The akiapola’au (Hemignathus wilsoni), or aki’, is a Hawaiian honeycreeper with such a small population and such a restricted range that he may well go extinct in this century. He’s hard to find, of course, but he’s well worth the effort.

The aki’s beak is most unusual but it’s perfect for gathering what he eats. He probes for spiders, beetles and caterpillars and, like a sapsucker, he drills rows of holes in an “aki’ tree” and returns when the sap wells up.

Despite his similar food requirements the aki’ doesn’t have a woodpecker beak. Instead his lower mandible is short and straight with a chisel tip while his upper mandible is long and thin, curved down, and flexible.

Each half of his beak has a different purpose. He chisels and pecks with the lower mandible or props it in place while he probes and scrapes with his upper mandible. As you can see in the top photo, there’s even a small gap between the two mandibles. How strange!

The males and females forage in different micro habitats. The females look similar, though paler.

The aki’ is listed as Endangered for good reason. His population is small and declining. As of 1995 there were only 800 individuals left on Earth, scattered in severely fragmented areas in the mountains above 5,000 feet.

Many things contribute to the aki’s decline including habitat loss from logging and farming and predation by introduced species, especially rats, cats and dogs. The aki’ is also threatened by avian diseases carried by mosquitoes; Hawaiian birds have no immunity to them. The mosquitoes, accidentally introduced to Hawaii beginning in 1826, cannot live in the cold climate above 5,000 feet. That’s why Hawaiian honeycreepers like the aki’ still survive there.

Unfortunately climate change is warming the Hawaiian mountains and the mosquitoes are moving up. How long will we still be able to find this beautiful bird with such an unusual beak?

(photos on by Aaron Budgor, Bettina Arrigoni and Eric Gropp via Flickr Creative Commons license. click on the captions to see the originals)

Tour Day 7: Mauna Kea, Saddle Road, the Big Island, Hawaii

p.s. I saw an aki’ yesterday. Yay!

Today our VENT birding tour has special permission to enter the Hakalau Forest National Wildlife Refuge on the eastern slope of Mauna Kea where there are more native birds than anywhere else on the islands. We’re going to see a lot of birds and a lot of them are endangered.

The refuge, founded in 1985 to protect Hawaiian rainforest birds and their habitat, is closed to the general public because the ohi’a trees (pictured above) are dying of a fungus that’s spread too easily by humans. Rapid Oh’ia Death kills the trees within a few days or weeks. Hundreds of thousands of trees have died since 2013. This is especially scary because the ohi’a is the most common native tree and so many birds rely on it. Many of them have unusual beaks.

The I’iwi (Drepanis coccinea), at top and below, is nearly the same color as ohi’a flowers. Vermilion red with a decurved bill that’s perfect for probing flowers and sipping nectar, he perches like a songbird or hovers like a hummingbird. He was so common when Polynesians first arrived in Hawai’i that they made his feathers into royal cloaks.

The ‘apapane (Himatione sanguinea), below, also feeds on ohi’a flowers and is red and black like the i’iwi. However his color is scarlet, his undertail coverts are white, and his dark bill has a gentle curve.

The Hawai’i akepa (Loxops coccineus) is a tiny orange-red bird with brownish primaries. This endangered crossbill feeds on spiders, insects and nectar in the ohi’a forest. Yes, his bill is curved and crossed!

And finally, the Hawai’i amakihi (Chlorodrepanis virens) is certainly not red but he has a curved beak that’s useful for gleaning, probing, and sipping while he eats spiders, insects, sap, nectar and fruit. He’s a versatile bird whose population is doing quite well with 800,000 to 900,000 on the islands.

What do these birds have in common other than their curved beaks? They are all Hawaiian honeycreepers.

(all photos are Creative Commons licensed. i’iwi at top by Gregory (Slobirdr) Smith on Flickr, i’iwi at yellow flowers by Robin Agarwal on Flickr, ‘apapane, akepa and Hawaiian amakihi by Bettina Arrigoni on Flicker)

Tour Day 6: Hakalau Forest National Wildlife Refuge on the island of Hawai’i

As I mentioned yesterday, our Hawaiian tour checklist has 108 birds on it of which 46 are introduced. Yes, 42% of the birds we expect to see would not be in Hawaii if people hadn’t brought them there.

The red-crested cardinal (Paroaria coronata), above, is one of them. A member of the tanager family native to northern Argentina, Bolivia, southern Brazil, Paraguay and Uruguay in South America, he was introduced to Hawaii in 1928. Being a land-based bird, he was stuck on the islands as soon as he got off the boat but he’s made himself at home in disturbed habitats and urban parks. Fortunately he’s not considered invasive so I’ll be happy to see him in Hawaii.

On the other hand, two bulbul species introduced to Hawaii in the 1960’s are not a happy sighting. Both have become invasive.

The red-vented bulbul (Pycnonotus cafer) is a prolific resident breeder of the Indian subcontinent who’s been introduced in tropical areas around the world. On the Pacific islands he’s become invasive and is now one of the world’s 100 worst invasive species — a dubious distinction.

Red-vented bulbuls are easily found in urban Honolulu.

The red-whiskered bulbul (Pycnonotus jocosus) is a fruit-eating bird of tropical Asia who’s not in the top 100 pests worldwide, but he’s invasive in Hawaii.

The two bulbul species made a difference in a very short time. According to Wikipedia, they changed the color of monarch butterflies in Hawaii over a period of just 20 years. The bulbuls prefer to eat orange-colored monarchs so orange ones are scarce now and white morphs are common.

(photos from Wikimedia Commons; click on the captions to see the originals)

Tour Day 1: Honolulu