Breeding dispersions and site fidelity of American redstarts (Setophaga ruticilla)

1996 ◽  
Vol 74 (12) ◽  
pp. 2238-2247 ◽  
Author(s):  
R. E. Lemon ◽  
S. Perreault ◽  
G. A. Lozano
Keyword(s):  
Site Fidelity ◽  
Adult Males ◽  
Male Population ◽  
Setophaga Ruticilla ◽  
Young Females ◽  
Breeding Territory ◽  
American Redstarts ◽  
Plumage Maturation ◽  
One Year ◽  
Older Males

We relate features of the breeding dispersions and site fidelity of American redstarts (Setophaga ruticilla) to breeding success and interpret the findings in terms of sexual selection. One-year-old male redstarts show delayed plumage maturation, making male dispersions particularly easy to appreciate. In our study site in New Brunswick, Canada, older males usually arrived early each breeding season and gathered in contiguous territories or neighborhoods, while subadult males arrived later and settled peripherally to the adults. Subadult males constituted about 40% of the male population, on average, yet only 5% of banded nestlings returned to the natal breeding ground. Also, newly adult males, 2 years old or more, constituted about 15% of all males. Nearly 50% of adult males returned, twice the return rate of subadults. Among returns, older males returned more often to the same territory than did those that were subadult the previous year. Regardless of age, returns of males in a subsequent year were predicted more by the duration of their stay on the breeding territory than reproductive success. Males outnumbered females. Females returned less often than their mates, but more often if they had fledged young. Females rarely returned to the same mate or territory, but often returned to the same vicinity. The subadult males seem to represent a special dispersive phase of the life history. The evidence indicates strong competition among males for territories and females, older males being more often successful in both circumstances.

Effects of age and photoperiod on reproduction and the spleen in the marsh rice rat (Oryzomys palustris)

2001 ◽  
Vol 280 (4) ◽  
pp. R1249-R1255 ◽  
Author(s):  
Kent E. Edmonds ◽  
Milton H. Stetson
Keyword(s):  
Adult Male ◽  
Reproductive Organ ◽  
Spleen Weight ◽  
Adult Males ◽  
Young Females ◽  
Reproductive Response ◽  
Body Weights ◽  
Marsh Rice Rat ◽  
Oryzomys Palustris ◽  
Older Males

To examine the interactions between age and photoperiod on reproduction and spleen weights, we exposed adult male and female rice rats of various ages to photoperiods of 16:8-h light-dark photoperiods (16L:8D) or 12L:12D. After 10 wk, animals were killed and the following data were recorded: weights of testes, seminal vesicles, uterus, ovaries, body, and spleen and, in addition, vaginal patency. Young adult males displayed a greater degree of testicular and seminal vesicle regression in short photoperiods than did older males; the testes of most older males did not regress in response to short photoperiods. Spleen weight was unresponsive to short photoperiods in all males, but was affected by age. Females, however, exhibited reproductive organ regression and decreased vaginal patency in response to short photoperiods at all ages examined. Body weights were affected by photoperiod in young females, and, as in males, photoperiod had no effect on spleen weights. These data suggest that the reproductive response to photoperiod in adult male rice rats declines with age, whereas in adult females it does not.

scholarly journals Social cues facilitate habitat selection: American redstarts establish breeding territories in response to song

2006 ◽  
Vol 2 (3) ◽  
pp. 337-340 ◽  
Author(s):  
Beth A Hahn ◽  
Emily D Silverman
Keyword(s):  
Habitat Selection ◽  
Local Population ◽  
Breeding Habitat ◽  
Conspecific Attraction ◽  
Adult Males ◽  
Settlement Cues ◽  
Migratory Songbirds ◽  
American Redstarts ◽  
Spring Arrival ◽  
Northern Temperate Forests

For migratory songbirds nesting in northern temperate forests, a short breeding season demands that males rapidly establish territories. Because critical insect and vegetation resources are unavailable during spring arrival, we suggest that conspecifics serve as settlement cues for males new to a local population. To test conspecific attraction, we conducted playback experiments with American redstarts Setophaga ruticilla . Experimental results demonstrate that song playbacks strongly attract conspecifics, recruiting an average of 4.2 additional males per plot; adult males new to our sites increased, while yearling males failed to respond. Yearlings arrived 6 to 10 days later than adults, raising the possibility that yearlings responded to songs of early arriving adults rather than to playbacks. Our work indicates that conspecific attraction is an important mechanism for breeding habitat selection in an established population of a migratory forest songbird, but the effect is moderated by age, reproductive experience and arrival timing.

Mating success of alternative male phenotypes and evidence for frequency-dependent selection in Chinook salmon, Oncorhynchus tshawytscha

2010 ◽  
Vol 67 (12) ◽  
pp. 1933-1941 ◽  
Author(s):  
Barry A. Berejikian ◽  
Donald M. Van Doornik ◽  
Rob C. Endicott ◽  
Timothy L. Hoffnagle ◽  
Eugene P. Tezak ◽  
...  
Keyword(s):  
Mating Success ◽  
Oncorhynchus Tshawytscha ◽  
Pacific Salmon ◽  
Adult Males ◽  
Frequency Dependent ◽  
Frequency Dependent Selection ◽  
Male Density ◽  
The Family ◽  
Breeding Groups ◽  
One Year

As with other species, frequency-dependent selection during reproduction has long been proposed as an important mechanism in maintaining alternative male reproductive phenotypes in Pacific salmon ( Oncorhynchus spp.). Jack salmon mature one year earlier than the youngest females in a population and are much smaller than older “adult” males. We tested the hypothesis that mating success of both phenotypes is consistent with the frequency-dependent selection model. By holding male density constant and varying the frequency of adults and jacks in eight separate breeding groups, we found that adult male access to females, participation in spawning events, and adult-to-fry reproductive success increased with their decreasing frequency in a breeding group. Jacks exhibited the same pattern (increasing success with decreasing frequency), although the relationships were not as strong as for adults. Overall, jack and adult males mated with a similar number of females, but jacks sired only 20% of all offspring. Observational data suggested that adult males benefited from sperm precedence associated with their ability to court females and enter the nest first at the time of spawning. Our work provides the first experimental evidence of frequency-dependent selection during mating in the family Salmonidae.

scholarly journals The development of affiliative and coercive reproductive tactics in male chimpanzees

2021 ◽  
Vol 288 (1942) ◽  
pp. 20202679
Author(s):  
Rachna B. Reddy ◽  
Kevin E. Langergraber ◽  
Aaron A. Sandel ◽  
Linda Vigilant ◽  
John C. Mitani
Keyword(s):  
Mating Success ◽  
Sexual Coercion ◽  
Adolescent And Young Adult ◽  
Adolescent Male ◽  
Male Mating ◽  
Adult Males ◽  
Reproductive Tactics ◽  
Males And Females ◽  
First Time ◽  
Older Males

Like many animals, adult male chimpanzees often compete for a limited number of mates. They fight other males as they strive for status that confers reproductive benefits and use aggression to coerce females to mate with them. Nevertheless, small-bodied, socially immature adolescent male chimpanzees, who cannot compete with older males for status nor intimidate females, father offspring. We investigated how they do so through a study of adolescent and young adult males at Ngogo in Kibale National Park, Uganda. Adolescent males mated with nulliparous females and reproduced primarily with these first-time mothers, who are not preferred as mating partners by older males. Two other factors, affiliation and aggression, also influenced mating success. Specifically, the strength of affiliative bonds that males formed with females and the amount of aggression males directed toward females predicted male mating success. The effect of male aggression toward females on mating success increased as males aged, especially when they directed it toward females with whom they shared affiliative bonds. These results mirror sexual coercion in humans, which occurs most often between males and females involved in close, affiliative relationships.

Effects of adults on survival and recruitment of Peromyscus leucopus

1987 ◽  
Vol 65 (10) ◽  
pp. 2519-2523
Author(s):  
Gregory H. Adler ◽  
Mark L. Wilson ◽  
Michael J. DeRosa
Keyword(s):  
Adult Female ◽  
Adult Male ◽  
Peromyscus Leucopus ◽  
Survival Rates ◽  
Adult Males ◽  
Control Grid ◽  
Young Males ◽  
Young Females ◽  
Breeding Seasons ◽  
And Control

A population of Peromyscus leucopus (white-footed mouse) in northeastern Massachusetts was manipulated for 3 years to determine the effects of adults on survival and recruitment. Two experimental grids were established, from which either all adult males or all adult females were removed continually. The effects of these two manipulations were compared with demography on a control grid. Manipulations had no apparent effect on breeding intensity of young, survival rates of adults, or residency rates of adults and young. Recruitment of adult males was higher on the adult male removal grid than on the control grid. Recruitment rates of adult males and of young males and young females were lower on the adult female removal grid than on the control grid. Survival rates of young males were higher on the adult female removal grid than on the control grid; this effect may have been due to either reduced adult female residency or adult male recruitment. All differences between experimental and control grids were noted only during breeding seasons. Adult males apparently limited recruitment of adult consexuals. The effects of manipulations on other measured parameters were inconclusive because of high immigration rates of adult males onto the adult male removal grid and reduced recruitment of adult males and decreased production of young on the adult female removal grid.

scholarly journals Low-frequency arterial pressure fluctuations do not reflect sympathetic outflow: gender and age differences

1998 ◽  
Vol 274 (4) ◽  
pp. H1194-H1201 ◽  
Author(s):  
J. Andrew Taylor ◽  
Todd D. Williams ◽  
Douglas R. Seals ◽  
Kevin P. Davy
Keyword(s):  
Arterial Pressure ◽  
Low Frequency ◽  
Total Activity ◽  
Sympathetic Outflow ◽  
Pressure Oscillations ◽  
Young Males ◽  
Young Females ◽  
Sympathetic Nervous ◽  
Mayer Wave ◽  
Older Males

Low-frequency arterial pressure oscillations (Mayer waves) have been proposed as an index of vascular sympathetic outflow. However, cross-sectional differences in these pressure oscillations may not reflect different levels of sympathetic nervous outflow in humans. Three groups of healthy subjects with characteristically different sympathetic nervous outflow were studied: young females ( n = 10, 18–28 yr), young males ( n = 11, 18–29 yr), and older males ( n = 13, 60–72 yr). Average R-R interval, arterial pressures, and systolic pressure variability at the Mayer wave frequency (0.05–0.15 Hz) did not differ among the three groups. Diastolic pressure Mayer wave variability was similar in young females vs. young males (39 ± 10 vs. 34 ± 5 mmHg2) and lower in older males vs. young males (14 ± 2 mmHg2; P < 0.05). In contrast, muscle sympathetic activity was lowest in young females (892 ± 249 total activity/min) and highest in older males (3,616 ± 528 total activity/min; both P < 0.05 vs. young males: 2,505 ± 285 total activity/min). Across the three groups, arterial pressure Mayer wave variability did not correlate with any index of sympathetic activity. Our results demonstrate that arterial pressure Mayer wave amplitude is not a surrogate measure of vascular sympathetic outflow.

Dominance Structuring of a Red-Winged Blackbird Roost

The Auk ◽  
1984 ◽  
Vol 101 (3) ◽  
pp. 551-555 ◽  
Author(s):  
Patrick J. Weatherhead ◽  
Drew J. Hoysak
Keyword(s):  
Deep Water ◽  
Agelaius Phoeniceus ◽  
Sexually Dimorphic ◽  
Adult Males ◽  
Sparse Vegetation ◽  
Dense Vegetation ◽  
Dimorphic Species ◽  
Older Males

Abstract Observations of the behavior of roosting male Red-winged Blackbirds (Agelaius phoeniceus) indicated that after hatching year (AHY) males were dominant over hatching year (HY) males. This dominance resulted in AHY males occupying central roost positions in dense vegetation and HY males occupying edge positions in sparse vegetation. Overall, the birds preferred positions over deep water, although the edge positions of HY males were over deeper water than were the positions of AHY males. These results are consistent with the two-strategies roosting hypothesis (Weatherhead 1983), in that the dominance of older males allows them access to roost positions with relatively low vulnerability to predation. In this study, these positions also appeared to be microclimatically superior. These results also suggest that the bright plumage of adult males of sexually dimorphic species may be advantageous in some nonbreeding situations in addition to their more commonly recognized role in reproduction.

scholarly journals Pyogenic granuloma - report of three cases in rare sites

2013 ◽  
Vol 12 (4) ◽  
pp. 445-448
Author(s):  
AN Sulabha ◽  
S Choudhari ◽  
G Suchitra
Keyword(s):  
Oral Cavity ◽  
Buccal Mucosa ◽  
Hard Palate ◽  
Medical Science ◽  
Surgical Excision ◽  
Pyogenic Granuloma ◽  
Patient Treatment ◽  
Young Females ◽  
One Year

Pyogenic granuloma is a benign, localized mass of exuberant granulation tissue produced in response to various stimuli. It is inflammatory hyperplasia of oral cavity commonly seen on gingival area and rarely on other parts of oral cavity such as lips, tongue, palate and buccal mucosa. It is seen predominantly in 2nd to 3rd decade of life in young females. Clinically manifesting as small red erythematous exophytic lesion, it must be biopsied to rule out other serious conditions. This article aims to present three cases of extra gingival pyogenic granulomas occurring in rare sites such as buccal mucosa, anterior hard palate and alveolar mucosa of completely edentulous ridge in maxilla. Pyogenic granuloma on buccal mucosa and anterior hard palate were seen in female patients with age of 40 years and 34 years respectively and pyogenic granuloma on alveolar mucosa of edentulous ridge in maxilla was noted in 70 years old male patient. Surgical excision was performed for all the lesion and follow up of one year did not show any recurrence. Please add little description of patient + treatment + followup results. DOI: http://dx.doi.org/10.3329/bjms.v12i4.16667 Bangladesh Journal of Medical Science Vol. 12 No. 04 October ’13 Page 445-448

Dispersal and site fidelity in Blue Grouse

1983 ◽  
Vol 61 (3) ◽  
pp. 570-573 ◽  
Author(s):  
Ian G. Jamieson ◽  
Fred C. Zwickel
Keyword(s):  
Site Fidelity ◽  
General Area ◽  
Adult Males ◽  
Same Sex ◽  
Breeding Sites ◽  
Sibling Pairs ◽  
Dendragapus Obscurus ◽  
Opposite Sex ◽  
Juvenile Males ◽  
Old Females

Ten years of banding and censusing data from Blue Grouse (Dendragapus obscurus) were analyzed with respect to dispersal of juveniles and site fidelity of yearlings and adults. Juvenile females dispersed farther than juvenile males. In sibling pairs of the same sex, brothers settled closer to one another than sisters. In sibling pairs with birds of opposite sex, females dispersed farther than males. Adult males first established territories close to where they had been sighted as yearlings, or nonterritorial adults, and most females returned in spring to the same general area where they had previously nested. Two-year-old females showed less fidelity to breeding sites they had used as yearlings than older females to sites they had used in previous years.

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