Ants have a reputation for ruining picnics. Well, being a bird in an ant-infested tree is no picnic, either.
Scientists watched birds foraging in trees in shade coffee plantations in Mexico. The Azteca instabilis ant lives in certain trees in the canopy where it forages for insects.
Birds did not avoid the trees, but when the ants were active they did not stay very long. The ants can be quite aggressive and may have been protecting themselves or access to their insect prey.
This article summarizes the information in this publication:
Philpott, S. M., Greenberg, Russell S. and Bichier, Peter 2005. The influence of ants on the foraging behavior of birds in an agroforest. Biotropica, 37: 467-470.
Ants limit bird foraging success via interference or exploitative competition. We compared bird foraging (number and duration of visits, bird species visiting) on ant (Azteca instabilis)-infested and ant-free tropical trees (Inga micheliana and Alchornea latifolia). Ants did not affect the number of bird visits or the number of species visiting. Ant presence shortened visit duration (overall and for insectivores) only on A. latifolia where ant activity was higher. Ants may thus hinder bird foraging on some tropical trees potentially shaping how predators affect arthropod communities; yet ant effects depend on bird foraging guild and ant activity.
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