(This takes 3½ minutes to read.)
Quoting Gar Smith’s ‘Stones to Drones: A Short History of War on Earth’:
In Norway, Hitler’s retreating troops methodically destroyed buildings, roads, crops, forests, water supplies, and wildlife. Fifty percent of Norway’s reindeer were killed.
This appears to be the author’s personal estimate; finding a book or other research that agrees with it has proven to be frustratingly difficult, which means that 50% could be an overestimate.
Nevertheless, there can be no doubt that the Axis destroyed a very substantial portion of Europe’s reindeer population. Quoting Foreign Commerce Weekly, vol. xxv, page 28:
The wanton killing of reindeer by the [Axis] during Norway’s occupation reduced herds by an estimated 25 percent. In an effort to provide food for their starving armies in Finland, the [Axis] scoured the mountains, often wiping out whole herds with blasts of machine-gun fire from fighter planes. Defying [Axis] orders, Lapp herdsmen fled with their herds to the most isolated mountain districts, there to await liberation.
News of Norway, vol. 7, page 156:
Nearly 15,000 reindeer will be imported from Sweden by the province of Nordland, in northern Norway. During the war, the [Axis] wantonly killed most of Nordland’s reindeer stock.
Norman Polmar’s & Thomas B. Allen’s World War II: the Encyclopedia of the War Years, 1941–1945, page 594:
The [Axis] declared a SCORCHED EARTH policy in northern Norway, evacuating the population, razing villages, killing cattle and reindeer.
Although the following quotes are not exactly about Norway, it is very safe to assume that most of the information remains applicable there as well. Quoting Lee Broderick’s, Iain Banks’s, & Oula Seitsonen’s ‘Military supply, everyday demand, and reindeer: Zooarchaeology of Nazi German Second World War military presence in Finnish Lapland, Northernmost Europe’ (mirror):
As an extreme example, the supply of remote outposts in Petsamo (Skolt Sámi: Peäccam) on the Arctic Ocean coast relied on men and draught animals, such as reindeer and imported mules, and later also on [Axis]-built cableways (Lundemo, 2020: 127, 137; Westerlund, 2008: 49, 115).
[…]
On the Arctic front, all warring sides relied also on reindeer transportation. For the [Third Reich] this was provided by the expert Sámi and Finnish reindeer handlers (Fig. 2; Lundemo, 2020: 101, 137). There is at least one receipt in the archives showing that the [Third Reich] occasionally bought the draught reindeer, sledges, and harnesses from the Finns (T-17944/50, 1942).
To begin with in 1941, when [Wehrmacht soldiers] arrived in Lapland, there were numerous incidents of shooting free-ranging reindeer for food. This was repeatedly forbidden in the standing orders of the [Axis] troops: “Reindeer is a domestic animal like cattle in Germany” (Junila, 2000: 140; also Lundemo, 2020: 61; RH2020-224, 1942).
[…]
The [Axis]-laid explosives injured and took lives of numerous locals and their reindeer in the post-war years, and unexploded ordnance is still yearly encountered.
[…]
The preservation condition of the assemblage tends towards moderate. Altogether 51% of the bones were identified to the species level, and further 31% to size and class (Table 2). The collected faunal assemblage is heavily dominated by the local semi-domesticated reindeer (70% of bones identified to species) herded in the area for centuries by both Sámi and Finns.
This is a highly interesting and significant finding, as the supplying of [Axis] troops and their prisoners with reindeer meat is absent from the historical documents, beyond the illegal shootings and selling of draught animals (Junila, 2000; Lundemo, 2020).
[…]
Both soldiers’ and prisoners’ bone assemblages are dominated by the indigenous reindeer herded by Sámi herders and Finnish settlers for centuries (e.g. Seitsonen and Viljanmaa, 2021; Turunen et al., 2018). Over 80% of identified bones from the prisoner contexts originate from reindeer, and over 60% in the soldiers’ deposits.
Reindeer remains were encountered at all sites except Inari Military Hospital. Some of the reindeer bones might relate to the illegal shootings as recorded in the historical documents (Junila, 2000; Lundemo, 2020).
[…]
Compared to the soldiers’ deposits, their diet appears to have been far less supplemented with imported meat. Then again, bones of indigenous reindeer dominate both the soldiers’ and prisoners’ faunal remains. This clearly illustrates the local replenishment of the food supply, likely related to unofficial bartering with the local herders. There is slight correlation between the proximity of the main supply arteries and the lower percentages of reindeer. At all sites situated over three kilometres away from the main routes, over half of the faunal remains consist of reindeer (sites 4, 6 and 8).
Quoting Eerika Anna-Maria Koskinen-Koivisto’s & Oula Seitsonen’s “‘Where the F… is Vuotso?’: heritage of Second World War forced movement and destruction in a Sámi reindeer herding community in Finnish Lapland”:
[Wehrmacht] troops, feeling and betrayed by their former brothers-in-arms, resorted to scorched earth tactics and destroyed virtually everything within their reach, from military installations to bridges, mile posts, culverts, private property, and livestock; the loss of reindeer, the foundation of herder livelihood and identity, troubled many Sámi families (Ursin 1980; Lehtola 1994, 144–146, 167; Tuominen 2015).
At the same time, [Axis soldiers] were also carrying out scorched earth tactics along the Norwegian northern coast in Finnmark, and forced the local population to exile (Olsen and Witmore 2014; Figenschau 2016). […] [T]he loss of reindeer shot by the [Axis] still seems to instigate sadness in the herders (M1–4).
(Emphasis added in all cases.)