Day 1: Arrive in Hilo on the Big Island of Hawaii - there are several choices of accommodation but we really enjoyed Kulaniapia Falls Bed & Breakfast. The old part of the town is very sweet and worth a wander around. You can start birding as you leave the airport but a definite stop should be Klonakapalu Pond only a couple of miles from the airport itself, en route to the B&B.
Day 2: After birding the grounds of the B&B before breakfast, head over to Volcano Park, stopping first at Volcano House (opposite the visitors center). then onto the Lava Plug which has some great birds, finishing your morning down at the water at the end of Chain of Craters Road.
You can get lunch in the town of Volcano and then spend the afternoon back in the park but on the other side of the highway up Mauna Loa Road. Couple of great spots here are the Bird Walk, also known as Kipukapuaulu and then driving on up the road to an area just passed the 2nd cattle grid.
The very end of the road is quite a long way up and doesn't offer much more - other than a good view! Back to the Inn for a second night.
Day 3:– Working up the east side of the island stop at Kalopa Recreational Area which is an interesting spot and offers a reasonable opportunity to bird. Keep heading north and then west along the top of the island to Waimea.. Not a great deal to see along the way but lunch at the Hawaiian Cafe is interesting, You can then keep going towards Ha wi, birding en route. After passing through Ha wi (which is a lovely little place) go to the the Mo'okini Luakini Heiau, which is quite difficult to find but offers a great piece of Hawaiian history. Depending on the time of year, this drive can provide great views of whales.
Driving back through Waimea and on down to Paniola keep an eye out for birds crossing the roads. We stayed at the Paniola Greens Resort, Waikoloa which was great.
Day 4: Take an organized trip with Hawaii Forest & Trail up to the Hake lau Forest off Saddle Road. This is the best way to get the Big Island endemics, and while expensive, is probably a good idea. Stay again tonight at the Paniola Greens resort.