Scientists
observed and reported various types of behavior at the area having placed
artificial feeders with variable in concentration sugar-water solutions
Date:
May 2, 2017
Source:
Pensoft Publishers
Being
the vertebrates with the highest metabolic rate thanks to their rapid wing
flaps, the hummingbirds have evolved various types of feeding behaviour. While
the nectar-feeders tend to go for food high in energy, strong competition affects
greatly their preferences and behaviour towards either dominance,
subordination, a strategy known as trapline and a fourth one named
hide-and-wait, conclude the Brazilian scientists Lucas L. Lanna, Cristiano S.
de Azevedo, Ricardo M. Claudino, Reisla Oliveira and Yasmine Antonini of
Universidade Federal de Ouro Preto. Their conclusions following six months of
observations in an Atlantic Forest remnant in southeastern Brazil are published
in the open access journal Zoologia.
To
test previous assumptions as well as their own hypotheses, the researchers
placed artificial bird feeders filled with variable in concentration
sugar-water solutions across four separate patches at the core of the forest
fragment.
The
scientists sought to find out whether the birds would show clear preference for
the most sugary food source; whether larger size and heavier weight would
guarantee better access to the most nutritious feeders; what strategies would
be adopted by each species; and which ones would prove the dominant and most
aggressive.
As
expected, the scientists concluded that the birds prefer the most sugar-dense
solutions. However, when subordinate species, such as the white-throated
hummingbird and the versicoloured emerald, confronted dominant species guarding
the most nutritious food sources, they would be either frightened or expelled
following a short chase. Subsequently, these hummingbirds would resort to the
feeders with low-sugar solutions.
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