Semen Collection and Cryopreservation in Hawaiian Forest Birds

The Hawaii Endangered Bird Conservation Program, established in 1993, employs hands-on technology to increase reproductive output in rare bird populations during this period of environmental crisis. This unique program has managed nearly 2,000 eggs of 22 species in the last 13 years, a record unsurpassed by any other passerine conservation program.

Among the species of special concern to the program is the ‘alala Corvus hawaiiensis, which is probably extinct in the wild. While captive breeding efforts have been a resounding success (from just 15 individuals in 1996 to 52 in 2006), some birds have not yet contributed to this limited gene pool. Two non-breeding males have been habituated for semen collection in a project designed to infuse their genes into the population through artificial insemination. As needed, additional males of other Hawaiian species will be similarly habituated for semen collection.

Viable sperm for insemination has been obtained after cryopreservation for a number of avian species, and protocols for each Hawaiian bird species will be developed. Comparison of semen extenders as well as cryoprotectant formulation, concentration, equilibration, and removal techniques will be empirically derived for each species, utilizing domestic or non-endangered models if necessary. The effects of cooling, freezing, and thawing rates will be assessed by repeating pre-freeze evaluations of motility, speed of progression, morphology, and acrosome and plasma membrane integrity. Ultimately, sperm cryosurvival will be evaluated by artificial insemination.