Ecology and Management of Avian Botulism on the Canadian Prairies

Recommendations

Info

38two lakes were subjected to carcass removal while two served as non-removal (control) lakes.Three wetl<strong>and</strong>s were revisited in 2000 <strong>and</strong> 2001, <strong>and</strong> treatments were crossed over.All wetl<strong>and</strong>s were shallow (maximum depth ≤ 2.5 m), but water levels were near basin capacitywhen work was conducted. Lakes had large areas <strong>of</strong> emergent vegetation utilized by moultingducks; vegetation was composed <strong>of</strong> bulrush (Scirpus spp.), cattail (Typha spp.), <strong>and</strong> whitetoprivergrass (Scholochloa festucacea; specific to Whitewater Lake), which ranged from sparseto thick.Carcass removal operationsOn carcass removal wetl<strong>and</strong>s, surveillance began as early as mid-May <strong>and</strong>, with the exception <strong>of</strong>Whitewater Lake in 1999 <strong>and</strong> Frank Lake in 2000, surveillance was usually initiated about two t<strong>of</strong>our weeks earlier than normal (see Part I). Areas <strong>of</strong> open water <strong>and</strong> vegetation were searchedusing airboats, whereas shorelines were searched on foot or with all-terrain-vehicles (see below).To increase effectiveness <strong>of</strong>carcass removal, researchcrews informed clean-uppersonnel <strong>of</strong> places wheremortality was occurring, sodead birds could be removedimmediately. The removaloperation at WhitewaterLake (1999) was delayeduntil early July butnonetheless had moremanpower <strong>and</strong> airboats thanhad been employedpreviously. Wetl<strong>and</strong>s weredivided into 1 km 2 sectors<strong>and</strong> Global PositioningSystem (GPS) (Garmin Inc.) units were used to help removal crews ensure complete wetl<strong>and</strong>coverage. Although toxic maggots can develop on carcasses in as little as two to three days(Reed <strong>and</strong> Rocke 1992), removal crews were only able to revisit sectors once per week atWhitewater Lake due to its large size. For this reason, large wetl<strong>and</strong>s such as Whitewater Lakewere not used after 1999, <strong>and</strong> more thorough searches were accomplished twice per week onsmaller wetl<strong>and</strong>s.Trapping <strong>and</strong> radio-marking mallardsAdult mallards in pre-moult <strong>and</strong> moult (emerging primaries
39mallards occurred on all study lakes. From 1 July to the second week <strong>of</strong> August, bait traps (seebelow) were placed simultaneously at several locations on each lake to capture moulting male<strong>and</strong> female mallards; a few werecaptured by drive-trapping. Weattempted to balance the sex ratio<strong>of</strong> radio-marked birds at each lake,but this was not always feasiblegiven timing <strong>of</strong> wing moult <strong>and</strong>sample size requirements (Table1). Visibly healthy mallards wereaged, sexed, weighed, <strong>and</strong> b<strong>and</strong>ed.They were also equipped with aback-mounted, prong <strong>and</strong> suturestyle radio transmitter (172-174MHz), using st<strong>and</strong>ard techniques(Mauser <strong>and</strong> Jarvis 1991) underlocal anesthetic (1 ml Marcaine),<strong>and</strong> released within 30 min toreduce stress (Cox <strong>and</strong> Afton 1998). A small temperature-sensitive probe, encased in flexibleplastic tubing, ran underneath the stainless steel anchor; when a drop (≥4 C) occurred in bodytemperature the transmitter pulse rate increased, indicating death. Transmitters were designedwith a normal signal detection range <strong>of</strong> ~4 km (~2.5 km when submerged) <strong>and</strong> a life span <strong>of</strong>~42 days, while retaining favourable features <strong>of</strong> small size <strong>and</strong> light weight (12 g). If a markedmallard died in July during b<strong>and</strong>ing, the transmitter was sterilized <strong>and</strong> re-used if sufficient lifespan (>30 days) remained. Methods were approved by the University <strong>of</strong> Saskatchewan’sCommittee on Animal Care (Protocol 19980040) on behalf <strong>of</strong> the Canadian Council <strong>of</strong>Animal Care.Radio-trackingSurvival was determined by tracking mallards daily (04:00 - 09:00 CST), sometimes morefrequently, for 30 days after release. After 30 days, surviving birds could not be tracked withcertainty because most had completed moult <strong>and</strong> become mobile. Bird locations <strong>and</strong> status (deador alive) were recorded each morning by tracking with a receiver linked to truck- or towermountedantennas. If the transmitter pulse rate increased, indicating death, the carcass wasretrieved (usually within 2-6 hrs) with the aid <strong>of</strong> a h<strong>and</strong>-held tracking system from an air boat.The location <strong>of</strong> each dead bird was determined with a GPS unit <strong>and</strong> the carcass was frozen fornecropsy. In some cases, birds were not found; these days were entered in the encounter historyas being missing. Signals were occasionally lost permanently; possibly because these birdsregained flight <strong>and</strong> left the wetl<strong>and</strong> near the end <strong>of</strong> the tracking period, or the transmitter wasshed or failed. In these cases, the encounter history was right censored (Williams et al. 2002).
Page 1: Ecology an
Page 4 and 5: iiThe model of bot
Page 6 and 7: ivTABLE OF CONTENTSEXECUTIVE SUMMAR
Page 8 and 9: 2Research from the 1970s supported
Page 10 and 11: 4(Coburn and Quort
Page 12 and 13: 6could potentially serve as substra
Page 14 and 15: 8additional lakes and</stro
Page 16 and 17: 10challenge because management assu
Page 18 and 19: 12Rocke TE, Bollinger TK. 2007. <st
Page 20 and 21: 14Table 1. Names and</stron
Page 22 and 23: 16PART IEFFICACY OF CARCASS CLEAN-U
Page 24 and 25: 18Our objectives were to determine:
Page 26 and 27: 20marked carcasses potentially avai
Page 28 and 29: 22Intensive search studyOn 18 Augus
Page 30 and 31: 24if extrapolated to Whitewater Lak
Page 32 and 33: 26Table 1. Characteristics
Page 34 and 35: 28Table 3. Number of</stron
Page 36 and 37: 30Table 5. Estimates of</st
Page 38 and 39: Figure 2. Map of W
Page 40 and 41: Figure 4. Variation of</str
Page 42 and 43: 36PART IISURVIVAL OF RADIO-MARKED M
Page 46 and 47: 40NecropsiesDead birds were include
Page 48 and 49: 42were right censored. One hundred
Page 50 and 51: 44design, possibly with a treatment
Page 52 and 53: 46Rocke TE, Bollinger TK. 2007. <st
Page 54 and 55: 48Table 2. Models used to assess ef
Page 56 and 57: 50Table 4. Models used to evaluate
Page 58 and 59: 52INTRODUCTIONMaggot-laden carcasse
Page 60 and 61: 54among categories after creating a
Page 62 and 63: 56LITERATURE CITEDBurnham KP, Ander
Page 64 and 65: 58Table 2. Candida
Page 66 and 67: 60PART IVLATE-SUMMER SURVIVAL OF MA
Page 68 and 69: 62In each year of
Page 70 and 71: 64Recovery rate comparisons - 1999D
Page 72 and 73: 66between the present study <strong
Page 74 and 75: 68Table 1. Number of</stron
Page 76 and 77: 70Table 3. Logistic analyses evalua
Page 78 and 79: 72Table 5. Direct recovery rates <s
Page 80 and 81: 741210ControlBotulism</stro
Page 82 and 83: 761614ControlBotulism</stro
Page 84 and 85: 78INTRODUCTIONAvian</strong
Page 86 and 87: 80(GPS) receivers (eTrex Venture, e
Page 88 and 89: 82mortality rate was calculated by
Page 90 and 91: 84samples from FG carcasses collect
Page 92 and 93: 86outbreaks in waterfowl (Table 4;
Page 94 and 95:
88birds and toxic
Page 96 and 97:
90LITERATURE CITEDBall G, Bollinger
Page 98 and 99:
92Williamson JL, Rocke TE, Aiken JM
Page 100 and 101:
94Table 2. Species composition <str
Page 102 and 103:
96Table 4. Estimates of</st
Page 104 and 105:
98iiviiiii1 0 1 2 km1 0 1 21 0 1 21
Page 106 and 107:
100PART VIVARIABILITY OF TYPE C CLO
Page 108 and 109:
102seasonal wetland</strong
Page 110 and 111:
104clinical signs of</stron
Page 112 and 113:
106RESULTSThe proportion of
Page 114 and 115:
108sediments in basins of</
Page 116 and 117:
110Williamson JL, Rocke TE, Aiken J
Page 118 and 119:
112Chaplin, SK botulism 3/5 (60) 1/
Page 120 and 121:
114Table 3. Annual and</str
Page 122 and 123:
116MAIN CONCLUSIONS AND RECOMMENDAT
Page 124 and 125:
Recommendation 8:The model
Page 126 and 127:
120APPENDIX 1AVIAN BOTULISM IN ALBE
Page 128 and 129:
122July 15, 2002ISBN: 0-7785-0962-1
Page 130 and 131:
1242BackgroundMunro (1927) provides
Page 132 and 133:
1264SUMMARY OF ALBERTA BOTULISM OUT
Page 134 and 135:
128Moyles, D. 1989. Avian</
Page 136 and 137:
13081) 1980 (Calverley 1980)Appendi
Page 138 and 139:
1321010) 1990 (F&W files)LakeDetect
Page 140 and 141:
134123 probable blue-green algal po
Page 142 and 143:
136APPENDIX 2EXPOSURE OF MALLARD DU
Page 144 and 145:
138Toxin was administered orally us
Page 146:
140LITERATURE CITEDCarmichael WW, B
show all

Ecology and Management of Avian Botulism on the Canadian Prairies

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?