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1

Prey size selection of insular lizards by two sympatric predatory bird species

100%
Padilla D. P., Nogales M., Marrero P.
Acta Ornithologica
|
2007
|
tom 42
|
nr 2
167-172
2

The key role of a Ring Ouzel Tardus torquatus wintering population in seed dispersal of the endangered endemic Juniperus cedrus in an insular environment

100%
Rumeu B., Padilla D. P., Nogales M.
Acta Ornithologica
|
2009
|
tom 44
|
nr 2
Although the Ring Ouzel has been considered accidental in the Canary Islands, it has been observed for the last five years in the high mountain zone of Tenerife (Canary Islands), showing it to be a regular winter visitor. Its interaction with female Juniperus cedrus cones and seeds was studied by analysing its wintering diet during January-April 2008. This juniper is endemic to the Canaries and Madeira and is classified as endangered by the IUCN. Previously, its sole long-distance disperser was known to be the Raven Corvus corax, which is unfortunately now extinct in the distribution range of J. cedrus. The results show that the diet of T. torquatus in Tenerife consists mostly of female J. cedrus cones (95% of the biomass consumed). Due to the large amount of seeds dispersed by Ring Ouzels and the effectiveness in seed germination, this winter visitor constitutes an important vector in the dispersal of J. cedrus that appears to have gone undetected in the past. This passerine plays a key role in its seed dispersal system, being able to move seeds over long distances, thus connecting fragmented populations of this plant. The present work is one of the few cases described in which a plant endemic to an oceanic island is so dependent on a winter visitor, and highlights the importance of insular environments in the wintering range of the Ring Ouzel. Owing to the absence of native long-distance seed dispersers, the future fate of this conifer is now probably dependent on the wintering population of this thrush.
3

Feeding ecology of feral cats on a heterogeneous subtropical oceanic island [La Palma, Canarian Archipelago]

100%
Medina F. M., Garcia R., Nogales M.
Acta Theriologica
|
2006
|
tom 51
|
nr 1
75-83
We found a total of 987 prey in the 500 scats of feral catsFelis silvestris catus Linnaeus, 1758 analyzed in the present study. Introduced mammals (rabbits, rats and mice) constituted the most important prey both in percentage and biomass. Reptiles were the second most important prey, being more frequent than birds and invertebrates. Mammals were the most frequently eaten group in all five main habitats of the island, being more frequent than the remainder of prey in the laurel forest. Rabbits appeared more often in the temperate forest, rats in the laurel forest and mice in the high mountain. Birds were more frequently captured in the three higher habitats (laurel and pine forest, and high mountain) than in the two lower ones (xerophytic shrub and temperate forest). Reptiles were preyed on less in the laurel forest than in the other main habitats. Morisita index indicates a high trophic overlap among the different habitats with the exception of the laurel forest which shows important differences from the other habitats. Levin’s niche-breadth was broader in the xerophytic shrub and narrower in the temperate forest, reaching intermediate levels in the other three main habitats. The results obtained in the present study evidence a general pattern in the trophic ecology among similar habitats in the different subtropical Canarian islands. However, some important differences exist that could be a function of the differential prey availability and composition in each ecosystem.
4

Seasonal diet of the Grey Heron Ardea cinerea on an oceanic island [Tenerife, Canary Islands]: indirect interaction with wild seed plants

100%
Rodriguez A., Rodriguez B., Rumeu B., Nogales M.
Acta Ornithologica
|
2007
|
tom 42
|
nr 1
77-87
5

Seasonal variation in the diet of wild rabbits Oryctolagus cuniculus on a semiarid Atlantic island [Alegranza, Canarian Archipelago]

100%
Martin M. C., Marrero P., Nogales M.
Acta Theriologica
|
2003
|
tom 48
|
nr 3
The diet of the wild rabbit Oryctolagus cuniculus (Linnaeus, 1758) on Alegranza Island (Canary Islands) was studied by microhistological examination of faecal samples. We compared the presence of each food-plant species in the faeces across a year in comparison with plant availability. Two areas were studied, Llano de la Vega and La Caldera. At the first site, Suaeda vera and Chenoleoides tomentosa were the most common plants, while at the latter it was Euphorbia regis-jubae. In general, species belonging to the Chenopodiaceae were most commonly eaten by rabbits. Plants such as Chenoleoides tomentosa and Salsola vermiculata were most important in the diet in every season. Levin's niche-breadth was broader across the seasons in the study site of La Caldera than at Llano de la Vega. Furthermore, this parameter yielded the highest values (broadest niche) during the spring at both sites. Most important plants eaten by rabbits showed green vegetative parts through all seasons. Rabbits selected some plants independently of their availability, even in this reduced insular environment. The feeding behaviour of rabbits in Alegranza, selecting certain species, must have had important consequences on the composition and distribution of the vegetation over the years. This negative effect on island vegetation has been shown to occur on many oceanic islands of the world where rabbits have been introduced.
6

Trophic habits of feral cats in the high mountain shrublands of the Macaronesian islands [NW Africa, Atlantic Ocean]

76%
Medina F. M., Oliveira P., Menezes D., Teixeira S., Garcia R., Nogales M.
Acta Theriologica
|
2010
|
tom 55
|
nr 3
241-250
Feral cats Felis catus Linnaeus, 1758 have contributed to the extinction of numerous native species on islands, which are clearly sources of global biodiversity. We studied the diet of this introduced predator in the Madeira and Cape Verde archipelagos, which harbour important colonies of endangered seabirds in the high mountain habitats, and compared the results with those obtained in the same habitat in the Canary Islands, Macaronesian archipelago. On Madeira, 461 prey were identified from 143 scat groups. Mammals, overall mice, constituted the basic diet appearing in 95% of cat scats. On Fogo (Cape Verde), 657 prey items were obtained from 145 scats, and mammals were also the most important prey, reaching a frequency of occurrence of 88%. Although introduced mammals were the main prey category on all Macaronesian islands, we observed variation in feral cat diet among these islands. Birds were more frequently consumed on Madeira, lizards on Tenerife (Canaries) and invertebrates on Fogo. No specific differences were observed in relation to La Palma. We suggest that the diet composition on these islands varies according to the respective availability of the different prey types.
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