scholarly journals Abundance and productivity of marbled murrelets (Brachyramphus marmoratus) off central California during the 2019 breeding season

Data Series ◽  
2020 ◽  
Author(s):  
Jonathan J. Felis ◽  
Emily C. Kelsey ◽  
Josh Adams ◽  
Cheryl Horton ◽  
Laura (Laney) White
Keyword(s):  
Breeding Season ◽  
Brachyramphus Marmoratus ◽  
Central California ◽  
Marbled Murrelets

scholarly journals Marine Habitat Selection by Marbled Murrelets (Brachyramphus marmoratus) during the Breeding Season

PLoS ONE ◽  
2016 ◽  
Vol 11 (9) ◽  
pp. e0162670 ◽  
Author(s):  
Teresa J. Lorenz ◽  
Martin G. Raphael ◽  
Thomas D. Bloxton
Keyword(s):  
Habitat Selection ◽  
Breeding Season ◽  
Marine Habitat ◽  
Brachyramphus Marmoratus ◽  
Marbled Murrelets

scholarly journals Age Ratios as Estimators of Productivity: Testing Assumptions on a Threatened Seabird, The Marbled Murrelet (Brachyramphus Marmoratus)

The Auk ◽  
2007 ◽  
Vol 124 (1) ◽  
pp. 224-240 ◽  
Author(s):  
M. Zachariah Peery ◽  
Benjamin H. Becker ◽  
Steven R. Beissinger
Keyword(s):  
Annual Variation ◽  
Age Classes ◽  
Survey Period ◽  
Brachyramphus Marmoratus ◽  
Breeding Sites ◽  
Central California ◽  
Adult Age ◽  
Marbled Murrelet ◽  
Unbiased Manner ◽  
Marbled Murrelets

Abstract The ratio of hatch-year (HY) to after-hatch-year (AHY) individuals (HY:AHY ratio) can be a valuable metric for estimating avian productivity because it does not require monitoring individual breeding sites and can often be estimated across large geographic and temporal scales. However, rigorous estimation of age ratios requires that both young and adult age classes are sampled in an unbiased manner, an assumption that is rarely tested. We estimated HY:AHY ratios for Marbled Murrelets (Brachyramphus marmoratus), a threatened seabird, using at-sea surveys and captures to assess whether age-specific differences in behavior and distribution result in biased productivity estimates in central California. AHY and HY Marbled Murrelets were distributed similarly at sea, and HY individuals did not congregate in nursery areas. Moreover, dispersal by radiomarked AHY Marbled Murrelets out of our survey area occurred at a low rate, and AHY densities were constant over the survey period, which suggests that AHY immigration and emigration did not significantly bias productivity estimates. HY density increased linearly over the survey period as expected if little dispersal occurred, which suggests that productivity estimates were not significantly biased by HY dispersal. Finally, simulation analyses indicated that annual variation in the timing of breeding resulted in only small biases in HY:AHY ratios. HY:AHY ratios were corrected for the proportion of AHY Marbled Murrelets that were incubating and the proportion of HY individuals that had not fledged at the time of sampling. Mean corrected HY:AHY ratios were low on the basis of both at-sea surveys conducted from 1996 to 2003 (0.032; SE = 0.011) and captures conducted from 1999 to 2003 (0.037; SE = 0.028), implying that productivity was poor in central California. Estimating age ratios may be an effective way of monitoring changes in reproductive success and identifying environmental factors that affect Marbled Murrelet populations, though tests of assumptions are needed in other regions. Le Rapport des Âges comme Estimateur de la Productivité: Tester les Hypothèses avec un Oiseau de Mer Menacé, Brachyramphus marmoratus

scholarly journals Intraspecific Variation in Commuting Distance of Marbled Murrelets (Brachyramphus marmoratus): Ecological and Energetic Consequences of Nesting Further Inland

The Auk ◽  
2001 ◽  
Vol 118 (4) ◽  
pp. 1036-1046 ◽  
Author(s):  
Cindy L. Hull ◽  
Gary W. Kaiser ◽  
Cecilia Lougheed ◽  
Lynn Lougheed ◽  
Sean Boyd ◽  
...  
Keyword(s):  
Breeding Season ◽  
Radio Tracking ◽  
Additional Energy ◽  
Brachyramphus Marmoratus ◽  
Nest Sites ◽  
Visitation Rates ◽  
Radio Transmitters ◽  
Additional Energy Expenditure ◽  
Water Birds ◽  
Marbled Murrelets

AbstractRadio transmitters were deployed on Marbled Murrelets (Brachyramphus marmoratus) at Desolation Sound, British Columbia, Canada, during the 1998 breeding season to assess individual variation in distance birds nested from foraging areas, and potential energetic and ecological consequences of commuting those distances. Radio-tracking from a helicopter was used to locate nests, and tracking from the air and boats was used to locate murrelets on the water. Twenty-three nests were found, with active incubation at 16, and active chick-rearing at 12. A minimum of 3 nests fledged chicks, 9 were failures, and 11 were unknown. Nests were at an elevation of 806 ± 377 m and a distance of 39.2 ± 23.2 km (range 12–102 km) from locations on the water. Birds spent an estimated 1.2 ± 0.7 h per day commuting to and from nests (range 0.3–3.5 h per day). It was estimated that birds expended 3,883 ± 2,296 kJ (range 1,200–10,144 kJ) over the breeding season when commuting to those nests, which was 5–41% of their estimated field metabolic-rate during the breeding season. There was no relationship between distance to nests and breeding success. Either Marbled Murrelets can accommodate that additional energy expenditure, or reduce commuting costs by modifying their foraging behavior. They may forage closer to nest sites when provisioning chicks, thereby reducing commuting costs with a payload, or alter nest visitation rates in relation to distance they nest from foraging areas. Nests further inland may also confer advantages that compensate for the added commuting, or birds might replenish body reserves at the end of the breeding season.

scholarly journals Techniques for Investigating Breeding Chronology in Marbled Murrelets, Desolation Sound, British Columbia

The Condor ◽  
2002 ◽  
Vol 104 (2) ◽  
pp. 319-330 ◽  
Author(s):  
Cecilia Lougheed ◽  
Brett A. Vanderkist ◽  
Lynn W. Lougheed ◽  
Fred Cooke
Keyword(s):  
British Columbia ◽  
Breeding Season ◽  
Radio Telemetry ◽  
Feeding Habits ◽  
Brachyramphus Marmoratus ◽  
Marbled Murrelet ◽  
Breeding Synchrony ◽  
Physiological Analysis ◽  
Using Data ◽  
Marbled Murrelets

AbstractWe used several methods to study the chronology and synchrony of breeding events of the Marbled Murrelet (Brachyramphus marmoratus) population at Desolation Sound, British Columbia, from 1996 to 1998. The timing of breeding events varied among years; on average the breeding season lasted from 21 April to 5 September. We assessed the biases of each method used by comparing the results to the estimate of the integrated breeding chronology. Counts of hatch-year birds at sea were biased toward earlier breeders, missing an estimated 24% of the fledglings. Two other methods, physiological analysis of the yolk precursor vitellogenin from blood samples and monitoring by radio-telemetry could produce a complete distribution of breeding events if sampling were done throughout laying. Observations in the forest, date of first observation of a fledgling at sea during the breeding season, and fish-holding behavior produced insufficient data to be used as sole indicators of breeding chronology of this species. In general, breeding synchrony in alcids, assessed using data from a literature review, was unrelated to feeding habits but increased with latitude (41% of the variation was explained by latitude). Marbled Murrelets, however, bred less synchronously than predicted for an alcid at this latitude (50°N).Técnicas para Investigar la Cronología Reproductiva de Brachyramphus marmoratus en Caleta Desolación, Columbia BritánicaResumen. Utilizamos varios métodos para investigar la cronología reproductiva de la población de Brachyramphus marmoratus en la Caleta Desolación de la Columbia Británica desde 1996 a 1998. Encontramos variaciones temporales en la época reproductiva entre años. En promedio, la estación reproductiva se extendió del 21 de abril al 5 de septiembre. Evaluamos el sesgo de los métodos utilizados comparando los resultados individuales con los resultados de la cronología obtenida al integrar todos los métodos. Los conteos de juveniles en el mar estuvieron sesgados hacia aquellas aves que anidan temprano, no detectando aproximadamente 24% de los juveniles producidos en la estación reproductiva. Los otros dos métodos, análisis fisiológico de muestras de sangre para detectar el precursor de vitelogenina en la yema y monitoreo por telemetría, podrían producir una distribución completa de las etapas reproductivas siempre que el muestreo se lleve a cabo a lo largo de todo el período de puesta. Las observaciones directas en los sitios de anidación, la fecha de la primera observación de juveniles en el mar y las observaciones de aves con pescado en el pico produjeron datos insuficientes para ser considerados indicadores únicos de la cronología reproductiva para esta especie. Con base en una revisión bibliográfica se investigó la sincronía reproductiva en álcidos, encontrándose que ésta no está relacionada con hábitos alimenticios pero que aumenta con la latitud (41% de la variación fue explicada por cambios latitudinales). Sin embargo, B. marmoratus se reprodujo menos sincrónico que lo predicho para un álcido a esta latitud (50°N).

scholarly journals Local Survival of Adult and Juvenile Marbled Murrelets and Their Importance for Estimating Reproductive Success

The Condor ◽  
2002 ◽  
Vol 104 (2) ◽  
pp. 309-318 ◽  
Author(s):  
Cecilia Lougheed ◽  
Lynn W. Lougheed ◽  
Fred Cooke ◽  
Sean Boyd
Keyword(s):  
Survival Rate ◽  
Reproductive Success ◽  
Breeding Season ◽  
Emigration Rate ◽  
Brachyramphus Marmoratus ◽  
Resident Population ◽  
Local Survival ◽  
Potential Problems ◽  
Radio Transmitters ◽  
Marbled Murrelets

Abstract Juvenile ratios estimated using numbers of hatch year (HY) and after-hatch-year (AHY) Marbled Murrelets (Brachyramphus marmoratus) counted concurrently during at-sea surveys have been used to estimate fecundity in this species. These “concurrent” juvenile ratios assume that HY birds remain in an area, and are likely biased because they do not account for potential differences in emigration rate of HY and AHY birds. We studied the emigration rates of adult and juvenile Marbled Murrelets marked with radio-transmitters. Juveniles had a high emigration rate compared to adults. The weekly local survival rate (ϕ) of newly radio-tagged HY birds was 27%. AHY local survival was 95% during incubation and early chick rearing, suggesting a resident population during the breeding season. We calculated juvenile ratios from 1996–1998 using (1) HY counts corrected for emigration and mean AHY counts around the breeding season peak, and (2) HY and AHY counts from concurrent at-sea surveys. The average “corrected” juvenile ratio (0.13 ± 0.05 SE) was higher than the “concurrent” juvenile ratio (0.04 ± 0.02 SE) but lower than estimates of fecundity from nest monitoring (0.18–0.22). Low juvenile ratios from at-sea surveys could result either from an unknown proportion of nonbreeding birds in the population, or, more likely, from differences in the at-sea distribution of AHY and HY birds. Fluctuation in the timing of the peak number of AHY birds across years might result in an uncorrectable bias in the counts. Because of biases and potential problems, caution is needed when interpreting juvenile ratios from at-sea surveys. Supervivencia Local de Brachyramphus marmoratus Adultos y Juveniles y su Importancia para Estimar Éxito Reproductivo Resumen. Utilizamos los cocientes entre individuos juveniles (nacidos en un año) y adultos (nacidos en años anteriores) de Brachyramphus marmoratus, censados simultáneamente durante conteos en el mar, para estimar la fecundidad de esta especie. Estos cocientes “simultáneos” de individuos asumen que los juveniles permanecen en una misma área, y podrían estar sesgados ya que no toman en cuenta diferencias en las tasas de migración de juveniles y adultos. Estudiamos las tasas de emigración de individuos juveniles y adultos de B. marmoratus marcados con radio-transmisores. Los juveniles tuvieron una tasa alta de emigración comparada con los adultos. La tasa de supervivencia local semanal (ϕ) para juveniles fue del 27%. La tasa de supervivencia local para adultos durante la incubación e inicio de la cría de polluelos fue del 95%, sugiriendo que se trata de una población residente durante la estación reproductiva. Calculamos el cociente entre juveniles y adultos para 1996–1998 utilizando (1) conteos de juveniles corregidos por emigración y promedio de adultos contados durante el pico de la estación reproductiva, y (2) juveniles y adultos contados simultáneamente durante los censos. El cociente “corregido” promedio entre juveniles a adultos (0.13 ± 0.05 EE) fue mayor que el cociente “simultáneo” (0.04 ± 0.02 EE) pero menor que las estimaciones de fecundidad obtenidas por medio del monitoreo de nidos (0.18–0.22). Los bajos cocientes obtenidos de conteos en el mar podrían explicarse por la presencia de una proporción desconocida de aves no-reproductivas en la población, o, más probablemente, por diferencias existentes en la distribución de juveniles y adultos en el mar. Fluctuaciones anuales en la sincronización del período pico de la estación reproductiva podrían introducir error a los conteos de adultos. Debido a estos sesgos y problemas potenciales, es importante interpretar con cautela los cocientes entre juveniles y adultos obtenidos de conteos en el mar.

Local Survival of Marbled Murrelets in Central California: Roles of Oceanographic Processes, Sex, and Radiotagging

2006 ◽  
Vol 70 (1) ◽  
pp. 78-88 ◽  
Author(s):  
M. ZACHARIAH PEERY ◽  
STEVEN R. BEISSINGER ◽  
ESTHER BURKETT ◽  
SCOTT H. NEWMAN
Keyword(s):  
Central California ◽  
Local Survival ◽  
Marbled Murrelets

Morphometric Variation in Marbled Murrelets, Brachyramphus Marmoratus, in British Columbia

2001 ◽  
Vol 82 (2) ◽  
pp. 41 ◽  
Author(s):  
Cindy L. Hull ◽  
Brett A. Vanderkist ◽  
Lynn W. Lougheed ◽  
Gary W. Kaiser ◽  
Fred Cooke
Keyword(s):  
British Columbia ◽  
Brachyramphus Marmoratus ◽  
Morphometric Variation ◽  
Marbled Murrelets
Sign in / Sign up

Export Citation Format

Share Document