CLIMATE: The Hawaiian Islands, thanks to their location in the middle of the Pacific Ocean above the Equator, have a balmy climate around the year. However for the large, mountainous islands, this climate is impacted by the high land mass of those mountains. This means that the predominant trade winds from the north east bring moisture to the east side of those islands, but the mountains block that moisture from reaching the west side.
DRY SCRUBLAND vs RAIN FOREST: See the map below that illustrates this phenomenon, which has a tremendous impact on the type of vegetation growing on those islands. On the west side, the more red the color the less rain is falling. As a result, mostly scrubland is found on that side. On the east side, copious amounts of rain create rain forests, marshes, water falls, etc.
BIRD HABITATS: These differences have an obvious influence on the bird habitats. Species that thrive on dry scrubland would not survive in the rain forest, and vice versa. This is well illustrated on the Oahu satellite map below, with the Ko’olau Mountain range greener, and the west side more brown.
Many initiatives have been undertaken over the years, and are still ongoing, for preserving bird habitat. Here are a few examples:
NATIONAL WILDLIFE REFUGES (for the large islands):
Hakalau Forest NWR (Mauna Kea east slope, Big Island)
Hanalei NWR (part of the Kauai National Refuge Complex)
Hulē’ia NWR (Kauai)
James Campbell NWR (Oahu, north east point)
Kakahaia NWR (Molokai)
Kealia Pond NWR (Maui, near Kihei)
Kilauea Point NWR (Kauai, north east point)
Oahu Forest NWR (Oahu, northern Ko’olau Mountains)
Pearl Harbor NWR (Oahu)
ISLETS STATE BIRD SANCTUARIES – The eastern shore of Oahu has many islets that are now state bird sanctuaries, and as such are protected. These small rocky islands are nesting grounds for many species of seabirds, such as boobies, tropicbirds, shearwaters, etc.
The Kawainui-Hamakua Marsh Complex: at over 800 acres on the Oahu east shore, this wetland is the largest in Hawaii. It is an ideal habitat for water birds such as the endangered Hawaiian Stilt (Ae’o), Hawaiian Coot (Alae Ke’oke’o) and Hawaiian Gallinule (Alae’ula).