1
An anno a ed checklis based on a decadal s udy on he wa e bi ds in
Pe u -Sundakamu hu Lake, Coimba o e, Tamil Nadu, India
(Supplemen a y)
G. Pa ameswa an(1)(4), R. Si ashanka (2)(4) and V idhi. R(3)(4)
(1) G. Pa ameswa an, 438/11, May lowe Apa men s, 130, Vi ekananda Road, Ramnaga , Coimba o e – 641009, Tamil Nadu, India.
Email: [email p o ec ed].
(2) R. Si ashanka , 5690/18, Halaso a, Jihla a, Czech Republic – 58601. Email: [email p o ec ed] [Co esponding au ho ].
(3) V idhi. R, 5690/18, Halaso a, Jihla a, Czech Republic – 58601. Email: [email p o ec ed].
(4) Associa ed wi h “Ko ai Bi de s” a olun ee o ganiza ion ha is in ol ed in communi y-based Ci izen Science in Coimba o e
(h ps://ko aibi de s.o g/)
In oduc ion:
This supplemen a y pape p o ides an anno a ed checklis o he wa e bi ds eco ded in Pe u -Sundakamu hu Lake (Pe u
Lake hence o h), Coimba o e, Tamil Nadu, India, om May 2014 ill Ap il 2024. Ou o 129 bi d species eco ded, we
analyzed he s a us and popula ion o 51 wa e bi ds.
Me hodology:
We conduc ed a o al o 108 coun s in Pe u Lake once a mon h in he pe iod om May 2014 o Ap il 2024, usually on
second Sa u days. We walked along he ixed 2 km oad du ing he mo ning o app oxima ely wo hou s and coun ed all
bi ds ha we e seen o hea d and eco ded he in o ma ion in a checklis . This coun can be cha ac e ized as a “ o al coun ”
because isibili y is nea ly 100%. We eco ded 51 wa e bi ds species comp ises o 13 win e mig an s and 14 local mig an s
(Table 6 o main publica ion). We pa ed down his lis o 37 species by elimina ing 14 species alling unde a e ca ego y
(Table 3 o main publica ion) because hey a e s a is ically insigni ican . The 37 species a e u he ca ego ized as 10 guilds
and 8 indi idual species (Pea ce e al. 2007). The anno a ion is p o ided wi h ollowing in o ma ion:
a) S a us o all he wa e bi d species (Table 2 in main publica ion).
b) Popula ion abundance (Table 3 and 3A in main publica ion).
c) Dashboa d isualiza ion o 37 s a is ically impo an wa e bi ds comp ising basic s a is ics abou hei
popula ion, mon hly end cha , ba cha showing popula ion dis ibu ion ac oss mon hs and yea ly end
cha indica ing he popula ion a ia ion.
d) The a ia ion in hei numbe s wi h high coun s and wa e le els.
e) No able beha io s including b eeding.
Resul s:
The bi d species eco ded in Pe u Lake du ing he s udy pe iod a e 129, belonging o 50 amilies and 19 o de s (Table 14).
O hese only he 51 wa e bi ds a e anno a ed. A dashboa d isualiza ion is p o ided o selec ed 37 wa e bi d species ha
p o ides s a is ical in o ma ion on hei popula ion and dis ibu ion. The e o ba depic ed in he yea ly end cha is a
“S anda d E o (SE) o he Sample Mean” calcula ed using ollowing o mula:
The x-axis o hese line g aphs ep esen s he calenda yea om May o Ap il and he y-axis ep esen s he mean o he
species wi h he e o ba s eco ded in ha pe iod. Fo example, May 2015 o Ap il 2016 is deno ed as 2015-16 and simila ly
o he es . The species accoun s a e based en i ely on he esul s de i ed om ou mon hly coun s.
Impac o Wa e Le el:
The wa e le el in his we land plays a key ole in de e mining he species composi ion and hei numbe s (Table 11). The
highes coun s o wa e bi ds we e ob ained when he wa e le el o he lake was ‘Medium’ (Table 12) when la ge locks o
dabbling ducks, eg e s, and sho ebi ds a e seen eeding in he mud la s, sho e and shallow wa e pools.
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Table 11: Summa y o wa e bi d coun s in Pe u lake (WB=Wa e bi d)
Pe iod
(No. o
coun s)
De ails
May
Jun
Jul
Aug
Sep
Oc
No
Dec
Jan
Feb
Ma
Ap
Summe
Sou hwes Monsoon
No heas
Monsoon
Win e
Summe
2014–15
(12)
Wa e le el
Low
D y
D y
Full
Full
Full
Full
Full
Full
Med
Med
Med
No. o WB species
11
11
12
20
20
18
28
26
29
36
36
25
To al coun o WBs
146
61
104
265
786
774
410
709
1598
2045
1278
605
2015–16
(12)
Wa e le el
Med
Low
Full
Full
Med
Med
Full
Full
Full
Med
Med
Med
No. o WB species
20
14
19
21
25
29
21
20
23
27
30
24
To al coun o WBs
275
90
150
295
780
612
165
153
202
660
868
624
2016–17
(12)
Wa e le el
Low
Low
Low
Low
Low
Low
Low
Low
Low
Low
Low
Low
No. o WB species
15
16
17
19
14
13
21
22
22
17
15
16
To al coun o WBs
345
195
124
134
142
211
277
280
380
176
192
139
2017–18
(8)
Wa e le el
Low
Su ey no done
Med
Med
Low
Low
Low
Low
Low
No. o WB species
8
21
31
15
17
14
12
17
To al coun o WBs
58
165
218
246
122
110
36
33
2018–19
(12)
Wa e le el
Low
Low
Full
Full
Full
Full
Full
Full
Full
Med
Med
Med
No. o WB species
9
15
19
19
18
18
19
22
23
30
25
28
To al coun o WBs
80
164
219
299
297
293
466
413
283
296
351
382
2019–20
Wa e le el
Low
Low
Low
Full
Full
Full
Full
Full
Full
Full
Full
Su ey
no
done
No. o WB species
17
14
16
17
16
15
15
14
15
22
20
(11)
To al coun o WBs
178
237
382
90
149
131
94
80
121
218
332
2020-21
Wa e le el
Su ey no done
Med
Full
Full
Full
Full
Full
Full
Full
Full
Full
No. o WB species
14
17
14
14
12
14
18
17
18
16
(10)
To al coun o WBs
114
141
121
63
79
50
109
301
179
210
2021-22
Wa e le el
Su ey no done
Med
Full
Full
Full
Su ey
no
done
Full
Full
Full
No. o WB species
21
12
15
13
17
20
18
(7)
To al coun o WBs
442
121
99
239
252
193
223
2022-23
Wa e le el
Med
Med
Full
Full
Full
Full
Full
Full
Full
Full
Full
Full
No. o WB species
19
20
19
18
18
15
21
18
21
21
22
26
(12)
To al coun o WBs
243
270
222
113
103
128
240
205
233
392
557
774
2023-24
Wa e le el
Full
Med
Med
Med
Med
Low
Low
Full
Full
Full
Med
Low
No. o WB species
22
21
14
21
15
23
23
18
19
19
21
21
(12)
To al coun o WBs
815
952
484
353
795
764
1068
169
162
519
509
959
Table 12: Mean coun o wa e bi ds ac oss wa e le els
Wa e le el
Numbe o occu ences
Sum o bi d coun
Mean coun
S anda d E o
D y
2
165
82.5
21.5
Low
28
7268
259.6
48.6
Med
23
13322
579.2
89.3
Full
55
16004
291
35.9
An h opogenic ac ions in Pe u Lake:
The h ee majo an h opogenic ac ions in Pe u Lake a e ollowing and hei de ailed impac s a e p o ided in he main
publica ion.
1. Comme cial ishing: The Comme cial ishing ope a ion was s a ed in Oc obe 2018 and is p ima ily ca ied ou in
he eas e n pa o he we land co e ing app oxima ely 69% o he wa e sp ead a ea. This has signi ican ly impac ed
he wa e bi d popula ion especially he win e mig an ducks and sho ebi ds, because he shallow pools and mud la s
whe e p ey is loca ed is absen . The logical alidi y o his in e ence along wi h he hypo heses is p o ided in he
“Logical Validi y o in e ence o a ious hypo heses” sec ion and Table 13 o his supplemen a y pape and he o e all
esul s in Table 9 o he main publica ion. In he main publica ion, Figu e 5 shows he annual a ia ion o wa e le el
ac oss he decade indica ing he highe wa e le els in he las i e yea s o aid “Comme cial ishing”.
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2. Road expansion: F om Ma ch 2019 onwa ds he we land was subjec ed o an enc oachmen in he o m o expansion
which was inished in Feb ua y 2021. This en ailed he emo al o ege a ion and he app op ia ion o he we land’s
a ea o a wo-lane oadway. An es ima ed 0.1 sq. km (c. 9% o wa e co e age a ea) has been enc oached o he
cons uc ion o a con ainmen wall o 1.5m in heigh along he pe ime e o he we land. E en hough he e was an
o e all decline o wa e bi ds, he bi ds ha we e dependen on he pe iphe y o he we land like he Rails declined
sha ply based on ou da a (Pa ameswa an e al., 2023).
3. Sandmining: F om June 2017 o Sep embe 2017, Pe u Lake was subjec ed o sandmining, echnically called
eclama ion (O’Connell 2000), which al e ed he cha ac e o he co e a ea o he we land. Deep pi s and a ines ha
esul ed om his ope a ion dis igu ed 69% o he wa e sp ead a ea. The opog aphy o he gen le-sloping bowl-
shaped we land ha was once hospi able o a ious wa e bi d g oups like ducks, sho ebi ds, and eg e s, de e io a ed
signi ican ly (Pa ameswa an e al., 2023).
Anse i o mes: Ana idae
1. Lesse Whis ling-Duck (Dend ocygna ja anica) has he dis inc ion o being a Residen (R) and as well as a Local
Mig an (LM). Acco ding o ou eco ds he popula ion o his species inc eases in win e , speci ically om Janua y
o Ma ch deno ing i s local mig a o y na u e. While i is eco ded h oughou he yea i is absen du ing he d y mon hs.
The e o e, i has he dual s a us based on i s nomadic habi s in sea ch o adequa e wa e le els (Ali 2002). The highes
coun o his species occu ed in he we land yea 2022-23, o h ee mon hs in a ow om Feb ua y-Ap il 2023 99,
105 and 99 indi iduals we e sigh ed. Also, chicks in he company o adul s we e also obse ed in No embe 2022 and
Ma ch 2023, p o ing i s occasional b eeding in Pe u Lake when condi ions a e a o able.
2. Co on Pygmy-Goose (Ne apus co omandelianus) is a Local Mig an (LM) duck in he a ea ha has no been eco ded
du ing he las ou yea s om May 2020 o Ap il 2024.
3. Ga ganey (Spa ula que quedula) is he mos nume ous o all he Win e Mig an (WM) ducks seen in Pe u Lake. I
is also he ea lies o a i e such as in he mon h o Augus and he las o lea e, which is by mid-Ap il o he ollowing
Based on ou da a se , we can unequi ocally s a e ha he win e mig an ducks, and win e mig an sho e bi ds ha e
declined in he lake since comme cial ishing s a ed in Oc obe 2018.
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yea . Du ing he ime ame om May 2020 o Ap il 2024, his once nume ous win e mig an has been sigh ed only
on ou occasions, which a e 2 in Sep embe 2021, 12 in No embe 2022, 7 in Oc obe 2023 and 6 in No embe 2023.
4. No he n Sho ele (Spa ula clypea a) is a Win e Mig an (WM) duck species ha has no eco ds in he las ou -yea
ime ame om May 2020 o Ap il 2024.
5. Indian Spo -billed Duck (Anas poecilo hyncha) is p ima ily a Residen (R) species ha has been consis en ly eco ded
since he incep ion o he su ey in Ma ch 2014. In win e some addi ional bi ds add o he exis ing esiden popula ion
inc easing i s numbe s om Sep embe o Ap il. This species’ numbe s ha e s eadily inc eased om Sep embe 2021
onwa ds and d ama ically om Ap il 2023 o Ap il 2024 and is he only bi d classi ied as Abundan . Du ing he we land
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yea o 2023-24, his species had iple digi numbe s on eigh o he wel e coun s anging om a low o 102 o a high
o 345. I is wo h no ing on ou sepa a e occasions he coun exceeded he wo hund ed ma k and hey a e 208 in
June2023, 345 in Sep embe 2023, 211 in Ma ch 2024 and 241 in Ap il 2024.
6. No he n Pin ail (Anas acu a) is a long dis an Win e Mig an (WM) duck species ha has no eco ds in he las ou -
yea ime ame om May 2020 o Ap il 2024.
7. Common Teal (Anas c ecca) is a Win e Mig an (WM) species ha also ha has no eco ds in he las ou -yea ime
ame om May 2020 o Ap il 2024.
8. Common Moo hen (Gallinula chlo opus) is a Residen (R) species ha was sigh ed h oughou he yea and when he
wa e le el was ei he ull o medium. F om Sep embe 2020 ill Ma ch 2021, i s coun s we e dep essed despi e
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a ou able wa e condi ions and he mos p obable eason was he dis u bance caused by oad expansion which ended
in Feb ua y 2021. The species has made a comeback especially om May 2022 ill Ma ch 2024. The highes coun s
we e 6,6,7 and 17 on No embe 2022, Ma ch 2023, Ap il 2023, and June 2023 espec i ely. A chick and a ju enile
we e spo ed in No embe 2020 and wo chicks we e seen on Ma ch 2023 and he eby es ablishing i s b eeding in his
lake.
9. Eu asian Coo (Fulica a a) This Residen (R) species was once eco ded in la ge numbe s, bu i s numbe has
signi ican ly educed. I is mos ly p esen when he e is su icien wa e , especially in high numbe s, when i s le el is
be ween medium and ull. F om Decembe 2019 ill June 2022, he e we e only wo eco ds o bi ds numbe ing h ee
and wo. The emo al o ege a ion and oad expansion along he lake bund could be he p obable easons o hei
long absence, despi e a o able wa e le els. F om July 2022 onwa ds un il Ap il 2023 has species has made a
spec acula comeback. In he we land yea 2022-23 he highes coun s we e 37, 49, 52, 42 and 58 om Decembe 2022
o Ap il 2023. Du ing he same we land yea , he e we e se en mon hly coun s when ju enile and imma u e chicks
we e also eco ded in he p esence o adul s con i ming i s b eeding s a us which spanned om Sep embe 2022 ill
Ap il 2023. Du ing he we land yea 2023-24, he signi ican coun s we e 200 in May 2023, 257 in June 2023 and 61,
68 and 67 in July 2023, Augus 2023 and Feb ua y 2024 espec i ely. In Ma ch 2024 a ju enile accompanied by adul s
was also eco ded con i ming i s b eeding s a us. The Eu asian Coo is a b eede du ing he monsoonal mon hs o July
and Augus (Ali 2002) and in Sou h India his b eeding season can ex end up o No embe (Rasmussen and Ande on
2012).
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10. G ey-headed Swamphen (Po phy io poliocephalus) is a Residen (R) species and eco ded in la ge numbe s un il
Ap il 2016 when he wa e le els mos ly a y om medium o ull. Since hen, hei p esence in he lake was e a ic
due o dis u bances like un egula ed comme cial ishing and oad expansion. A sligh inc ease in hei popula ion has
been obse ed since Feb ua y 2022 possibly due o he cessa ion o oad expansion. The highes coun was 45 eco ded
in June 2023 when he wa e le el was Medium. In Augus 2023, a ju enile bi d o his species was seen in he company
o wo adul s con i ming i s b eeding s a us in his we land.
11. Whi e-b eas ed Wa e hen (Amau o nis phoenicu us) is a Residen (R) species ha has been ound yea - ound in
he lake un il 2019. F om June 2019 ill Ap il 2024 co e ing a span o almos 5 yea s, he e had been only 8
8
ins ances when his bi d was seen in he lake. The majo eason o i s long absence is p obably due o oad
expansion and he pe manen loss o ege a ion along he bund. The highes coun s we e h ee, wo and wo in
Sep embe 2023, Ap il 2022, and No embe 2022 espec i ely.
12. Black-winged S il (Himan opus himan opus) is ideally classi ied as a Local Mig an (LM), bu i is p edominan ly
seen only in win e om Janua y onwa ds. I s p esence maybe ex ended o Sep embe in his loca ion, in o de o b eed
i he si ua ion is a ou able. This long-legged sho ebi d is an ideal indica o o es ablish he necessa y condi ion o
medium wa e le els and exposed mud la s. I s spo adic absence may be due o lack o such condi ions. I s high coun s
we e 13, 15, 15, and 20 in Ma ch 2021, Sep embe 2021, June 2022, and Ap il 2024 espec i ely. In June 2022 ou
ju eniles we e seen, in Augus 2023 a young ledgling was eco ded and in Ap il 2024 a ew bi ds we e seen si ing
on possible eggs indica ing i s b eeding success and po en ial in his loca ion.
9
13. Li le Ringed Plo e (Thino nis dubius) is p edominan ly a Win e Mig an (WM) species in ou lake. Howe e
occasionally, he esiden subspecies C.d.je doni had also seen be ween May and Augus indica ing i s p obable
b eeding in he we land. F om June 2019 ill Ap il 2024, we ha e had only 7 occasions o he bi d being eco ded and
he p obable cause o decline is he high-wa e le el in he lake due o comme cial ishing ha con inues o he p esen
day. The highes coun s we e i e and ou in July 2020 and Augus 2023.
14. Red-wa led Lapwing (Vanellus indicus) is a Residen (R) species ha was eco ded h oughou he yea in ou lake.
I s absence indica es ha he wa e le el is ei he oo ull wi h unexposed mud la s o oo d y when he e is ha dly any
p ey o consume. I s high coun s we e 15, 8, 17, and 15 in Oc obe 2021, May 2022, Augus 2023, and Sep embe
2023. B eeding eco ds in he o m o imma u e bi ds we e eco ded in May 2022 and in Augus 2023.
16
33. Li le Co mo an (Mic oca bo nige ) This Residen (R) co mo an species is eco ded a ound he yea and had he
dis inc ion o being he benchma k wa e bi d om May 2014 o Ap il 2020, which is he highes a e age coun o e
he speci ied pe iod. Thei popula ion is s able du ing he las ou yea s o coun and hey we e eco ded in high
numbe s when he wa e le els a e high. Howe e , hey we e seldom eco ded eeding in he lake and he p obable
explana ion based on hei beha io is ha hey ei he oos o nes in he ees loca ed a he a end o he lake by using
he wa e as a p eda o y ba ie (Sub amanya 2005 and C Sashikuma e al. 2014). Thei highes coun s we e 120 and
150 in Ma ch 2023 and Feb ua y 2024 espec i ely.
17
34. G ea Co mo an (Phalac oco ax ca bo) is a Residen (R) species ha is a wande e in sea ch o wa e and i s
sigh ing is based on his ea u e in ou lake. I had been spa se and low in numbe ill Augus 2021. Since hen, he
sigh ings ha e egula ly inc eased. The highes coun s a e 23, 23 and 24 in Sep embe 2021, Decembe 2021 and
Feb ua y 2024.
35. Indian Co mo an (Phalac oco ax uscicollis) is a Residen (R) species in Pe u Lake. F om he s a o he su ey
in May 2014 ill July 2018, his species was spa sely p esen . I s popula ion d ama ically inc eased om Augus 2018
onwa ds and has been equen ly eco ded since hen. Simila o he O ien al Da e , he species a ou high wa e
le els which has been he case in Pe u Lake since July 2018. The highes coun du ing he las 4 yea s is 81, 80 and
113 in May 2023, Ma ch and Ap il o 2024.
18
36. Glossy Ibis (Plegadis alcinellus) is a Win e Mig an (WM) in ou a ea ha was eco ded in highe numbe s mos ly
du ing Sep embe o Ma ch. The highes coun s o his species we e 49 and 60 eco ded in Feb ua y and No embe o
2022 and 2023 espec i ely. This species had been using he lake o he ini ial wo yea s o ou s udy (May 2014 ill
Ap il 2016) and had been la gely absen wi h spo adic occu ences ill Augus 2021. The species has s a ed using he
lake again in he win e mon hs du ing he las 3 yea s o he s udy.
37. Black-headed Ibis (Th eskio nis melanocephalus) is a Local Mig an (LM) species ha was eco ded e a ically and
in lowe numbe s. I s highes coun s we e 16 in June 2022 and 13 in Oc obe 2023 espec i ely.
19
38. Eu asian Spoonbill (Pla alea leuco odia) is a Local Mig an (LM) species which is also nomadic and e a ic in i s
occu ence. I s p e e ence is o s anding wa e wi h shallow dep h whe e i is o en seen eeding in he company o
Pain ed S o ks and Li le Eg e s. The highes coun s we e 32 in Ap il 2019 when he wa e le el was a medium and
25 in June 2019 a low wa e le el. The species had been absen since Augus 2019 ill Ap il 2024 excep in June 2022
when 5 indi iduals we e spo ed in he lake when we had Medium wa e le el.
Pelecani o mes: A deidae
39. Yellow Bi e n (Bo au us sinensis) and
40. Cinnamon Bi e n (Bo au us cinnamomeus) a e wo species ha occu ed e y a ely in ou lake ill Ap il 2016. Bo h
species had been absen in he lake o he pas 8 yea s.
41. Black-c owned Nigh He on (Nyc ico ax nyc ico ax) is a Residen (R) species wi h spa se sigh ings in ou lake,
which is also sec e i e and noc u nal. I has ne e been eco ded in he las decade du ing he d y mon hs o May and
June and was la gely absen om May 2016 ill July 2019 excep h ee occasions. The highes coun in he las i e
yea s was 16 on Ma ch 2020.
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42. Li le Eg e (Eg e a ga ze a) is a Local Mig an (LM) species which is eco ded consis en ly h oughou he yea in
he we land. I s highes numbe s a e usually eco ded when he wa e le el a ies om medium o low. The highes
coun du ing his ime ame was in Ap il 2019 and Ap il 2024 when 29 and 32 bi ds we e sigh ed. Due o sand mining
and wa e impoundmen o comme cial ishing i s o e all popula ion has educed since May 2017. Howe e , he
species was eco ded h oughou he yea excep No embe 2022 ill Janua y 2023 in his s udy pe iod. The popula ion
educ ion o his species be ween he i s and las 5 yea s is nea ly 45%.
43. Wes e n Ree Eg e (Eg e a gula is)is a species wi h Unce ain (U) s a us. This bi d was eco ded only once in ou
whole en-yea s udy pe iod in Ma ch 2015 whe e a single species was obse ed.
21
44. S ia ed He on (Bu o ides s ia a) is a species wi h Unce ain (U) designa ion in Pe u Lake. In he i s six yea s o
he coun , his species was eco ded a eigh ins ances wi h he highes coun o ou in Ap il 2016. I was eco ded
only ou imes in he las ou yea s whe e we spo ed a single indi idual a each o hese ins ances. These low eco ds
a e possibly due o i s shy and e i ing na u e along wi h i s sec e i e beha io .
45. Indian Pond He on (A deola g ayii) This species is a widesp ead Residen (R) ha is eco ded h oughou he yea .
The wa e le el p e e ence is medium o low wi h exposed mud la s. F om May 2020 o Ap il 2024 he highes coun s
we e 29, 29 and 36 in No embe 2022, Decembe 2022, and June 2023. The popula ion o his species has signi ican ly
d opped since May 2016 and he plausible easons could be dis u bances due o sand mining o he we land, he emo al
o ege a ion o oad building and comme cial ishing. The popula ion educ ion is nea ly 37% be ween he i s and
las 5 yea s.
46. Eas e n Ca le-Eg e (A dea Co omanda) This species is p incipally a Residen (R)/Local Mig an (LM) in ou a ea.
I used o be eco ded h oughou he yea be ween May 2014 ill May 2017. Since hen, i s popula ion has d opped
and has been eco ded only in e mi en ly including b ie absences in ou lake. The highes coun s in he las 4 yea s
a e 15, 12 and12 in Augus 2020, Sep embe 2020, and Feb ua y 2024. The popula ion educ ion is nea ly 53% be ween
he i s and las 5 yea s o ou 10-yea s udy.
22
47. G ea Eg e (A dea alba) is a Local Mig an (LM) species ha has been eco ded yea - ound in Pe u Lake om May
2014 o Ap il 2016. I s coun s usually anged be ween one and eigh , wi h a no able excep ion being in Ap il 2016,
when i was an as ounding 31 indi iduals possibly due o local mig a ion h ough he a ea. I was eco ded in low
numbe s om June 2016 ill Ap il 2024, which included many mon hs when hey we e absen . The highes coun s in
he las 4 yea s we e i e each in Ap il and Sep embe o 2021. The popula ion educ ion o his species be ween he
i s and las 5 yea s is nea ly 49%. Ou da a shows ha comme cial ishing migh be he p obable cause o his
decline.
23
48. In e media e Eg e (A dea in e media) This medium sized whi e eg e is a Local Mig an (LM) species whose highes
coun was an unusually high 61 in Ap il 2023 possibly due o he local mig a ion in he a ea. F om July 2016 o Ma ch
2021 i s sigh ings we e educed wi h an in e mi en pa e n. Howe e , since hen, he bi d has been consis en ly
eco ded wi h only a b ie absence be ween July ill Oc obe 2023. The popula ion has sligh ly inc eased by nea ly
19% when compa ing he i s and las i e yea s.
49. G ey He on (A dea cine ea) is a Residen (R) species ha is seen consis en ly in ou lake h oughou he yea in all
wa e condi ions. Howe e , he highes coun s a e usually egis e ed when he wa e le els a e ei he Low o Medium
and hey a e 41 and 51 in June 2023 and No embe 2023 du ing he las 4 yea s.
24
50. Pu ple He on (A dea pu pu ea) is a Residen (R) species ha was obse ed consis en ly om June 2014 o Augus
2016. Since hen, i s sigh ings ha e educed and we e inconsis en compa ed wi h he i s wo yea s o ou s udy. The
highes coun s du ing he las 4 yea s we e 6 bi ds each in Feb ua y 2021 and Ap il 2024. The popula ion educ ion
be ween he i s and las 5 yea s is nea ly 48%. This species is la gely c epuscula , pe haps shy, and sec e i e, keeping
o dense eed co e whe e i may be easily o e looked (Ali 2002).
Pelecani o mes: Pelecanidae
51. Spo -billed Pelican (Pelecanus philippensis) is a Local Mig an (LM) species ha was an i egula isi o o ou lake
and was eco ded only a i e occu ences be o e No embe 2016 wi h a highes o 25 in Sep embe 2015. In Janua y
2017, when he e was low wa e le el, a eco d 170 indi iduals o his species we e eco ded. In Ap il 2019, 95 bi ds
we e egis e ed a medium wa e le el. The species had been absen in he lake since Sep embe 2019 ill Ap il 2024
excep o a single ins ance whe e a single bi d was spo ed on Ma ch 2022.
25
Logical Validi y o in e ence o a ious hypo heses:
I
P = Comme cial ishing is ca ied ou
Q = Wa e le el is ull
R = Shallow pools and mud la s whe e p ey is ound a e non-exis en
S = Win e mig an ducks and sho ebi ds decline
Then, he ollowing a e he implica ions (based on ield obse a ion and da a analysis)
1. P → Q : I comme cial ishing is o be ca ied ou , hen he wa e le el mus be ull.
2. Q → R : I he wa e le el is ull, hen shallow pools and mud la s whe e p ey is ound a e non-exis en
3. R → S : I shallow pools and mud la s a e non-exis en whe e p ey is ound, hen he win e mig an ducks and
sho ebi ds popula ion decline.
4. A comple e se o possibili ies a e enume a ed in he u h able below, om which he ele an in e ence om
ow 1 is ex ac ed o es ablish he logical alidi y o ou a gumen ( ows 9,13,15 and 16 a e echnically called
acuous u hs, which a e i ele an )
Table 13: T u h able
No.
P
Q
R
S
P→Q
Q→R
R→S
P→S
Rows 1,9,13,15
and 16 ha e all
u h ins ances.
By logical
ansi i i y
P → Q
Q → R
R → S
The e o e, P→S is
a alid in e ence.
1
T
T
T
T
T
T
T
T
2
T
T
T
F
T
T
F
F
3
T
T
F
T
T
F
T
T
4
T
T
F
F
T
F
T
F
5
T
F
T
T
F
T
T
T
6
T
F
T
F
F
T
F
F
7
T
F
F
T
F
T
T
T
8
T
F
F
F
F
T
T
F
9
F
T
T
T
T
T
T
T
10
F
T
T
F
T
T
F
T
11
F
T
F
T
T
F
T
T
12
F
T
F
F
T
F
T
T
13
F
F
T
T
T
T
T
T
14
F
F
T
F
T
T
F
T
15
F
F
F
T
T
T
T
T
16
F
F
F
F
T
T
T
T
By he ule o logical ansi i i y de i ed om abo e able he conclusion is P → S, i.e., I comme cial ishing is
conduc ed, hen he win e mig an ducks and sho ebi ds popula ions decline.
Table 14: Bi ds o Pe u Lake, Coimba o e
Sl.No
Common name
Scien i ic name
S a us
Popula ion end in
Pe u Lake (A e age)
Dis ibu ion
s a us
ANSERIFORMES: Ana idae
1
Lesse Whis ling-Duck
Dend ocygna ja anica
R / LM
S able
Fai ly Common
2
Co on Pygmy-Goose
Ne apus co omandelianus
LM
Las sigh ed in Dec-2015
Ra e
3
Ga ganey
Spa ula que quedula
WM
Declining
Fai ly Common
4
No he n Sho ele
Spa ula clypea a
WM
Declining
Uncommon
5
No he n Pin ail
Anas acu a
WM
Declining
Uncommon
6
Common Teal
Anas c ecca
U
Las sigh ed in Feb-2019
Ra e
7
Indian Spo -billed Duck
Anas poecilo hyncha
R
Inc easing
Common
GALLIFORMES: Phasianidae
8
Indian Pea owl
Pa o c is a us
R
S able
Uncommon
9
G ey F ancolin
O ygo nis pondice ianus
R
S able
Uncommon
PODICIPEDIFORMES: Podicipedidae
