RUSSET-BACKED THRUSH 169 



western Guatemala, I found the bird abundant late in January in a 

 tract of low, dense thicket dominated by scattered great trees that 

 survived the destruction of the original forest. Here the thrush's 

 liquid monosyllables were heard on every hand during the morning 

 hours. It was surrounded by many other winter residents, including 

 worm-eating, hooded, Kentucky, Wilson's, and MacGillivray's 

 warblers. 



"In the basin of El General in southern Costa Rica, it winters chiefly 

 in the undergrowth of the high forest and, like its resident neighbors 

 of the same habitat, never forms true flocks. During most of its 

 sojourn here it is so retiring that, but for an infrequent call note, it 

 might easily be overlooked, despite its abundance. Sometimes it 

 ventures forth into the adjacent clearings, where the forest has been 

 felled and burned to plant maize, then the land temporarily abandoned 

 after the harvest. Such clearings are usually filled with a luxuriant 

 growth of that widespread 'fire weed' of tropical America, the jaboncillo 

 (Phytolacca rivinoides) , a kind of pokeberry, which during the early 

 months of the year bears a profusion of deep purple berries that 

 attract a multitude of birds, from big toucans and finches to little 

 tanagers, manakins, and honeycreepers. 



"The russet-backed thrush sometimes joins the mixed flocks of small 

 birds that follow the foraging swarms of army ants. Like most if not 

 all of these birds, it does not devour the ants themselves but snatches 

 up the insects and other small creatures driven from where they have 

 lurked beneath the fallen leaves, in rotting stumps and crevices in the 

 bark of trees. The thrush hovers about the outskirts of the swarm; 

 and I have not seen it dash into the midst of the fray to seize a fugitive, 

 in the manner of the tropical birds more adept at this kind of hunting. 

 What strange company for a bird hatched among northern spruce and 

 fir trees! Who that knows the russet-backed thrush only amid the 

 severe simplicity of a northern coniferous forest could imagine it in 

 the infinitely varied tropical silva, burdened with huge woody vines 

 and a hundred kinds of epiphytes, where it consorts on intimate terms 

 with such birds as manakins, woodhewers, antbirds, and ant-tanagers? 

 Truly these migratory birds lead double lives. 



"Late in February or early in March the russet-backed thrushes 

 begin to sing in an undertone. Soon their slender liquid spirals of 

 song arise in the forest on every side, not merely in isolated instances, 

 but again and again and again. Their soft quit is also heard oftener 

 now. In April they sometimes become so numerous that they have 

 appeared to me the most abundant bird in the region, save only the 

 migratory swallows passing northward in their myriads. Since the 

 resident birds of the understory of the tropical forest are in the main 

 parsimonious of song, at times early in April the russet-backed thrushes 



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