The foraging success of trap-building animals depends entirely on the characteristics of their traps (Scharf, Lubin, & Ovadia, 2011). Traps with sub-optimal design will capture fewer and/or inadequate prey, negatively affecting the quality and quantity of ingested food. For example, spider webs with small areas or reduced stickiness per square centimeter will intercept and retain fewer insects than larger and stickier webs, respectively (Opell, 1999). Given that the traps that animals build to capture prey are considered extended phenotypes and reflect how organisms optimize their foraging, their design should be subjected to

No abstract

Variations in moonlight can affect the vocal activity of many nocturnal birds, including the Great Potoo (Nyctibius grandis), a rarely seen bird usually detected through its characteristic calls. We evaluated the vocal activity of the Great Potoo in relation to moonlight in a Tropical Forest of Costa Rica. We surveyed potoos using four replicated 13-minute counts covering a single moon cycle at 31 points at La Selva Biological Station during March and April 2020. We detected seven Great Potoos on nights with 76-100% moonlight, three on nights with 51-75% moonlight, and none on nights with 0-50% moonlight. Great Potoos were more easily detected during moonlit nights, which is consistent with other studies of ‘lunarphilic’ nocturnal birds, and suggests that future studies modeling occupancy or habitat use of Great Potoos should consider moonlight as a covariate of detectability.

El Lechuzón Orejudo (Asio clamator) está ampliamente distribuido en el neotrópico. Sin embargo, la información sobre su biología reproductiva es poca. En Argentina, los registros de nidificación del Lechuzón Orejudo son escasos. Los mismos se concentran en el centro y noreste del país, sin haber hasta el presente registros de nidos en el noroeste. En abril de 2019 realizamos el primer registro de nidificación del Lechuzón Orejudo en el noroeste de Argentina, específicamente en la provincia de Salta. Este trabajo es un aporte importante sobre la distribución reproductiva del Lechuzón Orejudo en Argentina ya que, por un lado, expande el área de reproducción de la especie en nuestro país. Y a su vez, apoya la hipótesis que sugiere que el Lechuzón Orejudo muestra flexibilidad en la época de nidificación dado que nuestras observaciones ocurrieron durante una época del año poco reportada hasta el momento.

Owls are top predators poorly studied in the Neotropics. Their occurrences can be affected by forest structure and landscape features. We report Tropical Screech-Owl (Megascops choliba) and Ferruginous Pygmy-Owl (Glaucidium brasilianum) detections in relation to habitat characteristics in central Argentina. During the spring of 2019, we surveyed 250 ha of mountain forest, measured habitat characteristics in presences/absences sites, and estimated owls’ densities. M. choliba (0.16 individuals/ha) was positively associated with snag whereas G. brasilianum (0.05 individuals/ha) was positively associated with proportions of small trees. Our results suggest that these habitat characteristics might be important covariates when studying these two species.