| effects of el niño on distribution and reproductive performance of black brant. | climate in low-latitude wintering areas may influence temperate and high-latitude breeding populations of birds, but demonstrations of such relationships have been rare because of difficulties in linking wintering with breeding populations. we used long-term aerial surveys in mexican wintering areas and breeding areas in alaska, usa, to assess numbers of black brant (branta bernicla nigricans; hereafter brant) on their principal wintering and breeding area in el niño and non-el niño years. we us ... | 2006 | 16634306 |
| helminth community structure in two species of arctic-breeding waterfowl. | climate change is occurring rapidly at high latitudes, and subsequent changes in parasite communities may have implications for hosts including wildlife and humans. waterfowl, in particular, harbor numerous parasites and may facilitate parasite movement across broad geographic areas due to migratory movements. however, little is known about helminth community structure of waterfowl at northern latitudes. we investigated the helminth communities of two avian herbivores that breed at high latitude ... | 2016 | 27709067 |
| reference intervals for serum biochemistries of molting pacific black brant ( branta bernicla nigricans) in northern alaska, usa. | we determined reference intervals for nine serum biochemistries in samples from 329 molting, after-hatch-year, pacific black brant ( branta bernicla nigricans) in alaska, us. cholesterol and nonesterified fatty acids differed by sex, but no other differences were noted. | 2017 | 28094610 |
| ultimate regulation of fecundity in species with precocial young: declining marginal value of offspring with increasing brood size does not explain maximal clutch size in black brent geese. | lack 18:125-128 (1967) proposed that clutch size in precocial species was regulated by nutrients available to females during breeding. drent and daan 68:225-252 (1980) proposed the individual optimization hypothesis, whereby individual state determines the optimal combination of breeding date and clutch size. neither hypothesis accounts for variation in nutrients among females at the end of egg laying, strong right truncations in clutch size distributions, or the fact that many species with prec ... | 2017 | 27896480 |
| blood selenium concentrations in female pacific black brant molting in arctic alaska: relationships with age and habitat salinity. | blood samples collected from 81 female pacific black brant (branta bernicla nigricans) molting near teshekpuk lake, alaska, were analyzed for selenium concentration. the concentration of selenium in blood of after second year (hatched two or more years ago) females (0.84μg/g wet weight) was significantly greater than the concentration in second year (hatched the previous year) females (0.61μg/g wet weight). the concentrations of selenium we found in blood of black brant were 1.5 to 2 times great ... | 2016 | 27381988 |
| a likelihood-based approach for assessment of extra-pair paternity and conspecific brood parasitism in natural populations. | genotypes are frequently used to assess alternative reproductive strategies such as extra-pair paternity and conspecific brood parasitism in wild populations. however, such analyses are vulnerable to genotyping error or molecular artefacts that can bias results. for example, when using multilocus microsatellite data, a mismatch at a single locus, suggesting the offspring was not directly related to its putative parents, can occur quite commonly even when the offspring is truly related. some rece ... | 2015 | 24989354 |
| individual heterogeneity in black brant survival and recruitment with implications for harvest dynamics. | we examined individual heterogeneity in survival and recruitment of female pacific black brant (branta bernicla nigricans) using frailty models adapted to a capture-mark-recapture context. our main objectives were (1) to quantify levels of heterogeneity and examine factors affecting heterogeneity, and (2) model the effects of individual heterogeneity on harvest dynamics through matrix models. we used 24 years of data on brant marked and recaptured at the tutakoke river colony, ak. multievent mod ... | 2013 | 24324858 |
| [habitat use patterns of the black brant branta bernicla nigricans (anseriformes: anatidae) in natural and artificial areas of guerrero negro, baja california sur, mexico]. | the black brant is a common inhabitant of the western artic american tundra, which migrates to southern pacific coasts during the winter season. approximately, 31000 birds (31%) constitute the mexican population of brants at guerrero negro, ojo de liebre, and exportadora de sal lagoon complex; nevertheless, there is little information about the distribution patterns and zone usage. at guerrero negro lagoon (gnl), ojo de liebre lagoon (oll, both natural sites), and at exportadora de sal (essa, ar ... | 2013 | 23885600 |
| are there trade-offs between pre- and post-fledging survival in black brent geese? | 1. the growth period is an important determinant of fitness later in life through its effects on first-year survival and future reproduction. choices by adult females about where to rear their offspring strongly affect growth rates and offspring fitness in geese. 2. individual female black brent (branta bernicla nigricans) tend to raise their broods in the same areas each year, and these areas are consistently ranked with respect to growth rates of goslings. therefore, some females consistently ... | 2012 | 22304760 |
| trade-offs between offspring fitness and future reproduction of adult female black brent. | 1. successful reproduction requires numerous decisions, and some of which may require trade-offs between current and future reproduction. we studied effects of choice of foraging patches on gosling growth and future breeding by mothers in black brent (branta bernicla nigricans) geese. 2. specific foraging areas consistently produced high-quality goslings over 21 years. we found a consistent ranking of gosling mass, corrected for age, across brood rearing areas (bras) and years [akaike model weig ... | 2012 | 22303812 |
| carryover effects associated with winter location affect fitness, social status, and population dynamics in a long-distance migrant. | we used observations of individually marked female black brant geese (branta bernicla nigricans; brant) at three wintering lagoons on the pacific coast of baja california-laguna san ignacio (lsi), laguna ojo de liebre (lol), and bahía san quintín (bsq)-and the tutakoke river breeding colony in alaska to assess hypotheses about carryover effects on breeding and distribution of individuals among wintering areas. we estimated transition probabilities from wintering locations to breeding and nonbree ... | 2011 | 22030737 |
| fidelity and breeding probability related to population density and individual quality in black brent geese branta bernicla nigricans. | 1. patterns of temporary emigration (associated with non-breeding) are important components of variation in individual quality. permanent emigration from the natal area has important implications for both individual fitness and local population dynamics. 2. we estimated both permanent and temporary emigration of black brent geese (branta bernicla nigricans lawrence) from the tutakoke river colony, using observations of marked brent geese on breeding and wintering areas, and recoveries of ringed ... | 2008 | 18479339 |
| factors influencing route choice by avian migrants: a dynamic programming model of pacific brant migration. | we used stochastic dynamic programming to investigate a spectacular migration strategy in the black brant branta bernicla nigricans, a species of goose. black brant migration is well suited for theoretical analysis since there are a number of existing strategies that easily can be compared. in early autumn, almost the entire population of the black brant gathers at izembek lagoon on the alaska peninsula to stage and refuel before the southward migration. there are at least three distinct strateg ... | 2007 | 17920633 |
| feedback dynamics of grazing lawns: coupling vegetation change with animal growth. | we studied the effects of grazing by black brant (branta bernicla nigricans) geese (hereafter brant) on plant community zonation and gosling growth between 1987 and 2000 at a nesting colony in southwestern alaska. the preferred forage of brant, carex subspathacea, is only found as a grazing lawn. an alternate forage species, c. ramenskii, exists primarily as meadow but also forms grazing lawns when heavily grazed. we mowed plots of ungrazed c. ramenskii meadows to create swards that brant could ... | 2003 | 12684865 |