Yellow-vented Bulbul does swallow some fruits but not others

posted in: Feeding strategy, Feeding-plants | 8

In an earlier posting it was said that Yellow-vented Bulbul (Pycnonotus goiavier) does not swallow Alexandra palm (Archontophoenix alexandrae) fruits. It pecks on the outer pulp, leaving the fruit on the branch with patches exposing the seed.

With the MacArthur palm (Ptychosperma macarthurii) (above), I have noticed that this bird does swallow the fruits whole. Although I have not seen it regurgitating the seeds, I did find a few patches of faeces with seeds on my driveway. It is possible that the bulbul passed out the seeds?

However, I have been puzzled by the presence of many individual seeds of this palm, cleaned of pulp, scattered along my driveway (left). I do not grow this palm in my garden. These seeds must have been regurgitated by some birds. Can it be the Pink-necked green Pigeon (Treron vernans) that regularly perch on the overhanging ceram palm (Rhopaloblaste ceramica) fronds?

And why does the bulbul swallows fruits of the MacArthur palm but not those of the Alexandra palm? The answer lies in the size of the two seeds. Alexandra palm fruits are nearly round, 12×10 mm, with a single large round seed that is about 9×8 mm in dimension. The flesh is a thin layer of 2-3 mm thick. Although the fruit of the MacArthur palm is of similar size, the seed is very much smaller. It is 10 mm long but only 5 mm broad.

Obviously we have much to learn about the feeding habits of our common birds.

Transverse sections of fruits of MacArthur (left) and Alexandra (right) palms.

Seeds of MacArthur (left) and Alexandra (right) palms.

Scale in mm.
All images by YC.

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8 Responses

  1. […] Yellow-vented Bulbul (Pycnonotus goiavier), which has a smaller gape than the pigeon, similarly swallows the fruit whole. Details of the fruit in cross-section showing the pulp and seed can be seen HERE. […]

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  2. […] … Yellow-vented Bulbul eating Tabernaemontana corymbosa fruits Joseph Lai came across a …Bird Ecology Study Group Yellow-vented Bulbul does swallow …In an earlier posting it was said that Yellow-vented Bulbul (Pycnonotus goiavier) does not swallow […]

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  3. […] now. There is also an earlier post on the bulbul swallowing these fruits, this time from Singapore LINK. As for Javan Myna, this is the first record. All these birds are common species and generally […]

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  4. George Wong

    I’ve 2 bulbuls.other than papaya and apple what else can I feed them?

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  5. George Wong

    Other than papaya and apple what else can i feed my 2 bulbuls

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  6. Lee Chiu San

    Bulbuls will eat most soft fruits. I have learned from trial and error that they will try practically anything edible, including what we normally consider to be vegetables, such as cucumbers, gourds and squashes. Secret is to hang up the offerings at their eye level close to their perches.

    Please remember that bulbuls are omnivorous, and will suffer from malnutrition and other diseases caused by diet deficiencies if they do not receive animal protein. I always feed crickets, mealworms and hardboiled egg yolk to my birds.

    Some of them will also drink the nectar which I feed to lorikeets.

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