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 ◽  
...  

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.

Mammalia ◽  
2006 ◽  
Vol 70 (1-2) ◽  
Author(s):  
Borut Toškan ◽  
Boris Kryštufek

AbstractFive significant records of rodents are reported from the Upper Pleistocene and Holocene of Slovenia. The identification of black rat Rattus rattus from the Late Bronze/Early Iron Age (ca. 1400–400 cal. BC) at Podjamca is thought to be one of the first records in Mediterranean Europe from the pre-Roman period. Evidence is also presented for the presence of Apodemus agrarius at Podjamca (at least 7800 y BP) and Suhadole (first half of the 1st century AD); the latter falls outside the current species range. The discovery of Dinaromys bogdanovi in Early Mesolithic layers (ca. 9600–7800 y BP) at Podjamca and of Late Mesolithic age (ca. 7800–6000 y BP) at Mala Triglavca are the first Holocene records outside the recent range of the species. Cricetulus migratorius (Podjamca, ca. 9600–7800 y BP; Mala Triglavca, 7800–6000 y BP) and Sicista subtilis (Divje babe I, ca. 80–75 ky BP) are reported for the first time in this part of Europe.


Mammalia ◽  
2006 ◽  
Vol 70 (1-2) ◽  
Author(s):  
Borut Toškan ◽  
Boris Kryštufek

AbstractFive significant records of rodents are reported from the Upper Pleistocene and Holocene of Slovenia. The identification of black rat Rattus rattus from the Late Bronze/Early Iron Age (ca. 1400–400 cal. BC) at Podjamca is thought to be one of the first records in Mediterranean Europe from the pre-Roman period. Evidence is also presented for the presence of Apodemus agrarius at Podjamca (at least 7800 y BP) and Suhadole (first half of the 1st century AD); the latter falls outside the current species range. The discovery of Dinaromys bogdanovi in Early Mesolithic layers (ca. 9600–7800 y BP) at Podjamca and of Late Mesolithic age (ca. 7800–6000 y BP) at Mala Triglavca are the first Holocene records outside the recent range of the species. Cricetulus migratorius (Podjamca, ca. 9600–7800 y BP; Mala Triglavca, 7800–6000 y BP) and Sicista subtilis (Divje babe I, ca. 80–75 ky BP) are reported for the first time in this part of Europe.


2019 ◽  
Vol 25 (1) ◽  
Author(s):  
ASHOK KUMAR ◽  
ALPANA PARMAR ◽  
ANAND KUMAR BAJPEYEE

Young female Black rat (Rattus rattus), were administered monthly long acting steroid contraceptive to induce hypertriglyceridemia. It was observed that by 3 weeks of the second injection of estrogen containing mixed type of contraceptive, female rats developed consistent and frank hyperglyceridemia . TG in the treated rats was 195.8 ± 7.44 mg /100 ml as compared to 91.5 ± 6.27 mg/100ml in plasma of the control group.


2007 ◽  
Vol 34 (6) ◽  
pp. 443 ◽  
Author(s):  
Grant A. Harper

Burrowing seabirds are vulnerable to extirpation by introduced predators such as rats, but much evidence of predation is circumstantial. On Taukihepa, an island off southern New Zealand, two possible predators exist with sooty shearwaters (Puffinus griseus): the weka (Gallirallus australis), a large rail, and the ship rat (Rattus rattus), both introduced to the island. It was expected that chick predation would be principally by weka, the much larger of the two predators. To measure losses of sooty shearwater chicks to weka or rats, nests were monitored with burrow-scopes at six sites in the summers of 2003–04 and 2004–05. In three of the sites rats were removed on 4-ha grids by trapping. In the other three sites rats were not trapped. In addition, weka were removed from all six sites in 2005. Concurrent diet analysis of weka and rat stomachs was undertaken as well as stable isotopic analysis (δ13C, δ15N) of samples from rats and weka. These were compared with possible prey items including sooty shearwaters. Additional stable isotope samples were taken from Pacific rats (Rattus exulans), a small rat species present with weka and sooty shearwaters on nearby Moginui Island. Weka diet comprised ~40% of bird remains by volume and calculations using Isosource, an isotopic source portioning model, estimated sooty shearwaters contributed 59% (range: 15–71%) of weka diet during the sooty shearwater chick-raising period. Ship rats, in contrast, had very depleted δ13C isotope signatures compared with sooty shearwaters and bird remains contributed <9% of diet by volume, with Isosource calculations suggesting that ship rats consumed more passerine birds (mean: 30%; range 5–51%) than sooty shearwaters (mean 24%; range: 0–44%). In both summers, more chicks were lost on sites from which rats had been removed than on control sites. When weka were removed in 2005, fewer chicks were lost than in 2004 and significantly fewer weka-killed chicks were found on weka-removal sites than on non-removal sites. Weka were the principal predator of sooty shearwater chicks, depredating an estimated 9.9% of nests. Combining several techniques quantified the loss and identified the principal predator of a seabird in decline.


2015 ◽  
Vol 57 (2) ◽  
pp. 129-132 ◽  
Author(s):  
Gaspar PENICHE-LARA ◽  
Karla DZUL-ROSADO ◽  
Carlos PÉREZ-OSORIO ◽  
Jorge ZAVALA-CASTRO

Rickettsia typhi is the causal agent of murine typhus; a worldwide zoonotic and vector-borne infectious disease, commonly associated with the presence of domestic and wild rodents. Human cases of murine typhus in the state of Yucatán are frequent. However, there is no evidence of the presence of Rickettsia typhi in mammals or vectors in Yucatán. The presence of Rickettsia in rodents and their ectoparasites was evaluated in a small municipality of Yucatán using the conventional polymerase chain reaction technique and sequencing. The study only identified the presence of Rickettsia typhi in blood samples obtained from Rattus rattus and it reported, for the first time, the presence of R. felis in the flea Polygenis odiosus collected from Ototylomys phyllotis rodent. Additionally, Rickettsia felis was detected in the ectoparasite Ctenocephalides felis fleas parasitizing the wild rodent Peromyscus yucatanicus. This study’s results contributed to a better knowledge of Rickettsia epidemiology in Yucatán.


The Holocene ◽  
2011 ◽  
Vol 22 (7) ◽  
pp. 801-808 ◽  
Author(s):  
Juan Carlos Rando ◽  
Josep Antoni Alcover ◽  
Jacques Michaux ◽  
Rainer Hutterer ◽  
Juan Francisco Navarro

The Lava mouse ( Malpaisomys insularis), and the Canarian shrew ( Crocidura canariensis) are endemic of the Eastern Canary Islands and islets. The former is extinct while Canarian shrew survives in the two main islands and two islets. In order to provide insights regarding causes and processes contributing to the extinction of these endemic mammals: (i) we established last occurrence dates for Lava mouse, and first records for two exotic species – House mouse ( Mus musculus) and Black rat ( Rattus rattus) – through direct 14C AMS dating of collagen from bones; (ii) we analysed recent material from Barn owl ( Tyto alba gracilirostris) roosting sites to evaluate its impact on Canarian shrew in the presence of introduced rodents. The new data strongly suggest that the extinction of Lava mouse was the result of an accumulative process of independent disappearances (or ‘local extinctions’) affecting the isolated populations. The timing of the introduction of the Black rat on the main islands (before Middle Age European contact in Lanzarote and after Middle Age European contact in Fuerteventura) matches with the last occurrence dates for the presence of Lava mouse on these islands, and are very probably their cause. The losses of these Lava mouse populations occurred in an asynchronous way, spreading across at least six centuries. On small islands, hyperpredation emerges as the most plausible process to explain the disappearance of the Lava mouse in the absence of rat populations, although stochastic processes can not be definitively excluded.


1992 ◽  
Vol 19 (4) ◽  
pp. 405 ◽  
Author(s):  
NJ Gales ◽  
AJ Cheal ◽  
GJ Pobar ◽  
P Williamson

The Australian sea-lion, Neophoca cinerea, has a 17-18-month breeding cycle on islands off the west coast of Western Australia. Buller, North Fisherman and Beagle Is are the main pupping sites, with several very small colonies (n> 3) at the Abrolhos Is. The 4-5-month pupping seasons are synchronised at North Fisherman and Beagle Is, but the sea-lions from Buller I. breed one month later and those from the Abrolhos Is two months earlier. Pup production and pup mortality were highly variable between seasons over which observations were recorded: 129 pups were born at the main breeding sites in early 1988, the mortality in the first five months was 7.1%, whereas 181 pups were born in late 1989 of which 24.3% died. Pups remain in the vicinity of their natal islands for the first 4-5 months of life before leaving, perhaps on foraging trips, with their mothers. Most return to their natal island, although others haulout on islands up to 27 km away. Some male N. cinerea congregate in bachelor colonies on islands adjacent to the Perth metropolitan region during the non-breeding season and migrate up to 280 km north each breeding season. The status of the isolated, west-coast N. cinerea population is unknown. The current high level of human pressure on sea-lion terrestrial habitats and their food resources indicate a need for further monitoring of this species.


1978 ◽  
Vol 90 (2) ◽  
pp. 435-439 ◽  
Author(s):  
T. More ◽  
K. L. Sahni

SummaryThirty-nine adult ewes of identical body size and age were randomly taken from the Chokla breed. They were divided into four groups which were allowed water once in 24, 48, 72 and 96 h. Seven ewes from each of the first, third and fourth groups were mated for the first time in the spring and for a second time in winter, so that they lambed in the monsoon and summer season respectively. All the ewes were maintained on uncultivated pasture. Watering once in 72 and 96 h caused body weight loss up to 26%, compared with those watered daily. The ewes which failed to maintain pregnancy lost more than 30% of their body weights due to watering only once in 96 h and there were about 43 and 100% lambing in the first and second breeding cycle of the same ewes. The remaining groups displayed 100% lambing. The water-intake increased significantly in the third month of pregnancy in the group allowed water daily and water consumption was found to be about 13% of body weight, whereas the values for those watered once in 72 and 96 h were 9 and 8% respectively. The water-deprived animals were able to drink up to 32 % of their body weights within 2–3 min. It is concluded that breeding ewes could be watered once in 72 h without any loss of lambing during summer.


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