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BamaEcO April. 'i983.'

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DISCUSSSON

by : BERNARD TFECA,

desfgnated by QRSWM Lo be in charge OP . Research a.t the "CLIP/ FAO-RAF/8I./022 P X V ~ ~ c Z ; .

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E ie first rice fields wheke rice cultivation was mechcwized In West Africa, namely a.t Rickaid-Toll in Senegal, experienced a number of difficulties beca.use of bird at&acks on seeds and mature rice, to have destroyed 3076 o% t he areas sown i n 1958''(WdLflMAiW, 1960; ANO"4OUS 1976).

f - i;fl t According to estimates;, the water birds alone are supposed

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The birds concemied u e ~ e mainly Ethiopian duclrs 'such as the ' E&tian goose ( A l o p o m a c a ) the spur-winged duck,

(PLecmterUs Rambensk) , %he black-headed duck, (&-kidiozuli.s _me2?~9.otos) a the blackrifaced tree duck (pendrocygna Viduatal, and Dendrocygna fulva (m) bs well as palearctic cliaradrii l i k e the bLack--tailed godwit (Limosa. linios=) (MOmL, Xg6S) op -the rmff

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c Zn IWLi, aquatic btrds namely garganeys (a quer&) locally known as ttdougou-datlgoun were also blamecl for mch . dadage, aZrcacly i n 194g9 WX%C and WLMAZFLE wrote tha t W.icks cause the

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I I greatest dmage to the rice fLbLds, Z'he proportion. of rice f t e l d g . -

En w e U f X i c e du NLger i s estima-ted a t 10% and some-kiiqes ever 20%. n

On the othkr hand, KINGHORN, 1932, denied' .that -%he, i. 1, damage ~. done t o rice f i e lds is causecl by aquatic birds,

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c Because of my a s i i g k e rom the end ~f 1972 at

ÓRSTOM (Overseas ScierrtLfic and Technical Research O f f i c e ) and FAO (Food and Agriculture Orga.nlzation), I am n ~ w in a pQsiLion to dis- cuss $he issue of Lhe s i z e of the impact o f waeer b$r& on irrigated crops in the cleltas of' Senegal aiad. MaLi, ,

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' I , : .~P?," , - ' the *"nortl~ 'of Segou, 'Occksïöiially,,, I . 'che hamres-k && only ~. i'/3 o9 '

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that e>$ected. mainly becaime 'of aquatlë'birdk ," e s p e c h l l y .. * ' 'garganeys. &"'Jlhe Bozo 'flL&liemeri put k e & i c a l nets in' the' 'gicë f h d s and cap,-

. ... bred Large quantities 'of garganeys 'whibh weré f&md' later at the Bamako markets more thaa 300 km away (BORTOQ Lo,? personal commtuni-

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b 197h, I was able "GO visit the, Clffice ,du Niger in Mali h.l; d l ~ ~ r e were nat ni'any' duckt8 that year' and 'l$&refdre.'*no' d,anmge,

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. . , . s . ,.. : , , i l .. . . . .In 1975 in Senegal,' a few plots were dcis$rdyecL a-t sowing 1.

', iither'by' godwlts (J. Case) 01- by dendrocygna 'fuXva ' (about' 15' of ' . _

. ( * : 1 I _ . . . . . . . .... ' %he best p l o t s at Botmdotm),' ' "'

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. .ms0 in Senqal, at -the end of 1967-1977 cropping season and $he nex-k year durine tb9: 1977-1978 season, ducks mainly-spur- wliigcd aiid black-headed ducks, attacked large areas of1 'che ricel- f ie lds (TFeECA, 1979). Losses $'t. 54,5196 Q$ the 7ClQ ha in the M t B a p n basin, 7,$$ of t h e 2,000 h&.* a t Dagc?i,ra; 4,934 OP the 600 'ha a t %wnday and 2,0X% o$ the E300 lia a k Ronl-sr; in a - h e r woiids, if tho loss$s* are converted into area destroyed, about 8QO OLI$ of the 18,000 hectares culti- vated (4.5%) were des-koyed.

In January 1977, I was ab5e t o assess ,

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In December-Jantlaly 1978, the losses were dis.tributed i I I

, . differently: Rfchard Toll:. 38.17% of 1500 ha; N'Baga@ 23,9m of '

700 lia, Bowdouni, 9.98% of 6000 lia and elsewhere '@; -that is to areas c~afplet&.y destroyef),

these wouLd be 1,339 ha ou-t of 28,000 or 7,5$.

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*say, if the losses are converbedl

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II Mennlfrhile st M!Bme 011 -th$ banks a9 Lake Guiers where the avai labi l i ty of Presh wa-ter throughout the year made it possible to have an off-seascm crop by sowing in March-ApyXL at the end of the season, 5 observed Ln June i97'7, 52.68% :damage. on 1000 ha ( losses were due mainly t o spur-winged ducks ar@, t o a Lesser exœ

* ' ten t , io ihe diac1c-fac;cd t ree iiuoks), despite tbp very close watch kept -on ducks and war-tlioGs (T-choeks a e t h i o p l w ) , There m s one ac-kve watchman with an o i l Imip, lighting fims over arcas of about 15 ha, The other rice PiKLds we have .spoken ab.Gut have so, far not. been wel3. guarded at night and even not .a$ al& as in the case OP ~ c ~ i g a m . , I ,

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I zy\ Senega.1 I did not observe auy dmiagc e%th.er in tlie

hl'hr i n a smll d v f i v e l W @ d 1978-2979 season o r Ln -the. 1979-1980 season except i n January 1980 J rice field where the r ice harvested w a s l e f t lying in the very poorly*drained f ie lds . On' this a r ~ a l l rice field,, -L'lie black-faxd t ree ducks ihis trino ate IO$ o f the hamrested r ice which is practically insignificant f o r the wliole delta. ~

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&I Mz?lL, the infoi.lilat.ion T was able Lo ob-¡&in from Opera- t ion Riz Mopti, (first developed. plots i n 1974) Tirhich now cul t i - vates about 24,000 ha of r ice f i e l d s showed tfitia-t there vte3x-e se- rious duck sittacks on ly i n 1977-1978 even though 'there 81% a few attacks every year, It is interesting t o note "chat i -6 was during

':*the same cropplng season that thelre were serious attacks ia Sene- Orni thologis t s who worked i n the Mopti .!region also reported - 1 " gal,

these attacks t o me f o r the l$Y/"/'-1978 season but none f o r the 1978-15379 season (ROUX, persolial comunicakon) 1.

. . 7 Ei 1981-1982 when I had jus t arrived M Ncal*i, -the ducks

which v ve re numerous i n thes Nige;. central del ta , were very seLdam found in the r ice fields of the Operation Riz Mogti 'aïid the v&Ch-

fielcls In the north o% Mop-ti we:-@ there any group's of duck mostly garganeys) attacks' bezm 012 plots of ricci 6ha-t plad natured early bu% ceased immediately wit11 the rapid drainirtg b f $he rice fields, w$Z3, the r ice an a13 p20-t;~ reached maturkby, o n l y 60 ha of the Karba.ye r ice fields (710 ha), 120 ha 'of the Sevare, Nopti North f ie lds micl 10 hectares or so Ln -the Ouro-Nema fields situated i n zones c l i f f ictil-t t o drain, were, aplpwently,

' m m usually chased them away *quite ceasily. Only a t "che r ice (

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'!Lhe godwits and mflfs could damage sown seeds . i s

im in Ju%y when the migratsiy birds-liaye nearly I .

ope' t o bd'eed', . - 'I'hcir re"crii*n in August-Se&x?rJZ>er des with's few'vkry l a t e sewings of seed in"$& ejds can %hen be seri,ous$y &"ged :i (Por Instan$@ two $Lots

nearly all destroyed by ruffs). , The .few F ~ L X rice

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We have seen therefore -kh;ix-l; waterbird damage t o r ice fields ' is highly variable, Some, yetars, a.l;tacks are pract5calI.y nil while 3 , r " e s s certain r i c e fields suffer considerable bird damage, I

. . 1 ' I ~ e . t ; us try* io unciera.tan.it w~.ly. '

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'En Senegal'", thk river is embanked between l'Echa~d-TolL , , ( 1 I I , and Saint-Louis-on the Senegalese side ;rln other words on half of

.the del-ka, The flaod water can nevertheless flood the Plauritania

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, 6.1 1%' should howeve$'& noted tI5a-k during the d o u ~ s c of this

..s-tgdy.-no damage o r v e i y : l l t t l e dapage wqs cakiied'to +etldd .crops, Ithat laappened when the 'h.rst complaints were 'made"'in "che 50s op '?

the' Richard-To11 ricefields as vas mentioned i n the introduction.

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IvIas-t damage is caisecl at "clne maturity stage,

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P e s t Cdm-brol. in Rice. . PANS Plzmual Mo, 3 . Ceul.t;A-e Por Overseas Pest Research, Londan, .

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i979.

EvoZution d.es populations d f anakiclbs Qthiopiens e t estirnations des d6g8ks d!ana,tl;jd&s dans le

Note sur 1a reproduction du canard amh (v pambensis) au S&xdg;al.

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i".'.,.. .i' . * . I : ." '.',,I. *,.. *.% ' . , - _ . .- ., . . *-HrmQI<,~,*UWSlllrllVGU:Klu':..:i , ? M ' h - . l I : . ' i-. yu, ..... _ . ...--. .. *. .. - . ._

._ . -" . . ARDA/83/ARR-31 . .. . . . . 1 . .

. . "REGIONAL PROJECT ON RESEARCH AI'JD TRAINING IN THE 'PXOTECTIOI'i OF ~. . . ... . ~ . .

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CROPS AGAINST G R A I N EATING SIRDS *