Antler casting in relation to parturition in semi-domesticated female reindeer

We investigated the timing of the right and left antler casting in semi-domesticated reindeer (Rangifer tarandus tarandus L.) in relation to parturition using 139 antlered adult individually marked females in 2008-09 between May 5 and June 2; a period when all calves were born and all females cast their antlers. We analysed time of casting of right and left antler in relation to pregnancy, female age and body weight, weight and sex of the calf, and birth date.  Seven of the females were non-pregnant (barren) and cast their antlers during the second week of May and at the same time as some of the females that gave birth initiated antler casting. Postpartum retention of antlers varied from 0 to 15 days. We found no difference between left and right antler casting schedule and within two days apart, 91% of the females had cast both antlers. The maximum number of antler castings per day occurred on the seventh day after parturition. Of the 132 females that gave birth, 7 females (5.3%) cast both antlers 5 – 23 days before calving, three females cast right antler 6 – 10 days before and the left antler 2 – 5 days after calving and one female that bore only a left antler casted a day before calving. Antler casting among lactating females was related only to female age, indicating that older females cast antlers earlier than younger females (i.e. 3 days earlier than the pooled mean of 7.6 days). Apart from calving date being two days later among the 7 females that alternated their casting schedule, female body weights, calf sex and calf birth weight among them did not differ between the two years. We conclude that it is a small but consistent antler casting overlap between barren and pregnant/lactating females, indicating that the control mechanism for casting of antlers is not “fool proof” and that antler status prior to parturition does not accurately predict pregnancy status in this domestic reindeer group

Body composition and population regulation of Svalbard reindeer

After severe winters, body weight, fat, and lean tissue of the high Arctic Svalbard reindeer may be reduced by 50, 90-97 and 30-40% respectively. Absence of harassment from predators, insects and man allows surviving animals to rapidly restore body reserves during the summer. That accumulation of large pre-winter body reserves is essential, as the reindeer's survival and population control is dependant upon use of winter forage which is resistant to grazing but poor in quality.Kroppssammensetning og bestandsregulering hos svalbardrein.Abstract in Norwegian / Sammendrag: Etter harde vintre kan kroppsvekt, fett og magert vev bli redusert med henholdsvis 50, 90 - 97% henholdsvis. Fravær av forstyrrelser av rovdyr, insekter og mennesker tillater overlevende dyr å fornye sine kroppsreserver raskt gjennom sommeren. Denne akkumulering av store kroppsreserver før vinteren er livsviktig, da reinens overlevelse og bestandskontroll er avhengig av et vinterfor som er motstandsdyktig mot beiting, men er av dårlig kvalitet.Huippuvuorten porojen ruumiinkokoonpano ja eläinkannan säätö.Abstract in Finnish /Yhteenveto: Ankarien talvien jälkeen voi ruumiinpaino, rasva ja laiha kudos vähetä 50, 90-97 ja 30-40 % jokainen erikseen. Petoeläinten, hyönteisten ja ihmisten häiriöiden poisjäädessä on eloonjääneillä eläimillä mahdollisuus uusia nopeasti ruumiin vara-aineet kesän kuluessa. Tamä suurien ruumiin vara-aineiden kasaantuma ennen talvea on elintärkeä, koska porojen eloonjääminen ja eläinkannan valvonta on riippuvainen talvilaitumesta, joka sietää laiduntamisen, vaikka se on huonoa laatua

The Return of Caribou to Ungava

A.T. Bergerud, Stuart Luttich, & Lodewijk Camps. “The Return of Caribou to Ungava.” McGill-Queen’s University Press, Montreal, Quebec. 586pp. ISBN 978-0-7735-3233-5

Management of wild reindeer in Norway

Wild reindeer in Norway are found in 26 separate management areas. Predators are virtually absent from all areas and hunting is the most important factor determining population development through alterations of herd size and structure. Average population density (animals/km2) after hunt was 1.96 in Hardangervidda, 1.18 in North Rondane and between 0.78 and 0.87 in Rondane South, Snøhetta, North Ottadalen and Forelhogna. Body size and female pregnancy rates followed a reverse trend. Average net increase of the herds varied from 42.2±10.0% in Forelhogna to 18.8±8.0% in Rondane North. In areas with animals in prime physical condition a high versus a low average harvest rate of calves resulted in a similar number of animals harvested, but a lower total yield of meat and revenue from hunting licences. At a winter population density of 0.8 - 2.0 animals/km2 annual harvest (per km2) of wild reindeer amounts to 0.23 - 0.51 animals, 9 - 18 kg meat and 286 - 850 NKr from sale of hunting licences. There was a significant relationship between body size expressed as carcass weights or mandible length and harvest success

Wild reindeer calf recruitment variations; biology or methodology?

The two field methods, ground counts and aerial photography, currently used for calculating population estimates and calf recruitment for Norwegian wild reindeer (Rangifer tarandus) produce different results. Using population count data by both methods from the same years in various areas, I systematically compare estimates of sex and age components and decipher reasons for the discrepancies found in previous estimates made by each method. Data for aerial photography counts were found in the literature, while original data is presented for ground counts. Calf recruitment (calves/100 females) and the proportion of adult males (males 1+ years/100 animals 1+ years) in herds of reindeer in Norefjell-Reinsjøfjell (1993-98), Rondane North (1995-97) and Setesdal-Ryfylke (1995, 1998) were recorded from ground counts of post calving groups in June-July. The estimates for number of calves per 100 females 1+ years were lower and more variable than number of calves per 100 females 2+ years. A variable number of yearling females in the groups and difficulties in correctly sexing yearlings are contributing factors. The estimates for number of calves/100 females 1+ years were higher than calves/100 animals 1+ years due to the inclusion of young males in the latter. Among animals 1+ years in the post-calving groups, males (mostly yearling males) composed from 4.7 to 27.9 %. Nevertheless, both calculation methods for calf recruitment were consistently higher for ground count data than when using counts from air photographs, confirming that the two methods do not produce comparable results. Explanations for this discrepancy are (1) that calves may be easier to overlook on air photographs than in ground composition counts and (2) that the yearling male components in the post calving groups are unaccounted for when using air photographs. June recruitment rates (calves/100 females 1+ years) in Rondane North were also estimated from composition counts recorded from ground counts in October and from air photographs of post calving groups in June/July. Rates ranged from 44 - 56 from ground counts in 1985-92 and 1995-97, compared to 37 - 65 from air photographs the same years. The air photograph method is based on the assumption that few males are present in the post-calving groups and that the variability in calf recruitment figures reflects variations in reproduction and postnatal calf mortality. The reported ground composition counts challenge the validity of the air photography method commonly used for assessment of calf recruitment or calf mortality in the post-calving wild reindeer groups. While aerial photography may be worthwhile for over-all population counts, ground observations might be necessary for more precise calculations of specific population components, such as age and sex proportions and calf recruitment estimates.Abstract in Norwegian / Sammendrag:Estimerte rekrutteringsvariasjoner for villreinkalver avhenger av metodevalg De to metodene som i dag anvendes til bestemmelse av kalvetilvekst i juni-juli hos villrein (Rangifer tarandus) i sørnorske villreinområder, flyfotografering av fostringsflokkene og strukturtellinger fra bakken, gir forskjellige resultater. Ved å sammenligne populasjonsdata innsamlet ved de to metodene i samme områder og i samme år, har jeg søkt å finne årsakene til at de to metodene har produsert ulike rekrutteringsdata. Populasjonsdata fra flyfotograferingsmetoden er samlet fra publiserte kilder, mens originale data presenteres for bakkestrukturtellingene. Kalvetilvekst (kalver/100 simler 1 år+) og andelen bukk (bukker 1 år+/100 dyr 1 år+) i reinsflokker i Norefjell-Reinsjøfjell (1993-98), Rondane Nord (1995-97) og Setesdal-Ryfylke (1995, 1998) ble registrert gjennom strukturtellinger fra bakken av fostringsflokker i juni-juli. Kalvetilvekst basert på kalv per 100 simler 1 år+ var lavere og mer variabel enn tilvekst basert på kalv per 100 simler 2 år+. Et variabelt antall åringssimler i flokkene og problemer med kjønnsbestemmelse av åringer er viktige årsaker til variasjonene. Antall kalv per 100 simler 1 år+ var gjennomgående høyere enn antall kalv per 100 dyr 1 år+ på grunn av at yngre bukker er inkludert i den siste kategorien. Bukker (hovedsakelig åringsbukk) utgjorde fra 4.7 til 27.9% av dyr 1 år+ i fostringsflokkene. Begge beregningsmåtene (kalv per 100 simler 1 år+ og kalv per 100 dyr 1 år+) ga høyere rekrutteringstall enn tilsvarende tall basert på flyfotos og bekreftet at de to metodene ikke produserte samme resultat. Forklaring på denne forskjellen i rekrutteringsestimat kan tenkes å henge sammen med (1) at kalvene er lettere å overse på flyfotos enn fra bakken og (2) at andelen åringsbukk i fostringsflokkene ikke kan bestemmes på flyfotos og følgelig heller ikke korrigeres for. Beregnet kalverekruttering i juni ble også estimert i Rondane Nord på basis av bakkestrukturtellinger i oktober og sammenlignet med tilsvarende tall beregnet på basis av flyfotos fra juni-juli de samme årene. Rekrutteringsratene (kalv per 100 simle 1 år+) målt på bakken varierte fra 44 til 56 i 1985-92 og 1995-97 sammenlignet med 37 til 65 målt på flyfotos. Flyfotograferingsmetoden er basert på antagelsen om at det er få bukker i fostringsflokkene i juni-juli, og at variasjonen i rekrutteringstallene reflekterer årlige variasjoner i tilvekst og tidlig kalvedødlighet. Bestandsstrukturdata registrert ved bakkeregistreringsmetoden utfordrer holdbarheten i flyfotometoden som anvendes til bestemmelse av kalverekruttering og tidlig kalvedødlighet i de forskjellige villreinområdene. Mens flyfotografering synes overlegen for bestemmelse av bestandsstørrelse, synes bakkeregistrering å være nødvendig for en mer presis beregning av populasjonsparametere så som alders- og kjønnssammensetning og tilveksttall i villreinbestandene

Calving time and foetus growth among wild reindeer in Norway

Mean calving dates among 7 wild reindeer (Rangifer t. tarandus) herds in southern Norway varied between the 6th and the 27th of May. Ln transformed foetus weights relate linearly to ln age in days. Regression analyzes based upon 225 days pregnancy predicts birth wet weights between 4600 and 7500 g in the different areas and years. At 130 days, foetus weights varied between 547 and 746 g (mean=681, standard deviation s=63) in all areas and years, indicating that foetus growth up to this size is independent of mothers body weight or condition. During the remaining 95 days of pregnancy, very poor body condition, reflected in dressed weights, resulted in slower foetus growth and smaller regression estimated birth weights. The foetus weight variation recorded at similar dates within areas and sampling years indicates a dispersed breeding time mostly within two ovulations. A small sample of foetuses from pregnant yearlings and calves indicate that these cohorts conceive later than 2 yr + females. Assuming similar foetus growth pattern among all female age cohorts within areas, yearlings conceive around 1 week later and calves (in Ottadalen) more than 3 weeks later than 2 + yr olds

Growth rate and body size differences in Rangifer, a study of causes and effects

The paper discusses growth rate- and body size differences in Rangifer; their causes and effects. Growth rates and autumn body weights vary considerably both within and between Rangifer subspecies. The variation measured is within limits found in animals of same genetical stock subjected to different environments. Reproductive age, pregnancy rate, calving time and mortality either are or may be functionally related to autumn body weights. The differences in growth rates and body size among Rangifer in different areas are caused primarily by differences in environmental factors during the summer, including stress. The quality of the winter pastures has a minor effect on the body size in areas where the summer conditions allow the animals to grow at their maximum rate. In areas where maximum growth rates for various reasons are counteracted, severely overgrazed winter pastures will contribute to reduced body size. Stress in the terms of human disturbance, insects and predators and the effect on Rangifer activity pattern and hence on growth rates and body size need to be more thoroughly dealt with.Forskjeller i vekst og størrelse hos Rangifer, en studie over årsaker og virkninger.Abstract in Norwegian / Sammendrag: Arbeidet diskuterer årsaker til og virkninger av vekst- og størrelsesforskjeller hos Rangifer. Vekst og høstvekter varierer betydelig både innen og mellom de enkelte Æangj/er-underartene. Variasjonene er imidlertid ikke større enn de som er beskrevet i bestander med samme genetiske utgangspunkt og utsatt for ulike miljøforhold. Alder ved kjønnsmodning, drektighetsfrekvens, kalvingstid og dødelighet er eller synes å være relatert til høstvektene. Vekst-og størrelsesforskjeller hos rein og caribou i ulike områder skyldes i første rekke forskjeller i miljøfaktorene om sommeren, stress inkludert. Kvaliteten av vinterbeitene har liten effekt på kroppsstørrelse i områder hvor forholdene sommerstid tillater maksimal veksthastighet. I områder hvor dette av forskjellige grunner ikke skjer, vil sterkt overbeitede vinterbeiter bidra til reduserte kroppsvekter. Stress i form av menneskelige forstyrrelser, insekter og rovdyr og effekten på reinens/caribouens aktivitetsbudsjett og derigjennom på vekst og kroppsvekt har krav på større forskningsinteresse.Rangiferin kasvun ja suuruuden eroavaisuuksia. Tutkielma syistå ja vaikutuksista.Abstract in Finnish / Yhteenveto: Tyo kåsittelee syitå ja vaikutuksia Rangiferin kasvu - ja suuruuseroavaisuuksista. Kasvu ja syyspainot vaihtelevat huomattavasti sekå yksittåisisså Rangifer - alalajeissa ettå lajien kesken. Vaihtelu ei ole kuitenkaan suurempi kuin se mitå on kerrottu laumoista, joilla on sama perinnollinen låhtokohta ja jotka ovat joutuneet erilaisten ymparistotekijoiden vaikuttamiksi. Sukukypsyysikå, tiinehtyvyystaajuus, vasonta-aika ja kuolleisuus on tai nåyttåå olevan suhteessa syyspainoihin. Syy kasvu - ja suuruuseroavaisuuksiin poroilla ja karibulla eri seuduilla nåyttåå ensi sijassa olevan ympåristotekijoiden eroavaisuudet kesållå, stressi mukaanluettuna. Talvilaitumien laadulla on pieni vaikutus ruumiin suuruuteen seuduilla, joissa olosuhteet kesåaikaan sallivat enimmåiskasvunopeuden. Seuduilla, joissa tåta ei tapahdu - eri syistå johtuen, voimakkaasti ylirasitetut talvilaitumet vaikuttavat alentuneisiin ruumiinpainoihin. Stressi, inhimillisten håirioden muodossa, hyonteiset ja petoelåimet ja poron/karibun vaikutus toimintaan sekå siten kasvuun ja ruumiinpainoon ovat seikkoja, jotka vaativat suurempaa tutkimuskiinnostusta

Rangifer population ecology: a Scandinavian perspective

Population ecology is concerned with measuring changes in population size and composition, and identifying the causes of these fluctuations. Important driving variables include animal body size and growth rate, and their relationship to reproduction and mortality. Among wild and domestic reindeer (Rangifer tarandus tarandus), reproductive performance, calving time, calf birth weight and neonatal mortality are strongly correlated to maternal weight. Heavy females enjoy higher pregnancy rates, calve earlier, and give birth to heavier calves which have a higher neonatal survival rate than light females. Most studies indicate that both weaning weight of a calf and mature body weight correlate to its birth weight. Calf body weight and composition influence the rate of attainment of sexual maturity. Females which breed as calves suffer reduced growth and give birth to smaller calves, which suffer higher neonatal mortality and lower rates of postnatal growth. A yet unresolved question is whether reindeer body weight, and hence reproductive performance and neonatal mortality, are more strongly influenced by winter than by summer grazing conditions. This paper reviews population ecology studies on wild and domestic reindeer and promotes the view that body size in Rangifer is determined primarily by grazing conditions during the summer

Wild reindeer in Norway – population ecology, management and harvest

Wild reindeer in Norway, presently (winter 2005-06) numbering some 25 000 animals, are found in 23 more or less separated areas in the mountainous southern part of the country (see map in appendix). All herds are hunted and management is organized in close cooperation between owner organizations and state agencies. I will provide a historical review of the wild reindeer management and research in Norway and conclude with the present situation. We identify 3 types of wild reindeer on basis of their origin: (1) the original wild reindeer with minor influence from previous domestic reindeer herding activities (Snøhetta, Rondane and Sølenkletten), (2) wild reindeer with some influx of animals from past domestic reindeer herding in the area (Nordfjella, Hardangervidda, Setesdal-Ryfylke) and (3) feral reindeer with a domesticated origin (reindeer released or escaped from past reindeer husbandry units; Forolhogna, Ottadalen North and Ottadalen South, Norefjell-Reinsjøfjell and several smaller areas). In Norway, genetic origin (wild or domesticated), body size and reproductive performance of reindeer differ among areas. Feral reindeer have higher body weights and enjoy higher reproductive rates than their originally wild counterparts. These differences may partially be explained by differences in food quality and availability among the populations. However, there is a growing suspicion that other explanatory factors are also involved. Wild reindeer are more vigilant and show longer fright and flight distances than feral reindeer. Number of animals harvested was 4817, or ca. 20% of the total population in 2005, but varies between 40% in feral reindeer areas to below 20% in some of the "wild" reindeer areas. Causal factors behind this variation include differences in age at maturation, postnatal calf mortality and herd structure. The Norwegian Institute for nature research (NINA) in cooperation with the Directorate for nature management (DN) allocate considerable resources to monitoring 36 wild reindeer herds and pastures, especially winter pastures. A total of 8 wild reindeer areas are monitored annually (the monitoring program was initiated in 1991), recording calf recruitment rates in nursery bands in June/July from aerial photographs and herd composition from ground counts of rutting groups in September/October. Carcass weights and mandibles are sampled at regular intervals from harvested animals in the same areas in order to investigate reindeer body weight development. The botanical part of the monitoring program is concentrated on renewal growth of lichen in areas under variable reindeer grazing pressure, and annual measurements of radiocesium load in plants and reindeer meat from fall-out areas following the Chernobyl accident in 1986. Reindeer research relating to the wild reindeer herds in southern Norway is mainly conducted by NINA in Trondheim and the Biology Institute, University of Oslo. Most mountain ranges and wild reindeer populations in Norway are experiencing an increase and expansion of human use, including infrastructure such as road and power-lines, and private cabins, tourism/recreation, etc. Present research activities focus on wild reindeer area use, behaviour and activity budgets in selected areas on a 24 hour and a seasonal basis by use of GPS-technology. An important part of the ongoing projects emphasizes a close monitoring and investigation of reindeer behaviour and activity in relation to human activities and infrastructure. Furthermore, development and quality control of methods for measurement of response towards anthropogenic activities and population reproduction and early calf mortality are included in the research activities.Villrein i Norge; Populasjonsøkologi, forvaltning og jaktAbstract in Norwegian / Sammendrag: Villreinen i Norge utgjør i 2005-06 en vinterbestand på ca. 25 000 dyr fordelt på 23 stort sett isolerte villreinområder (kart i appendiks) som jaktelig sett forvaltes enkeltvis og i et samarbeid mellom rettighetshavere og statlige forvaltningsorganer. Presentasjonen gir en historisk fremstilling av villreinforvaltningen i Norge og den forskningsutvikling som ligger bak dagens situasjon. Vi har 3 typer villrein i Norge: (1) den opprinnelige med liten tamreininnblanding karakterisert ved områdene Snøhetta, Rondane og Sølenkletten, (2) villrein med varierende innslag av tamreinpåvirkning (Nordfjella, Hardangervidda, Setesdal-Ryfylke) og (3) villrein med tamreinopphav (dvs. forvillet tamrein; Forolhogna, Ottadalen Nord og Ottadalen Syd, Norefjell-Reinsjøfjell og en rekke mindre områder). Reinens kroppsvekter i kategori 3-områdene er vesentlig høyere enn de i kategori 1 og 2. Forskjeller i beiteforhold områdene i mellom er nok medvirkende årsak, men adferdsundersøkelser som omfatter vaktsomhetsadferd og frykt- og fluktadferd i ulike områder tyder på at vaktsomhet og aktivitetsmønster kan være andre viktige påvirkningsfaktorer. Avkastningen i form av felte dyr var i 2005 ca. 20% av samlet vinterbestand, men varierer mellom 40% i områder der kroppsvektene er store til under 20% der reinen har lavere kroppsvekter. Forklaringsfaktorer omfatter forskjeller knyttet til alder for kjønnsmodning og reproduksjon, postnatal kalvedødlighet og kjønns- og alderssammensetning i de ulike villreinområdene. Norsk villreinforvaltning i regi av Norsk institutt for naturforskning (NINA)/Direktoratet for naturforvaltning (DN) satser store ressurser på overvåkning av villrein og deres beiter, særlig vinterbeiter. Til sammen 7 spesielt utvalgte villreinområder overvåkes årlig (start 1991) med flyfotografering av fostringsflokker i juni/juli for å bestemme kalvetilvekst og bakkeregistreringer om høsten for å bestemme bestandsstruktur. Med jevne mellomrom innsamles også kjever og slaktevekter fra høstjakten for å vurdere reinens kondisjonsutvikling i overvåkningsområdene. I den botaniske del av overvåkningsaktivitetene måles gjenvekst av lav i områder utsatt for vekslende beitepress og radiocesiumbelastningen etter Tsjernobylulykken i 1986 i næringsplanter og i kjøttprøver fra felt villrein i de områdene som ble hardest rammet av nedfall. Villreinforskningen er særlig lokalisert til NINA og Universitetet i Oslo. Forskningsaktivitetene omfatter måling av reinens adferd og aktivitet gjennom døgnet og dyrenes sesongmessige områdebruk i relasjon til menneskelig infrastruktur i utvalgte områder ved hjelp av bl.a. GPS-instrumentering og utvikling og kvalitetskontroll av metodeverktøy til bestemmelse av reproduksjon og tidlig kalvedødlighet

Antler development in reindeer in relation to age and sex

Yearling male and adult female reindeer (Rangifer tarandus tarandus) are similar in size and shape. If sexual clues are hidden, it can be difficult to distinguish between them. Antlers can be a useful aid in classifying yearling males and adult females, depending on whether specific antler characteristics are identifiable for these two groups. We recorded antler characteristics in a domestic reindeer herd (Vågå) and found considerable overlap in antler height, width and circumference between the different age and sex groups. Total tines and number of tine split-offs are use¬ful for the field biologist when discriminating among adult females, yearling males and 2.5 year-old males. For example, when using the tine split-offs with the suggested classification, 79% of the observed adult females and 76% of the yearling males were classified correctly. The antler height, width and circumference provide other biological dif¬ferences between groups, but are not easy to use to identify free ranging reindeer. This is due to the great overlap in antler size between the groups and measuring difficulties in a field study situation. Male and female calves have very similar antlers, and only the antler width is possible for sex discrimination, giving 67% accuracy of discriminating between these two groups