Sometime early next year HCN will provide a breakdown of the dividend. It will be broken down into
- ordinary income - short-term cap gains - mid-term cap gains - long-term cap gains - unrecaptured section 1250 gains - return of capital (ROC)
This will be broken out for each dividend payment. Some or most of the categories may be 0.
No taxes are paid on ROC but you must track this and adjust (reduce) your cost basis when you sell. If the stock is held long enough ROC converts ordinary income/short-term CG to long-term cap gains.
Your broker should receive this information and pass it on to you sometime early next year. At any rate it should be provided at HCN's web site. Watch the Yahoo! news links in early 2012 as the announcement of the dividend tax treatment also shows up there.