Migratory bird use of shade coffee: the role of structural and floristic features

Abstract

Shade coffee plantations support high numbers of Neotropical migratory birds, but relatively little is known about the structural and floristic attributes used by individual species. From 2005 to 2007, we studied the relationship between habitat characteristics and Neotropical migratory birds in shade coffee plantations in the Venezuelan Andes.Our results indicate that density of migrants was significantly related to both structural and floristic attributes of coffee farms. Specifically, upper canopy foragers were positively associated with number of large trees ([38 cm dbh), tree canopy height, and understory vegetation density. Low canopy and ground foragers were positively associated with numbers of small (8-23 cm dbh) and medium (23-38 cm dbh) trees and increased shade cover. Moreover, certain tree species, especially Inga spp., Erythrina spp. and Acnistus arborescens, were important components of habitat for those species that forage in the canopy. For example, our detailed foraging observations showed that Inga trees were used in greater proportion than available throughout plantations by Cerulean Warblers (Dendroica cerulea), a species of high conservation concern. Overall, our research suggests that suitability of coffee plantations for migratory birds may be improved by managing for particular structural and floristic characteristics of plantations.

Prioritizing tropical habitats for long-distance migratory songbirds: an assessment of habitat quality at a stopover site in Colombia

“…At these elevations premontane forest has been extensively replaced by coffee plantations, as elsewhere in the Neotropics (Komar 2006, IDEAM 2010. Although shade-grown coffee can provide habitat for overwintering migratory birds (Tejeda-Cruz and Sutherland 2004, Komar 2006, Bakermans et al 2012, its value as stopover and premigratory fueling habitat, when energetic requirements are elevated, is unknown. In this paper, we (1) assess the relative quality of shade coffee and premontane forest as stopover habitat for two species of Nearctic-Neotropical migratory birds on spring migration in the Sierra Nevada de Santa Marta; (2) compare and contrast the ability of seven different measures to distinguish the relative quality of shade coffee and premontane forest at a stopover site in Colombia (Table 1); and (3) discuss the possible impact stopover-habitat use may have on the subsequent migratory strategy of birds in this important region.…”

Foraging behavior of migrant warblers in mixed-species flocks in Venezuelan shade coffee: interspecific differences, tree species selection, and effects of drought

“…We found that two foliage‐gleaners (Blackburnian and Cerulean warblers) attacked prey at the same rate, and all three foliage‐gleaners (Blackburnian, Cerulean, and Tennessee warblers) foraged in Inga more than expected based on availability. Bakermans et al () also noted that Cerulean Warblers exhibited a preference for foraging in Inga . During the non‐breeding season, Greenberg et al () found that three warblers in the Black‐throated Green Warbler ( Setophaga virens ) complex also attacked prey at the same rates, but found that these warblers differed in selection of foraging substrates (pine vs. oak).…”

“…Other researchers have found that flocking species with similar foraging behaviors forage at different heights in a variety of systems (Greenberg , Hutto , Eguchi et al , Greenberg et al ). Other investigators have also reported differences in foraging heights of male and female Cerulean Warblers, although whether this is a result of sexual segregation or other factors remains unknown (Bakermans et al , Muñoz and Colorado ). With their lower foraging height, Cerulean Warblers appeared to forage in shrubs and small trees more than the two other foliage‐gleaners and, interestingly, Cerulean Warblers were also most abundant at our two sites with small trees and shrubs.…”

“…Shade coffee farms were generally 3–5 ha in area interspersed with other land uses, including cattle pastures with residual trees, low density residential housing, remnant forest patches, especially in riparian areas, and Sierra de la Culata National Park (for a more complete description of the area, see Bakermans et al , ). We were not able to consider landscape context in our study, although along with elevation, this could have influenced flock composition at our sites (Colorado ).…”

“…Based on importance values, dominance of Inga ranged from 7% to 65% among sites, and we identified at least 10 tree species at most sites. Canopy cover as measured with a densiometer ranged from 70% to 86% (Table ), although estimates of shade cover based on foliage hits were lower (Bakermans et al , ).…”