It turns out there are 100 species in the Zosterops genus (minus three recently extinct). They range from Africa to India, Southeast Asia, China, Japan, Australia and many islands in the Indian and Pacific oceans.
These versatile little birds — only the size of a chickadee — usually arrive at new locations on their own. They showed up in New Zealand in 1832 and 1856, presumably blown east in a storm from Australia.
Humans helped white-eyes get to Hawaii. We introduced Japanese white-eyes to Oahu in 1929, but these resourceful little birds have now spread to all the other Hawaiian Islands.
Wherever they go, Zosterops tend to differentiate themselves quickly and become new species. Maybe the Japanese white-eye in Hawaii will morph into the “Hawaiian white-eye” in a few hundred years.
See more about the silvereye in this vintage blog: Eye Ring.
Have you ever wished for a tool that could accurately count a single bird’s voice among dozens of singers? You aren’t alone. Ornithologists are eager for a way to census birds using field recordings, but the sheer volume of data and complexity of bird song makes this a daunting task. A free tool that can identify huge volumes of song data doesn’t exist yet, but the Kitzes Lab at the University of Pittsburgh is creating one.
In December 2018 Assistant Professor Justin Kitzes of the Department of Biological Sciences won an AI for Earth Innovation Grant, awarded by Microsoft and National Geographic, to develop the first free open source model for identifying bird songs in acoustic field recordings. Its name is OpenSoundscape.
OpenSoundscape uses machine learning, a subset of artificial intelligence (AI), to scan recorded birdsong and algorithmic hunches to arrive at a song’s identity. To do this the Kitzes Lab starts with real life recordings.
Audio Moth in the field(photo courtesy Kitzes Lab)
The team brings the recorders back to the lab and downloads the sound files to the database. (Some day the software will be able to triangulate GPS from several Audio Moths and determine a single songbird’s location!)
AudioMoth recorder used by field study at Kitzes Lab (photo by Kate St. John)
Here’s one recording of at least six individual birds. OpenSoundscape is learning how to identify them.
An Audio Moth recording from the field (courtesy Kitzes Lab)
It makes a spectrogram of the sound file (below), then picks out each pattern and uses algorithms and the classifier library to identify the individual songs.
The more songs it successfully identifies, the better its algorithms become.
By the end of 2019 the OpenSoundscape models, software, and classifier library of birdsong will be ready for researchers on a laptop, cloud service or supercomputer. Ornithologists will be able to gather tons of data in the field and find out who was singing.
p.s. WESA featured this project in their Tech Report on 26 Feb 2019. Click here to listen.
(credits: photo of ovenbird by Aaron Budgor on Flickr, Creative Commons license. Photo of Audio Moth on a desk by Kate St. John. All other photos and sound file, courtesy the Kitzes Lab)
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 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?
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.
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.
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)
The brahminy starling (Sturnia pagodarum) from the Indian subcontinent was named for his black crest because it resembles the sikha hairstyle worn by Brahmins. He looks like a Brahmin when his feathers are at rest (above).
In the winter of 2012 Pittsburghers noticed we had very few blue jays in our area. It was such a mystery that I posted an article in February asking folks to tell me if they’d seen any blue jays lately. Seven years later the responses are still coming in.
Most people respond when they don’t see any blue jays because they miss them. It turns out that blue jay frequency varies throughout the year and can drop locally when the habitat changes, especially if oaks are cut down. (Blue jays rely on acorns.)
Our blue jay count surges during spring and fall migration because a lot of them breed north of us. In Allegheny County (Pittsburgh) there’s also a mysterious mini-surge every year in mid February. What’s that about?
Northern mockingbird blocks a northern cardinal (photo by Marge Van Tassel)
This week I wrote about northern mockingbirds having knock-down drag-out fights during the breeding season. Did you know that mockingbirds are also territorial in the winter? Even though they’ve migrated far from their breeding territory they vigorously defend their wintering zone.
Last winter Marge Van Tassel had a pushy mockingbird in her Armstrong County yard. She sent this photo saying, “The male of the pair in our yard chased all birds away from the food bowl last year when he was in it. He even chased this female cardinal back to a bush.”
Squirrels eventually figure out a puzzling bird feeder, but have you ever noticed that birds do too? Lone songbirds usually can’t do it, but scientists have proven that a flock can. The bigger the flock the better.
I learned this years ago when I set up a “goldfinch-only” thistle feeder whose holes forced birds to perch upside down to eat the seeds. This is easy for American goldfinches but not for the birds I meant to foil — house sparrows. Lone house sparrows gave up on this feeder but the flock tried a lot of methods. A few of them would land right-side up and slowly fall forward until they were upside down. One of them put out his wing to grab the feeder. The rest of the flock followed.
On Throw Back Thursday, learn how songbird flocks can solve puzzles faster than individuals in this vintage article: Two Heads Are Better Than One.
The more birds at our feeders the merrier we are … and so are they.
(photo from Wikimedia Commons; click on the caption to see the original)
Northern Mockingbirds fighting #1 (photo by Beth Signorini)
Northern Mockingbirds fighting #2 (photo by Beth Signorini)
Northern Mockingbirds fighting #3 (photo by Beth Signorini)
Northern Mockingbirds fighting #4 (photo by Beth Signorini)
Northern Mockingbirds fighting #5 (photo by Beth Signorini)
Northern Mockingbirds fighting #6 (photo by Beth Signorini)
In case you think that songbirds are meek and innocent creatures consider the northern mockingbird (Mimus polyglottus). He always has “attitude” and he’s willing to engage in a knock down drag out fight.
Beth Signorini captured these two during the breeding season.
