foraging ecology of red-vented bulbul pycnonotus cafer in university premises and nearby forest...
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Shalini Rajakaruna,Rajarata University of Sri Lanka. International Forestry and Environment Symposium 2011 Annual Symposium organized by Department of Forestry and Environmental Science, University of Sri Jayewardenepura, Nugegoda, Sri Lanka http://fesympo.sjp.ac.lk/TRANSCRIPT
HABITAT Y THROUGH AN INDICATOR SPECIES- Pycnonotus caferS.L. Rajakaruna, S.wickramasingheFaculty of Applied sciences, Rajarata University of Sri Lanka,Mihinthale
Foraging Ecology of Red vented Bulbul (Pycnonotus cafer), in university premises and near by
forest patch, in Mihinthale , Sri Lanka.
S.L. Rajakaruna, S.wickramasingheFaculty of Applied sciences, Rajarata University of Sri
Lanka,Mihinthale.
Red vented bul bul (Pycnonotus cafer)Morphology
-Short crest giving the head a squarish appearance
-Body is dark brown with a scaly pattern
-The rump is white
-The vent is red
-The black tail is tipped in white
Habitats
-Dry scrubs-Open forests -Plains and cultivated lands
Food-Fruits-Petals of flowers- Nectar- insects and occasionally geckos. -They have also been seen feeding on the leaves of Medicago sativa..(Dinesh Bhatt and Anil Kumar,2001)
The research problem.The Red vented Bulbul is one of the most common
birds.
Has a wide distribution
Found in all types of habitats
Omnivorous bird who represents the foraging behaviors of many birds.
But no evidence about the ecological role of this bird in the dry zone of Sri Lanka.
ObjectivesTo identify the foraging behavior of Red
vented Bulbul in the study site.
To determine the recourse use and extent of partitioning while foraging.
To analyze the impact of the foraging behavior red vented Bulbul on the vegetation.
Study siteThis study was confined to the faculty
premises of Faculty of Applied Sciences Rajarata University of Sri Lanka which is at the periphery of the Mihinthale sanctuary. (LAT 8° 19' 60" N / LON 80° 31' 0" E)
It is within the dry zone of Sri Lanka
Annual rainfall is less than 1000mm
Average temperature 33-35 0c.
Faculty of Applied Sciences
Mihintale forest
Sri Lanka, North central province
Study site
1:18000
Mihintale forest
Mihintale Divisional Secretariat
Methodology Observations were taken along transect of
300m in length and 50m width
Scan sampling method was used to observe the foraging behavior
No counts were made during heavy rains
Methodology contd…For each foraging attempt, microhabitat
details such as,-height above the ground
-substrate from which food is taken and
-the plant species used for feeding
were recorded
Methodology contd…Mainly the frequencies of pecking and
swallowing were observed
other activities as preening, resting, roosting, and social behavior also were concerned
Vegetation analysis was done to identify the plants preferred by Red vented Bulbul
Results and discussion Food preference
Bulbuls are dominant or important frugivores and seed dispersers of open secondary vegetation throughout tropical and subtropical Asia (Lever 1987, Corlett 1998).
Insect association with the fruits consumed by Red vented Bulbul
Fruiting tree Presence or Absence of insects
Grewia flavescens NO
Bauhinia racemosa YES
Azadirachta indica YES
Areca triandra NO
Ficus caulocarpa (unripe)
YES
Lantana camara NO
Special observationThey prefer the unripe fruit of Ficus
caulocarpa Refuse the ripe fruit of the same treeWhen fruits were plucked, opened and
observed ,fig wasps were present in the unripe fruit
Utilization of plants
Azadirachta indica Bauhinia racemosa
Utilization of plants
Schleichera oleosa Drypetes sepairia
Niche occupancy of Red vented BulbulHeight classes
A: 0mB: 0-2mC: 2.1-4mD: 4.1-6mE: 6.1-8mF: 8.1-10mG: 10.1-12mH: <12m
Niche occupancy of Red vented Bulbul
FEDCBA
33.33
55.56
77.78
100.00
Observations
Sim
ilari
ty
HEIGHT CLUTER WITH OTHER BEAHVIORS (JANUARY)Height clusters with different behaviours (January)
H G F E D C
•Two major clusters•H,G.F•C,D,E• Occupancy similarity in 2 major clusters 33.33%•H,G classes occupancy similarity 100%•H & G differs from F in 55.56%
H,G - RestingF- RestingE- Feeding, Preening and RestingD- Feeding , PreeningC- preening
DDCCHGGBBFFEEAA
36.55
57.70
78.85
100.00
Observations
Sim
ilari
ty
HEIGHT CLUTER WITH OTHER BEAHVIORS IN FEBRUARYHeight clusters with different behaviours (February)
•Two major clusters •Occupancy similarity 36.55%•A,E, F similarity is higher •B,G,H similarity is higher•C,D similarity is higher
A- FeedingE- FeedingF- FeedingB-Preening G-FeedingD-Roosting
HFEDGCBA
59.64
73.09
86.55
100.00
Observations
Sim
ilari
ty
DendrogramSingle Linkage, Euclidean Distance
Height clusters with different behaviours (March)
•Similarity 59.64%•Occupancy of the H height class is less similar to other classes.
A- FeedingB-FeedingC-FeedingE- FeedingF-Feeding, RestingH-Resting•Two major clusters
End of the rainy season and the Beginning of the breeding season
ConclusionNiche occupancy
All the height classes have been used for feeding except H (<12m)
Mostly for feeding – E (6.1-8 m)Mostly for Resting – H(<12m)Mostly for preening- B(0-2m), C(2.1-4m),D(4.1-6)The height class preferred the most by Red vented
Bulbul is
E, (6.1-8.m)
Conclusion contd…Plant preference
Red vented Bulbuls show a heights preference in Asadirachta indica for feeding.
Scleichera oleosa for resting.Drypetes sepairia for roosting.
Food preferenceConsumed most frequently insects (59%),Then fruits ( 21.9%)
There is no considerable adverse impact of Red vented Bulbul foraging behavior on the vegetation in the study site.
As the important plants in the study site, for the survival of birds have been identified, the findings of this study can be used for the habitat refreshment of the ecosystem too.
Conclusion contd…
Recommendations…To increase the duration of the study to
increase the accuracy.
To compare the niche occupancy of Red vented Bulbul with the niche occupancy of other species of Bulbuls.
To carry out the same study in an undisturbed forest patch and compare the two sites.
Special Thanks to….Dr. Asanga WijethungaMr. Duminda S. B. DissanayakeMr. Aruna Senevirathne Mr. Supun WellappuliarachchiMr. Adrian Gabriel Mr. Ravi Muthukrishna Mr. Lasith Rajakaruna
Thank you!