Russian tank losses in Ukraine have passed 1,000, according to the Oryx intelligence blog that tracks equipment losses in the fighting, highlighting the attrition suffered by Russian forces in more than six months of war.Over half of Russias tank losses recorded by Oryx, which verifies destroyed, captured or abandoned tanks using open source information, occurred in the first 50 days of the war as Russian forces attempted to seize the Ukrainian capital.Losses have fluctuated throughout the conflict, said Jakub Janovsky, a contributor to Oryxs tally, which is based on open source information.In the first month Russia lost an insane number of tanks and other vehicles because the Russians were spread so thin over a huge area of Ukraine, he said.In particular, Ukrainian forces used portable Western-supplied anti-tank weapons to destroy advancing Russian columns, including many tanks, in the areas north of Kyiv.Of the 1,012 Russian tank losses documented by Oryx in an update Saturday, 34 percent were abandoned by their crew, a high percentage that military analyst Rob Lee attributed to poor planning and logistical failures in an article Tuesday.A lot of tank losses are happening because tanks are damaged or have some mechanical malfunction and are later destroyed because they can't be recovered, Janovsky said.As the conflict in Ukraine became a war of attrition in the countrys east and south, Moscow has begun taking old tanks out of storage.The U.K.-based International Institute for Strategic Studies estimated before the start of the invasion that Russia had 2,800 tanks in active service and another 10,000 in storage.Older Russian tanks are an increasingly common sight on the battlefield.At the beginning of the conflict, the most modern Russian tanks, like the 2016 version of the T-72B3 and the T-80BVM, were dominating our list, Janovsky said.But as Russia replaced these losses with older tanks, like T-72Bs, these have now become one of the most common tanks on the list.Just under a third of all Russian tanks lost in Ukraine were Soviet-built, according to Oryx.While Oryx analyzes video footage and photographs to ensure they are documenting legitimate losses, the group admits their estimates are likely to be conservative.We have some partial data from earlier in the war that showed that Russian actual losses were about 30% higher than what we have on our list, Janovsky said.Open source analysts might also be missing abandoned or destroyed tanks as the war becomes more static and frontline fighting is less well documented.The Ukrainian military said Tuesday that they had destroyed 2,077 Russian tanks since the start of the invasion in February.Russia does not provide information on its military losses.Either way, it is clear that the way tanks are used in Ukraine is changing.Both sides seem to be a bit more careful with their use of tanks than they were in the early days of the war, Janovsky said.