MINISTRY OF AGRICULTURE AND RURAL DEVELOPMENT
VIETNAM NATIONAL UNIVERSITY OF FORESTRY

STUDENT THESIS

DETECTING THE PRESENCE OF NOCTURNAL BIRDS IN CAT TIEN
NATIONAL PARK USING BIOACOUSTICS METHOD

Major: Natural Resources Management
Code: D850101
Faculty: Forest Resources and Environmental Management

Student: Vũ Huyền Linh

Student ID:1453092355

Class: K59B_ Natural Resources Management

Course: 2014 - 2018

Advanced Education Program
Developed in collaboration with Colorado State University, USA

Supervisor: Assoc.Prof.Vu Tien Thinh

Hanoi, 2018


ACKNOWLEDGMENT
Firstly, I would like to express my sincere gratitude to my supervisor
Assoc.Prof.Vu Tien Thinh for his great support, patience, motivation, and immense

knowledge. His guidance was really helpful so this thesis has been finished. I am very
grateful to him for enlightening me the first glance of the thesis.
Besides, I would like to extend my thanks to Ms. Nguyen Thi Hoa, member of the
Department of Wildlife in the Vietnam National University of Forestry for guiding me to
apply RAVEN software on the process of analyzing data. There are no words to show my
appreciation to her for assisting and helping me during the period of two months when I
did my thesis in the office of the Department of Wildlife.
I also would like to thank my fellow labmates Ms. Lan Tran for the stimulating
discussions, for the sleepless nights we were working together before deadlines, and for all
the fun we have had in the last years. Also, I want to send my thank to my friend, Mr. An
Le for his insightful comments, encouragement and hard questions which incented me to
widen my thesis from various perspectives.
Last but not least, I would like to thank my family: my parents, my brothers, and
sisters for supporting me spiritually throughout writing this thesis and my life in general.


ABSTRACT
LIST OF FIGURE
LIST OF TABLE
ABBREVIATIONS
CHAPTER 1: INTRODUCTION .......................................................................................... 1
CHAPTER 2: STUDY GOALS, OBJECTIVES ................................................................... 4
2.1. Goals ............................................................................................................................... 4
2.2. Objectives ....................................................................................................................... 4
CHAPTER 3: STUDY SITES ............................................................................................... 5
3.1. Natural condition ............................................................................................................ 5
3.1.1. Geographical location .................................................................................................. 5
3.1.2. Geography conditions .................................................................................................. 6
3.1.3. Hydrology Soil ............................................................................................................. 8
3.1.4. Climate ......................................................................................................................... 8

3.1.5. Flora ........................................................................................................................... 10
3.1.6. Fauna .......................................................................................................................... 11
3.1.7. Forest type.................................................................................................................. 11
3.2. Social features ............................................................................................................... 13
CHAPTER 4: METHODS ................................................................................................... 15
4.1. Study site selection ....................................................................................................... 15
4.2. Data Collection ............................................................................................................. 15
4.3. The locations recorders in Cat Tien National Park ....................................................... 18
4.4. Sound Analysis ............................................................................................................. 21
4.5. Pre-analysis of results ................................................................................................... 24
CHAPTER 5: RESULTS ..................................................................................................... 26
5.1. Determining the presence of nocturnal birds in Cat Tien NP ....................................... 26
5.1.1. Nocturnal bird detected species from the recording in the study site ........................ 26
5.1.2. The comparison between the spectrograms of detected birds and the spectrogram of
sample targeted birds in Cat Tien NP. ................................................................................. 27
5.1.3. Determining the frequency of appearance of the nocturnal bird in Cat Tien NP. ..... 33
5.2. Determining the distributions of some bird species and favorite habitat for the targeted
bird in Cat Tien NP. ............................................................................................................. 36
5.2.1. Distribution of nocturnal bird species of them at 7 location in Cat Tien NP ............ 36
5.2.2. Distributions of detected bird species and their favorite habitats in Cat Tien NP ..... 39
CHAPTER 6: DISCUSSION............................................................................................... 42
6.1. Detected the presence of the nocturnal bird in Cat Tien NP ........................................ 42
6.2. Distribution of some bird species and favorite habitat for the detected birds in each
forest types Cat Tien NP ...................................................................................................... 44
CHAPTER 7: CONCLUSION ............................................................................................ 47
REFERENCE....................................................................................................................... 48
APPENDIX .......................................................................................................................... 49


ABSTRACT

Detection and recognition of birds are important to reduce bird mortality and,
thereby, in order to protect endangered species. Consequently, we need to find out exactly
what their presence and habitats are. When a bird sings, it's telling you what it is and where
it is. Especially, determining of bird sound from nocturnal birds is difficult to study.
Researching the nocturnal bird species is a painstaking process, with every piece of data
collected to understand their habitats. However, surveying for nocturnal birds by the
traditional method had many limitations and often did not give accurate information, which
causes many difficulties for conservation. Some methods can hurt the birds, as well as the
researchers, could have trouble if they researched in bad conditions or in the dark. In this
thesis, the utility of automated bioacoustics recorders was examined and the associated
classification by RAVEN software which was used as a way to survey for the nocturnal
bird species. The survey was conducted at 7 study sites which belong to three communes in
Cat Tien National Park, Dong Nai province from August 17th to October 4th, 2018. The
thesis detected 5 bird species divided into 2 orders and 2 families in the total of 9 targeted
bird species at the 7 locations with different habitat types in Cat Tien National Park. The
data obtained from the recorders revealed that nocturnal bird was most active just at
midnight and before dawn, and least active during the dusk. As a result, the study found
that recording at both midnight and dawn or only at dawn would give reasonably high
levels of detection. The study also pointed out that their frequencies of occurrence of bird
vary among species. Moreover, some bird species sing many times in the recordings. On
the contrary, some birds species sing only one in recordings. The thesis also found that
almost detected birds live in Bang Lang Da Co forest and Tuong mountain and a small
number of them live in Bau Sau, Rang stream and Cat Tien center which are mainly
evergreen forests.


LIST OF FIGURE
Figure 4.1: Map of study site in Cat Tien National Park ..................................................... 15
Figure 4.2: An automatic recorder was attached to a tree ................................................... 16
Figure 4.3: The location of 30 automatic recorders in Cat Tien National Park. .................. 18

Figure 4.4: The interface of the RAVEN software .............................................................. 21
Figure 4.5: The process of converting spectrogram’s frequency by Audacity software. .... 22
Figure 4.6: The interface of correlation configuration. ....................................................... 23
Figure 5.1: The detection of percentage nocturnal bird in 7 locations in Cat Tien NP ....... 27
Figure 5.2: The percent of the active time during surveying time of Oriental Scops Owl .. 33
Figure 5.3: The percent of the active time during surveying time of Asian Barred Owlet . 33
Figure 5.4: The percent of the active time during surveying time of Spot-bellied Eagle-Owl
............................................................................................................................................. 34
Figure 5.5: The percent of the active time during surveying time of Brown Hawk-Owl .... 34
Figure 5.6: The percent of the active time during surveying time of Great Eared-Nightjar 35
Figure 5.7: Map of nocturnal bird detected species in the study site................................... 37
Figure 5.8: Forest types of recorded locations in Cat Tien ................................................. 41


LIST OF TABLE

Table 3.1: Area according to forest status and land types in Cat Tien National Park ........... 6
Table 3.2: Climate of Cat Tien National Park. ...................................................................... 9
Table 3.3: The species recorded in Cat Tien National Park ................................................ 11
Table 4.1: List of targeted bird species in Cat Tien National Park ...................................... 17
Table 4.2: Characteristics of 30 automatic recorders in study sites in Cat Tien National
Park ...................................................................................................................................... 19
Table 4.3: Birdsong detected at location … in …. from….................................................. 23
Table 4.4: List of nocturnal bird species detected in the study site. .................................... 24
Table 4.5: The most active time during surveying time of nocturnal bird .......................... 24
Table 4.6 Distribution of nocturnal bird species of them in Cat Tien NP ........................... 25
Table 4.7: Characteristics of 30 automatic recorders in study sites in Cat Tien National
Park ...................................................................................................................................... 25
Table 5.1: List of nocturnal bird species detected in the study site. .................................... 26
Table 5.2: Comparison between the spectrogram of Great Eared-Nightjar and the sonogram

of sample Great Eared-Nightjar ........................................................................................... 28
Table 5.3: Comparison between the spectrogram of Asian Barred Owlet and the sonogram
of sample Asian Barred Owlet ............................................................................................. 29
Table 5.4: Comparison between the spectrogram of Brown Hawk-Owl and the sonogram
of sample Brown Hawk-Owl ............................................................................................... 30
Table 5.5: Comparison between the spectrogram of Spot-bellied Eagle-Owl and the
sonogram of sample Spot-bellied Eagle-Owl ...................................................................... 31
Table 5.6: Comparison between the spectrogram of Oriental Scops-Owl and the sonogram
of sample Oriental Scops-Owl ............................................................................................. 32
Table 5.7: The most active time during surveying time of nocturnal bird .......................... 35
Table 5.8 Distribution of nocturnal bird species of them in Cat Tien NP ........................... 38
Table 5.9 Distributions of bird species detected and favorite habitat of them in Cat Tien NP
............................................................................................................................................. 40


ABBREVIATIONS
EBA

Endemic Bird Area

IUCN

International Union for Conservation of Nature

NP

National Park

WWF


World Wildlife Fund

UNESCO

United Nations Educational, Scientific and Cultural Organization

LC

Least Concern


CHAPTER 1: INTRODUCTION
For centuries, deforestation, farming, urbanization, and other human activities have
wreaked bird species generally and wild animal species in particular and sent them to the
verge of extinction. That's also why management of endangered bird species requires
detailed information on the distribution and abundance of the species that are often hard to
obtain. Thesis understands the importance of detection and recognition of birds’ species to
reduce bird mortality and protect endangered species, which is the aim of the thesis. In this
thesis, bioacoustics method with high-end sound recorders and advanced RAVEN software
were used to detect the presence of the nocturnal bird in Cat Tien NP to and provide base
data for conservation purposes.(
Birds (Aves) are some of the most amazing animals on earth. They are very diverse
groups of animals with amazing characteristics. They are a group of endothermic
vertebrates, characterized by feathers, toothless beaked jaws, the laying of hard-shelled
eggs, a high metabolic rate, a four-chambered heart, and a lightweight but strong skeleton.
Their bodies are covered with feathers and they have wings. Feathers have three functions:
flight, temperature regulation, and display (wikipedia.org). Nocturnal birds are quite
different from their diurnal (daytime) relatives. Physically, these birds have a number of
traits different from more familiar daytime birds. They have dull plumage colors because
bright colors which are difficult to see at night, most nocturnal bird species lack red, blue,

orange or other bold colors. Instead, these birds have more muted plumage with shades of
brown, gray, black and white. Males and females typically look very similar. Moreover,
camouflaged patterns are common among nocturnal birds. When these birds are roosting
during the day, strongly camouflaged plumage helps them blend into their surroundings
and keeps them safe from predators. Nocturnal birds often have eyes that are exceptionally
large in relation to their head and body size. These oversized eyes help collect what limited
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light is available to enhance their vision. In addition to larger eyes for better vision, other
senses, such as hearing and smell, maybe acuter in nocturnal birds than in diurnal birds.
For example, owls have facial disks that help enhance their hearing. Birds that are active at
night also behave differently than daytime birds. When they are spotted during the day,
they may seem relatively tame and calm, but that is a defense mechanism rather than a sign
of mellow behavior. These birds will instinctively freeze and remain immobile when they
feel threatened in the daylight, hoping that their camouflage conceals them and trying not
to attract additional attention by moving (Melissa mayntz, 2018). In the thesis, I have
chosen which 9 species are the most popular bird species to research include: Barn Owl
(Tyto-Alba -Scopoli 1769), Oriental Scops-Owl (Otus-sunia - Hodgson, 1836), Spot-bellied
Eagle-Owl (Bubo nipalensis - Hodgson, 1836), Brown Fish-Owl (Ketupa zeylonensis Gmelin, 1788), Asian Barred Owlet (Glaucidium cuculoides - Vigors, 1831),Brown HawkOwl (Ninox scutulata - Raffles, 1822), Collared Scops Owl (Otus bakkamoena Pennant,1769), Great Eared-Nightjar (Lyncornis macrotis - Vigors,1831). (birdlist.org)
The thesis was studied in Cat Tien National Park, which covers 71,920 hectares
(278 square miles) of lowland forests and swamps in southern Viet Nam and is home to
numerous birds and mammals. It is approximately 160 km (100 miles) northeast of Ho Chi
Minh City. There are many mammals including a number of primate species such as the
endemic Golden-cheeked gibbon, Bears, Elephant, and Gaur. Many birds can be found
such as Germain's Peacock Pheasant, Bar-bellied Pitta, and the rare endemic Orangenecked Partridge. The diversity of the Park has been recognized by WWF when this
international organization selected the Park as one of 200 global ecological zones including
the land and its water area with its well-known biological diversity. In 2001 Cat Tien
National Park has been listed by UNESCO as the 411th biosphere Reserve Zone in the
world. However, determining of bird sound from nocturnal birds are very difficult to study.

2


Researching the nocturnal is a painstaking process, with every piece of data. I need to
understand the habitat it requires and its landscape. Surveying for nocturnal birds by the
traditional method has many limitations and often do not give accurate information, cause
many difficulties for conservation. Some methods can hurt the bird and the researchers
could have trouble if they research in bad conditions and in the dark. So, the method used
in the thesis is the bioacoustics method with high-end sound recorders automatic and
advanced RAVEN software help easily to identify the sounds of each species at different
points in Cat Tien NP. Acoustic communication in birds is rich and lends itself to one of
the primary ways in which birds make their presence is known to each other, as well as one
of the most direct ways for humans to detect them, often at times when they are difficult to
see. Further, the vast majority of birds have songs or calls that serve as a species-specific
acoustic signature that readily announces their presence. This abundance of sound provides
a readymade source of information that can be used to explore the composition of bird
diversity in particular regions of interest. Moreover, electronic developments and
subsequent miniaturization of the equipment have opened up new horizons for bioacoustics
in recent years. Today, it is easy and cheap to obtain basic equipment for bio-acoustical
research, and even powerful laptops can now be used in the field along with high-end
sound recorders and advanced software. These new technologies have transformed the way
sounds can be sampled, analyzed, stored and accessed. As a consequence, currently, the
collections of animal sounds produced by insects, amphibians, mammals, and birds for
communication, are widely used and applied for research. (Gianni Pavan, 2008).
I hope this thesis will give the best results in the detected of nocturnal birds through
the use of the bioacoustics method in Cat Tien National Park.

3



CHAPTER 2: STUDY GOALS, OBJECTIVES
2.1. Goals
This thesis aims to use bioacoustics method with high-end sound recorders and
advanced RAVEN software to detect the presence of the nocturnal bird in Cat Tien NP to
and provide base data for conservation purposes.
2.2. Objectives
The study has 2 main objectives as follows:
Objective 1: Determining the presence of nocturnal birds in Cat Tien NP.
Objective 2: Determining the distribution of 9 target bird species and favorite
habitat for the targeted bird in Cat Tien NP.

4


CHAPTER 3: STUDY SITES
3.1. Natural condition
3.1.1. Geographical location
Cát Tiên National Park (Vietnamese: Vườn quốc Gia Cát Tiên) is a national park
located in the south of Vietnam, approximately 150 km north of Ho Chi Minh City. It has
an area of about 720 km2 and protects one of the largest areas of lowland tropical forests
left in Vietnam.
Geographical coordinates:
- North Latitude: From 11 20'50 "to 11 50'20"
- East Longitude: From 107 009'05 "to 107 035'20"
The area of Cat Tien National Park is 82,637.3 ha, including:
- Lam Dong Province is 27,374.7 ha
+ Cat Loc area: 27,317.9 ha.
+ Dao Tien area: 56.8 ha.
- Binh Phuoc province is 4,382.8 ha.
- Dong Nai province is 50,879.7 ha.

+ Nam Cat Tien area: 39,527.1 ha.
+ Dac Lua protection forest: 1,418.0 ha.

5


Table 3.1: Area according to forest status and land types in Cat Tien National Park
Type of land, type of forest

Acreage (ha)

%

Total natural area

71.920,0

100

I- Forest land

64.417,2

89,6

1. Natural forest

64.006,9

89,0


283,5

0,4

- Medium forest (IIIA2)

9.474,7

13,2

- Degraded forest (IIIA1)

5.036,3

7,0

- Young forest (IIB)

12.351,1

17,2

- Mixed woodland (Wood– Bambusa procera
(HG))

20.792,4

28,9


- Bamboo forest (L)

16.068,9

22,3

410,3

0,6

II- Land without forests.

4.609,8

6,4

- Grassland, shrubs

4.609,8

6,4

III- Another land

2.893,0

4,0

- Land full of water (ĐNN)


150,6

0,2

- Water surface (MN)

415,4

0,6

2.327,0

3,2

- Rich forest (IIIA3 – IIIB)

2. Plantation

- Burnt-over land (NRHH)

3.1.2. Geography conditions
Cat Tien National Park is geologically in the transiting area from the SouthernCentral Highland to the Southern plain including typical geological features of the end of
Truong Son mountain range and South East of Vietnam, with 5 following major terrain
types:

6


- High mountain with slope side: It mainly locates in the North of Cat Tien
National Park. The elevation is 200m – 600m above sea level, slope 150 - 200 with some

areas are over 300. The topography is mostly sloping at the mountainsides, the areas in the
center of river, stream and at the top are flat. The division grade is complex and is the
beginning of small streams flowing into the DongNai river.
- Medium-high mountain with slope side: Locating at the West South of Cat Tien
National Park with an elevation of 200m - 300m, slope 150 - 200, high division. Big
streams as Dac Lua, Da Tapok are formed by this hilly midland and finally pour into Dong
Nai river.
- Low and flat hill: Locating at the East South of Cat Tien National Park with an
elevation of 130m - 150m, the slope of 50 - 70, little division.
- Dong Nai river bench and hill connecting to the swamp: At the West South of
Cat Tien National Park, with a mean elevation of 130m.The gradient is 5-7° and partial
separation.
- Stream bench mixed with lake and swamp: This type of terrain includes small
streams, scattering flooded lands, lakes and ponds in the branch of Dac Lua stream and the
central area in the north of the Park. It is often in lack of water in the dry season but
flooded in the rainy season. In the dry season, the water exists only in big swampy areas
such as Bau Sau, Bau Chim, Bau Co, ... The elevation of this area is less than 130m
The National Park grade is down from the North to the South and West to East,
elevation of 626m in Loc Bac and 115m in, Nui Taong.

7


3.1.3. Hydrology Soil
Cat Tien National Park consists of three main structures: Sediment, Bazal, and
Jatropha have developed into four main soil types:
- Land developed in Bazal (Fk): This type of land has the largest area( nearly 60%
of the natural area of the NP) and is mainly distributed in the South of the Cat Tiên
National Park. It is one of the richest nutrient soils, good soil, deep, thick (red or reddish
brown and dark brown) and has many rocks from the volcano are not fully weathered. On

this land, the forest grows well, there are many species of precious trees and the ability of
forests to recover quickly
- Land developed on sandstone (Feldspar Stone) (Fq): occupying the second
largest area of the NP about 20% is distributed mainly in the area of Cat Loc
- Land developed on clay (Fs): the area is not large, mainly in the south,
alternating with Bazal land. The soil here is fertile but the mechanical components are so
heavy so when deforestation that leads the soil root degradation quickly.
- Land developed on ancient alluvium (Fo): (gray soil on ancient alluvium ):
including the types of soil deposited along streams and along the Dong Nai River also
occupy a large area in the north and southeast of Cat Tien National Park. This soil is poor
in nutrients. The water level is quite shallow to help the growth and development of forest
trees during the dry season.
3.1.4. Climate
Cat Tien National Park is located in the tropical monsoon climate with two distinct
rainy and dry seasons. Rainy season is usually from May to October, dry season usually
from November to April next year.

8


The climate of the two regions is also quite different between the North and the
South of Cat Tien National Park. Because of the terrain of Cat Tien National Park is
located in two areas: mountains and hills of different heights
Data collected from two hydro-meteorological stations:
- Cat Tien Station (Lam Dong): collecting rainfall data and Bao Loc station (Lam
Dong province) for collecting data on temperature and humidity (Cat Loc area)
- Ta Lai station (Dong Nai): collect data on precipitation and Ben Cat (Binh
Duong) to collect data on temperature and humidity. (Cat Tien area).
Table 3.2: Climate of Cat Tien National Park.
Describe


Cat Loc Area

Cat Tien Area

1

Average annual temperature (oC)

21,7

26,5

2

The highest average temperature (oC)

23,0 ( 6 month)

28,6 (6month)

3

Lowest average temperature (oC)

21,1 (12 month)

20,5 (1month)

4


The average amount of rain per year (mm)

2.675

2.175

5

The highest monthly rainfall (mm)

494,8 (9month)

368 (9month)

6

The lowest monthly rainfall (mm)

23,8 (2month)

11 (2month)

7

An average number of rainy days per year
182
(day).

145


8

Average annual humidity (%)

82

9

The average time for rain in the rainy season
10 (from 3-12month)
(month)

8 (from 4-11month)

10

Rainfall in rainy season / Annual rainfall (%).

88,3

87

9

97,4


As such, Cat Loc area has low average annual temperature and annual average
rainfall and humidity are higher than in the South Cat Tien and West Cat Tien. So, Plants

also have a different distribution of vegetation and vegetation composition.
3.1.5. Flora
Cat Tien NP is known with 3 main vegetation covers: Closed evergreen tropical
humid rain forest; closed semideciduous tropical humid rain forest; closed deciduous
tropical humid rainforest.
According survey results show that the plant composition of Cat Tien National Park
is 1,618 species of plant, belonging to 706 genera, 167 families, 57 orders, and 10 classes
of 06 different plant species.
Including endemic species, rare species of plants in Vietnam, IUCN results are as
follows:
There are 25 species belonging to 25 genera, 17 families, 13 families are
discovered in Dong Nai (collected according to species name in "Vietnamese Herbs" by
Pham Hoang Ho, 2003).
Big trees: 176 species; small trees: 335 species; Mini plants: 345 species, floristic
composition: 311 species; vine: 238 species; Epiphyte, phytoparasite plants: 143 species;
Semi-plant: 62 species.
Specious plants: 38 species of 13 families such as Afzelia Xylocarpa, Dalbergia sp.,
Pterocarpus macrocarpus, Sindora siamensis, Dispyros martima, Xylia xylocarpa, ... that
have listed in Vietnamese Red Book.
The endemic gene and local endemic trees: 22 species of 12 families such as Thien
Thien Dong Nai, Ve Tuyen Ngot of Thien Ly family.

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3.1.6. Fauna
According to the research, there are 1,498 species of wildlife belonging to 216
families, 51 in CT National Park. The number of species in the animal classes (show in
Table below).
Table 3.3: The species recorded in Cat Tien National Park

Class

Orders

Families

Species

Mammalia

11

31

104

Bird

18

66

351

Reptile and Frog

4

21


128

Fish

9

32

159

Insect

9

66

756

Total

51

216

1.498

3.1.7. Forest type
Cat Tien National Park is divided into 5 types of forest as follows:
- Evergreen broad-leaved forest: mainly in the southwest and northwest of Cat
Loc and southeast of the area of Nam Cat Tien, are cut into small flats, usually good land

areas. The majority is trees of Dipterocarpaceae such as Dipterocarpus alatus,
Dipterocarpus intricatus, Dalbergia alatus, Dalbergia mammosa, Afzelia xylocarpa,
pterocargus macrocarpus.
- Deciduous forest (Often green leaves with half fallen forest): in the North East
of Cat Tien, near the Dong Nai River. often green leaves with half fallen forest. The land is
shallow and drier than evergreen broadleaved forest. Mainly are trees with fallen leaves in
the dry season as Lagerstroemia calyculata, Tetrameles nudiflora, Anogeissus acuminate.

11


- Bamboo forest: distributed in the east and south of the park. This is also affected
by human beings. After the rice fields made by destroying the forest and be ignored
creating favorable condition for the growing of bamboos. The two popular bamboos are
Bambusa procera and Gigantochloa sp. Forming big parts of the forest. There is only La
Nga bamboo exists in the flooded area.
- Trees mixed with bamboo forest (mixed forest): This is affected by the human
beings, the forest often green with half of which have leaves fallen by a forest fire, toxic
chemicals, the forest canopy is opened and bamboos have occupied. Popular trees are
Mesua sp, Eagerstoernia calyculata, Xylia xylocarpa, and two main bamboos are Bambusa
procera; Gigantochloa sp.
- Floodplains, wetlands, and lakes: Cat Tien National Park has large areas of
swampland and unpolluted water resources. In the rainy season, the flooded area may
exceed 2,500 ha - especially near the lakes (Bau Sau, Bau Chim, and Bau Co). The area
may also include relatively small (down to <1 ha) areas of forest swamp clearings in
depressions of forest land. Besides, Flooded plantation area is a favorable location for
Crocodylus siamensis, aquatic plants, and animals, water birds, freshwater grasses. Big
animals such as Sus Scrofa, Cervus Unicolor, Bos Gaurus, ... often gather here in dry
season. The popular water trees are Dai Phong Tu, Loc Vung, ...
Besides forest, the Park contains:

- Grassland: often as a result of previous cultivation. Although 'degraded', these
zones can provide good viewing of mammals and birds.
- Other land use includes plantation (including cashew in the south of the park),
settlement cultivation (now greatly reduced), scrub, etc. De-forested land may become
infested with immigrant invasive species.

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3.2. Social features
Cat Tien National Park is also especially significant to the socio-economy of the
region as its ecosystem takes an active part in the control of flood, at the same time it is
also forest protecting for the water source of Tri An Hydro electrical Power Plant, a
freshwater source supplied for Dong Nai province, Ho Chi Minh city, and Ba Ria - Vung
Tau province.
The buffer zone of Cat Tien National Park has 36 communes and 8 districts of 4
provinces: Dong Nai, Binh Phuoc, Lam Dong and Dak Lak with around 17,000
inhabitants.
- At present, there are 9 residential clusters in Cat Tien National Park. Cat Loc
area in Lam Dong province has:

+ Phuoc Cat Commune: There are 3 clusters living along the Dong Nai River with
about 80 households, of which 28 are S'Tieng ethnic and 12 households are Chau Ma
ethnic.

+ Tien Hoang Commune: There are 2 residential clusters, about 230 households
are mainly Chau Ma ethnic.

+ Gia Vien Commune: These include 12 households of the Chau Ma ethnic
minorities

- These ethnic groups live along the banks of the Dong Nai River from Ta Lai and
Tan Phu in Dong Nai province to Dak Lak and Lam Dong provinces for generations and
are members of the Khmer ethnic group.
Tay Cat Tien Area in Binh Phuoc Province: There are 232 communities of Tay,
Nung and Dao ethnic minorities living in Cat Tien National Park since 1990-1991.
Nam Cat Tien area of Dong Nai province has:
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+ Ta Lai Settlement area: There are 292 households are S'Tieng and Chau Ma
ethnic

+ Dak Lua area: There are 38 military families who stay behind to do economic
after peace.
Most of the local people live mainly on agricultural products. In the time bad
harvest conditions, they often go to the forest to exploit forest products, hunting, trapping
birds, wild animals ... which cause many difficulties for forest protection force.

14


CHAPTER 4: METHODS
4.1. Study site selection
The study covered some areas in Cat Tien National Park including

- Bang Lang Da Co forest
- Rang Stream in South Cat Tien
- Dang Ha commune
- Bau Sau station
- Cat Tien center.

- Da Bong Kua station area belonging Dak Lua commune
- Tuong Mountain area belonging Dak Lua commune

Figure 4.1: Map of study site in Cat Tien National Park
4.2. Data Collection
At the first phase of the process, the recorders were installed at survey locations in
Cat Tien NP with a time period when their calling activity usually happened during the
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night (from 5 p.m to 6 a.m). Besides, GPS was used to determine the exact survey
locations in Cat Tien NP. Totally, 7 sites were surveyed. These locations were determined
based on favorable topographic conditions and follow instructions of an experienced staff
in Cat Tien NP.

Figure 4.2: An automatic recorder was attached to a tree
In each survey location, two to four full-spectrum recorders were placed. The
recorders had a microphone on both left and right sides and were attached to a tree. The
recorders were set to record throughout the night time between 5 p.m and 6 a.m.
Recordings were saved to disk at 30-minute intervals to prevent the loss of an entire
evening’s recordings in case the batteries ran out. These 30 min segments were saved in a
compressed format. Each recorder continued to record until the batteries ran out of power.
This resulted in an average recording period of three or four nights. Battery and memory
card would be changed when moving the recorders to other areas.

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Many automatic recordings were used at the same time. The location of the birds in
the area between the recorders will be accurately determined. The distance from the

recorders to the birds was determined by the software ArcGIS 10.3, based on the
coordinates of the machine and coordinates emitted sound calculation.
Sound data was analyzed using the RAVEN (Cornell Lab of Ornithology) software
to detect the sound of targeted bird species. Raven is “a software program for the
acquisition, visualization, measurement, and analysis of sounds”. List of targeted bird
species consists of 11 bird species, divided into 3 families and 2 orders in Cat Tien
National Park that was shown below (Table4.1)
Table 4.1: List of targeted bird species in Cat Tien National Park
Order name

No

Common
Name

Scientific name

Vietnamese
name

Family name

1

Barn Owl

Tyto-Alba
(Scopoli 1769)

Cú Lợn Lưng

Xám

Tytonidae

Strigiformes

NoData

2

Oriental
Scops-Owl

Otus-sunia
(Hodgson, 1836)

Cú Mèo Nhỏ

Strigidae

Strigiformes

Stable (LC)

4

Spot-bellied
Eagle-Owl

Bubo nipalensis

(Hodgson, 1836)

Dù dì Nêpan

Strigidae

Strigiformes

Stable (LC)

5

Brown FishOwl

Ketupa
zeylonensis (Gmel
in, 1788)

Dù dì Phương
đơng

Strigidae

Strigiformes

Decreasing
(LC)

6


Asian
Barred
Owlet

Glaucidium
cuculoides
(Vigors, 1831)

Cú Vọ

Strigidae

Strigiformes

Increasing
(LC)

7

Brown
Hawk-Owl

Ninox scutulata
(Raffles, 1822)

Cú vọ lưng
nâu

Strigidae


Strigiformes

Decreasing
(LC)

8

Collared
Scops Owl

Otus bakkamoena
(Pennant, 1769)

Cú mèo
khoang cổ

Strigidae

Strigiformes

Stable (LC)

9

Great EaredNightjar

Lyncornis
macrotis (Vigors,
1831)


Cú muỗi mào

Caprimulgidae

Caprimulgiformes

Stable (LC)

17

IUCN


4.3. The locations recorders in Cat Tien National Park
During the period from August 17th to September 30th, 2016, 7 areas were surveyed
within the boundary of Cat Tien National Park, Dong Nai Province. Each area was
surveyed for 3-4 days. The survey areas were mainly located in the eastern part of Cat Tien
NP. This area had evergreen forests and suitable habitats of the bird species. The locations
of 30 automatic recorders in Cat Tien National Park were described in this map below:

Figure 4.3: The location of 30 automatic recorders in Cat Tien National Park.
Recorders in study sites were distributed on three forest types include evergreen
forest, bamboo forest, and mixed wood-bamboo forest. In particular, the evergreen forest
has is further divided to the rich evergreen broad-leaved forest, medium evergreen broadleaved forest, poor evergreen broad-leaved forest, regrowth evergreen broad-leaved forest.

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