Hawaii Volcanoes National Park is a gem, a place that provides many delights to many people. An active volcanic vent where the molten lava spews into the Pacific, currently inactive calderas where you can hike through fields of hardened lava, and watch the steam from vents that show the heat that lies not too far underground, isloated stands of native trees (kipuka) that stand surrounded by the old volcanic flows that did not destroy them. All that and birds too, tropicbirds nesting in the calderas, Apapanes, I'iwis, Amakihis, in the trees in the park headquarters parking lot. Within the park there are a number of distinct, birdy places. Kipuka Puaulu, the "Bird Park", is a fine example of this peculiar island habitat. Located close to but still separated from the area around the park headquarters, this is a pleasant place to walk around. There is a clear loop trail, and a number of native birds that you might see: Oma'o, Elepiao (in the canopy), Apapane, and an occasional Amakihi. Mostly though, you will see many exotics, Japanese White-eyes, Kalij Pheasants, Cardinals, House Finches, and at times Hwamei. In short this is a reasonable place to visit. The total circuit can be walking in half an hour or so, and there is a good picnic area on the right hand side of the road perhaps half a mile from the kipuka. In short, a good place to take a picnic lunch and have a brief walk thereafter. The site can be found by following Rte 11 west from the park headquarters to Mauna Loa Road, and following the signs.
Saddle Road The Saddle Road (Rte 200), which runs west from Hilo, is the shortest route from the wet side of the Big Island to the dry Kona coast. Running gradually up the gentle slope of the massive Mauna Kea, it passes through grasslands, bleak lava fields, and scattered areas of forest. some fine birding country. Rte 200 once had an (undeserved) bad reputation. True, it has some stretches of sharp curves, and in the past there were sections that were not well maintained. Car rental companies would not allow renters to use it. That now seems to be a problem of the past. Common sense driving practices should avoid problems.
(Check with the rental company before signing for a car, to be sure that the road is allowable). With a few (admittedly important) exceptions, a standard two-wheel vehicle will get you where you need to go.
Pu'u La'au is the best reason for renting a 4-wheel vehicle, at least for one day, during a visit to the Big Island. Pu'u La'au is the place to see the Palila, an endangered finchlike honeycreeper that lives only on the slopes of Mauna Kea, and there only where there are stands of mamane trees (the Palila's basic food source). At the 43.3 mile mark (from Hilo) an unpaved road leads off to the right (uphill). Rental agencies do not want their (regular) vehicles on such roads, and with good reason. The soil on this road is fine red dust. When wet it is extremely slippery. When dry it can be like russet-colored talcum powder. The road is periodically graded and gravelled. At its best it probably is quite safe for a regular car; at less than its best there might be problems. Check with your rental agency, and if you cannot find one willing to let you chance the drive, rent a 4-wheel vehicle and have an opportunity to see a rare endemic. The hill (pu'u) called Pu'u La'au is 4.1 miles from the Saddle Road. There is a cabin at this point, and a grove of eucalyptus trees. Park here and walk along the road through the eucalyptus grove. About a mile from the cabin there is an area with mamane trees. Follow such trails as you can find and scan the mamane for Palila in search of green seed pods. Other endemics here include the (rare) Akiapola'au, plus I'iwi, Hawaii Amakihi, Elepaio and Apapane.