement of the voltage-sensitive Na+ channel in possibly regulating in part NO system and apoptosis in a cytochrome c,dependent manner in global ischemia in the gerbil, and thus warrants further investigation. © 2008 Wiley-Liss, Inc. [source] Nest groups of wild bonobos at Wamba: selection of vegetation and tree species and relationships between nest group size and party sizeAMERICAN JOURNAL OF PRIMATOLOGY, Issue 7 2010Mbangi N. Mulavwa Abstract We examined the location of nest groups, spatial distribution of nests within a nest group, and attributes of individual nests of wild bonobos at Wamba, Democratic Republic of Congo. We also examined the seasonal factors influencing nesting behavior and compared the nest group size with the 1,hr party size during daytime. We defined a nest group to be a cluster of nests that were built in the same evening and found within 30,m from the other nearest nest. Examination of the largest gap within a nest group suggested that 30,m was an acceptable cutoff value. Monthly rainfall or fruit abundance did not significantly influence the monthly mean nest group size. Nests were built in the swamp forest for as many as 13% observation days, suggesting the need for reevaluation of the use of swamp forest by bonobos. The use of swamp forest was influenced not by seasonal rainfall or fruit abundance, but by the fruiting of specific species. Preferred tree species for building nests accounted for 19.8% of standing trees, which suggested that the selection of sleeping sites was not largely restricted by the distribution of specific species. The mean 1,hr party size was almost identical through the day and was similar to the mean nest group size. Parties of bonobos sometimes split into smaller nest groups, especially when feeding on non-preferred fruits during fruit scarcity. By contrast, when feeding on preferred fruits while ranging in large parties, they often aggregated to form even larger nest groups. When sleeping in small- or middle-sized nest groups, they tended to aggregate the next morning. These tendencies may reflect the gregarious nature of bonobos who prefer to range or sleep together as far as circumstances allow. Am. J. Primatol. 72:575,586, 2010. © 2010 Wiley-Liss, Inc. [source] Differences of behavior, use of resources and physical conditions between dominant and subordinate hens in furnished cagesANIMAL SCIENCE JOURNAL, Issue 3 2007Tsuyoshi SHIMMURA ABSTRACT The objective of the present study was to search for differences in the behavior, use of resources and the physical condition between dominant and subordinate birds in furnished cages. In total, 60 commercial White Leghorn layers were used. At the age of 54 weeks, these birds were divided into two groups. Each group consisted of six cages with four birds per cage and six cages with six birds per cage. The dominance hierarchy was measured, to identify the highest dominant bird and the lowest subordinate bird in the hierarchy of each furnished cage. Behavioral observations using scanning techniques at 10 min intervals were conducted on the birds at 57 and 67 weeks of age for 3 days, respectively. Their physical condition (bodyweight and claw length) was also measured. Dominant birds used the dust bath more (P < 0.1) and nest box less (P < 0.01) than subordinate birds did. The use of the nest box decreased for subordinate birds from 57 to 67 weeks of age (P < 0.05). The dominant birds performed aggression and exploring more frequently than the subordinate birds (P < 0.001 and P < 0.05, respectively). In the comfort behaviors, the dominant birds performed dust-bathing, as well as the using the dust bath, more than subordinate birds did (P < 0.1). In their exploring behavior, including scratching and litter pecking, dominant birds performed both behaviors more frequently, as well as using the dust bath and dust-bathing in it, than subordinate birds did (P < 0.1 and P < 0.05, respectively). Aggression decreased for dominant birds from 57 to 67 weeks of age. In contrast, eating (P < 0.1) as well as drinking (P < 0.1) and other comfort behaviors (P < 0.1) increased for subordinate birds from 57 to 67 weeks of age. There was no significant difference between dominant and subordinate birds in their physical conditions. In conclusion, dominant birds had priority to use the dust box compared with the subordinate birds in the furnished cages. Conversely, the subordinate birds stayed in the nest box more than the dominant birds did. In the furnished cages, equipping the nest box was important not only for the birds to perform nesting behavior, but also for the subordinate birds to use the facility as a refuge especially just after introduction to the cage. [source] Female oxytocin gene-knockout mice, in a semi-natural environment, display exaggerated aggressive behaviorGENES, BRAIN AND BEHAVIOR, Issue 4 2005A. K. Ragnauth Compared to results from a generation of neuropharmacological work, the phenotype of mice lacking the oxytocin (OT) peptide gene was remarkably normal. An important component of the current experiments was to assay OT-knockout (OTKO) and wild-type (WT) littermate control mice living under controlled stressful conditions designed to mimic more closely the environment for which the mouse genome evolved. Furthermore, our experimental group was comprised of an all-female population, in contrast to previous studies which have focused on all-male populations. Our data indicated that aggressive behaviors initiated by OTKO during a food deprivation feeding challenge were considerably more intense and diverse than aggressive behaviors initiated by WT. From the measures of continuous social interaction in the intruder paradigm, it emerged that OTKO mice were more offensively aggressive (attacking rumps and tails) than WT. In a test of parental behaviors, OTKO mice were 100% infanticidal while WT were 16% infanticidal and 50% maternal. Finally, ,alpha females' (always OTKO) were identified in each experiment. They were the most aggressive, the first to feed and the most dominant at nesting behaviors. Semi-natural environments are excellent testing environments for elucidating behavioral differences between transgenic mice and their WT littermates which may not be ordinarily discernible. Future studies of mouse group behavior should include examining female groupings in addition to the more usual all-male groups. [source] | ||||||||||