Is foraging behavior associated with habitat use patterns in South American migrant landbirds of the central Monte desert?

CUETO, V.R.; J. LOPEZ DE CASENAVE

Veracruz, Mexico

Congreso; IV North American Ornithological Conference; 2006

American Ornithological Union

Long- and short-distance South American migrant landbirds have a marked pattern of habitat use in the central Monte desert, Argentina, being more abundant in open mesquite woodlands than in creosotebush shrublands. Foraging behavior of the most abundant species of long- distance (White-crested Elaenia and Crowned Slaty-Flycatcher) and short-distance (Gray-crested Tyrannulet and Cinnamon Warbling-finch) migratory species was studied to understand its relationship to the pattern of habitat use. The foraging maneuver most commonly used by White-crested Elaenia and Gray-crested Tyrannulet was hover with short flights between perch and prey. Crowned Slaty-Flycatcher used sally (with long flights), and Cinnamon Warbling-finch gleaned food from substrates. Hovering species foraged mostly in the shrub strata, Crowned Slaty-Flycatcher used primarily the tree stratum and Cinnamon Warbling-finch foraged mostly in the herbaceous stratum and on the ground.  All of these species were selective in their use of plant species for foraging, using creosotebush less often than expected by chance.  We discuss how foraging behavior of these species could restrict their use of the different habitats of the central Monte desert landscape. Considering that human activity in this ecosystem trends towards habitat simplification, we also consider conservation scenarios for South American migrant landbirds in this arid zone.