SENTINEL BEHAVIOR OR VIGILANCE AT A MACAW CLAYLICK?

Abstract ∙ Sentinel behavior (co‐ordinated vigilance) has been observed for a range of bird species living in family groups, usually in arid environments, but the behavior has never been formally identified for parrots. Riverside clay‐licks are sites where parrots and other species congregate to consume soil, usually in large numbers. Birds feeding on the clay are vulnerable to attack from predators. The Red‐and‐green Macaw Ara chloropterus can be observed in the vicinity of claylicks for much of the morning, although they spend only a small amount of time feeding on the clay itself. I investigated patterns of vigilance at a riverside claylick in Peru to test whether or not the birds engage in true sentinel behavior. There was no evidence for coordination of vigilance, and overall vigilance increased with the presence of more birds on the claylick, contrary to expectation. In addition, tall perches that should serve as sentinel positions were generally occupied less when birds were feeding on the claylick, and the probability of birds on the clay increased with increasing group size. Probability of calling, which could include warning information, was not higher as a function of bird presence on the clay, but was best explained by group size. All macaws maintained a generally high state of vigilance in the vicinity of the claylick, suggesting there was no reliance on a sentinel system. Further work is needed to understand the dynamics of this behavior for this species at one of southeastern Peru’s most important ecotourism resources. Resumen ∙ Comportamiento de centinela o vigilancia en un sitio de colpa de guacamayos? El comportamiento de centinela (es decir la vigilancia coordinada) ha sido registrado para diversas especies de aves que viven en grupos familiares, en especial en ambientes áridos, pero este comportamiento no ha sido descripto para especies de loros y guacamayos. Los sitios de colpa a la vera de los ríos, son lugares donde loros y otras especies se congregan para consumir tierra y minerales, a menudo en grandes números. Las aves en los sitios de colpa son vulnerables a depredadores. El Guacamayo Aliverde (Ara chloropterus) puede ser encontrado en los alrededores de sitios de colpa durante gran parte de las mañanas, pero solo una fracción de tiempo es empleada en consumir tierra. En este trabajo investigué los patrones de vigilancia del Guacamayo Aliverde en un sitio de colpa en Perú, para determinar si estos son compatibles con comportamie