Endozoochory largely outweighs epizoochory in migrating passerines

Submitted by avianbiology on 27 January 2014.

Fruits and seeds are critical food sources for many European passerines during their autumn migration, which in turn contributes to the dispersal of seeds, either internally (endozoochory), or externally, when seeds adhere to the body surface (epizoochory). In this paper the authors looks at the relative importance of theese different seed-dispersal pathways.

Read what the authors has to say about their study below:

Birds are famous for being proficient dispersers of many seeds, what can be particularly relevant during migrations. Any ecology textbook will say that birds can carry seeds both internally (after the birds ate the fruits -endozoochory), or externally (when seeds get attached to their feathers or beak- epizoochory), however the relative importance of both mechanisms as not yet been evaluated. On an unusual effort, we joined the force of nine bird ringers to capture birds simultaneously for a week, in nine locations across Portugal in order to study seed dispersal by migrating birds. We retrieved nearly 2000 seeds dispersed by 20 bird species, and approximately half of them during migration. We found that the number of seeds attached to the bird’s bodies is only a tiny fraction (<1%) of those dispersed internally, nevertheless, we found that seeds do not need to have special adaptations for epizoochory, in order to be successful hitchhikers.

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