MOVEMENTS OF SINGLE BIRDS AND MIXED-SPECIES FLOCKS BETWEEN ISOLATED FRAGMENTS OF CLOUD FOREST IN ECUADOR

Movements of birds between isolated fragments of cloud forest at 2900 - 3000 m were studied in southern Ecuador. Twenty-nine (38%) of the di urnal forest-bird species moved over clear-cut areas between isolated fragments 35 - 110 m apart. They ranged from the 6 g Black-throated To dy-Tyrant (Hemitriccus granadensis) to the > 800 g Bearded Guan (Penel ope barbata). The frugivorous Great Thrush (Turdus fuscater) made 48% of all movements between the fragments. The Great Thrush excluded, fru givorous birds still moved more frequently between fragments than inse ctivorous and omnivorous birds; edge-canopy birds moved more frequentl y between fragments than interior and edge-canopy-interior birds. Spec ies greater than or equal to 15 g moved more frequently between fragme nts than smaller species. The majority of movements occurred between f ragments of tall forest and smalt distance (65 - 80 m) apart compared to fragments of low forest and greater distance (80 - 100 m). Three mi xed-species flocks were present in the study area. The largest flock ( 21 species, 49 - 54 individuals) roamed over a continuous tract of for est and contributed individual to one of the other flocks (11 - 12 spe cies, 24 - 25 individuals), which used a fragmented home-range of mini mum 6 - 7 ha. From time to time the latter nock separated into smaller units. Within the home area mixed-species flocks were observed more f requently in tall forest (75.8%) than in low forest.