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Traplining foraging behavior in a tropical hummingbird species phaethornis superciliosus Garrison, Jennifer Susan Eileen
Abstract
Traplining nectarivores are those that visit widely dispersed and often nectarrich flowers that cannot be directly defended and are thought to follow similar routes on different foraging bouts. Phaethornis superciliosus is a large (6 g) hummingbird found in the lowland tropical forests of Central and South America, and is considered a preeminent example of a traplining hummingbird. Though P. superciliosus is considered a trapliner, no detailed studies of its movements have confirmed this. Through field observations and enclosure experiments on P. superciliosus, I examined whether they followed similar routes on different foraging bouts, and considered some factors which could affect their visitation rates to patches of flowers. In the field, birds' arrival and departure angles to/from a patch were quite similar over one to several days, and different birds used different arrival and departure directions from the same patch. This supports the idea that they were following routes, and that these routes were based on the locations of patches of flowers, rather than on open flyways through the forest. Both my field and enclosure studies suggest that P. superciliosus can detect and respond to changes in nectar production rates at individual patches along their traplines. Birds in the enclosure increased or decreased relative use of feeders when I manipulated their nectar production rates. Because traplining birds do not defend their flowers from competitors, they should respond to competition by returning sooner to flowers visited by other nectarivores (exploitative defense). In my field study, I observed a positive relationship between how long a bird waited between visits to a patch and the number of competitive visits by other birds to the patch. There was a positive relationship between the amount of nectar removed from the feeder and birds' relative use of the feeder, indicating that birds do respond to competition. The currently accepted model of constant net energy intake by territorial hummingbirds does not accurately reflect feeding behavior of traplining birds. P. superciliosus has a gross nectar intake that decreases through the day, mirroring nectar production rates in its food-flowers. I present a simulation model in which trapliners have decreasing rather than constant net energy intake rates. Model birds with decreasing net intake rates can meet their energetic needs with fewer flowers than model birds with constant net intake.
Item Metadata
Title |
Traplining foraging behavior in a tropical hummingbird species phaethornis superciliosus
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Creator | |
Publisher |
University of British Columbia
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Date Issued |
1995
|
Description |
Traplining nectarivores are those that visit widely dispersed and often nectarrich
flowers that cannot be directly defended and are thought to follow similar
routes on different foraging bouts. Phaethornis superciliosus is a large (6 g)
hummingbird found in the lowland tropical forests of Central and South America,
and is considered a preeminent example of a traplining hummingbird. Though P.
superciliosus is considered a trapliner, no detailed studies of its movements have
confirmed this. Through field observations and enclosure experiments on P.
superciliosus, I examined whether they followed similar routes on different
foraging bouts, and considered some factors which could affect their visitation rates
to patches of flowers.
In the field, birds' arrival and departure angles to/from a patch were quite
similar over one to several days, and different birds used different arrival and
departure directions from the same patch. This supports the idea that they were
following routes, and that these routes were based on the locations of patches of
flowers, rather than on open flyways through the forest.
Both my field and enclosure studies suggest that P. superciliosus can detect and
respond to changes in nectar production rates at individual patches along their
traplines. Birds in the enclosure increased or decreased relative use of feeders when
I manipulated their nectar production rates.
Because traplining birds do not defend their flowers from competitors, they
should respond to competition by returning sooner to flowers visited by other
nectarivores (exploitative defense). In my field study, I observed a positive
relationship between how long a bird waited between visits to a patch and the
number of competitive visits by other birds to the patch. There was a positive
relationship between the amount of nectar removed from the feeder and birds'
relative use of the feeder, indicating that birds do respond to competition. The currently accepted model of constant net energy intake by territorial
hummingbirds does not accurately reflect feeding behavior of traplining birds. P.
superciliosus has a gross nectar intake that decreases through the day, mirroring
nectar production rates in its food-flowers. I present a simulation model in which
trapliners have decreasing rather than constant net energy intake rates. Model birds
with decreasing net intake rates can meet their energetic needs with fewer flowers
than model birds with constant net intake.
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Extent |
3967441 bytes
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Genre | |
Type | |
File Format |
application/pdf
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Language |
eng
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Date Available |
2009-01-31
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Provider |
Vancouver : University of British Columbia Library
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Rights |
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.
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DOI |
10.14288/1.0099029
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URI | |
Degree | |
Program | |
Affiliation | |
Degree Grantor |
University of British Columbia
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Graduation Date |
1995-11
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Campus | |
Scholarly Level |
Graduate
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Aggregated Source Repository |
DSpace
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Item Media
Item Citations and Data
Rights
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.