Effect of Northern Pygmy-Owl (Glaucidium gnoma) Eyespots on Avian Mobbing

Len Broberg

doi:10.2307/4090106

Effect of Northern Pygmy-Owl (Glaucidium gnoma) Eyespots on Avian Mobbing

The Auk ◽

10.2307/4090106 ◽

2003 ◽

Vol 120 (3) ◽

pp. 765-771

Author(s):

Len Broberg

Keyword(s):

Glaucidium Gnoma

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Northern Pygmy-Owl (Glaucidium gnoma)

10.2173/bna.nopowl.02 ◽

2000 ◽

Author(s):

Denver W. Holt ◽

Julie L. Petersen

Keyword(s):

Glaucidium Gnoma

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Effect of Northern Pygmy-Owl (Glaucidium Gnoma) Eyespots on Avian Mobbing

The Auk ◽

10.1093/auk/120.3.765 ◽

2003 ◽

Vol 120 (3) ◽

pp. 765-771 ◽

Cited By ~ 1

Author(s):

CAROLINE DEPPE ◽

DENVER HOLT ◽

JOSH TEWKSBURY ◽

LEN BROBERG ◽

JULIE PETERSEN ◽

...

Keyword(s):

Empirical Evidence ◽

Potential Function ◽

Potential Functions ◽

Forest Birds ◽

Color Patterns ◽

Ecological Functions ◽

Glaucidium Gnoma ◽

Small Forest

Abstract Eyespots (color patterns resembling eyes) are present in many taxa and often have important ecological functions. In some taxa, potential functions of eyespots have not been extensively examined, as is the case with pygmy-owls (Glaucidium spp.), many of which bear a conspicuous eye-like pattern on their nape. Using wooden replicas of Northern Pygmy-Owls (G. gnoma), with and without eyespots, we tested one potential function: whether eyespots affect mobbing behaviors of small forest birds. We measured the orientation of mobbing behaviors (where birds perched and flew at the model) and intensity of mobbing bouts (duration of bouts and number of mobbing individuals). Eyespots affected the most proximal behavior, close passing (flights directly at the model, resulting in an approach within 0.5 m). When eyespots were present, mobbers shifted away from eyespots, providing the first empirical evidence for a link between eyespots and avian mobbing.

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