Influence of Group Size and Habitat Type on Reproductive Success in Common Murres (Uria aalge)

The Auk ◽  
1995 ◽  
Vol 112 (2) ◽  
pp. 390-401 ◽  
Author(s):  
Julia K. Parrish
Keyword(s):  
Reproductive Success ◽  
Group Size ◽  
Habitat Type ◽  
Uria Aalge ◽  
Common Murres

Extra-pair copulations in common murres I: a mate attraction strategy?

Behaviour ◽  
2006 ◽  
Vol 143 (10) ◽  
pp. 1241-1262 ◽  
Author(s):  
Maureen L. Cameron-Macmillan ◽  
Carolyn J. Walsh ◽  
Sabina I. Wilhelm ◽  
Anne E. Storey
Keyword(s):  
Reproductive Success ◽  
Uria Aalge ◽  
Success Rates ◽  
High Quality ◽  
Mate Attraction ◽  
Extra Pair Paternity ◽  
Socially Monogamous ◽  
Common Murres ◽  
Breeding Seasons

AbstractWe investigated the behavioural context of pair (PCs) and extra-pair copulations (EPCs) in individually-marked socially-monogamous, long-lived seabirds, common murres (Uria aalge). Since forced EPCs have been documented for this species, we first examined which sex controls successful (cloacal contact achieved) copulation. The finding that all successful copulations required female cooperation and crouching suggested that benefits of successful EPCs accrue primarily to females. In a group of murres for which paternity analyses indicated no extra-pair paternity, behavioural observations over five breeding seasons showed that individual females engaged in EPCs primarily under two circumstances: (1) before they were reunited with their mates, and (2) when they were in the process of re-pairing. There was no such relationship between EPCs and re-pairing for males. Successful EPCs occurred with familiar neighboring males of apparent high quality, indicated by their high ledge attendance and prior reproductive success rates. Thus, EPCs may be used by females to attract potential high quality mates in situations where females are attempting to re-pair as a result of divorce or mate death.

scholarly journals Ecological interactions and habitat modification in nesting Common Murres, Uria aalge

1996 ◽  
Vol 6 (3) ◽  
pp. 261-269 ◽  
Author(s):  
Julia K. Parrish ◽  
Robert T. Paine
Keyword(s):  
Reproductive Output ◽  
Habitat Modification ◽  
Haliaeetus Leucocephalus ◽  
Uria Aalge ◽  
Ecological Interactions ◽  
Bald Eagles ◽  
Predator Removal ◽  
Common Murre ◽  
Corvus Caurinus ◽  
Common Murres

SummarySeabird populations suffer from a variety of natural and human-induced sources of mortality and loss of lifetime reproductive output. On the outer coast of Washington State, Common Murre Uria aalge populations have been in decline for approximately the last decade and are currently reproductively active only at Tatoosh Island. These murres nest in two basic habitat types: crevices (25% of the population) and larger cliff-top subcolonies (75%). Murres in cliff-top subcolonies have suffered dramatic reductions in reproductive success in recent years relative to conspecifics nesting in the crevices, primarily due to egg predation by Glaucous-winged Gulls Larus glaucescens and Northwestern Crows Corvus caurinus, facilitated by the presence of Bald Eagles Haliaeetus leucocephalus. Because predator removal is not feasible and creation of additional crevice habitat is difficult, expensive and potentially ineffective, we have designed a temporary habitat modification (the “silk forest”) which replaces the natural vegetation cover and modifies the interaction between murres and eagles. Within the test subcolony, murres nesting under and immediately adjacent to the silk forest produced nearly twice as many eggs per square metre as their conspecifics nesting in adjacent exposed-ground areas.

Seasonal Habitat Use by Nubian Ibex (Capra Nubiana) Evaluated with Behavioral Indicators

2011 ◽  
Vol 57 (3) ◽  
pp. 223-246 ◽  
Author(s):  
Solomon A. Tadesse ◽  
Burt P. Kotler
Keyword(s):  
Group Size ◽  
Age Structure ◽  
Time Allocation ◽  
Environmental Variables ◽  
Time Budget ◽  
Habitat Type ◽  
Time Budgets ◽  
Behavioral Models ◽  
Risk Of Predation ◽  
Focal Observation

Nubian ibex (Capra nubiana) prefer steep terrain in their landscape to reduce risks of predation and human nuisance disturbances. They also use vigilance and time allocation to manage risk of predation. We studied time budgets and habitat selection of Nubian ibex to: (1) identify the habitat variables to which Nubian ibex were behaviorally responsive; (2) investigate how time budget responses of Nubian ibex were related to season, slope condition, group size, and sex-age structure; and (3) develop behavioral-based models that account for the variations in the behaviors of Nubian ibex across the landscape and seasons.To quantify time budgets, we took regular field observations on focal individuals of Nubian ibex classified according to their habitat, group size, sex, and age. For each focal observation, we quantified environmental variables that were thought to influence the behavioral responses of ibex. Then, we developed behavioral models by correlating the proportion of behaviors measured in focal animal observations to the influential environmental variables. The behaviors of Nubian ibex significantly varied with sex and age structure, season, habitat type, and slope conditions. Adult females are more vigilant than adult male ibex, especially in the spring. This correlates with breeding and nursing activities. Based on the characteristics of the habitat, ibex behave to minimize risks of predation and human nuisance disturbances while maximizing their food intake.

scholarly journals Fitness of breeders in social Damaraland mole-rats is independent of group size

2021 ◽  
Author(s):  
Jack Thorley ◽  
Hanna Bensch ◽  
Kyle Finn ◽  
Tim Clutton-Brock ◽  
Markus Zöttl
Keyword(s):  
Reproductive Success ◽  
Group Size ◽  
Survival Rates ◽  
Group Living ◽  
Adult Survival ◽  
High Survival ◽  
Successful Reproduction ◽  
Related Group ◽  
Group Members ◽  
Using Data

Damaraland mole-rats (Fukomys damarensis) are usually viewed as an obligatorily group living eusocial species in which successful reproduction is dependent on reproductive altruism of closely related group members. However, the reproductive ecology of social mole-rats in their natural environment remains poorly understood and it is unclear to what extent successful reproduction is dependent on assistance from other group members. Using data from a 7-year field study of marked individuals, we show that, after dispersal from their natal group, individuals typically settled alone in new burrow systems where they enjoyed high survival rates, and often remained in good body condition for several years before finding a mate. Unlike most other eusocial or singular cooperative breeders, we found that Damaraland mole-rats reproduced successfully in pairs without helpers and experimentally formed pairs had the same reproductive success as larger established groups. Overall there was only a weak increase in reproductive success with increasing group size and no effect of group size on adult survival rates across the population. Juveniles in large groups grew faster early in life but their growth rates declined subsequently so that they eventually plateaued at a lower maximum body mass than juveniles from small groups. Taken together, our data suggest that the fitness benefits of group living to breeders are small and we suggest that extended philopatry in Damaraland mole-rats has evolved because of the high costs and constraints of dispersal rather than because of strong indirect benefits accrued through cooperative behaviour.

Exceptional variation in the appearance of Common Murre eggs reveals their potential as identity signals

The Auk ◽  
2021 ◽  
Author(s):  
Tim R Birkhead ◽  
Jamie E Thompson ◽  
Amelia R Cox ◽  
Robert D Montgomerie
Keyword(s):  
Uria Aalge ◽  
Quantitative Evidence ◽  
Breeding Group ◽  
Common Murre ◽  
Trimodal Distribution ◽  
Common Murres ◽  
Egg Traits ◽  
Breeding Groups ◽  
Different Parts

Abstract We studied the ground colors and maculations of 161 Common Murre (Uria aalge) eggs laid by 43 females in 3 small breeding groups on the cliffs of Skomer Island, Wales, in 2016–2018. Both the colors and maculations varied much more among than within females, providing quantitative evidence for the egg traits that might facilitate the parents’ ability to identify their own eggs on the crowded breeding ledges where the density is typically ~20 eggs m–2. Ground colors had a trimodal distribution of hue values (whitish to pale brown, pale blue, or vivid blue-green) and maculations ranged from none to complex squiggles and blotches. The eggs laid by each female in different years were similar to one another, and replacement eggs laid by females within years were also more similar to their first egg than to other eggs in the same breeding group. Egg appearance did not differ among the 3 breeding groups that we studied. Our findings thus support anecdotal observations that, within and between years, female Common Murres lay eggs that have similar ground colors and maculations. We do not, however, find evidence that there is much difference among the eggs laid in different parts of a colony.

Does habitat type modify group size in roe deer and red deer under predation risk by Iberian wolves?

2008 ◽  
Vol 86 (3) ◽  
pp. 170-176 ◽  
Author(s):  
I. Barja ◽  
S. Rosellini
Keyword(s):  
Predation Risk ◽  
Group Size ◽  
Cervus Elaphus ◽  
Red Deer ◽  
Roe Deer ◽  
Habitat Type ◽  
Capreolus Capreolus ◽  
Antipredator Response ◽  
The Mean ◽  
Grouping Behavior

We examined whether group size in red deer ( Cervus elaphus L., 1758) and roe deer ( Capreolus capreolus (L., 1758)) under predation risk by Iberian wolves ( Canis lupus L., 1758) is affected by the type of habitat in which the deer reside. We hypothesized that group size (i) would be larger in open than in closed habitats, since it is an antipredator response, and (ii) would vary more with habitat type in the species that had higher wolf predation rates. In the study area, wolves were the only predator of wild ungulates, with roe deer being the main target prey. We performed monthly transects along paths to observe the group size of red and roe deer. In roe deer, the mean group size was significantly higher in open than in closed habitats, serving as an antipredator response. However, in red deer, habitat type did not affect group size. The results indicate that under predation risk by wolves the habitat type influences the grouping behavior of roe deer but not red deer. Furthermore, compared with forests, heaths offer less protection from predators and species in this habitat would benefit from larger group sizes.

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