May 13 was an exciting day: our first `alala of the 2012 season hatched at the Keauhou Bird Conservation Center! Just like all our previous `alala breeding seasons, this first chick was eagerly awaited and anxiously nurtured through its first few days (see video below). Over the past three weeks, another seven `alala chicks have hatched. Crucially, on May 31, we celebrated reaching the major milestone of 100 ‘alala in the entire world population! This is quite an achievement for a population that was down to a low of 20 individuals in 1994 and is currently considered extinct in the wild. In fact, following subsequent hatches, the population currently stands at 102 birds. We are hoping for several more chicks in the weeks to come.
This year, we have continued to apply the strategy of “assisted hatching” for several of our eggs. For example, our first two chicks are siblings from the same clutch of eggs, and both required assistance to hatch successfully. Their mother, #152 Po Mahina, is only 3 years old, and this was her very first clutch. Already it seems that Po Mahina has a tendency to lay long, narrow eggs, almost torpedo-shaped. This had implications for these two chicks; in the very final stages of the incubation period, each should have been ready to chisel the cap off its eggshell with the egg tooth on the beak. However, in both cases, the chick’s head and neck was wedged so tightly into the narrow egg that they were unable to rotate inside to cut through the shell. Consequently, these chicks were in serious danger of dying from exhaustion or asphyxiation before even having the chance to hatch. In both cases, we performed the avian equivalent of a Caesarian section. With great deliberation, we carefully peeled back the eggshell piece by piece, pausing to investigate for landmarks in the hatching process (such as the retraction of blood vessels and yolk sac) before finally releasing the head and gently extracting the chick from the remnants of its shell.
Obviously, assisting the hatch of a chick from its shell is considered a last resort, a result of the breakdown in the chick’s normal, natural hatching processes. It is quite probable that the high incidence of assisted hatching cases is a consequence of inbreeding depression, caused by the shallow gene pool of the `alala flock. It is tremendously satisfying to watch other hatchlings burst out of their shell under their own steam!
Those first two chicks are now nearly a month old and barely recognizable from the pink, naked, and helpless neonates that were extracted from their shells. With a covering of pin feathers and equipped with a raucous voice to rowdily beg for food, they are making great progress. Eventually, these two will become members of our captive-breeding flock. However, with the `alala population now exceeding 100 birds, our Hawaii Endangered Bird Conservation Program continues to be in a strong position to make plans with our partners for releasing and reestablishing `alala back in the wild.
Richard Switzer is an associate director of applied animal ecology at the San Diego Zoo Institute for Conservation Research. Read his previous post, Maui Bird Conservation Center Open House.