The Tennessee Warbler is a common nectar "thief" on its wintering grounds in tropical forests. Most nectar-eating birds, bats, and insects probe a flower from the front to get the nectar, spreading pollen on their faces in the process. But Tennessee warblers pierce the flower tube at the base, lapping up the nectar without helping pollinate the flower. The Tennessee Warbler is a small and active warbler that hops and flits through the upper forest canopy seeking invertebrates from the tips and surfaces of leaves. Breeding males aggressively defend their territories from other males, singing from perches in the upper two-thirds of trees. Pairs are seasonally monogamous, with no known extra-pair copulation. Female Tennessee Warblers incubate the eggs, with males feeding females during this period. Both sexes feed the nestlings upon hatching. On migration and in winter, Tennessee Warblers often form foraging flocks with other species. During the non-breeding season they are generally gregarious and tolerant both of other Tennessee Warblers and other species, although they can be aggressive in defending nectar sources.
Photographer: Dave Saunders