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James S Sedinger – One of the best experts on this subject based on the ideXlab platform.
Dynamics of Dispersed-Nesting Black Brant on the Yukon-Kuskokwim DeltaJournal of Fish and Wildlife Management, 2020Co-Authors: James S Sedinger, Thomas V Riecke, Phillip A. Street, Julian B. FischerAbstract:
The number of black brant Branta Bernicla nigricans nests within major breeding colonies on the Yukon-Kuskowkim Delta has declined since 1992. It has been hypothesized that these declines are parti…
incubation capacity contributes to constraints on maximal clutch size in brent geese Branta Bernicla nigricansIbis, 2017Co-Authors: Alan G Leach, Amanda W Van Dellen, Thomas V Riecke, James S SedingerAbstract:
Lack (1967) proposed that clutch size in species with precocial young was determined by nutrients available to females at the time of egg formation; since then others have suggested that regulation of clutch size in these species may be more complex. We tested whether incubation limitation contributes to ultimate constraints on maximal clutch size in Black Brent Geese (Black Brant) Branta Bernicla nigricans. Specifically, we investigated the relationship between clutch size and duration of the nesting period (i.e. days between nest initiation and the first pipped egg) and the number of goslings leaving the nest. We used experimental clutch manipulations to assess these questions because they allowed us to create clutches that were larger than the typical maximum of five eggs in this species. We found that the per-capita probability of egg success (i.e. the probability an egg hatched and the gosling left the nest) declined from 0.81 for two-egg clutches to 0.50 for seven-egg clutches. As a result of declining egg success, clutches containing more than five eggs produced, at best, only marginally more offspring. Manipulating clutch size at the beginning of incubation had no effect on the duration of the nesting period, but the nesting period increased with the number of eggs a female laid naturally prior to manipulation, from 25.4 days (95% CI 25.1–25.7) for three-egg clutches to 27.7 days (95% CI 27.3–28.1) for six-egg clutches. This delay in hatching may result in reduced gosling growth rates due to declining forage quality during the brood rearing period. Our results suggest that the strong right truncation of Brent clutches, which results in few clutches greater than five, is partially explained by the declining incubation capacity of females as clutch size increases and a delay in hatching with each additional egg laid. As a result, females laying clutches with more than five eggs would typically gain little fitness benefit above that associated with a five-egg clutch.
carry over effects of winter location contribute to variation in timing of nest initiation and clutch size in black brant Branta Bernicla nigricansThe Auk, 2012Co-Authors: James S Sedinger, Jason L Schamber, David H WardAbstract:
ABSTRACT. We assessed carry-over effects from winter location on timing of nest initiation and clutch size of Black Brant (Branta Bernicla nigricans) using observations of individually marked brant breeding at the Tutakoke River colony in Alaska, and wintering along a latitudinal gradient at three areas on the Pacific coast of Baja California: northernmost Bahia San Quintin (BSQ), Laguna Ojo de Liebre (LOL), and southernmost Laguna San Ignacio (LSI). Black Brant initiated nests according to a north—south trend in winter location, although year was a stronger predictor of initiation date than was wintering site. Female Black Brant that wintered at BSQ initiated nests 2.2 days earlier than females from LSI. Conversely, Black Brant showed only a weak south—north trend in clutch size; individuals from LSI laid slightly larger clutches than individuals from BSQ, probably because a smaller proportion of only high-quality females from the southernmost wintering area in Baja California were able to attain the nut…
David H Ward – One of the best experts on this subject based on the ideXlab platform.
activity budgets daily energy expenditure and energetic model of black brant Branta Bernicla nigricans during winter and spring along the lower alaska peninsulaWildfowl, 2019Co-Authors: Bryan L Daniels, David H Ward, Jeffrey M BlackAbstract:
Black Brant Branta Bernicla nigricans have one of the most specialised of goose diets during the non-breeding season, utilising coastal habitats to up-end and feed on dense beds of intertidal Common Eelgrass Zostera marina. Past studies suggested that Black Brant may not reach energetic requirements during diurnal foraging on eelgrass beds and must use alternate, less energetically beneficial foraging strategies ( e.g . searching for and consuming sparse drifting eelgrass and night-time eelgrass bed foraging) to meet energy demands. Time-activity budgets and daily energy expenditure (DEE) were quantified and use of alternate foraging strategies during periods of limited food availability were described for Black Brant along the Lower Alaska Peninsula in Kinzarof and Izembek Lagoons during winter (February–March) and spring (April–May) 2011. Based on 577 instantaneous flock scans across seasons and tide stages, predominant Black Brant activities were vigilance (41%), foraging (33%), comfort (16%) and locomotion (8%). Estimated mean DEE across months and locations was 1,181 ± 110 kJ/day. Flight costs accounted for an estimated 23–46% of expended energy in winter and spring, roosting 22–27%, thermoregulatory costs 13–18%, foraging 8–15% and vigilance 10–17% in spring. Black Brant only met daily energetic requirements by employing alternate foraging strategies, particularly nocturnal foraging, which offset their DEE by 21–43% in winter and 17–28% in spring.
patrones de uso de sitios naturales y artificiales por Branta Bernicla nigricans anseriformes anatidae en guerrero negro baja california sur mexicoRevista De Biologia Tropical, 2013Co-Authors: Israel Martinez Cedillo, David H Ward, Roberto Carmona, Gustavo D DanemannAbstract:
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, 31 000 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, artificial site) we determined by monthly censuses (from November 2006 to April 2007, 08:00-16:00h) and observed: (1) season and site effects on population structure (age groups), and (2) the tide level relationship with the abundance and proportion of feeding birds. Within a total of 150 observa- tion hours and 98 birds, our results showed a general 0.68 proportion of adults, that was higher in winter than in spring. The statistics analysis showed no effects by site on the proportion of feeding birds, but we observed a temporal decrease at ESSA and at GNL. In contrast the proportion of feeding birds at OLL was constant. We observed an increase in the juveniles between winter and spring. This increase is related with the differential migration, which mentions that the juveniles are the last to leave the wintering area. In winter the relations of the tide level with the abundance of Brant were: direct at ESSA, inverse at OLL and no relation found at GNL. In spring, no relation was observed in the sites. The proportion of Brants feeding at OLL (the site with the higher abundance) was independent of the tide level. This is related with two possible behaviors of the geese: (1) they can move through the lagoon and take advantage of the tidal lag, which is up to four hours; and (2) they can modify their feeding strategies, more on floating eelgrass (Zostera marina). Rev. Biol. Trop. 61 (2): 927-935. Epub 2013 June 01.
foraging home ranges of black brant Branta Bernicla nigricans during spring stopover at humboldt bay california usaWildfowl, 2013Co-Authors: Jeffrey M Black, David H WardAbstract:
Foraging home ranges of Black Brant Branta Bernicla nigricans (n = 8) were quantified to determine proportional use of available intertidal habitat during spring migration stopover at Humboldt Bay, California, USA. The average foraging range area was 232 ha (s.d. ± 156 ha) of which 114 ha (s.d. ± 43 ha) was comprised of their primary food, eelgrass Zostera marina; the other habitats included mudflat/sandbar and deep water channels. This amounted to individuals using an average of 16% of the available eelgrass in the bay (716 ha). Potential consequences are discussed for Black Brant remaining faithful to a relatively small proportion of available habitat. Individual Black Brant may employ different foraging strategies in different parts of Humboldt Bay to obtain nutrients and body stores to fuel migration and subsequent breeding.
Barwolt S Ebbinge – One of the best experts on this subject based on the ideXlab platform.
a multifactorial explanation for variation in breeding performance of brent geese Branta BerniclaIbis, 2008Co-Authors: Barwolt S EbbingeAbstract:
The dramatic differences in annual breeding success of Dark-bellied Brent Geese Branta b. Bernicla are generally interpreted as being caused by variable conditions on the arctic breeding grounds. The recently revived discussion on this issue mentions, in particular, the cyclic variation in abundance of lemmings, resulting in cyclic variation of predation pressure on bird nests by arctic foxes, as the main factor determining whether Brent Geese are able to breed successfully or not. New data on the spring condition of Brent Geese in Western Europe and wind conditions during migration from the spring staging areas to the breeding grounds show that these factors also influence breeding output.
brent goose Branta Bernicla Bernicla feeding behaviour during incubation taimyr peninsula russiaPolar Biology, 2007Co-Authors: Maud Poisbleau, Herve Fritz, Sebastien Dalloyau, Charlesandre Bost, Barwolt S EbbingeAbstract:
Incubating birds must balance the time and the energy invested in incubation with the energy acquisition for their survival. Many factors such as weather and predation influence this trade-off. In Arctic geese, only females incubate, and they leave the nest regularly to feed while males invest in keeping their nests and mates safe. This study conducted on Big Bird Island (Taimyr Peninsula) during the summer of 2004 examined the incubation behavior of dark-bellied brent geese Branta Bernicla Bernicla to assess the effect of date, period of day and weather conditions on the incubation and feeding behaviors of females and males. Females were at their nests only for 65% of the total time observed. This very low value, compared to other goose species, could be the result of the combined effects of good weather conditions, low predation pressure and opportunities to feed close to the nest. We found differential adjustments of male and female behaviors. Females appeared to focus on the trade-off between feeding and incubating, in relation to weather conditions, and on their own energy balance. Males appeared to respond primarily by the absence of the female from their nest.
changes in body mass and hormone levels between wintering and spring staging areas in dark bellied brent geese Branta Bernicla BerniclaJournal of Avian Biology, 2006Co-Authors: Maud Poisbleau, Herve Fritz, Marcel M Lambrechts, Colette Trouve, Barwolt S EbbingeAbstract:
We document seasonal changes in body mass and plasma hormone levels (testosterone and triiodothyronine) between winter and spring quarters in dark-bellied brent geese Branta Bernicla Bernicla. Body mass increased between winter and spring, whereas body size was the same for the birds sampled in winter and those in spring. Adults and males were larger and heavier than juveniles and females. Plasma testosterone levels did not differ significantly between winter and spring, and did not vary with sex, age and morphometry. Plasma triiodothyronine (T3) levels were significantly higher in spring than in winter, and were higher for males than for females. However, T3 levels did not vary significantly with age and body measurements. To explain the findings, we discuss potential impacts of social dominance