Uiversity of Alberta 1 October 2009 Tracks The Newsletter of the Norther Border Study With our last trappig seaso behid us, we are ow eterig the fial stages of field work for the Border Study. While we are ot plaig ay additioal deer captures, deer trackig will cotiue through ext sprig as we follow already collared deer through the witer ad sprig migratio. Meawhile, our focus is ow turig to aalyzig the movemet ad habitat data we have bee collectig over the last 3 years. We also have recetly retured from presetig some of our work at the Third Iteratioal Coferece o Chroic Wastig Disease i Park City, Utah. The coferece was atteded by both scietists ad maagers sharig experieces o CWD to fid better ways of maagig the spread of the disease i cervid populatios. Joiig us this year is a ew MSc studet, Barry Nobert, who worked as a field techicia with the Border Study i summer 2008. Barry s thesis will focus o modelig deer movemets ad habitat selectio to idetify potetial corridors for CWD spread. Our field crew is still beig led by Eric Browrigg. If you have ay questios related to the activities of the field crew this fall you should direct them to Eric (780-858-2895), who lives at our field house just outside Chauvi, ad he will get back to you as soo as he ca. Fially, with the hutig seaso upo us, we would like to remid all huters that it is perfectly legal to shoot a collared deer. We do ask that you cotact Eric Browrigg, a Fish & Wildlife office, or Dr. Merrill at the Uiversity of Alberta (see addresses at the ed of the ewsletter) ad provide the followig iformatio about the harvested deer: date ad locatio harvested, ear tag umber, sex, ad species. We also ask that you retur the radio-collar, which you ca drop off at a Fish & Wildlife office, or else you ca cotact us to make arragemets. Field Studies Tom Habib, Barry Nobert, Eric Browrigg, & Dr. Evely Merrill Collared i New Study Area I 2006, prior to ay CWD-positive deer beig located i the Border North area, we established 4 1 Figure 1. Study area of the Border Study ear Chauvi, AB, showig 5 pricipal study blocks (gree areas). blocks for itesive study based o their ladscape characteristics ad whether deer reductio would occur i the area. I the last year we added a fifth study block, Cresthill. This block is located south of Hwy 610 betwee Edgerto ad Chauvi, AB, east of Highway 899, west of Highway 894, ad orth of Towship Rd 425 (Figure 1). The locatio of the block was chose because CWD positive deer had bee foud i this geeral area, ad because Ribstoe creek i the area was hypothesized to be a corridor of deer movemet. The block icludes lads associated with the Cresthill Grazig Associatio as well as a few other large private pastures. Oil ad gas developmets are located o the east ad west boudaries of the block. We bega capturig ad collarig deer i this area i witer 2008-2009 (see below). Capture ad Collarig I witer 2008-2009, we captured ad collared 48 deer usig Clover traps (=13) or helicopter etguig (=35). Five of the collars were deployed iside Provicial parks (1 i Dillberry Lake Provicial Park ad 4 i Waiwright Dues Ecological Reserve).
Figure 2. Hadlig ad preparig a radiocollar for a captured mule deer. Groud trappig was ot as successful as previous years (18.6 trap ights/deer i 2008-2009 vs. 7.9 trap ights/deer i 2006-2007) ad was highly variable across study blocks. We attribute lower success rate to several reasos. First, warm witer temperatures ad ufroze groud forced us to shut dow trappig i Dillberry Park for 32 days at the begiig of the seaso. Whe the groud is ot froze, traps become ustable ad may collapse o deer, which puts them at risk. This resulted i 320 lost trap ights durig what is typically a productive part of the trappig seaso. Secod, whe trappig resumed after Christmas, we experieced low temperatures for much of Jauary which teds to reduce deer movemet ad trappig success. Our hadlig protocols do ot allow us to keep traps active at temperatures below -20 o C for the welfare of the deer ad safety of hadlers. Third, we operated fewer traps i the Metiskow capture block because we did ot eed to deploy a large umber of collars to meet our quota i that regio. Fourth, trappig success outside Dillberry Park was very poor with oly 3 collars beig deployed ad 6 deer beig caught, icludig 3 faws which we do ot collar because of complicatios accommodatig eck growth withi the collars. We are ot sure why success was low but it may have bee related to warmer temperatures that melted sow ad exposed more food o the groud, makig it difficult to attract deer to the baited traps. All collars (=20) deployed i the ew Cresthill capture block were deployed by helicopter capture due to limited road access i the block. No collars were deployed i Battle Creek study block this year because there remaied a high umber of collared deer i the area. At the time of publicatio, we have 110 collars deployed o 56 white-tailed ad 54 mule deer, ad 25 of these are GPS collars. Herd Characteristics for Populatio Modelig Oe goal of the Border Study is to develop populatio-level models of disease spread to predict how the deer i this regio will respod to CWD over time. I order to develop these models, we eed to calculate several populatio growth parameters, icludig deer reproductive ad survival rates, ad age compositio of the herd. We are usig field data from the last 3 years as well as data collected from huter ad recet witer herd reductio programs to estimate these values. Fecudity Durig the 2005 ad 2006 CWD witer herd reductio programs, Alberta Sustaiable Resource Developmet examied the uteri of a subset of culled female deer ad recorded the umber of foeti preset. This is very valuable iformatio obtaied o the herd s productivity. We used these data collected from 166 mule deer (147 adults, 19 faws) ad 381 white-tailed deer (296 adults, 85 faws) to estimate fecudity for each species-age class. The average umbers of male or female foeti were ot cosiderably differet betwee the two species (Table 1). Survivorship Adult Survival. Durig the past 3 years of the Border Study, there were a total of 156 radiocollared deer (85 WTD ad 71 mule deer) that did ot lose their radiocollars for at least oe year. We used data from these aimals to calculate aual survivorship for each of 3 age-sex classes per species (adult females, adult males, ad yearlig females; we do ot yet have eough data to calculate survival for yearlig males). Data were pooled across all three years (2006-2008) to develop the estimates (Table 2). Adults were defied as deer greater tha two years of age. We did ot collar faws i this study, but we estimated faw survivorship from doe-faw ratios (see below). Female survivorship (Table 2) was high for both species (0.84 for white-tailed deer ad 0.87 for mule deer). Male survival appeared lower i mule deer tha white-tailed deer but due to low sample size, we will ot statistically test this hypothesis util data from 2 Table 1. Average fecudity (faws/ female) i mule (=166) ad white-tailed (=381) deer, 2005 ad 2006. Age Mule WTD Adult 1.65 147 1.75 Faw 0.11 19 0.31 296 85
2009 are available. Female yearlig survival also appeared to be lower tha adults. We cosider this aalysis prelimiary with additioal survival aalysis usig more sophisticated aalyses ad factors ifluecig survival to follow i the ext year. Table 2. Aual survivorship of radiocollared whitetailed ad mule deer i the Border Study, 2006-2008. Species Age Sex Survivorship White-tailed Mule Adult F 0.84 Adult M 0.85 Yearlig F 0.74 Adult F 0.87 Adult M 0.58 Yearlig F 0.67 Faw survival. We collected iformatio o deer group size ad compositio data opportuistically throughout the study from groud observatios. We used data collected from 2006-2008 to calculate faw:doe ratios for two time periods: late summer/ early fall (September) ad late witer/early sprig (April). We compared these ratios to the ratio at birth (from fecudity data described above) to calculate the miimum faw survival rates from parturitio through to September ad April. These prelimiary estimates (Table 3) represet miimum faw survival rates because the comparisos betwee faw:doe ratios do ot accout for doe mortality durig the time period. We coducted this aalysis for both species, but faws were ot separated by sex at this time. Table 3. Estimated survival of mule ad white-tailed deer faws to late summer (September) ad late witer (April) i the Border Study i 2006-2008. Mule White-tailed September 0.558 421 0.501 April 0.516 173 0.539 66 14 17 53 16 12 135 159 Migratio We defied migratios as movemets > 5 km from a summer to a witer rage with a cosistet movemet betwee rages. A total of 136 GPS ad VHF white-tailed ad mule deer were moitored for a period of at least oe year, ad 40 (29%) showed migratory movemets. Across all years, 34% of female ad o male white-tailed deer migrated, while 30% of female ad 16% of male mule deer migrated. Overall migratio rates for each species were similar (Table 4). Migratio times were highly variable. While sprig migratio teded to begi i April, the earliest observed migratio bega o March 23, ad the latest o May 14. The earliest ad latest fall migratios were o December 13 ad Jauary 4, respectively. Table 4. Species ad sex of collared deer (=136) classified as migratory (made movemets >5km). also must have bee active for over a year; mortalities ad lost collars were ot icluded. Total Migrators Percet Mule Whitetailed Total Dispersal Female 53 16 30.2% Male 6 1 16.7% Total 59 17 28.8% Female 70 23 32.9% Male 7 0 0.0% Total 77 23 29.9% 136 40 29.4% Dispersal is distict from migratio because it ivolves a deer adoptig a ew home rage without returig to its origial oe. Based o collars with kow fates over at least oe etire year ( = 136), 4.4% (=6) have dispersed. There is o patter amog species or sex give the small sample size, but both sexes ad species dispersed. Oe white-tailed buck iitially collared alog the Battle River i 2007 dispersed orth to a area ortheast of Paradise Valley, Figure 3. Herd of deer grazig i a agricultural field i early sprig. 3
Figure 4. Movig white-tailed deer observed durig a sightability trial. AB (~20 km). I 2006, a white-tailed doe dispersed ortheast from Dillberry Lake Provicial Park to orth of Neilburg, SK (~40 km). Two white-tailed does (oe i 2007 ad oe i 2008) dispersed from Metiskow block orth to areas west of Waiwright Dues Ecological Reserve (both ~16 km). I 2007, oe mule doe from Battle block dispersed ortheast to a area east of McLaughli, AB (~7 km). I 2008, oe other mule doe from Ribstoe block dispersed southwest of Loe Rock, SK (~17 km). At preset there seems to be o cosistet directioality i the dispersal of these 6 deer. Sightability Model Developmet I this regio, aerial surveys are the primary tool used to estimate deer populatio umbers. However, it is commo with may species for a percetage of aimals to go udetected i aerial surveys. Other studies have show that detectibility, or sightability as it is called, ca be iflueced by factors such as amout of sow cover, forest caopy cover, deer group size, ad observer iexperiece. Durig the witers of 2007-2008 ad 2008-2009, we developed a sightability model that ca be used to correct aerial survey populatio estimates for deer missed durig the actual survey. We coducted 100 sightability trials (usig 46 radiocollared mule deer ad 54 radiocollared white-tailed deer) followig the procedures used by previous studies. The trials cosist of mimickig a survey i a area where we kow a radiocollared deer is located, but the survey crew does ot kow its exact locatio. They perform a search of the trial block coutig all deer. If they do ot observe the radiocollared deer, the they use radiotelemetry to fid the deer immediately after the survey is completed to record whether the deer was ideed i the survey block ad the evirometal factors of why the deer was missed. These data ca the be used to correct survey umbers. Fial aalysis is ogoig, but work to date suggests that the most importat factors for sightig a deer are deer group size, sow cover, deer activity (whether the deer is bedded, stadig, or movig), ad light itesity (bright light reflectig off sow reduces sightability). Fial results of the sightability study will be available i a MSc thesis. Desity Aerial surveys were coducted i WMU 234 i Jauary 2007, 2008, ad 2009 by Alberta Fish ad Wildlife. Durig these surveys, exteded effort was put ito coductig a complete (full aerial coverage) aerial cesus i 4 of the 5 study blocks of the Border Study. The Cresthill block was ot established util witer 2008-2009, so it was ot cesused i the precedig witers. Other areas i the regio were surveyed by trasects accoutig for ~50% of its area i 2007 ad 25% i 2008. Due to budget costraits, Battle block was covered by a similar 25% coverage trasect survey i 2009. As expected, desities betwee Jauary 2007 ad 2008 decreased i those blocks affected by the CWD herd reductio program i March 2007 (e.g. Ribstoe ad Dillberry blocks, Fig. 5). I cotrast, the desities of u-culled blocks remaied similar or icreased betwee Jauary 2007 ad 2008. Desity (/km 2 ) 8.00 7.00 6.00 5.00 4.00 3.00 2.00 1.00 0.00 Battle Metiskow Dillberry Ribstoe Uculled Study Blocks 2007 2008 Culled Study Blocks Figure 5. Chages i combied white-tailed ad mule deer desity withi 4 of the 5 study blocks, based o aerial surveys from i 2007 ad 2008. 4
Figure 6. Resource selectio fuctio values for mule deer across the etire CWD study area. A high RSF value (gree areas) idicates that a deer would be more likely to select that area relative to areas with a lower RSF value (red areas). Habitat Selectio We coducted a prelimiary aalysis of deer habitat selectio withi their home rages usig locatio data from 31 GPS-collared deer captured betwee December 2006 ad April 2007. We developed a resource selectio fuctio (RSF), which is a measure proportioal to the probability that a deer will select a resource withi its home rage. RSFs were developed for both species i witer ad summer. I geeral, both species teded to avoid roads ad select areas close to or with a high proportio of tree/shrub cover. Mule deer also selected rugged areas, while white-tailed deer did ot exhibit this preferece. These iitial results give isight ito how deer utilize the study area (Fig. 6). Geetic Studies Dr. Catherie Culligham & Dr. David Coltma The geetic aalysis of mule ad white-tailed deer populatios across Alberta ad Saskatchewa has made cosiderable progress. The objective of this research is to look at deer movemet by trackig the movemet of their gees, ad relate these movemets to the risk of CWD spread. Stephaie Nakada, who has bee resposible for the mule deer aalysis, has successfully fiished her MSc degree. The results of her thesis are ow beig compiled for publicatio by Dr. Catherie Culligham. Catherie is a post-doctoral fellow workig o the project, ad she is also compilig the results of the geetic aalysis of white-tailed deer. Mule We have completed aalysis of 2706 mule deer samples collected from 23 geographic areas from throughout their distributio i Saskatchewa, Alberta, ad the Alberta-British Columbia border. We foud that geographically distat populatios also differ geetically from each other; this idicates that geographically proximate groups exchage more migrats tha distat groups, suggestig the spread of CWD will maily occur at a local level. We also foud a associatio of movemet with rivers, where movemet is potetially ehaced alog river corridors, but slightly restricted across rivers. I terms of disease spread, this meas geographic spread may be greater alog rivers, rather tha across. At a local scale, we foud that females were more likely to be related whe separated by less tha ~1 km. We also foud that CWD-ifected eighbours are more related tha uifected eighbours. Take together, these fidigs suggest that local social orgaizatio may be a importat factor i the local spread ad persistece of CWD. White-Tailed Aalysis of over 1800 white-tailed deer samples across Alberta, Saskatchewa ad easter British Columbia has idicated there is little geetic struc- 5
For more iformatio o the Border Study, please cotact: Field Studies Eric Browrigg (780) 858-2895 Tom Habib thabib@ualberta.ca Barry Nobert brobert@ualberta.ca Dr. Evely Merrill emerrill@ualberta.ca Geetic Studies Dr. Culligham Dr. Coltma cathy.culligham@ualberta.ca david.coltma@ualberta.ca Figure 7. Isolatio by distace amog mule deer samplig locatios across Alberta, Saskatchewa ad easter British Columbia. Populatios geographically proximate are geetically similar ad as geographic distace icreases so does geetic distace. ture. The small amout of structure we do fid is explaied by distace. This meas that herds of deer i close proximity are very similar ad this similarity decreases with distace (Fig. 7). This is ot surprisig, because white-tailed deer are a mobile species that has bee expadig westward. However, British Columbia has geetically diverget populatios, idicatig that the Rocky Moutais may be a potetial barrier to dispersal. Similar to mule deer, we fid females livig i close proximity are more likely to be related, but this patter occurs at a smaller scale (< 500 m) ad to a smaller degree. The differeces i relatedess betwee the two species could be a factor i differeces i disease prevalece, as there are more observed cases of CWD i mule deer tha white-tailed deer. Fudig Agecies ad Co-operators: Alberta Prio Research Istitute Alberta Coservatio Associatio Alberta Fish ad Wildlife Uiversity of Alberta Saskatchewa Eviromet Safari Club Norther Alberta Chapter Alberta Professioal Outfitters Society These studies are coducted i collaboratio with the Uiversity of Saskatchewa uder the supervisio of Dr. Tret Bolliger. Ackowledgemets We would like to thak the 150+ ladowers who cotiue to participate i this project by allowig us to access their lad, as well as the thousads of huters across Alberta who submit deer heads for CWD testig. Saskatchewa Eviromet 6