scholarly journals Breeding behaviour and diet of Rufous Owls Ninox rufa in the Darwin Botanic Gardens

2021 ◽  
Vol 38 ◽  
pp. 221-228
Author(s):  
William Riddell
Keyword(s):  
Rattus Rattus ◽  
Breeding Cycle ◽  
Botanic Gardens ◽  
Flying Foxes ◽  
Calling Behaviour ◽  
Nestling Period ◽  
Pellet Analysis ◽  
Natal Home ◽  
Enterolobium Cyclocarpum ◽  
Breeding Seasons

The breeding cycle of a pair of Rufous Owls Ninox rufa was observed over five breeding seasons, 2016–2020, in the Darwin Botanic Gardens, Northern Territory. A pair failed or did not breed in four of those years and raised one fledgling in 2018. The Owls occupied a hollow 2.5 m above ground in the trunk of an exotic Earpod Tree Enterolobium cyclocarpum. In 2018, laying occurred sometime between 11 June and 2 July, hatching between 21 and 25 July, and fledging (first true flight) on 6 September, with branching on 2–5 September, giving a nestling period of 44–48 days. The juvenile remained dependent until mid November, giving an estimated post-fledging dependence period of 10 weeks. For the following 3 weeks, it roosted alone within its natal home range, increasingly far (270–320 m) from the nest tree and roosting adults. Calling behaviour (including duetting by the pre-laying pair), courtship, copulation and parental behaviour and routines are described. From observations and pellet analysis, the Owls’ diet consisted of 78% mammals [Common Brushtail Possums Trichosurus vulpecula arnhemensis, flying-foxes (probably all Black Flying-foxes Pteropus alecto) and rats (probably Black Rats Rattus rattus)] and 22% birds (passerines and non-passerines up to Orange-footed Scrubfowl Megapodius reinwardt in size) by number.

Introduced predators and cavity-nesting seabirds: unexpected low level of interaction at breeding sites

2008 ◽  
Vol 86 (9) ◽  
pp. 1068-1073 ◽  
Author(s):  
L. Ruffino ◽  
K. Bourgeois ◽  
E. Vidal ◽  
J. Icard ◽  
F. Torre ◽  
...  
Keyword(s):  
Rattus Rattus ◽  
Breeding Cycle ◽  
Mediterranean Islands ◽  
Breeding Sites ◽  
Low Level ◽  
Black Rat ◽  
Cavity Nesting ◽  
Introduced Predators ◽  
Puffinus Yelkouan ◽  
First Time

The mechanisms by which introduced predators and long-lived seabirds interact and even coexist are still poorly known. Here, the interactions between the widely introduced black rat ( Rattus rattus (L., 1758)) and an endemic Mediterranean cavity-nesting seabird, the yelkouan shearwater ( Puffinus yelkouan (Acerbi, 1827)), were for the first time investigated for a set of 60 suitable breeding cavities throughout the entire breeding cycle of this seabird. Our results pointed out that rat visits to cavities were significantly higher when shearwaters had left the colony for their interbreeding exodus. Among the set of suitable breeding cavities, yelkouan shearwaters preferentially selected the deepest and the most winding cavities for breeding. Very few rat visits were recorded at the shearwater-occupied cavities and no predation event was recorded. These intriguing results reveal a low level of interaction between introduced black rats and yelkouan shearwaters, which may have facilitated their long-term coexistence for thousands of years on some Mediterranean islands.

Variability in the Responses of Black-Billed Magpies To Natural Predators

Behaviour ◽  
1983 ◽  
Vol 87 (3-4) ◽  
pp. 209-235 ◽  
Author(s):  
Deborah Buitron
Keyword(s):  
Adult Mortality ◽  
Potential Predator ◽  
Alarm Calling ◽  
Investment Theory ◽  
Nestling Period ◽  
Parental Investment Theory ◽  
Clear Cases ◽  
Breeding Seasons ◽  
Innate Fear ◽  
Predator Behavior

AbstractEncounters between black-billed magpies (Pica pica) and a variety of natural predators were observed during 3 breeding seasons in Wind Cave National Park, South Dakota. How a magpie responded to a potential predator appeared to depend on (1) the type of predator and the threat it posed to magpie eggs, nestlings, fledglings, and adults; (2) the behavior of the predator; and (3) the reproductive stage of the magpie. Raptors were the most frequently encountered potential predators, with magpies reacting more strongly to falcons than to hawks. Reactions to crows and squirrels were most frequent and intense during laying and incubation, while raptors in flight and coyotes were responded to most vigorously during the second half of the nestling period and the first two weeks of fledgling. Perched raptors were almost always mobbed vigorously. Diving to within 2 m of a predator appeared to be effective in driving it away. The roles of chasing and alarm calling were less clear, but in addition to alerting mates and offspring to danger, such behavior would impede efficient hunting by the predator and so might contribute to its departure. Only one successful act of predation was observed, but the evidence suggested that owls, hawks and falcons were responsible for most fledgling and adult mortality. No clear cases of nest predation by crows or squirrels occurred, but some clutches of eggs and broods of young nestlings disappeared. Although mates usually mobbed predators together, males were slightly more active, possibly because males were larger and because females were often occupied in the nest with incubation and brooding. Observations of wild fledglings and hand-raised magpies suggest that magpies have an innate fear response to a variety of stimuli and that fledglings gradually learn what to continue fearing from parents, other magpies, and their own experiences. I suggest that although parental investment theory may be basically correct in predicting that young increase in value to their parent as they approach independence, a variety of other factors may affect anti-predator behavior, such as (1) the types of predators likely to be encountered and the relative danger they pose to different age classes; (2) the ability of the parents to successfully drive off a particular predator; (3) the ability of the parents to re-nest that year; (4) the likelihood that a pair will be able to fledge young the following year.

The Female Reproductive-Tract of the Australian Sea Lion, Neophoca-Cinerea (Peron, 1816) (Carnivora, Otariidae)

1991 ◽  
Vol 39 (3) ◽  
pp. 351 ◽  
Author(s):  
RA Tedman
Keyword(s):  
Reproductive Tract ◽  
Female Reproductive Tract ◽  
Breeding Cycle ◽  
Embryonic Diapause ◽  
Sea Lion ◽  
Neophoca Cinerea ◽  
Australian Sea Lion ◽  
Uterine Mucosa ◽  
Breeding Seasons ◽  
Uterine Glands

This first account of the morphology of the female reproductive tract of the Australian sea lion, Neophoca cinerea, is based on examination of 15 specimens. The morphology of the female reproductive tract is similar in most respects to that in other pinniped species; only features peculiar to the species are described. The Y-shaped, bicornuate uterus is for the most part septate, but has a common uterine canal that is relatively much longer than that in other otariids. The uterine mucosa of newborns is slightly hypertrophied and regresses considerably by 3 weeks postpartum. During the embryonic diapause the uterine mucosa has serrated luminal epithelium, coiled uterine glands, and tall luminal and glandular epithelia. The mucosa of the adult vagina decreases in thickness from 100-mu-m at about 2 weeks postpartum to 20-mu-m 14.5 weeks postpartum, indicative of the regressive phase typical of the delay period in other pinnipeds. The urethral meatus lacks urinary papillae, unlike most other pinnipeds. A relatively large clitoris is present, and an os clitoridis was collected from one old individual. A monoestrous cycle seemed to occur in four animals, but a polyoestrous cycle is suspected in at least one individual. Ovulation occurs from alternate ovaries in successive pregnancies. Corpora albicantia are retained for at least three breeding seasons and probably longer. Implantation occurs in the midsection of the uterine cornu, ipsilateral to the ovary that released the egg. The maximum period of embryonic diapause cannot be ascertained from the available data, although a delay of about 8-9 months is possible if the breeding cycle (pregnancy cycle) lasts about 18 months.

scholarly journals Reproductive biology of Synallaxis albescens (Aves: Furnariidae) in the cerrado of central Brazil

2012 ◽  
Vol 12 (4) ◽  
pp. 266-269 ◽  
Author(s):  
Miguel Ângelo Marini ◽  
Sheila Silva Rodrigues ◽  
Mariana Batista Silveira ◽  
Harold Francis Greeney
Keyword(s):  
Life History ◽  
Reproductive Biology ◽  
Reproductive Strategies ◽  
Life History Evolution ◽  
Average Height ◽  
Central Theme ◽  
Central Brazil ◽  
Nestling Period ◽  
Nesting Substrate ◽  
Breeding Seasons

Understanding the causes and consequences of variation in reproductive strategies is a central theme in studies of avian life history evolution. This study describes the reproductive biology of Synallaxis albescens (Furnariidae) in the cerrado biome of central Brazil. We monitored 35 nests during the 2003 to 2011 breeding seasons, visiting them every 2-4 days. Synallaxis albescens breeds from mid-September to mid-January, builds a retort-shaped nest, and generally lays three immaculate white eggs. Eggs weighed 1.75 g and measured 19.7 by 14.4 mm. Most nests studied were in open cerrado or shrub grassland at an average height above the ground of 0.3 m, with a preference for Davilla elliptica (Dilleniaceae) shrubs as a nesting substrate. Incubation period averaged 18.1 days, while the nestling period averaged 13.6 days. Of 16 closely monitored nests, four were successful (25%), 11 were depredated (69%), and one was abandoned. Predation was similar during incubation (45%) and nestling (55%) phases. In general, the breeding biology of S. albescens was similar to that described previously for this species and for related Furnariidae.

Weights, Breeding, and Survival in European Sparrowhawks

The Auk ◽  
1983 ◽  
Vol 100 (2) ◽  
pp. 344-354 ◽  
Author(s):  
I. Newton ◽  
M. Marquiss ◽  
A. Village
Keyword(s):  
Egg Production ◽  
High Weight ◽  
Egg Laying ◽  
Breeding Cycle ◽  
First Year ◽  
Accipiter Nisus ◽  
Nestling Period ◽  
Food Shortages ◽  
Independent Life

Abstract No significant diurnal variation in mean weight was detected in trapped European Sparrowhawks (Accipiter nisus). Weights of males fluctuated rather little through the year, but were highest in March and lowest in August. During the breeding cycle, males lost weight slightly in the prelay/early laying periods, when they were feeding females in preparation for egg production, and in the late nestling/postfledging periods, when they were feeding large young. Weights of females fluctuated greatly during the year: they were highest in May at the time of egg laying and lowest in August at the end of breeding. Females increased in weight by 40-50 g (15%) in the 10-20 days before laying; lost about 20 g over the laying period, on average; maintained high weight through much of incubation; and lost weight during the nestling period. The main functions of the extra body reserve are probably to buffer the female against temporary food shortages during incubation and to enable her to feed the chicks preferentially in the nestling period. Females that did not lay eggs remained low in weight throughout the early part of the breeding season and were then significantly lighter than breeders. Moreover, females that laid large clutches were heavier throughout the prelaying and laying periods than were females that laid small clutches, and females that subsequently hatched their eggs started incubation at a significantly greater weight than did those that deserted their eggs. We suggest that clutch size and breeding success are dependent on the female being able to maintain high weight during the periods she is dependent on the male for food and, hence, on the hunting success of the male. First-year birds of both sexes weighed less than adults throughout the year and were especially light during their first 2 months of independent life. This was probably a period of high mortality, especially in males, in which a clear relationship emerged between weight and survival prospects.

scholarly journals Indirect Influence of African Swine Fever Outbreak on the Raven (Corvus corax) Population

Animals ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 41 ◽  
Author(s):  
Jakub Gryz ◽  
Dagny Krauze-Gryz
Keyword(s):  
Crucial Role ◽  
African Swine Fever ◽  
Farm Animals ◽  
Domestic Pig ◽  
Breeding Parameters ◽  
Direct Observations ◽  
Pellet Analysis ◽  
Forest Mosaic ◽  
Breeding Seasons ◽  
Second Period

Carrion plays a crucial role in the raven’s diet. In the past, domestic pig carrion was widely available in Poland. This changed with an African swine fever (ASF) outbreak and the introduction of strict procedures aimed at stopping the virus from spreading. We compared data from Central Poland (field and forest mosaic, study area of 105 km2) for two periods, i.e., before (2011–2014) and after the ASF outbreak (2015–2018). In breeding seasons, nests of ravens were found, juveniles were counted, and the time when juveniles left their nests was recorded. Diet composition data were based on pellet analysis and direct observations of feeding birds. The number of breeding pairs dropped from 12.3 to 7.5 in the second period. Breeding parameters were similar. However, birds in the second period had fewer fledglings per successful pair. Domestic pig carrion was found to be an important food item, and with its limited supply, ravens changed their diet, i.e., they fed on the carrion of dogs and cats or preyed on small vertebrates more often. Overall, our study points to a crucial role of the availability of the carrion of big farm animals (i.e., domestic pig) in maintaining the high density of breeding raven populations.

Birth to weaning: parturition, duration of lactation, and attendance cycles of Australian sea lions (Neophoca cinerea)

1993 ◽  
Vol 71 (10) ◽  
pp. 2047-2055 ◽  
Author(s):  
Lesley V. Higgins ◽  
Leila Gass
Keyword(s):  
Significant Variation ◽  
Site Fidelity ◽  
South Australia ◽  
Maternal Investment ◽  
Breeding Cycle ◽  
Sea Lions ◽  
Long Period ◽  
Neophoca Cinerea ◽  
Breeding Seasons ◽  
Over Time

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.

Condition Changes and Choice of Social Environment in African Buffalo Bulls

Behaviour ◽  
1989 ◽  
Vol 108 (3-4) ◽  
pp. 297-323 ◽  
Author(s):  
H.H.T. Prins
Keyword(s):  
Body Condition ◽  
Dominance Hierarchy ◽  
Mammalian Species ◽  
Breeding Cycle ◽  
African Buffalo ◽  
Social Environments ◽  
Northern Tanzania ◽  
Dominance Interactions ◽  
The Social ◽  
Breeding Seasons

Abstract1. The social behaviour of the African buffalo (Syncerus caffer) was studied between 1981 and 1985 in Lake Manyara National Park, northern Tanzania. Emphasis is placed on the relationships between adult bulls (i.e. older than 7 yrs). 2. These bulls were transient members of the buffalo population of the study area. At any time ± 150 adult bulls were in the area. During the study period 240 individual bulls were recognized, and the number of the 'bull pool' during this period was estimated to be 630. 3. Every few weeks, the bulls switched between the herd state and bachelor state, and wandered from herd to herd, presumably in search of oestrus cows. 4. They did not form stable associations, and when bachelor, they preferentially associated in temporary groups of 3 to 5 bulls. 5. Adult bulls engaged in sparring and showed dominance interactions very rarely. In a dyadic encounter, dominance interactions were only observed between bulls of the same body condition. Encounters involving individuals in different condition resulted in dominance being established without interaction. Fighting is extremely rare and likely to be lethal to both opponents. 6. The switching between both social environments was related to condition loss in the mixed herd and to condition gain in the bachelor state. This resulted in a 'rotating dominance hierarchy'. The bachelor phase is an essential part of the breeding cycle of an adult bull. 7. The necessity of a bachelor phase to recoup body condition may well be a general feature in mammalian species with long breeding seasons.

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