|
Boa constrictor (individual 1) predating Rufous-bellied Thrush
on a trumpet tree. The black arrow
indicates the bird's wing
and the white arrow points out a conspecific
(individual 2) on a
parallel branch. Photo Gilson da Rocha Santos.
|
Sit-and-wait predators remain motionless for long periods of time, waiting
for prey to come within range of their reach. The choice of locations for the ambush can determine the success of the predator, and some snakes
species (e.g., Boa constrictor; Crotalus horridus; Echis coloratus; Epicrates inornatus; Gloydius shedaoensis) increase their
chances of prey capture by selecting microhabitats that are frequently visited
by the prey.
In a recent paper by Rocha-Santos et al. (2014) the authors reports on the Boa constrictor
using fruiting Trumpet trees (Cecropia spp.).
Cecropia are fast growing pioneers,
associated mainly to secondary forests, found throughout the Neotropical area,
from the south of Mexico to the north of Argentina. They can reach up to 22
meters and have long fruiting periods (up to 12 months) and they attract
several omnivore and frugivorous species, including passerines, galliforms,
parrots, marmosets, bats and coatis.
Boas are robust snakes that can reach up to 300 cm of total length.
They are habitat generalists present throughout the Neotropics area, present in
rainforests, savannas and wetlands. They are sit-and-wait strategists capable
of detecting prey, probably using visual, thermal and chemical stimuli and they
feed efficiently in terrestrial and arboreal environments. Published records
suggest they prey on most major groups of vertebrates.
The authors observed the predatory behavior of boas during fieldwork in
a Cerrado remnant of 50 ha belonging to Private Natural Heritage Reserve,
Universidade Federal de Mato Grosso do Sul, Campo Grande, Brazil. The reserve is located in an urban area, which
is surrounded by boulevards and buildings of the UFMS campus. Vegetation is
composed by trees reaching 15-18 m tall, smaller trees, shrubs, and herbaceous
plants.
They observed the capture of a Rufous-bellied Thrush (Turdus rufiventris) by a boa on the
branch of a 8 m trumpet tree. The Rufous-bellied Thrush landed on the branch,
about 50 cm, from a snake probably in search of fruit, and was instantly captured
and constricted. The snake touched the bird with its labial scales, inspecting
it, and started ingesting by the bird’s head. Ingestion lasted about 14min, and
the snake returned to its initial position (partially aligned on the branch).
At the same time, we spotted two other snakes positioned on parallel branches
in same tree. The snakes were separated
by 0.5 to 2 m of space.
The following morning the three snakes were in the same positions,
probably the same individuals sighted in the previous day. And the authors
observe another Rufous-bellied Thrush landing on a branch near the second
individual. However, the bird managed to dodge the attack, escaping capture.
Three minutes later the third snake captured a Great Kiskadee (Pitangus sulphuratus). No interactions
among the snakes were observed.
Citation
Rocha-Santos, G. D., Barbier, E., & Bordignon, M. O. (2014). Sweet
trap:
Boa constrictor (Serpentes:
Boidae) preying on passerines on
Cecropia
pachystachya (Urticales: Cecropiaceae) in fruiting period
. Biota
Neotropica, 14(2): 1-4.