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Hawaii: Native Birds and Plants

Ohelo fruit is a native Hawaiian cranberry, favored by many frugivorous birds.

What is the connection between plants and birds? Plants can provide birds with shelter, nesting material and nest sites; food in the form of nectar, fruits and seeds, leaves. They can even harbor invertebrates. Birds, in return, protect plants from those invertebrates, assist in pollination, and disperse seeds. Sometimes, bird and plant species evolve “together” to the mutual benefit of both species, exemplified in Hawaii by the hoawa Pittosporum glabrum and its large seeds that lie within a tough outer shell. The `alala is the only known existing, native species that can deal with this robust fruit.

Susan Culliney, a masters student in collaboration with Colorado State University, has been studying `alala at the Keauhou Bird Conservation Center (KBCC) to investigate their ecological relationships with a variety of native Hawaiian fruits, including hoawa. The study has focused on the `alala’s role in seed dispersal and germination, a role currently unfilled due to the `alala being extinct in the wild.

The MBCC greenhouse is bursting at the seams.

For many years now, the East Maui Irrigation Company has provided the Maui Bird Conservation Center (MBCC) staff with access to protected forest, where we carefully select small branches of ohia Metrosideros polymorpha and koa Acacia koa for perching. We collect native berries for dietary enrichment, giving potential release birds the opportunity to develop a “search image” for native fruits that will benefit them when they are released.

Recently, we have also begun to look for ways to develop our own native plant resources. The MBCC already sustains a few native plants from which we have gathered seeds. We have also been fortunate enough to obtain seeds from other sources, including the KBCC. We are delighted to have the assistance and advice of Anna Palomino, a local nursery owner who recently developed a native plant nursery within walking distance of the MBCC. Anna is propagating some of the more difficult native plants and has generously offered an “exchange” program: we bring her compromised plants, such as plants that have spent time in `alala aviaries, and we receive healthy ones to put into use around the facility. With this plant swap, we hope to provide a more consistent supply of healthy plants for aviaries while reducing our losses.

From these small seedlings, large koa trees will rapidly grow.

We have always made attempts at native plant propagation, with varying degrees of success; however, within the past year, our efforts really began to focus on designating a small amount of time every week on plant propagation, despite jam-packed days filled with bird husbandry, facility maintenance, and aviary upkeep. The facility greenhouse is now literally overflowing with native plant seedlings, to the point where we are hoping for a second greenhouse to house our propagation efforts!

Thanks to the green thumbs of Research Associate Michelle Smith, 10 species of native plants have sprouted, including pilo Coprosma spp., hoawa, and aalii Dodonaea viscose. Over 100 koa seedlings are 4 to 6 inches tall, and our most recent success is the germination of ohia seeds. Eventually, these plants will be valuable in multiple facets: we will distribute appropriate plants to our captive flock for enrichment and foraging.

Other plants will be planted on facility grounds; over the long-term, the plants will provide perching material and food for our captive birds and, we hope, create an oasis of native plant life that will entice wild native birds, such as `amakihi Hemignathus virens, to utilize facility grounds as habitat. Finally, seedlings may act as educational tools during tours, which visitors will be able to take home to promote the preservation of Hawaiian plants and habitats, helping to spread the kokua and aloha.

Joshua Kramer is a senior research associate at the Maui Bird Conservation Center, managed by the San Diego Zoo. Read his previous post, Nene Visitors.