Variable Reproductive Success of Bald Eagles on the British Columbia Coast

1998 ◽  
Vol 62 (2) ◽  
pp. 518 ◽  
Author(s):  
John E. Elliott ◽  
Ian E. Moul ◽  
Kimberly M. Cheng
Keyword(s):  
British Columbia ◽  
Reproductive Success ◽  
Bald Eagles

scholarly journals Bald Eagles, Haliaeetus leucocephalus, Feeding on Spawning Plainfin Midshipman, Porichthys notatus, at Crescent Beach, British Columbia

2003 ◽  
Vol 117 (4) ◽  
pp. 601 ◽  
Author(s):  
Kyle Hamish Elliott ◽  
Christina L. Struik ◽  
John E. Elliott
Keyword(s):  
British Columbia ◽  
Nous Avons ◽  
Food Source ◽  
Haliaeetus Leucocephalus ◽  
Potential Importance ◽  
Bald Eagles ◽  
Porichthys Notatus ◽  
Tide Height ◽  
Consumption Rates ◽  
Plainfin Midshipman

We observed Bald Eagles feeding on Plainfin Midshipman near Crescent Beach, British Columbia, in May and June 2001 and 2002. We quantified consumption rates and eagle numbers during this period, illustrating the potential importance of this food source to breeding eagles. Tide height was the only significant factor influencing consumption rates, likely because this variable reflected the availability of midshipman prey.Nous avons observé les Pygargues à tête blanche alimenter sur les Crapauds à nageoire unie près de Crescent Beach, Colombie-Britannique, en maie et juin 2001 et 2002. Nous avons mesuré les cadences de consommation et les nombres de pygargues pendant cette période, illustrant l’importance potentielle de cette source de nourriture pour les aigles. La taille de marée était le seul facteur significatif influençant les cadences de consommation et les nombres de pygargues pendant la période d’étude, probablement parce que cette variable a reflété la disponibilité des crapauds.

Observations of Breeding Bald Eagles in Southeastern British Columbia

The Murrelet ◽  
1984 ◽  
Vol 65 (1) ◽  
pp. 22
Author(s):  
L. Scott Forbes ◽  
Gary W. Kaiser
Keyword(s):  
British Columbia ◽  
Bald Eagles

Why breed early? A study of reproductive tactics in Peromyscus

1977 ◽  
Vol 55 (5) ◽  
pp. 862-871 ◽  
Author(s):  
Daphne J. Fairbairn
Keyword(s):  
British Columbia ◽  
Reproductive Success ◽  
Peromyscus Maniculatus ◽  
Frequent Occurrence ◽  
Deer Mice ◽  
Reproductive Tactics ◽  
Selection Pressures ◽  
Bimodal Pattern ◽  
Early Peak ◽  
Males And Females

Female deer mice (Peromyscus maniculatus) near Vancouver, British Columbia, were found to have a bimodal pattern of breeding. This paper compares the success of females that attempted to breed in the early peak of breeding with that of females that did not breed until the later breeding peak. While the average success was about the same for the two tactics, early breeding had a much higher variance. It is suggested that this difference in variances would result in eventual elimination of the early-breeding phenotype, unless it were favored by other factors. Differences in the selection pressures on males and females, and the relatively frequent occurrence of years of good reproductive success for early-breeding females, may contribute to the maintenance of this phenotype in the population. A hypothesis is presented to explain both the bimodality of the breeding pattern, and the dominance of the second breeding peak.

scholarly journals The relative contribution of individual quality and changing climate as drivers of lifetime reproductive success in a short-lived avian species

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Lisha L. Berzins ◽  
Russell D. Dawson ◽  
Christy A. Morrissey ◽  
Robert G. Clark
Keyword(s):  
British Columbia ◽  
Life History ◽  
Reproductive Success ◽  
Environmental Conditions ◽  
Avian Species ◽  
Life History Trait ◽  
Lifetime Reproductive Success ◽  
Positive Effects ◽  
Changing Climate ◽  
Animal Populations

AbstractAnimal populations are influenced strongly by fluctuations in weather conditions, but long-term fitness costs are rarely explored, especially in short-lived avian species. We evaluated the relative contributions of individual characteristics and environmental conditions to lifetime reproductive success (LRS) of female tree swallows (Tachycineta bicolor) from two populations breeding in contrasting environments and geographies, Saskatchewan and British Columbia, Canada. Female swallows achieved higher LRS by breeding early in the season and producing more fledglings. Other measures of female quality had virtually no influence on LRS. Genetic factors did not predict LRS, as there was no correlation between life-history components for sister pairs nor between mothers and their daughters. Instead, climate variability—indexed by spring pond density (i.e., abundance of wetland basins holding water) during years when females bred—had strong positive effects on female LRS in more arid Saskatchewan but only weak positive effects of moisture conditions were detected in wetter British Columbia. Overall, several life history trait correlates of LRS were similar between populations, but local environmental factors experienced by individuals while breeding produced large differences in LRS. Consequently, variable and extreme environmental conditions associated with changing climate are predicted to influence individual fitness of distinct populations within a species’ range.

Sign in / Sign up

Export Citation Format

Share Document