Great Basin Canada Goose Nesting on the Mid-Columbia River, Washington: An Historical Perspective and Update, 1981-1990
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estnrg of Oreat Basin Conadu geese. lrarta randdcnsis nlolliti. ai 20 isiands il the Honforcl Iteach of the mid (rlurnbir ltirer has been runered i i fue l9 ; :1 . Nes t .our ts dec l i red f ro r r o rer :J0 i l n i 1958 ro a lo \ r o f l01 l ! ) l9 ;5 . S i rxe th .o . r . i r t .ou , , ts ! r | e ! s e d t o l l , e l L o | . 2 7 1 n j l 9 8 9 ' ' 1 . h e i l . . l n j e n j 1 9 6 0 1 9 7 l ; i s r l t I j h u l e d t r l t e l o l q i e l e L l s s o | L l island-. near rhe citr ol RichLrnd. The rreLrge rmual nesr .ounr lor l9il L 1990 \{rs 215. [ighr! percent ol the nest-. irere suoesr l r t iono1( ianudageesea long lhe loSt remrnrn lgun jnpounder lsec t iono1the( i a I e r e l a t e d t o l h e c h a l g i | g e ! \ j r o | l ] e ! t ' j i r l u d n ] g . o o t e | l e d ! t i l ] . i ] e ! 01 lo rs le rn tuDi l , ) r i lg ; i as {ss ins r . \ i ronD.o t r l .hang. . Introduction The nesting popLrlat ion of Oreat Basin Canacla gccsc, Bruntu conotlensis rrolf i r i" along thc nrirJColunrbia Rirer orr thc f .S. I)cpaltrncnt of l inels'r I lanforr l Sitc ( l lanfrrrd Rcach) has bccn srr lvcycrl annuallr since 195i3 (Hanson and EherhardL lq l | . I i t z r ' r r n , l R i , k , r l J l ' , l t : t r . T l r i l ' . , 1 ' . r . r f clatcs thc survev br revierring previous tlends and providing ncrr inlbrmation ohtaincd in the vears 19Bl-1990. I ' r ior to I971. sinEile-pass kmce through) plutonium prodlrclion reac{ors irere operated along the Huribrd Reach and rele:rsed raclio nucl idcs into thc Columbia Rivcr. Once the lcactols rrcrc shutdorrn in calh l97l. racl ionL rc l i de t oncen t ra t i ons i r r r i r e r r l a te l and b io ta clecl inecl (Cushing et o1. -t9l l I i . Radionrul ide concerrtraLions in Canarla S{xrse cggs rcrc'r 'cr-v lo$ in the rears fcr l lowing rcactol shutdoln (Rickarcl and Srtcanv 197i. Rickard and Pricc 1990). Follol ing reactor shutdoln. r-ccrr:at ional usagc oIthc ColLrmbia Rir,er increased. and regulaLed r irerf lots bec:rme more e\trerne. W'ood! \ 'egetaLion. espec iallv nrrrlber'ry trees. MonLs alba. and reed crnar! grass. I)haLais anlndirracea. hrve lloulished along the Hanfbld Reach shorel ine (Fir:Leisen et al. 1980. Rickard et al. I9B2J. Di-.rrantlement ancl cleanup of the old renctor arels is not a major mission of the Hnnfold Site. Sur"reys ol the ne-"t ing pcr-formancc of Canada gccsc plo! idc infor 'matir)n neede(l l1) e!aluale poprrlat ion r-csponscs t , , . r , , , r t i r r u a l l r , l r : r r r 3 i r r g r i r . r i r r . r | \ i . , | | | r | | | | . Study Area The Han lo rd Reach o f t he Co l r r r nb ia R i re r cx t rnd ing upstream f iom Riclr land. S'ashington (Figure l) is the onl_-v unirnpounded lir.er segment upstrenn from l irnnevi l le DarrrThe area contains 20 islands thnt historicallv have been u-.ed m nesting h ritat bv GreaL Basin Canada geese. \ ' laps oi each of the nesting islands r,".itir major ve€tetrtion tvpe-c ['ere prcscntcd b,v Dc$,aard { l9Bl i . Tnformation on thc etnlogv o[ Canacla goose broods in thc l lanfold Reach rrere described in Eberhaldt el al. (1989). Somc ofthc islands h{vc chanpicd 1c€rctntivclv since 1970 . pa rL i r : u l a r l r I s l ands 18 . 19 , anc l 20 . as a re,.ult of raised pool ele\.ntions of Lake Vallula. the impoundrnent creaLed bv N{cNarrdam in 1955. Here. the establ i-shment oi tree and shrub rrillot's. Salir spp.. and rdnk hrrbaccolrs spccrcs rootct l in soi l and mud subslralcs; c.g.. rccd crnarv gr-ass har,e feplaced lhc spafsc. short-qtaLrrred plant comrnunities rooted in cobble stones and grarels lhich r lere arlapted to Lhc historical scasonal lloocling regime ol the liee lloving Columbia Rivcr (Fickeiscn et al. 198O). Accr: lcralcd slumping olthe S'hite Blulfs ini t iated br irr igaLion 'water seepage lrom the Columbia Basin lrrigation projcct h.u shotened the riverine distance behleen Locke Island and the blulfs and Island 7 is now conncctcd to thc blulls br a lantl bridgc. Methods Islands lere selrrched lbr goose nests hv \{alking thc lcngth anrJ brcarl th ofcach. Scarch tcam sizcs ' l o * l , o n r r ' q r r i n r n r t ! . n \ s l r o , , l , i b f v . n l Northl 'est Science. Vol. 6U. No. 1. 199,X 37 Locke lsland il il Columbia River Priest Rapids Dam I Rivor Flow . Reaclor Aroas (lnactivo) (!) lsland Number --Hanford Sito Boundary E===I= Kilometers 77) Hantord SltU I owns|Ie (Abandoned)