Reproductive biology, breeding seasons, and growth of eastern chipmunks, Tamias striatus (Rodentia: Sciuridae) in Canada

1972 ◽  
Vol 50 (8) ◽  
pp. 1069-1085 ◽  
Author(s):  
Lorraine C. Smith ◽  
Donald A. Smith
Keyword(s):  
Reproductive Age ◽  
Adult Size ◽  
Museum Specimens ◽  
Adult Males ◽  
Tamias Striatus ◽  
Breeding Condition ◽  
Eastern Chipmunks ◽  
June July ◽  
Breeding Seasons ◽  
Size Data

Reproductive, age, and body-size data from 1403 museum specimens from Manitoba to Nova Scotia and data on live chipmunks studied in the field in southeastern Ontario were analyzed. Schedules of the major stages of reproduction and growth are summarized graphically. Most adult males are in breeding condition (with large testes in black scrotal sacs and macroscopic tubules in caudae epididymidon) from March to June. As females can breed in March–April and (or) June–July, eastern chipmunks are unique among hibernating sciurids in that they have two breeding seasons per year. These occur over much of the Canadian range, with distinct waves of young appearing above ground in June and September. Spring breeding is probably annual and ubiquitous but records are too few to reveal the local frequency of summer breeding. Young have emerged in four consecutive Septembers at Stanley Corners, Ontario. Litter sizes from embryo and scar counts averaged 4.8 and 4.9. Although the young attain adult size and dentition in 3 months, most do not breed until 11 months old. We have questioned or explained conflicting reports and conclude that the breeding habits of Canadian chipmunks are essentially similar to those described by some U.S. workers.

Oestrus, copulation, and related aspects of reproduction in female eastern chipmunks, Tamias striatus (Rodentia: Sciuridae)

1975 ◽  
Vol 53 (6) ◽  
pp. 756-767 ◽  
Author(s):  
Donald A. Smith ◽  
Lorraine C. Smith
Keyword(s):  
Local Population ◽  
External Genitalia ◽  
Copulatory Behavior ◽  
Supplementary Data ◽  
Considerable Variability ◽  
Tamias Striatus ◽  
Population Breeding ◽  
Eastern Chipmunks ◽  
Breeding Seasons

Weekly livetrapping in a southeastern Ontario woodlot throughout 2 years of aboveground activity by Tamias striatus lysteri, plus supplementary data, provided information on changes in the external genitalia of female chipmunks before, during, and alter oestrus. The main stages are described and tentatively named. Oestrus was marked by a deep pink, greatly distended vulva and eventually by an elongated aperture. Our finding that oestrus lasted at least 3 days and up to 10 days is new. Post-oestrus, in which the vulva was less distended, persisted throughout half or most of gestation. There was much variability among individuals in the duration of oestrus and related stages. Copulatory behavior is described. Most observations of oestrus and copulation in Canada relate to the summer breeding season.In our local population, breeding occurred in both spring and summer, 1972, but only in spring, 1973. There was considerable variability among individual females of breeding age regarding participation in one or both breeding seasons in 1972. Among females breeding in the summer of 1972, those that had bred in the spring came into oestrus near the time when their spring young emerged from their burrows, and later than those that had not bred in the spring.

scholarly journals Age of maturation and behavioral tactics in male yellow ground squirrel Spermophilus fulvus during mating season

2014 ◽  
Vol 60 (6) ◽  
pp. 700-711 ◽  
Author(s):  
Nina A. Vasilieva ◽  
Ekaterina V. Pavlova ◽  
Sergey V. Naidenko ◽  
Andrey V. Tchabovsky
Keyword(s):  
Body Size ◽  
Ground Squirrel ◽  
Life History Theory ◽  
Social Activity ◽  
Indirect Evidence ◽  
Adult Size ◽  
Adult Males ◽  
Mating Season ◽  
Active Season ◽  
Good Physical Condition

Abstract Life-history theory predicts that in hibernators age of maturation is related positively to body size and negatively to the duration of active season aboveground. Yellow souslik is a large-sized ground squirrel with long hibernation, which suggests late maturation. We used four-year field observations of marked individuals to determine the age of maturation in males through analysis of age-dependent variation in body size, mass, androgen status, timing of spring emergence, ranging patterns and social behavior during the mating season. Yearling males were smaller, lighter, had lower level of fecal testosterone, emerged later and had smaller home ranges than older males. Social activity and the number of females encountered did not differ between age classes. After the second hibernation none of the studied parameters varied with age. Cluster analysis revealed two behavioral tactics: “active” males (adults only) emerged earlier, ranged more widely, initiated more contacts, encountered more females and were heavier than “passive” males (both yearling and adult). Thus, males of S. fulvus reached adult size and matured after two hibernations, which is relatively fast for such a big species with short active period. Indirect evidence for copulations and high variation among yearlings in all parameters suggest that some of them might successfully compete with adults. Active tactic of wandering and searching for females is energetically costly, and probably only adult males in good physical condition can afford it, whereas passive tactic of residing is energy saving and good for adults in poor condition and for yearlings that are continuing to grow.

Hibernation of eastern chipmunks (Tamias striatus) maintained under controlled conditions

1972 ◽  
Vol 50 (1) ◽  
pp. 95-105 ◽  
Author(s):  
Grace Workman Scott ◽  
Kenneth C. Fisher
Keyword(s):  
Temperature Sensors ◽  
Endogenous Rhythm ◽  
Bottom Temperature ◽  
Tamias Striatus ◽  
Controlled Conditions ◽  
Eastern Chipmunks ◽  
First Time ◽  
Periodic Arousals

The hibernation pattern of captive eastern chipmunks maintained under controlled conditions of light and temperature was examined. It was consistent with the view that hibernation results from an endogenous rhythm with a periodicity of about a year, probably temperature independent.Continuous recording from nest bottom temperature sensors was tested for the first time with this species and found to be more accurate than the sawdust technique for detecting arousals. It also provided useful information about trends in body temperature.The hypothesis that a shift in the temperature at which heat-producing responses are mobilized occurs during hibernation and that it is responsible for the pattern of periodic arousals, is discussed in relation to the observations made.

The ecology of the deer mouse Peromyscus maniculatus in a coastal coniferous forest. II. Reproduction

1974 ◽  
Vol 52 (1) ◽  
pp. 119-131 ◽  
Author(s):  
R. M. F. S. Sadleir
Keyword(s):  
Deer Mouse ◽  
Coniferous Forest ◽  
Deer Mice ◽  
Reproductive Phenology ◽  
Corpora Lutea ◽  
Temperature Changes ◽  
Four Seasons ◽  
Different Types ◽  
Breeding Condition ◽  
Breeding Seasons

The duration and intensity of reproduction in deer mice was followed for four seasons by live and dead trapping. Three populations living in different types of forest habitat had synchronous breeding seasons, although there were major differences between years in the time of onset and cessation of breeding and in the proportion of females in breeding condition. No consistent relationships were found between either density changes or the incidence of parasitism and reproductive phenology. In the absence of overt food fluctuations there was a relationship between unseasonable temperature changes and breeding. Sudden increases in temperature may have stimulated the onset of breeding but its cessation before the autumn equinox was always associated with a considerable decrease in temperature if this occurred after April. In 57 pregnancies the corpora lutea count was 4.75 ± 1.12 and embryo count was 4.52 ± 1.16. [Formula: see text].

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 Evidence of breeding activity of subadult Turdus thrushes in Argentina

2019 ◽  
Vol 27 (3) ◽  
pp. 149-152
Author(s):  
Exequiel Barboza ◽  
Patricia Capllonch ◽  
Fernando Diego Ortiz ◽  
Alex E. Jahn
Keyword(s):  
Population Dynamics ◽  
Life History ◽  
Bird Species ◽  
Life History Strategies ◽  
Brood Patch ◽  
Breeding Condition ◽  
Different Populations ◽  
Males And Females ◽  
Breeding Seasons ◽  
Subadult Female

AbstractLittle is known about the age at which many Neotropical bird species first attempt to breed. We evaluated the breeding condition of 515 adult and subadult males and females among four species of Turdus thrushes (T. nigriceps, T. chiguanco, T. amaurochalinus and T. rufiventris) in Tucumán, Argentina during three breeding seasons (2015 to 2018). We registered a total of 126 individuals with brood patches and cloacal protuberances, which accounted for 24.5% of thrushes in breeding condition that we sampled. Forty thrushes had a brood patch (31.7% of those in breeding condition), of which 11 were subadults (8.7%). Eighty-six thrushes (68.3%) had a swollen cloacal protuberance, 18 of which were subadults (14.3%). Only a few of the subadults in breeding condition built nests, incubated eggs or raised nestlings. Of 130 nests we found, only 3 belonged to a subadult thrush (in all cases, a subadult female with an adult social mate), one of which was successful. Further research on these patterns among various Neotropical bird species could lead to important insights into the life history strategies that characterize different populations, and how these ultimately affect their population dynamics.

The green turtle, Chelonia mydas, in Queensland: breeding males in the southern Great Barrier Reef

1993 ◽  
Vol 20 (4) ◽  
pp. 513 ◽  
Author(s):  
CJ Limpus
Keyword(s):  
Great Barrier Reef ◽  
Green Turtle ◽  
Carapace Length ◽  
Chelonia Mydas ◽  
Barrier Reef ◽  
Adult Males ◽  
Green Turtles ◽  
Adult Females ◽  
Breeding Seasons ◽  
Slow Growing

Breeding male green turtles, Chelonia mydas, at any one courtship area in the southern Great Barrier Reef mate with females that will nest on rookeries spread throughout the region. In comparison with the breeding females from the same breeding unit, the males are smaller in curved carapace length, and a higher proportion of males remigrate for additional breeding seasons at 1-2-year intervals. Like the adult females, adult males are slow-growing, averaging 0.046 cm year-1. Each male appears to display a fidelity to a particular courtship area, to which it returns in successive breeding migrations. At the conclusion of the courtship period, the males disperse to widely scattered feeding areas.

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