BACKGROUND Intraguild predation (IGP) is widespread but it is often neglected that guilds commonly include many layers of dominance within. This could obscure the effects of IGP making unclear whether the intermediate or the bottom mesopredator will bear higher costs from the emergence of a new top predator. METHODOLOGY/PRINCIPAL FINDINGS In one of the most extensive datasets of avian IGP, we...

Sir, Acanthocephalan (“spiny-headed”) worms are enteroparasites of birds characterised by a retractile proboscis armed with rows of thorns (Lacina & Bird, 2000). They penetrate the intestinal mucosa with the proboscis causing inflammation and nodules (Heidenreich, 1997). An arthropod (insect or mollusk) becomes the first intermediate host ingesting acanthocephalan eggs that contain the larvae (...

I N the past several years I have kept eight Sparrow Hawks (F&o sparverius) in captivity for use in experiments in prey selection and the motivation for predatory behavior. Four of the birds were taken from nests at approximately two to three weeks of age and were hand-reared in my laboratory and four were trapped as free-flying birds. All birds were handled frequently and became quite tame. Th...

Type material of Litomosoides hamletti Sandground, 1934 from Glossophaga soricina soricina in Brazil and L. penai Jiménez-Quirós & Arroyo, 1960 from Carollia perspicillata azteca in Costa Rica, was examined. The morphology of the spicules shows that these species belong to the carinii group. Their synonymy with L. guiterasi Pérez Vigueras, 1934, from Artibeus jamaicensis yucatanicus in Cuba, do...

The presence of lower-field myopia (described in chickens, pigeons, quail and amphibians) allows these animals to keep the ground in focus while performing other visual tasks. A relationship has also been reported between the eye height and the degree of myopia observed. All of the animals reported in the literature to date are ground-foraging species. Using infrared neutralizing video retinosc...