Friday, May 29, 2015

Watching a Worm-eating Warbler

 [Worm-eating Warblers are known for their somewhat unique foraging habit: hanging upside down on (often dead) clumps of leaves to extract tasty bits like caterpillars.  Here, one does just that. Note the rolled-up leaf  the warbler has its feet around - many butterfly and moth larvae will curl themselves inside leaves for protection during the day, emerging to feed on the leaves at night.  Belleplain State Forest, NJ, May 27, 2015.  Click to enlarge photos.]

My son Tim called it epic.  We chanced upon a foraging Worm-eating Warbler at very close range in Belleplain State Forest, NJ early Wednesday morning, and spent several minutes watching it as it foraged in classic wormie fashion, hanging upside down at leaf clusters. Using different foraging styles is one way birds in a forest, or anywhere, can partition resources - not that they choose to do that, it's just what has evolved and allowed different species to coexist in the same place at the same time. Thus Worm-eating Warblers avoid competition with, say, neighboring Red-eyed Vireos, which tend to spot-and-stalk openly visible caterpillars higher in the canopy.

 [Now we can see the Worm-eating Warbler's target - a caterpillar wrapped in silk, rolled up in the leaf, hoping to stay safe for the day.  Not so for this one - the worm-eating shortly extracted it, flew off to the ground with it, pummeled it with its bill, and ate it.]

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