Nesting Success and Nesting Height in the Critically Endangered Medium Tree Finch (Camarhynchus pauper)

When different introduced species across trophic levels (parasite, predator) invade island systems, they may pose significant threats to nesting birds. In this study, we measure nesting height and infer causes of offspring mortality in the critically endangered Medium Tree Finch (Camarhynchus pauper), an island endemic restricted to Floreana Island on the Galápagos Archipelago. Considering all nests at which a male built a nest, sang and attempted to attract a female (n = 222 nests), only 10.4% of nests produced fledglings (5% of nests had total fledging success, 5.4% of nests had partial fledging success). Of the 123 nests chosen by a female, 18.7% produced fledglings and of 337 eggs laid, 13.4% produced fledglings. Pairing success was higher for older males, but male age did not predict nesting success. All nests with chicks were infested with avian vampire fly larvae (Philornis downsi). We attributed the cause of death to avian vampire fly if chicks were found dead in the nest with fly larvae or pupae (45%) present. We inferred avian (either Asio flammeus galapagoensis or Crotophaga ani) predation (24%) if the nest was empty but dishevelled; and black rat (Rattus rattus) predation (20%) if the nest was empty but undamaged. According to these criteria, the highest nests were depredated by avian predators, the lowest nests by rats, and intermediate nests failed because of avian vampire fly larvae. In conclusion, there is no safe nesting height on Floreana Island under current conditions of threats from two trophic levels (introduced parasitic dipteran, introduced mammalian/avian predators; with Galápagos Short-Eared Owls being the only native predator in the system).

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Aegialomys galapagoensis (Rodentia: Cricetidae)

Mammalian Species ◽

10.1093/mspecies/sez013 ◽

2019 ◽

Vol 51 (981) ◽

pp. 92-99

Author(s):

Joyce R Prado ◽

Alexandre R Percequillo

Keyword(s):

Natural Resources ◽

Rattus Rattus ◽

Critically Endangered ◽

Santa Fe ◽

International Union ◽

Major Threat ◽

Galapagos Archipelago ◽

Santiago Island

Abstract Aegialomys galapagoensis (Waterhouse, 1839) is a sigmodontine rodent commonly called the Galapagos rice rat. It is a medium-sized rodent, characterized by dense, soft, yellow or copper, weakly grizzled pelage; the dorsum is grayish or brownish and the ventral pelage is pale. It is endemic to the open habitats of the Galapagos Archipelago, occurring on three islands, Santa Fé Island (Barrington Island), San Cristóbal Island (Chatham Island), and Santiago Island (James Island). Restricted populations are considered a major threat to A. galapagoensis conservation throughout most of its range, as well as competition with Rattus rattus. A. galapagoensis is listed as “Vulnerable” by the International Union for Conservation of Nature and Natural Resources, and is listed as “Critically Endangered” on the Ecuador National list.

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MODULATION OF TRIGLYCERIDES IN FEMALE RATTUS RATTUS WITH STEROID CONTRACEPTIVE ALGESTONE ACETOPHENIDE (DHPA)

FLORA AND FAUNA ◽

10.33451/florafauna.v25i1pp78-80 ◽

2019 ◽

Vol 25 (1) ◽

Author(s):

ASHOK KUMAR ◽

ALPANA PARMAR ◽

ANAND KUMAR BAJPEYEE

Keyword(s):

Mixed Type ◽

Rattus Rattus ◽

Young Female ◽

Female Rats ◽

Control Group ◽

Black Rat ◽

Long Acting ◽

Steroid Contraceptive

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.

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Late-Holocene asynchronous extinction of endemic mammals on the eastern Canary Islands

The Holocene ◽

10.1177/0959683611430414 ◽

2011 ◽

Vol 22 (7) ◽

pp. 801-808 ◽

Cited By ~ 7

Author(s):

Juan Carlos Rando ◽

Josep Antoni Alcover ◽

Jacques Michaux ◽

Rainer Hutterer ◽

Juan Francisco Navarro

Keyword(s):

Canary Islands ◽

Late Holocene ◽

Middle Age ◽

Rattus Rattus ◽

Tyto Alba ◽

Isolated Populations ◽

European Contact ◽

Black Rat ◽

Local Extinctions ◽

Ams Dating

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.

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

Canadian Journal of Zoology ◽

10.1139/z08-070 ◽

2008 ◽

Vol 86 (9) ◽

pp. 1068-1073 ◽

Cited By ~ 13

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.

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A comparative study of the chromosomes of the Norway rat (Rattus norvegicus ERXL.) and the black rat (Rattus rattus L.)

Journal of Morphology ◽

10.1002/jmor.1050440306 ◽

1927 ◽

Vol 44 (3) ◽

pp. 515-538 ◽

Cited By ~ 18

Author(s):

G. Pincus

Keyword(s):

Comparative Study ◽

Rattus Norvegicus ◽

Rattus Rattus ◽

Norway Rat ◽

Black Rat

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Extreme rainfall-related clutch size variation in the Critically Endangered Raso Lark Alauda razae of the arid Cape Verde islands

Bird Conservation International ◽

10.1017/s0959270918000163 ◽

2018 ◽

Vol 29 (2) ◽

pp. 321-326 ◽

Cited By ~ 6

Author(s):

M. de L. BROOKE

Keyword(s):

Population Size ◽

Clutch Size ◽

Size Variation ◽

Extreme Rainfall ◽

Cape Verde ◽

Critically Endangered ◽

Strongly Correlated ◽

Cape Verde Islands ◽

Rainy Period ◽

Island Endemic

SummaryThe Raso Lark Alauda razae is a single island endemic confined to the island of Raso in the Cape Verde islands. It has been studied via short (11–20 day), similarly-timed visits every year from 2001 to 2017. These November/December visits have occurred towards the end of the main rainy period (August–October) in the Cape Verdes. Average clutch size ranged from zero (no nests found) to 3.57 in different years and was strongly correlated with rainfall in the three months preceding the year’s visit, but not with population size, which varied 25-fold during the study period. Since the nomadic pursuit of rain is not an option for the Raso Lark, the species adjusts clutch size according to conditions prevailing on Raso.

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Rattus rattus Black Rat : Fr. Rat noir; Ger. Hausratte

Mammals of Africa : Rodents, Hares and Rabbits ◽

10.5040/9781472926937.0333 ◽

2016 ◽

Keyword(s):

Rattus Rattus ◽

Black Rat

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Sabal lougheediana (Arecaceae), a critically endangered, endemic palm species from Bonaire

Phytotaxa ◽

10.11646/phytotaxa.420.2.1 ◽

2019 ◽

Vol 420 (2) ◽

pp. 95-101

Author(s):

M. PATRICK GRIFFITH ◽

QUIRIJN COOLEN ◽

MICHELLE BARROS ◽

LARRY R. NOBLICK

Keyword(s):

Conservation Status ◽

Critically Endangered ◽

Fiber Bundles ◽

Island Endemic ◽

Palm Species ◽

Leaf Segments ◽

Diagnostic Key ◽

Erect Leaf

A new palm species, Sabal lougheediana, is described and illustrated. This critically endangered island endemic, native solely to Bonaire, is characterized by a compact crown of leaves, erect leaf segments, distinctive leaf scars, and frequently vascularized fiber bundles in leaflet transection. Detail on history, morphology, range, habitat, and conservation status is presented, along with a diagnostic key.

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The ecological impacts of commensal species: black rats, Rattus rattus, at the urban–bushland interface

Wildlife Research ◽

10.1071/wr15048 ◽

2015 ◽

Vol 42 (2) ◽

pp. 86 ◽

Cited By ~ 15

Author(s):

Peter B. Banks ◽

Helen M. Smith

Keyword(s):

Exotic Species ◽

Urban Areas ◽

Rattus Rattus ◽

Research Priorities ◽

Ecological Impacts ◽

Black Rat ◽

Urban Impacts ◽

Commensal Species ◽

Commensal Rodents ◽

Black Rats

Exotic species have had devastating impacts worldwide and are a major threat to native wildlife. Human commensal species (hereafter commensals) are a special class of exotic species that live largely off the resources associated with human activity. The encroachment of commensals from an urban area into surrounding bushland has been frequently overlooked as an important component of urban impacts, even though human-commensals are common to many urban regions globally. In this review, we present theoretical and empirical evidence for the processes and outcomes occurring when exotic commensal species encroach into native bushland. Specifically we ask when, how and why exotic commensal species encroach into bushland, what determines whether they establish, and what are the ecological consequences. We focus on the black rat, Rattus rattus, arguably the archetypal commensal species with a cosmopolitan distribution and the greatest potential for ecological damage of all the commensal rodents. We expect that the processes that we outline apply to other commensal species more broadly. We argue that commensals are in fact natives of the urban milieu and only become alien when they encroach into peri-urban bushland. We propose that the mechanisms of this encroachment will be different from those of other, non-commensal exotic species because urban areas act as dispersal hubs to overcome many of the barriers of invasion that other exotic species face. We suggest that resource supplementation by urban areas creates a great potential for promoting encroachment, invasion as well as impact. However, biotic and abiotic barriers to invasion are still relevant for commensals, highlighting the need to maintain the integrity of ecosystems and wildlife populations in urban edges so as to prevent commensal incursion. We examine how commensal black rats affect wildlife via three fundamental mechanisms, namely, predation, disease transfer and competition for resources, and also consider their possible positive impacts acting as functional replacements for lost natives. We conclude the review with an outline of research priorities and future directions that are essential for progressing our understanding of the ecology of commensal species.

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