Patterns of movement in the small dasyurid (Ningaui yvonneae)

2007 ◽  
Vol 55 (5) ◽  
pp. 299 ◽  
Author(s):  
Darren G. Bos ◽  
Susan M. Carthew

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.

Author(s):  
Maureen Gerondeau ◽  
Christophe Barbraud ◽  
Vincent Ridoux ◽  
Cécile Vincent

It has been suggested that the large grey seal colonies around the British Isles form local populations within a metapopulation, and that seal movements outside the breeding season lead to considerable overlap between individual home ranges. Individual behaviour and population dynamics of small peripheral colonies may also play a role in the metapopulation. We studied the French grey seal colony of the Molène archipelago, at the southern-most limit of the species' range. We analysed photo-identification data with capture–mark–recapture techniques in order to estimate the total seasonal abundance of grey seals in the archipelago and to quantify the seasonal rates of occurrence or movements of male and female seals. We found that between 58 (95% confidence interval: 48–71) and 98 (95% CI: 75–175) individuals hauled out in the archipelago during the summers of 1999 and 2000. The use of multistate models allowed the assessment of seasonal site fidelity and indicated that it varied between key periods of the annual cycle, particularly for females. Males showed a constant fidelity rate of 56% from one season to another. Hence, even though they showed high inter-annual site fidelity, they did not seem to have a preferred season for using the archipelago. On the contrary, female grey seals showed the highest site fidelity between moult and summer (around 80%), and the lowest fidelity between summer and the breeding period (34–43%). Thus, females seem to use the Molène archipelago preferentially in summer and leave the site before the breeding season, which explains the very low local pup production. Philopatry may explain this pre-breeding emigration, and we suggest that most grey seals observed in the Molène archipelago were born and breed in other local breeding populations, probably the south-western British Isles.


2003 ◽  
Vol 30 (1) ◽  
pp. 15 ◽  
Author(s):  
K. E. Moseby ◽  
E. O'Donnell

Nine bilbies were reintroduced to a 14-km2 reserve free of rabbits, cats and foxes in South Australia in April 2000. The survival, growth and ecology of the population were studied for 17 months after release by means of radio-tracking and trapping. Reproduction was continuous over the study period, with juveniles successfully recruited into the population. Home-range size of female bilbies averaged 0.18 km2 and was significantly smaller than home ranges of males, which averaged 3.16 km2. Wild-born subadults had smaller home ranges than adults. While male home ranges, and male and female home ranges overlapped considerably, females appeared to maintain areas discrete from other adult females. Bilbies showed a significant preference for dune habitat. As swale habitat appears too hard for burrow construction and males moved greater distances from diurnal burrows than females, males are likely to access food reserves that are under-used by females. Both males and females reused at least 30% of their burrows, and females displayed long-term site fidelity. The release was considered successful and suggests that despite historical damage from rabbits and stock, bilbies are able to successfully recolonise parts of their former range in arid South Australia once rabbits, cats and foxes are removed.


2000 ◽  
Vol 27 (6) ◽  
pp. 583 ◽  
Author(s):  
M. Giese ◽  
S. D. Goldsworthy ◽  
R. Gales ◽  
N. Brothers ◽  
J. Hamill

The long-term effects of oiling on the breeding success of rehabilitated oiled little penguins (Eudyptula minor) were examined over two consecutive breeding seasons following the Iron Baron oil spill in 1995. The commencement of egg laying was delayed among rehabilitated oiled penguins compared with non-oiled birds during the 1995/96 breeding season. During that season, hatching success (number of eggs hatched from those laid) was no different in nests containing rehabilitated oiled penguins than in those containing non-oiled birds, but overall egg success (number of pre-fledging chicks from the number of eggs laid) was significantly lower among rehabilitated oiled birds. This effect was predominant in nests containing a rehabilitated oiled female, where the probability of successfully fledging any chicks was 22% lower than in nests containing a non-oiled female. During the 1996/97 breeding season, there was no significant difference between either the hatching or egg success of rehabilitated oiled penguins and non-oiled birds. In both seasons, the pre-fledging masses of chicks from rehabilitated oiled penguins were significantly lower than those from non-oiled birds. The chicks of rehabilitated oiled penguins were therefore expected to have lower survival than chicks raised by non-oiled parents. Results indicate that oiling not only reduced the number of chicks raised by rehabilitated oiled penguins in the short term, but also decreased the quality of young produced for at least two seasons following the spill.


2001 ◽  
Vol 28 (2) ◽  
pp. 165 ◽  
Author(s):  
Craig Miller ◽  
Mike Elliot ◽  
Nic Alterio

The home range of stoats (Mustela erminea) was determined as part of a programme to protect Okarito brown kiwi chicks (Apteryx australis) ‘Okarito’, from predation. Twenty-seven stoats were fitted with radio-transmitters and tracked in two podocarp (Podocarpaceae) forests, in south Westland, New Zealand, from July 1997 to May 1998. Home-range area was determined for 19 animals by minimum convex polygons and restricted-edge polygons, and core areas were determined by hierarchical cluster analysis. The mean home ranges of males across all seasons calculated by minimum convex polygon (210 28 ha ( s.e.)) and restricted-edge polygon (176 29 ha) were significantly larger than those of females across all seasons (89 14 ha and 82 12 ha). The mean home range of males calculated by minimum convex polygon during the breeding season (256 38 ha) was significantly larger than the mean home range pooled across the non-breeding seasons (149 16 ha), whereas that calculated by restricted-edge polygon was not significantly different. The mean home range of females during the breeding season was not significantly different from that in the non-breeding seasons when estimated by either method. Overlap of home ranges was observed within and between sexes in all seasons, with the greatest proportion of home range overlap being male–female. The mean home range of females in spring and summer is used to guide the spacing of control stations.


The Condor ◽  
2005 ◽  
Vol 107 (1) ◽  
pp. 133-137 ◽  
Author(s):  
Jennifer Nesbitt Styrsky

AbstractNest-site fidelity is associated with previous reproductive success in birds but is thought to be rare among territorial, open-cup nesting passerines. I investigated nest reuse decisions by Spotted Antbirds (Hylophylax naevioides) in central Panama. A quarter of all nest attempts were located at a previously used nest site, often within an extant nest structure. Within a breeding season, pairs preferred to reuse previously successful nest sites overall and were more likely to return to these sites for a consecutive nest attempt than they were to previously depredated nest sites. The fates of two nest attempts at the same location, however, were not associated with each other. The preference of Spotted Antbirds for reusing successful nests may be a short-term strategy to avoid sites recently discovered by predators, as pairs did reuse previously depredated nest sites for later nest attempts and did not prefer successful nest sites from previous breeding seasons.Influencia de la Depredación sobre la Reutilización de Sitios de Nidificación en un Ave Paserina Neotropical que Construye Nidos de Copa AbiertaResumen. La fidelidad al sitio de nidificación está asociada con el éxito reproductivo previo en las aves, pero se cree que ésta no es común entre especies Passeriformes territoriales que construyen nidos de copa abierta. En este estudio investigué las decisiones de reutilización de nidos en Hylophylax naevioides en el centro de Panamá. Una cuarta parte de todos los intentos de nidificación se ubicaron en lugares previamente empleados para nidificar, a menudo al interior de estructuras de nidificación remanentes. Dentro de una temporada reproductiva, las parejas prefirieron reutilizar sitios de nidificación exitosos en general y fueron más propensas a regresar a esos sitios para intentos de nidificación consecutivos, que a sitios en donde sus nidos fueron depredados. Sin embargo, los resultados de dos intentos de nidificación ocurridos en el mismo sitio no estuvieron asociados entre sí. La preferencia de emplear repetidamente sitios existosos podría ser una estrategia de corto plazo empleada por H. naevioides para evitar lugares recientemente descubiertos por depredadores, ya que las parejas reutilizaron sitios donde sufrieron depredación en intentos posteriores y no prefirieron lugares exitosos de estaciones reproductivas previas.


1993 ◽  
Vol 71 (10) ◽  
pp. 2047-2055 ◽  
Author(s):  
Lesley V. Higgins ◽  
Leila Gass

Parturition, time to weaning, and female attendance patterns were studied over four breeding seasons in Australian sea lions, Neophoca cinerea, on Kangaroo Island, South Australia. Females generally exhibited site fidelity in their choice of birth sites, and arrived a mean of 1.8 days prior to birth. After birth, females stayed ashore a mean of 9.8 days before departing on their first foraging trip. Trips to sea were about 48 h in length although there was significant variation over time. Stays ashore were about 33 h long and were much less varied than trips to sea. Females moved pups away from the natal areas after about 1 month, and began spending less time with them while they were ashore. Linked with the extended breeding cycle of 17.6 months was an equally long period of maternal investment. Females suckled their pups for 15 – 18 months, or until about 1 month before the next birth. Twenty-nine percent of females did not pup consecutively each breeding season, but continued to suckle their offspring until the next birth, some for as long as 40 months.


1999 ◽  
Vol 47 (3) ◽  
pp. 307 ◽  
Author(s):  
John L. Read

Three sympatric diplodactyline geckos were studied in chenopod shrubland over a six-year period in northern South Australia. Females of each species were significantly larger than males. Rhynchoedura ornata and Diplodactylus conspicillatus, both termite specialists, consistently produced multiple clutches of two eggs in a long breeding season each year, whereas the reproductive output of D. stenodactylus, a dietary generalist, was more erratic. Females of the two Diplodactylus species bred in three consecutive years, whilst R. ornata seldom lived for more than two years. Mean relocation distances ranged from 26 to 35 m, which suggests that some individuals of all species maintained home ranges. However, many individuals of each species, especially R. ornata, were apparently transitory over areas greater than the 1-ha study site.


1996 ◽  
Vol 23 (3) ◽  
pp. 249 ◽  
Author(s):  
CM Bull ◽  
I Williamson

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.


2012 ◽  
Vol 39 (2) ◽  
pp. 137 ◽  
Author(s):  
Rebecca R. McIntosh ◽  
Simon D. Goldsworthy ◽  
Peter D. Shaughnessy ◽  
Clarence W. Kennedy ◽  
Paul Burch

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.


1991 ◽  
Vol 39 (6) ◽  
pp. 673 ◽  
Author(s):  
GH Baker

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.


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