BIRD SURVEY TECHNIQUES

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BIRD SURVEY TECHNIQUES
By Asad R Rahmani
Based on the manual prepared by Salim Javed
Rahul Kaul
Indian Bird Conservation Network (IBCN) Bombay
Natural History Society
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• WWhy Count Birds?
• Fundamental questions
• Elemental arithmetic tendency to count
• Necessary to devise a strategy and new
• plans
• Doing something in a systematic manner
• Interesting and necessary to know more
• about birds

3

• WWhere to count?
• Any area garden, orchard, park, forest,
  wetlands, grassland, desert
• Unstudied area
• Important staging area
• Threatened area
• Sanctuary or a national park
• Research site(s)

4

• When to count birds?
• Breeding season
• Winter counts
• Seasonality and timing of count is very
• important
• During migration

5

• How to plan a survey
• ? Permission from forest department/ relevant
  authority
• ? Make local contacts
• ? Logistics i.e. places of stay, routes etc
• ? Necessary funds
• ? Area maps Toposheets, vegetation maps,
  aerial photos
• ? Literature (checklist of birds and
  plants, reports, research
• papers, working plan)
• ? Data sheets, pen, field note book, pad
• ? Equipment Binocular, camera, compass,
  altimeter, GPS
• ? Fieldguides, reference books and papers

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Which site(s) to select
We have to ask the following questions ?
What is the purpose of census? ? IBA or EBA
? Sanctuary or National Park Size
logistics, time frame, budget and the
size of the team
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  Strategies A. Non-sampling strategy ?
Total count in an area e.g. Siberian cranes
in Keoladeo ? Nest count e.g. Greater
Adjutant stork colony ? Territory mapping
e.g. Bengal florican display grounds
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• Sampling strategy
• ? Counting a small representative population
  and
• then extrapolating about the total
  population
• e.g. random, stratified or systematic random

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Important points to remember - ? Do not
unnecessary collect large data ? Maximize your
efforts ? Determine sample size ? Collect
right type of data
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To determine effective sampling efforts, first
answer - Two major questions 1. How many
samples to take? 2. What should be the plot
size so that most species are covered ?  
To answer these questions, we need to
plot Species Discovery Curve. Species
Discovery Curve is plotting of number of species
detected or discovered per unit of sampling
efforts (length of transect, time spent walking a
transect or standing on a point).
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Species discovery curve showing a cumulative
total of species seen in riparian habitat in
Dudwa National Park, India over a 30 day period
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What is distance sampling?   Distance
sampling involves collection of
data where distances of objects are
estimated or measured. e.g. Line
transects Point Counts Cue
counts (calls, territory)
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WWhat is Line Transect ? Line transect
is based on the theory of walking along
a predetermined route at a regular
interval to record the Birds on
or near the line.    
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Methodology or Study Design

• Site Selection
• ? Random or systematic
• ? Stratified covering different habitats
  within the study area
• ? Stratified random randomly choosing areas in
  different
  habitats

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B. Where can one monitor Line Transects?
? Best in open, flat habitat ?
Also conducted in hilly areas ? Homogeneous
habitat preferred   C. Where to place Line
Transects ? accessibility and
terrain ? straight line, not zig-zag ?
avoid along roads, streams or contour of hills
? well spaced out (minimum 200 m apart) ?
random, stratified or linear (hilly terrain)
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D. Permanent or Temporary transect
If permanent - ? mark with stones or
colour posts (trees) ? divide the transects
in to 40-50 m segments   E. What should be
Transect Length? It varies according to
species, habitat and aim of study
? single species study ? community study
? rare or common species ? diversity of
habitat How to determine transect
length? ? preliminary checklist ? few test
runs ? species area curve

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What is Species Area Curve ? Species area
curve is drawn by plotting the sighting
frequency of birds with increasing transect
length. After a point, species discovery curve
tends to stabilise, which means that with
subsequent increase in the line of the transect
there is little or no corresponding increase in
the new species being added. The point at which
curve flattens out (asymptote) can then be
considered as adequate for sampling birds.
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  35   S P E C I E S   5
Species area curve for obtaining the length of
the transect
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E. What should be the speed of
travel? ? walk in standard pace (about
8-10 m/minute) ? time duration should
not vary more than 10 among
transects     F. What time of the day?
? preferably morning
? 15-25 minutes after sunrise
? continue for 2-3 hours     G. In
which weather condition? ?
sunny weather ? avoid raining or
windy days ? keep tract of weather
condition of study area
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H. How often (periodicity) ? ? weekly or
fortnightly or monthly (intensive study) ?
seasonal (long term study, 5-10 years) ? once or
twice a year (very long term study, 20-25
years or more) I. How many replicates ? ?
Minimum two replicates of each transects ?
Minimum of 6 monitoring in each season   J. Open
width or fixed width ? ? Open width All birds
are noted irrespective of their
sighting distance   ? Fixed width or Belt
transect Birds seen up to a certain
distance (width on either side of transect
length) are only noted

 
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Biases in census counts ? Observer
bias ? Effect of habitat ? Bird
behaviour ? Weather    How to do
analyses of the collected data? A.
Simple method n
D -----------------
2L x
Y   n total number of
individuals Llength of the transect
Y mean perpendicular
distance B. Computer programmes
1. TRANSECTS-II 2. DISTANCE
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How to determine the width distance? It
depends upon the birds being censused and type of
habitat.   Data collection
What to record ? ? number of individuals of
a species ? perpendicular distance ?
sighting angle and sighting distance ? sex
(male, female if possible) ? age (adult,
juvenile) ? activity (singing, foraging,
flying, etc) ? substratum (ground, bush, tree
etc)   If the bird is not seen but heard,
records its call and try to
judge the distance.
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Perpendicular Distance
Frequency histogram of perpendicular distances
(number of individual detected decrease with
increasing distance from the line)
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Question What is perpendicular
distance? Answer Perpendicular
distance is the distance of the bird
from the transect line.  
Should we record the exact distance?
? Recording exact distance is difficult (e.g. 11
m, 16 m) ?Therefore, record in group intervals
(0-5m, 5-10m, 10-15m).  
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PD Perpendicular Distance SD
Sighting Distance O Observer L
Transect Line ? Object


?
PD SD L
 Recording of perpendicular distances and
sighting angles in line transect sampling



 
 
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The Fourier series (FS) estimator used in the
analysis is the expansion of probability density
function (pdf), f (x). Fourier series estimator
is a robust non-parametric procedure in which the
difference in detectability between different
habitats is taken care of by pooling robustness
of FS estimator and its estimation efficiency.
n F (0) D
--------------- 2L  
n Total number of bird groups seen L
Length of the transect F (0)
Probability density function
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N No of objects L Length of transect  Y Mean
perpendicular
Distances 10, 12, 15, 5, 10, 25
 
D n / 2LY 6 / 2 x 500 x 12.8
(6 / 12800) x 10000 4. 6 birds / ha
N 6 L 500 Y 12.8
 
A simple way of calculating density from
ungrouped perpendicular distances
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Advantages of Line
Transect        ? More economical ?
Greater species turnover      ? Larger area is
covered in relatively shorter time   ?
Applicable throughout the year ? Permanent
transects can be monitored for a longer period of
time ? Can be used in most of the habitat
types (except wetlands)   ? With little care
can also be used for hilly terrain
Disadvantages of Line Transect         
? Distances are not correctly measured      ?
Movement of observer may disturb the
birds      ? Chances of missing skulking or shy
birds are great
 

       
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Assumptions of Line Transect
? No bird is missed   ? Transect
is a straight line   ? Every detection
is independent   ? Points/objects are
fixed at initial sightings and they do
not move before being detected  
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Precautions to be taken   ?
Try to keep line as straight as possible   ?
Make special effort to find those birds that are
close to the transect   ?
Distances should be measured correctly   ?
Transect should be long enough to allow detection
of at least 40 individuals  
? Transect should be representative of a
habitat   ? Observer must be interested,
competent and trained
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Point Count Method Point Counts can be
imagined as transects of zero length conducted
at zero speed.    Types of Point
Count 1. Plot Counts (fixed radii
for all species) 2. Point Counts with
variable radii, by species 3. Point
Counts with unlimited radii (Total Counts)
 
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What are the assumptions? ?
birds do not approach the observer or flee.
? all the birds are detected at the point of the
observer. ? birds do not move much during
the count period ? birds behave
independently of one another. ? distance
estimates are accurate ? birds are fully and
correctly identified.
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Advantages of Point Counts ?
less time consuming ? duration can be
controlled ? total attention to detect birds
? small homogenous habitats can also be
studied     Disadvantages of
Point Counts ? generating bird list is slower
? many species are missed ? area sampled in one
unit is small  
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• How to select points for counting ?
• ? Points to be counted are to be laid out
  systematically or
• selected randomly in the study area.
•  ? Points should ideally be 200 meters apart to
  avoid double
• counting.
•  ? In a small area, lesser points should be
  monitored to
• avoid duplication
•  ? In small patches of habitat, inclusion of
  points near the
• edges should be done with caution depending
  on the
• objectives of the study. 

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What should be the Count duration?
? It can vary from 2-20 minutes   Record
only these birds seen during Count duration. Do
not include for analysis those birds seen while
walking between two points.    How far
Point counts should be done ?
? Not very far (gt 200 m) ?
Not very close (lt20 m)   ?
Ideally 50 to 100 m apart

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At what time it should be done
? ? 15-20 minutes
after sunrise ? Evening
counts can be done    
How to record distance ? ? Record
birds distance from the observer
(yourself)        ?Record distance in categories
(0-25m, 25-50m and gt50m)
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• Data recording
• 1. Number of individuals of each species
  detected within a 20-25 m radius surrounding the
  observer. The radius will vary depending upon the
  habitat type.
• 2. Number of individuals of each species detected
  beyond the 25m radius but still within the same
  habitat.
• 3. All individuals detected while the observer
  walked between count points are recorded but the
  data are not used in the analysis. Species
  recorded during this period will contribute to
  the completeness of species list for the site.
• 4. Birds that originally were detected outside
  20-25m radius boundary but later move within 25m
  of the observer are recorded as occurring within
  the fixed radius circle. This facilitates
  comparison among vegetatively different habitats.
  Objective is to count each individual bird once
  and only once.

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• Analysis
• ? density, species diversity, richness and
  species composition
• can be calculated
•   ? enter large data in EXCEL and LOTUS
•   ? sample data matrix can be generated
  using SPECDIVRS.BAS.
• ? follow the instructions given in
  statistical books and/or
• take help of a good bio-statistician

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• 
  POINT COUNT
• Date Locality
  Altitude Habitat
  Observer Salim
• Lat Long
  Slope Weather
  Sheet
• Time Start Time End Visibility
  Aspect
• Sr. No. Bird Species
  Time No. Sex Age
  Distance Height Activity
  Plant spp. Hgt. Remarks
• Blue Whistling Thrush 0710 2
  - - 10 m
  0 m Foraging -
  -
• 2. Minivet
  0810 4 -
  -- 5 m 1 m
  Foraging - -
• 3.
• 4.

Example of a data sheet for point count used in
Ranikhet, Kumaon Himalayas
 
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  Comparison of transect and point count census
methods __________________________________________
__________________________________________________
________ S. No. Items
Transects
Point Counts Duration
____________________________ Short
Long _____________________________________________
__________________________________________________
_____ 1. Saturation of observer with cues from
bird Little Some Much 2. Birds moving
into and out of the range Few Some
Many 3. Speed of generating species
list Fast Medium Slow 4. Birds missed by
flushing No Yes Yes 5. Skulking birds
missed Yes No No 6. Total count/unit
line Same Same Same 7. Attention
divided Yes No No 8. Area sampled in
one unit Large Small Small 9.
Bias Small Small Small 10.
Precision High High
High ____________________________________________
__________________________________________________
______ Desirable method Small bias and high
precision
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Species Richness Methods Species richness methods
are simple methods of counting or generating
species list and then making useful
interpretation from them. Depending upon the
area, type of survey, whether single species or
multi-species, a species richness method can be
conducted.     Types of species
richness methods 1. Encounter Rates 2.
McKinnons Species Richness Method 3. Timed
Species Count 4. Mist netting
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  1. Encounter Rates
? species seen per unit efforts (time,
distance etc) ? useful for single
species or multiple-species surveys
? data gives only relative abundance not
density It gives number of
birds/unit area or number
of birds/unit time that can be compared with
other habitats/areas/seasons.
 
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Data sheet for collecting encounter
rate data


DATA SHEET _______________________________________
___________________________________________ Date
Locality Habitat Time Start
Time End Weather Visibility
Aspect Slope Altitude
Coordinates Observer SJ Transect/Trail
Length Transect Sheet
  ______________________________________________
____________________________________ Bird
Species Time Flock Size
Habitat Sex Age Activity    ______________________
__________________________________________________
__________ Roseringed Parakeet 0645
2 MF M A Perching Redvented Bulbul
0650 1 MF
- SA Feeding Green Bee- eater 0700
4 MF - A Perching
Data Sheet
 
     
 
 
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A common method of presenting encounter rate
data _____________________________________________
__________________________________________________
_________________________________ Sites No.
of birds No. of hours Birds/hour
Transect Length Birds/km _________________
__________________________________________________
_____________________ Site 1 2 5
2/5 3km 2/30.6/km Site 2 3 2
3/2 2km 3/21.25/km Site
3 5 3 5/3 2km 5/2
2.5/km ___________________________________________
_____________________________________________

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How to present multi-species survey data? ?
Calculate encounter rate of each species ?
Enter data in EXCEL or LOTUS ? Present data in
descending order or classification-wise ?
Categories the encounter rate (very
common 20-25 sightings common 15-20 sightings
etc)
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Encounter rates from a multi-species survey from
a standard one hour walk at each
site _____________________________________________
__________________________________________________
_________________________________ Species
Site 1 Abundance
Site2 Abundance __________________
__________________________________________________
__________ Rose-ringed Parakeet 5 5/hr 2 2/
hr Ring Dove 2 2/hr 1 1/hr Green
Bee-eater 0 0/hr 2 0/hr
Emerald Dove 4 4/hr 1 4/hr
Red breasted Flycatcher 1 1/hr 0 0/hr __________
__________________________________________________
__________________________________________________
_______ Common 5-10 Very Common 10-25
Uncommon 1-5

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Advantage of Encounter rate data ?
quick and easy method, especially in hilly
terrain ? easy calculation ? data comparable
across sites/seasons/habitats ? diversity and
richness can be calculated

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2. McKinnon's Species Richness Method ?
developed by McKinnon Philip (1993) in
Indonesia. ? quick and easy to know richness
? useful for rapid surveys in difficult habitats
? useful for multi-site surveys
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What is the methodology? ? walk in an
area till a given number of species are recorded
? the number of species could be 10, 15, 20, 25
or 30 ? but it should be constant for all the
sites   ? once a given number of species(e.g.
20) have been seen, go to another area
and record the same number of species (i.e.
20).   ? prepare 10 to 15 such lists from
different parts of the study area ? common
species will get recorded in several lists. ?
in species rich areas, listing will be very fast
? note starting and ending times, habitat
condition, weather etc.
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Analysis ? By
plotting the cumulative total of species detected
against the number of lists, species
discovery curves can be produced.   ? This
species discovery curve for each site is a
measure of species diversity and can
be plotted to compare several sites   ? If
additionally numbers of individuals are also
recorded these values can be used to
compare species diversity based on discovery
curve but also indices of richness and
diversity.   ? Number of time a species
reappears in subsequent lists can be converted
into frequency of occurrence, which gives
some idea about relative abundance of
that species when compared with other species.  
? An index of relative abundance can also be
generated by dividing the number of
lists a species appears in by the total number of
lists. An index between 0-1 is
produced for each species.
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• Advantages of McKinnons Species
  Richness method
• ? The method is simple, quick and does not
  require any special
• observer skills and equipment.
•   ? A very useful method for multi-species
  survey.
•   ? Can be used in difficult terrain.
•   ? Can be used for different habitats.
• Precautions
•  
• ? Each list should be independent
•   ? Lists should be made away from each other so
  same individuals
• are not counted again.
•   ? For different habitats, separate lists
  should be prepared.
•   ? Number of lists should be according to
  available habitat.

 
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• Data sheet for recording species
• __________________________________________________
  __________________________________________________
  
• DATA FORMAT FOR McKinnons LIST
• __________________________________________________
  __________________________________________________
  
• Sr. N. List 1
  List 2
  List 3
  List 3
• ________________________________________
  __________________________________________________
  _____
• Species
  No Species No
  Species No
  Species No
• __________________________________________________
  __________________________________________________
  
• 1. Roseringed Parakeet 1
  Collared Bushchat 1 Small Blue
  Kingfisher 1 . ..
• 2. Ring Dove
  2 Rubythroat 1
  . .. . ..
• Little Brown Dove 1 Black
  Drongo 1 .
  .. . ..
• 4. Green Bee Eater 5
  Jungle Crow 1
  . .. . ..
• 5. Collared Bushchat 1
  Greyheaded Flycatcher 1 .
  .. . ..
• 6. Pied Myna
  2 Shikra 1
  . .. . ..
• 7. Purple Sunbird 1
  House Crow 2
  . .. . ..
• 8. Jungle Babbler 2
  Purple Sunbird 2
  . .. . ..
• 9. Crow Pheasant 1
  Pariah Kite 1
  . .. . ..
• 10. Purple Sunbird 1
  Greyheaded Flycatcher 1 .
  .. . ..
• 11. Greyheaded Flycatcher 1
  Grey Tit 2
  . .. . ..

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3. Timed Species Counts (TCS) Principle ? Common
species are generally detected earlier than the
rarer forms, therefore the time taken to
detect a bird forms a measure of its
abundance.   Methodology  ? Take observations for
a certain time, say one hour.  ? Divide one hour
in six 10 minute time periods  ? All the species
seen in the first 10-minute time period
are recorded.  ? Then go to another site and
record species not recorded earlier.  ? Repeat
this six times, 10 minute period each  ? Never
record a species twice.  ? Make a minimum of
10-15 visits to the study area at
different seasons/months.  ? During each visit,
try to cover at least 1 km2 area
 
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• Analysis
•  
• ? All species recorded are ranked according to
  their time period.
• Thus, species recorded in the first 10
  minute interval are
• ranked 6 followed by 5 for the species
  recorded in the second
• 10 minute interval and so on.
• ? Unrecorded species are ranked 0.
• ? An index of relative abundance of species is
  calculated as the
• mean score for each species across all
  survey visits to the site.
• Therefore scores between a maximum value of
  six and a
• minimum value of 1/n (n is the number of
  repeated surveys)
• are obtained.

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• Advantages
•  
• ? simple, easy and quick
• ? amateur birdwatcher can do it
•  
•  
• Disadvantages
• ? provides only crude relative indices of
  abundance.
• ? comparisons of different species within area or
  between areas
• can be made but these need to be interpreted
  with caution
• because of differential detectability of
  species in different
• habitats/areas.
• ? flocking species may end up with lower indices
  compared to the
• more widely dispersed ones because flocked
  species may not be
• recorded in subsequent time-periods once the
  flock has been
• recorded

56
Hypothetical data set to demonstrate the use of
TSC method
57
Ranking of the above dataset using Timed Species
Counts __________________________________________
__________________________________________________
____________________________________ Species
Visit1 Visit2 Visit3
Total rank score Mean rank score Species
rank _____________________________________________
__________________________________________________
_________________________________Yellowbellied
Fantail Flycatcher 6 3 2
11 3.66
10 Jungle crow
6 6 6
18 6.0
1 Collared Bush chat
6 4 1
11 3.66
10 Slaty headed Parakeet
5 4 3
12 4.0
9 Tailor Bird
5 4 1
10 3.33
14 White-cheeked Bulbul
5 5 4
14 4.66
5 Long-tailed Minivet
5 4 4
13 4.33
7 Grey tit
4 5 4
13 4.33
7 Hmalayan Griffon Vulture
4 3 4
11 3.66
10 Green backed Tit
4 5 5
14 4.66
5 Kestrel
4 3 2
9 3.0
16 Strong footed Bush warbler
4 5 6
15 5.0
3 Verditer Flycatcher
4 6 6
16 5.33
2 Himalayan tree creeper
3 5 3 11
3.66
10 Yellow rumped leaf warbler 3
3 0 6
2.0
17 Large Hawk cuckoo 3
6 6 15
5.0
3 White crested Kalij 2
0 3 8
1.66
18 Beautiful Nuthatch 1
0 0 1
0.33
20 Streaked Laughing Thrush 2
1 1 4
1.33
19 Black Drongo 3
3 4 10
3.33
14 _____________________________________________
___________________________________________
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4. Mist netting Principle ? By trapping
birds in a standardized way, bird populations or
communities of different sites can be
compared.     Methodology ? a fixed number
of nets are operated for a fixed period of time
at different sites. ? the birds caught by
these nets are recorded, measured, ringed
and released ? data are recorded in a format ?
results are expressed as birds caught/net/hour
59

• Analysis
•  
• ? many ways of analysing data
• ? variations in population size and structure
  over years or
• between sites can be detected.
• ? species diversity and similarity indices can
  be generated to
• study the bird communities at various sites
  
• ? survival rates and productivity can also be
  examined using
• this technique by calculating the rate of
  adults to juveniles
• caught after the breeding period
• Beside this, we also get longevity, survival,
  site-fidelity, moult, breeding and migration data.

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Advantages ? good method for
detecting shy, skulking birds ? very rich source
of information ? confirmed identification ?
photographic evidence available ? very good
learning process    Disadvantages  ?
labour intensive exercise ? problems of
permissions  ? costly and time consuming  ?
ringing training and licence required  ? not
good for short rapid surveys  ? birds become net
shy

Biases Results can be
influenced by the way the nets are laid and the
location where they are laid and therefore
comparisons between sites may be difficult unless
sites selected are truly random.
61
BBreeding Bird counts Why count during
breeding season?   ? birds become comparatively
conspicuous ? most birds sing or display ?
most birds have territories during breeding
season ? movement become restricted so easy to
count ? many birds come back every year to same
area for breeding ? some birds nest in colonies
hence easy to count  WWhat are the methods of
counting breeding birds 1. Territory mapping
2. Call counts . Nest counts
62
1. Territory mapping ? most birds, especially
males defend territories ? song and display can
be easily detected and pinpointed ? territorial
males can counted and mapped ? density of singing
males per hectare/sq. km can be calculated
 
D
A
J
G
A
B
H
G
HG
ABA
F
C
E
B
C
C
C
Territory mapping for Painted Francolin from calls
63
Advantages ? provides good data ?
calculation very easy ? can be graphically
illustrated ? repeatable every year/season ?
provide information about bird-habitat
association   Disadvantages ? time
consuming and expensive ? needs expertise and
patience ? can be done in breeding season
only ? could disturb the nesting
birds   Assumptions Birds live in pairs in
non-overlapping territories
64
2. Call Count ? many bird species call during
the breeding season. ? good for Galliformes
species ? call can be counted from a strategic
place ? can be repeated every season ? can be
compared across habitats and sites
65

• Methodology
• ? most species have distinct calls
• ? species can be identified by calls
• ? observers sit 300-500 m apart and note every
  call
• ? direction of call and time are also noted
• ? before starting, observers synchronise watches
• ? observations starts early morning when most
  birds call
• ? counts should be stopped 15-20 minutes after
  the first call
• is heard

66
Analysis ? observers sit together and
compare call locations ? duplicate records are
deleted ? after the records have been pruned,
the minimum number of birds calling is
noted ? density of calling birds is estimated
from the total study area
67
Advantages, disadvantages and biases
? excellent method for vocal but skulking
birds ? non-invasive method and does no
disturb the birds ? simple and does not
require much equipment ? easy to monitor
trend for a number of years ? birds can
be stimulated to call by call play-back ?
fairly accurate estimates of abundance indices  
68

• Disadvantages
• ? difficult to identify call and distance by
  inexperienced observers
• ? counts have to be repeated 4-5 successive
  mornings to account for
• the large variation in calling of birds.
• ? birds may also be over-estimated if call
  counts are conducted for
• long durations
• ? birds tend to shift their locations after
  initial calling and there is a
• chance that a bird might be counted twice
  if call counts are
• prolonged.
• ? day to day variation in number of calling
  males
• ? density estimation of calling males or pairs
  only, not of non-
• breeding individuals

69
N
Observer
 
K2
T1
K3
T2
K1
   Call count sheet commonly used for counting
pheasants
70
3. Nest Counts ? over one-eighth birds nest in
colonies ? nests or pairs of a colony can be
counted or estimated ? nest site fidelity is
seen so birds come to same area every year ?
breeding population can be estimated easily ?
comparative data can be obtained across
years/sites ? photography can be used for
estimation/counting ? in small colonies, total
nest can be counted ? in large colonies, sample
surveys can be done  
71
Advantages   ? easy and interesting ?
generates good statistical data ? generates
media interest in conservation ? easy to monitor
from year to year  
Disadvantages ? may disturb the birds if not
done carefully ? the whole colony may not be
approachable ? nests in dense colonies are not
easy to count
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? Caution   ?Most species of birds are sensitive
to disturbance during the breeding season, so
extreme caution should be taken while counting
the nests or pairs. It is preferable to count the
nest from a distance. Nest count can also be made
after the breeding is over (e.g. flamingo,
pelicans). A bare minimum time should be spent
near a nesting colony. Most counts should be done
in the morning or evening, and never during hot
mid-day. ?? In protected areas, first get
permission from the forest officials.
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If you cannot follow rules, DO NOT COUNT