* Jobless claims, factory orders, durable goods data due
* Staples, Costco shares down after results
* Futures up: Dow 31 pts, S&P 3.5 pts, Nasdaq 4.5 pts
NEW YORK, March 6 (Reuters) - U.S. stock index futures ticked higher on Thursday ahead of labor and factory data, while developments in the Ukrainian crisis kept traders on edge.
* Crimea's parliament voted to join Russia on Thursday and its Moscow-backed government set a referendum for March 16 on the decision, in a dramatic escalation of the crisis between Russia and the West over the Ukrainian Black Sea peninsula.
* Moscow stocks fell 2.5 percent and the ruble weakened 0.8 percent versus the U.S. dollar after the Crimean vote. A U.S.-traded Russian ETF fell 2.1 percent in light premarket trading.
* The U.S. economic calendar includes weekly applications for unemployment insurance at 8:30 a.m. EST (1330 GMT), with sales and orders for long-lasting items due at 10:00 a.m. EST.
* S&P 500 e-mini futures rose 3.5 points and were above fair value, a formula that evaluates pricing by taking into account interest rates, dividends and time to expiration on the contract. Dow Jones industrial average futures rose 31 points and Nasdaq 100 futures added 4.5 points.
* On Wednesday, major U.S. equity indexes were little changed, with the S&P 500 down just 0.1 point from its record close Tuesday.
* Costco shares fell 3 percent in light premarket trading after the warehouse club operator's quarterly profit fell 15 percent, missing analysts' estimates.
* Shares of Staples dropped 9 percent in premarket trading after the largest U.S. office supplies retailer forecast a fall in sales and said it would close up to 225 stores in North America by 2015.