Population ecology of the Australian frog Crinia signifera: adults and juveniles

1996 ◽  
Vol 23 (3) ◽  
pp. 249 ◽  
Author(s):  
CM Bull ◽  
I Williamson
Keyword(s):  
Breeding Season ◽  
Population Ecology ◽  
South Australia ◽  
Adult Mortality ◽  
Large Size ◽  
Early Emergence ◽  
The Common ◽  
Males And Females ◽  
A Site ◽  
Breeding Seasons

A population of the common Australian frog Crinia signifera Girard, 1853 was studied over a 3.5 year period at a site near Bridgewater in South Australia. In this population, C. signifera are long lived and iteroparous, with some individual males and females participating in at least four consecutive breeding seasons. Adult survivorship was high (up to about 70% per annum) for both males and females. Metamorphosis occurred from October to January and some individuals reached maturity within a year. However, most individuals reached maturity in the second breeding season following metamorphosis. Survival of juveniles ranged from 5 to 72% per annum, with individuals emerging early having higher survival than those that metamorphosed late. However, it was not clear whether increased survival was associated with early emergence or large size at emergence. The data support the argument that iteroparity is favoured in situations in which preadult mortality is higher and less predictable than adult mortality.

Observations on the biology of the common torpedo (Torpedo torpedo, Linnaeus, 1758) and marbled electric ray (Torpedo marmorata, Risso, 1810) from Egyptian Mediterranean waters

1994 ◽  
Vol 45 (4) ◽  
pp. 693 ◽  
Author(s):  
SH Abdel-Aziz
Keyword(s):  
Reproductive Biology ◽  
Breeding Season ◽  
Reproductive Cycle ◽  
Strong Correlation ◽  
Maximum Size ◽  
Size At Maturity ◽  
Torpedo Marmorata ◽  
Food Items ◽  
The Common ◽  
Males And Females

The reproductive biology and diets of Torpedo torpedo and T. marmorata from Egyptian Mediterranean waters are described. Males and females reached a maximum size of 39.1 and 40.8 cm total length (TL), respectively, in T. torpedo and 38.6 and 61.2 cm TL, respectively, in T. marmorata. The size at maturity of males of T. torpedo and T. marmorata is 18 and 25.5 cm TL, respectively, and of females, is 22 and 35.5 cm TL, respectively. Both species exhibit aplacental viviparity. T. torpedo has a restricted breeding season, and individual females appear to breed annually, whereas T. marmorata females appear to have a more extended reproductive cycle (probably breeding every two years). In both species, males are capable of mating every year. In T. torpedo, mating occurs between December and February, ovulation in March-April, and parturition in late August and September after five to six months of gestation. Individuals of T. marmorata mate between November and January, ovulate between December and February, and give birth the following December after 10-12 months of gestation. Mean embryos sizes are 7.3 cm TL (range 4.6-8.2 cm TL) for T. torpedo and 8.5 cm TL (range 5.8-10.1 cm TL) for T. marmorata. Observations in Egyptian Mediterranean waters show a strong correlation between ovarian and uterine fecundity and the length of the mother in both species. Fish are an important component of the diet of the two species, as, to a lesser extent, are crustaceans for T. torpedo and cephalopods for T. marmorata. Juveniles eat a wide variety of food items, whereas adults feed only on fish.

Reproduction of Pseudomys novaehollandiae (Muridae) in the Wild

1980 ◽  
Vol 7 (3) ◽  
pp. 385 ◽  
Author(s):  
CM Kemper
Keyword(s):  
Breeding Season ◽  
New South ◽  
Reproductive Organs ◽  
First Year ◽  
Reproductive Condition ◽  
South Wales ◽  
In The Wild ◽  
Males And Females ◽  
Preputial Glands ◽  
Breeding Seasons

A total of 291 P. novaehollandiae were observed during a 4-y study in the Nelson Bay and Smith Lake regions of New South Wales. Reproductive organs were examined from males and females, May 1972-May 1974; reproductive condition of females was noted during a CMR study, August 1974-July 1976. Breeding seasons (conceptions and births) occurred between August and early January (4-5 months) in the first 3 years and between September and March (7 months) in the last year. Second-year females produced three or four litters in short seasons, four or five litters in the long season and up to 20 offspring per season. First-year females produced one litter in short seasons and one or two litters in the long season. Mean litter size was 4.56 (2-6). Ovarian follicles were largest in September and smallest in May. Small, inactive CL persisted in parous females until May. Placental scars were present in all sampled months. Vaginae remained closed during the non-breeding season. In mature males testes and epididymides contained sperm from July to March. Vesicular, prostate and preputial glands were enlarged and secretory from September to December. Testes were smallest and least developed in May and June. Males were divided into five categories depending on age and overall reproductive condition. Sexual maturity was reached in the breeding season of birth by some males (33%) and females (13-88%). More females matured early when population density was low. Food abundance and quality may have been important variables in regulating the timing of the breeding season.

A test of the condition-bias hypothesis using Brown-headed Cowbirds trapped during the breeding season

1991 ◽  
Vol 69 (10) ◽  
pp. 2686-2692 ◽  
Author(s):  
Kevin W. Dufour ◽  
Patrick J. Weatherhead
Keyword(s):  
Breeding Season ◽  
Molothrus Ater ◽  
Foraging Strategies ◽  
Feeding Response ◽  
Poor Condition ◽  
Males And Females ◽  
Using Data ◽  
Breeding Seasons ◽  
Mist Net ◽  
Trap Bias

We examined trap bias relative to body condition, age, and sex using data collected from Brown-headed Cowbirds (Molothrus ater) decoy trapped during the 1987 and 1988 breeding seasons. A condition bias was evident, as decoy-trapped birds were in poor condition relative to those caught by mist net in an adjacent roost. This occurred in both sexes and independently of study year and male age. Paradoxically, however, males in better condition when first trapped were more likely to be recaptured in the same season, possibly reflecting more widespread movement, and hence fewer encounters with traps, by birds in poor condition. Hatching-year birds were more likely than adults to be recaptured in the same season. Trapped samples were strongly male biased, which probably reflects a difference in nutritional requirements, and thus foraging strategies, between males and females during the breeding season. This study indicates that biases among birds trapped by methods that rely on a feeding response are likely to be widespread and difficult to predict, suggesting that interpretation of data from such samples always requires caution.

scholarly journals Abundance of raptors and habitat preferences of the common buzzard Buteo buteo and the common kestrel Falco tinnunculus during the non-breeding season in an agricultural landscape (Western Slovakia)

2014 ◽  
Vol 7 (1) ◽  
pp. 37-42 ◽  
Author(s):  
Vladimír Nemček
Keyword(s):  
Breeding Season ◽  
Human Activities ◽  
Agricultural Landscape ◽  
Agricultural Land ◽  
Habitat Preferences ◽  
Falco Tinnunculus ◽  
Common Buzzard ◽  
Buteo Buteo ◽  
The Common ◽  
Breeding Seasons

Abstract Habitat use and preferences by raptors were studied during three non-breeding seasons (2011-201 3) in an agricultural landscape in western Slovakia. The non-breeding season on agricultural land showed high variation and changes in the cover of habitats related to human activities. The most abundant raptor species were the common buzzard Buteo buteo (L.) (1 52 individuals) and the common kestrel Falco tinnunculus (L.) (78 individuals). The common buzzard preferred alfalfa and avoided ploughed fields. The common kestrel showed a high habitat preference for alfalfa, corn fields, stubbles and fallow. It also avoided ploughed fields and wheat.

Ecology of Red-winged Blackbird parasitism by haematozoa

1991 ◽  
Vol 69 (9) ◽  
pp. 2352-2359 ◽  
Author(s):  
Patrick J. Weatherhead ◽  
Gordon F. Bennett
Keyword(s):  
Sexual Selection ◽  
Breeding Season ◽  
Parasite Prevalence ◽  
Agelaius Phoeniceus ◽  
Older Individuals ◽  
Parasite Resistance ◽  
Blood Samples ◽  
Prevalence Estimates ◽  
Males And Females ◽  
Breeding Seasons

We sampled haematozoa in Red-winged Blackbirds (Agelaius phoeniceus) over three consecutive breeding seasons in eastern Ontario to identify factors that affect the reliability of quantifying parasites as this pertains to testing Hamilton and Zuk's hypothesis of sexual selection. Parasite prevalence and intensity varied seasonally, indicating that for samples to be reliable they should not be taken either early or late in the breeding season, and analysis should be limited to prevalence (presence versus absence). Among males (but not females), parasite prevalence increased with age, indicating that all individuals are not exposed to parasites early in life, and therefore tests of the "parasite" hypothesis of sexual selection are best restricted to older individuals. Resampling of known individuals within and between years showed that some individuals changed from positive to negative. Prevalence estimates also varied by year, indicating that reliable estimates of prevalence for a species, necessary for interspecific tests of the parasite hypothesis, will require extensive sampling. Overall, parasite prevalence did not vary with habitat. Parasites were detectable in only 1 of 119 nestlings sampled, indicating either lack of exposure or inadequate time for infections to reach detectable intensities. In either case, it is not possible to test the assumption that parasite resistance is heritable using blood samples from nestlings. Although males and females were parasitized by the same array of parasites, the distribution of specific parasites differed significantly (males were more heavily parasitized by leucocytozoids). If males and females generally differ in either exposure or resistance to specific parasites, the coevolutionary dynamics between host and parasite and the implications for sexual selection will require reassessment.

Patterns of movement in the small dasyurid (Ningaui yvonneae)

2007 ◽  
Vol 55 (5) ◽  
pp. 299 ◽  
Author(s):  
Darren G. Bos ◽  
Susan M. Carthew
Keyword(s):  
Breeding Season ◽  
Site Fidelity ◽  
Average Distance ◽  
South Australia ◽  
Home Ranges ◽  
Movement Behaviour ◽  
Population Composition ◽  
Short Term ◽  
Time Of Year ◽  
Breeding Seasons

The movement behaviour of a small dasyurid (Ningaui yvonneae) was investigated using mark–recapture data collected over 28 months from a population in the Middleback Ranges, South Australia. We were particularly interested in assessing variability in patterns of movement between the sexes and across seasons, as this has potentially important implications for population composition and dynamics. The species was found to be fairly mobile, with frequent and sometimes large movements relative to the size of the animal (up to 900+ m). Average distances moved between recaptures within and between trap sessions were 84 m and 160 m respectively, with nearly half of all recorded movements being between trapping grids (i.e. >80 m). Relatively high recapture rates (many separated by more than 100 days) and measures of site fidelity indicated that the species was not particularly transitory, but probably establishes large and/or drifting home ranges. However, patterns of movement varied considerably according to sex and the time of year. Female N. yvonneae were generally more sedentary than males, with few females moving between trapping grids, and most short-term movements (<100 days apart) being less than 70 m. Movements of females for which the records were separated by more than 100 days tended to be larger, with an average between-capture distance >200 m. In contrast, males often moved between trapping grids, even over short periods. Some short-term movements were more than 600 m in length, and the average distance moved within trapping sessions was >100 m. During the breeding season, males more than doubled the average distances moved between recaptures, when they were presumably roaming in search of females. For females, movement distances were similar during the prebreeding and breeding seasons, but were significantly smaller in the postbreeding season, when they were caring for young.

Estimating pup production in a mammal with an extended and aseasonal breeding season, the Australian sea lion (Neophoca cinerea)

2012 ◽  
Vol 39 (2) ◽  
pp. 137 ◽  
Author(s):  
Rebecca R. McIntosh ◽  
Simon D. Goldsworthy ◽  
Peter D. Shaughnessy ◽  
Clarence W. Kennedy ◽  
Paul Burch
Keyword(s):  
Breeding Season ◽  
South Australia ◽  
Rate Of Change ◽  
Estimation Methods ◽  
Sea Lion ◽  
Mark Recapture ◽  
Australian Sea Lion ◽  
Rate Of Decline ◽  
Breeding Seasons ◽  
Pup Mortality

Context The Australian sea lion population at Seal Bay Conservation Park, South Australia, was estimated to be declining at a rate of 1.14% per breeding season, on the basis of maximum counts of live pups in each of 13 breeding seasons (Shaughnessy et al. 2006). The reliability of the pup-production estimates used to identify this decline is uncertain. Aims Our aims were to obtain representative and repeatable estimates of pup production and to assess the current rate of decline. Methods We compared four estimates of pup abundance over five breeding seasons (2002–03, 2004, 2005–06, 2007, 2008–09), including the count of cumulative new births, the maximum live-pup count, the number of pups given passive integrated transponder (PIT) tags, and mark–recapture methods using the Petersen estimate. Key results A total of 90% of pup births occurred over a mean of 124 days (s.d. = 14). Final estimates of pup production (from the largest of the four estimation methods used) in the five seasons were 227 (CL 221–239), 288 (CL 273–302), 219 (NA), 260 (CL 254–272) and 268 (CL 268–269). The average estimate of pup mortality was 28.6% (s.d. = 6.3%). The decline in the population at Seal Bay over 17 breeding seasons on the basis of maximum counts of live pups was 0.51% per year or 0.76% per breeding season. However, this trend was not based on best estimates of pup production. On the basis of final estimates for the last five breeding seasons, there is no declining trend. Conclusions The count of cumulative new births was the most reliable measure of pup production; the Petersen mark–recapture estimate provided a check for accuracy and confidence limits about the estimate. Implications The actual rate of change and the expected trajectory of the Seal Bay population remain uncertain. Ongoing monitoring is a priority for this site, using the reliable methods of estimating pup production identified in the present study.

Production of Eggs and Young Snails by Adult Theba-Pisana (Muller) and Cernuella-Virgata (Da Costa) (Mollusca, Helicidae) in Laboratory Cultures and Field Populations

1991 ◽  
Vol 39 (6) ◽  
pp. 673 ◽  
Author(s):  
GH Baker
Keyword(s):  
Breeding Season ◽  
South Australia ◽  
Shell Size ◽  
Shell Diameter ◽  
Laboratory Cultures ◽  
Theba Pisana ◽  
Positive Correlations ◽  
Breeding Seasons

The fecundities of two terrestrial helicid snails, Theba pisana and Cernuella virgata, were measured in laboratory cultures. The breeding seasons of both species extended from autumn to spring, with most eggs and largest clutches being laid in autumn. Significant positive correlations between shell size and total number of eggs produced, numbers of clutches and clutch sizes were demonstrated for both species, but these correlations were generally weak and not consistently significant for snails collected from different habitats. In field populations in pastures in South Australia, the numbers of juvenile T. pisana and C. virgata (> 6 mm in shell diameter) produced per adult were inversely related to the densities of adults at the start of the breeding season. Possible reasons for this variation in production are discussed. Previous studies with other species of helicid snails have suggested that crowding can reduce the sizes of adults and hence their production of young. Such an explanation is inadequate in this case.

scholarly journals Bird-window collisions in the summer breeding season

2014 ◽  
Author(s):  
Stephen B. Hager ◽  
Matthew E. Craig
Keyword(s):  
Breeding Season ◽  
Passer Domesticus ◽  
Abundant Species ◽  
Dispersal Patterns ◽  
Long Distance ◽  
American Robin ◽  
Vireo Olivaceus ◽  
A Site ◽  
Breeding Seasons ◽  
Permanent Residents

Birds that reside in urban settings face numerous human-related threats to survival, including mortality from bird-window collisions (BWCs). Our current understanding of this issue has largely been driven by data collected during spring and fall migration, and patterns of collision mortality during the summer breeding season remain relatively unexplored. We assessed BWCs during four breeding seasons (2009- 2012) at a site in northwestern Illinois, USA, by comparing the abundance, richness, migratory class, and age of the species living around buildings to species mortally wounded by window collisions. We also systematically assessed the daily timing of BWCs throughout the breeding season. We documented BWCs in 4 of 25 (16%) species and 7 of 21 (33%) species in 2009 and 2010, respectively. The relationship between BWCs and abundance depended on age. For adults, BWCs were highest in the least abundant species, e.g., Red-eyed Vireo (Vireo olivaceus), and lowest in species with high abundance values, e.g., House Sparrow (Passer domesticus). For juveniles, mortality was greatest for the most abundant species, and the American Robin (Turdus migratorius) accounted for 62% of all juvenile carcasses. Early in the breeding season, collision mortality was restricted to adults of Long- distance Migrants, whereas juveniles of all three migratory guilds (Long-distance and Short-distance Migrants and Permanent Residents) died at windows from late June through early August. Daily mortality for all species was highest between sunrise - 1600 h and lowest from 1600 h - sunrise the next day. Generally, the species observed as carcasses matched birds considered a ‘high risk’ for BWCs, e.g., Ruby-throated Hummingbird (Archilochus colubris), and those considered ‘low risk’ were not observed as carcasses, e.g., Blue-gray Gnatcatcher (Polioptila caerulea). Our results suggest that the number of BWCs during the breeding season does not necessarily increase with abundance, but rather appears related to variation among species and age classes, which may have important implications on the population health of affected species. The mechanisms driving these differences are unknown, but may be related reproductive behavior, flight speed, distance movements, and dispersal patterns.

Breeding biology and haul-out pattern of the New Zealand fur seal, Arctopehalus forsteri, at Cape Gantheaume, South Australia

1994 ◽  
Vol 21 (3) ◽  
pp. 365 ◽  
Author(s):  
SD Goldsworthy ◽  
PD Shaughnessy
Keyword(s):  
New Zealand ◽  
Sex Ratio ◽  
Breeding Season ◽  
Age Distribution ◽  
South Australia ◽  
Operational Sex Ratio ◽  
Fur Seal ◽  
Median Date ◽  
Breeding Seasons ◽  
Bay Islands

New Zealand fur seals, Arctocephalus forsteri, breed at Cape Gantheaume (36�04'S,137�28'E), Kangaroo Island, South Australia, on broken rock platforms. In 1988-89, pups were born between late November and mid-January, 90% of them over 34 days between 3 December and 6 January. The median date of birth was 21 December. A re-analysis of data for this species from three breeding seasons at the Open Bay Islands (South Island, New Zealand, 43�52'S,l68�53'E) indicates that: (i) the breeding season at Cape Gantheaume occurs 5-12 days later than at the Open Bay Islands, (ii) the period containing 90% of births was the same duration for both populations, and (iii) the median date of birth spanned seven days in three seasons at the Open Bay Islands. In addition, the timing and duration of the pupping season varied within the Cape Gantheaume colony, it being later in recently colonised areas. We suggest that this pattern is a consequence of changes in the age distribution of females through the colony. The sex ratio of pups born in the colony over four breeding seasons did not differ significantly from 1:l. Females were mated on average 7.4 days after birth and left for sea 2.3 days later. The mean date of observed matings was 29 December; copulations lasted about 13 min. The operational sex ratio (OSR) in the colony was 8.6 females per territorial male (the maximum ratio of territorial males to pups was 1:16), which was within the range reported for other southern fur seal species. In two consecutive breeding seasons, the estimated fecundity rate of adult females averaged 67%. Non-breeding animals (sub-adult males, juveniles and yearlings) occurred in areas not occupied by breeding animals. The number of juveniles ashore increased after the breeding season, but no pattern was found for sub-adults and yearlings. Yearlings were uncommon in the colony at all times; it is suggested that they are mostly pelagic and do not moult in their second year.

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