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Myadestes palmeri

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Puaiohi: Released and Breeding

A released puaiohi

Winter in Hawaii is usually thought of as a “snowbirds” paradise; people flock to the islands to get away from the nasty storms associated with mainland winters. This year, here on the islands, we got to experience our own sort of winter storm. Throughout the months of February and March we were pelted with winds and rain, leaving everyone quite soggy and begging for sun. With some of the rainiest months in recent history came some new inhabitants for the island of Kauai. The crews at the Keauhou and Maui Bird Conservation Centers transferred 22 puaiohi Myadestes palmeri to the Alaka’i Wilderness Preserve for release, with special thanks to Hawaiian Airlines for giving the endangered birds their VIP seats on the plane.

This year marked the 14th release of puaiohi to the Alaka’i Wilderness Preserve. On February 13, the first 12 birds made their journey from the Keauhou Bird Conservation Center on the Big Island to Kauai and were released one week later. We apply a “soft release” principle, where the birds are housed in a hack tower for one week to get accustomed to their surroundings before having to fend for themselves; after release, we offer them supplemental food near the release site. Before these birds are released, we fit them with a small radio transmitter, attached by means of a backpack. Using radio telemetry, we can track the individuals and find out how they are doing. Our partner, the Kauai Forest Bird Recovery Project, does most of these tracking efforts, helping us evaluate the movements and survival of the release birds.

This wild bird is paired with one of the HEBCP's released birds, making their nest at an artificial nest site, evidence of successful conservation measures in action. Photo credit: Mitch Walters

The first group was lucky to have nice weather for the first few days after release, enabling the birds to explore their new home in suitable weather. This being said, quite a few dispersed farther than anticipated. The second group of 10 birds traveled from the Maui Bird Conservation Center (MBCC) on February 28, delayed by a day due to storms. From then on, this group struggled just to stay dry. The puaiohi were released on March 8, again a few days late, but seemed to do quite well, considering the unusual weather. Several of them were spotted feeding at the supplemental feeding stations, which was a relief to the crews.

Since this year spring’s release, one particular female has been of interest: puaiohi #345, a young bird who hatched at the MBCC in 2011. In the past month, this particular female has been observed paired with a wild male and, crucially, incubating eggs in a nest of her own; further proof that our released puaiohi adjust to life in the wild and are contributing to the survival of the wild population. We are hoping that this nest produces chicks and helps to ensure the population keeps growing.

Over the last 13 years, 222 puaiohi that were hatched and raised through the Hawaii Endangered Bird Conservation Program have been released back to the wild. Over the same time frame, the wild puaiohi population is estimated to have doubled to more than 500 birds; it is thought that numbers are currently remaining stable. While we love to report success stories such as this, our conservation partnership has decided to temporarily halt our puaiohi release effort. This partnership is now moving on to the next phase of species recovery, re-focusing efforts from captive propagation to protecting the species in its natural setting. This includes predator control, providing artificial nest boxes that are predator proof, and habitat restoration.

With efforts to protect the wild nests and habitat of puaiohi, as well as other critically endangered species on the island of Kauai, we hope to see many more nests in the future, just like that of #345’s.

Rachel Kingsley is a research associate at the San Diego Zoo Keauhou Bird Conservation Center in Hawaii.

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200 Puaiohi Released!

A young puaiohi is released into the Alakai Wilderness Area.

The San Diego Zoo’s Hawaii Endangered Bird Conservation Program achieved a monumental milestone on October 12 when we released 12 captive-bred puaiohi Myadestes palmeri, or Kauai thrush, into the Alakai Wilderness Area on the island of Kauai. This brings the total number of captive-bred puaiohi released to precisely 200. This was our 13th release in 12 years.

The puaiohi is found only on the Hawaiian island of Kauai and is now restricted to habitat within the Alakai Wilderness Area. Survey teams currently estimate the surviving population of wild puaiohi to be around 500 individuals, but accurate estimates are difficult due to rough terrain and the naturally secretive behavior of the species. Notably, this number is twice the population that was estimated in the late 1990s.

Following each captive-breeding season (see 1st Hatch of Hawaiian Bird Breeding Season), we decide which puaiohi to release and which to keep, based on genetics and demography of the captive population, with release candidates having the most represented genes in the captive population. After they are selected, each bird receives a physical examination and blood screening to ensure proper health and fitness for survival in the wild.

This year we decided on 12 juveniles for release; it is thought that younger birds are less likely to be chased off by resident adults (or each other), as their juvenile plumage displays them as non-threatening in established territories. Additionally, young birds have young minds, which are thought to be more flexible in adapting to their new habitat and wild food sources.

Early in the morning of October 5, we caught up the 12 release candidates and put them into their travel carriers. Departing from Kahului airport, Hawaiian Airlines treated the birds to near-celebrity status, not only by donating flights to Kauai, but also smoothing the processes of checking in, security screening, and boarding. Transferring birds between islands can be extremely stressful for both the birds and us, but Hawaiian Airlines personnel created a minimal-stress experience, for which we are tremendously grateful (the birds as well!).

Upon arrival on Kauai, the puaiohi were transported to the release site, where they settled into their acclimatization aviaries. Over the next week the birds experienced the new sights and sounds of the surrounding Kauai forest, sampled some of the local food provided daily by our fieldworkers (native berries such as lapalapa and pilo), and grew accustomed to the Alakai weather.

A released puaiohi surveys its new home.

Then, on October 12, after 7 days of becoming habituated to the Alakai, the 12 eager puaiohi emerged from their pre-release aviaries. They excitedly “attacked” the surrounding plant and invertebrate populations, foraging on juicy berries and scavenging through tree bark and moss clumps for tasty insects. Most of the birds left the area to explore other parts of the Alakai, although two birds remained faithful to the area around the release aviaries, benefiting from the supplemental food we provided. Of the two birds who stuck around, one stayed for 7 days post-release, while the other continued to frequent the release area when our field team exited the Alakai, 14 days after the aviaries had been opened for the release.

Normally, we would have a better idea of survival for the complete group of birds, but this year radio-transmitters were not put on the birds. Transmitters offer the opportunity to track the reclusive birds throughout the Alakai Wilderness Area, providing survival and dispersal information to monitoring teams. But data taken over the past 11 years indicates the success of releases: of the released birds whose status is known at the end of the 28-day post-release monitoring period, 66 percent are confirmed to be alive. Additionally, birds released in the past have been observed successfully breeding and adding to the wild population. So even though we don’t know for sure the fates of our youngsters released in October, we have high hopes they will settle in the Alakai, helping to create and maintain the future wild population of puaiohi.

A big mahalo for the help and support provided by Hawaiian Airlines, the Kauai Forest Bird Recovery Program, and the Koke’e Resource Conservation Program, without whom the releases this year would not have been possible.

Joshua Kramer is a research associate with the San Diego Zoo’s Hawaii Endangered Bird Conservation Program. Read his previous post, Nene Goslings Released on Maui.

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Puaiohi: 300th Chick

On Tuesday, May 26, 2009, the Hawaii Endangered Bird Conservation Program reached a new landmark in its species recovery program for the puaiohi Myadestes palmeri: this fluffy-downed chick (pictured) represents the 300th chick to hatch since managed-care propagation efforts began in 1996.

The puaiohi is one of the four target passerine (perching birds) species for our program’s bird breeding activities. In fact, the puaiohi is undoubtedly our most productive species; it was only April 2006 that marked the hatching of the 200th chick (see post, The 200th Puaiohi).

Even more crucially, the puaiohi is the subject of an ongoing release effort in its last stronghold, the Alakai Swamp, a wet upland plateau on the island of Kauai. Working with our partners, the Kauai Forest Bird Recovery Project, we have released 176 puaiohi since 1998 (see post, Spreading the Puaiohi across the Alakai).

So far, chick #300 is growing rapidly and developing well, fueled by its diet of bee larvae, papaya, scrambled egg, cricket, and mealworm guts. Initially, hand-rearing feeds are painstakingly provided on the hour, 15 times per day; the frequency is reduced as the chick grows and becomes more robust. We hope this youngster will continue to make good progress and will either be retained in the breeding program at the Maui and Keauhou Bird Conservation Centers or will be released to boost the critically endangered population in the wild.

Richard Switzer is the conservation program manager for the San Diego Zoo’s Institute for Conservation Research, Hawaii Endangered Bird Conservation Program.