Birds Behaving Badly
The Bizarre Green Pigeons of Oiso
(All Photos by Rick Martin. Video by Havard Ferstad. This articles originally appeared on Ignition.co, now offline.)
I left by train just after 5am on a Saturday morning. The Friday night booze fumes lingered, with most commuters at that hour sleepily making their way home. I was going to Oiso, located just south-west of Tokyo proper in Kanagawa. If you are in the mood for a scenic day trip out of the capital city, Oiso is a fun place to check out. Its long beach is a relatively well-known summer getaway. But I'm not much of a swimmer, and I wasn't going there for a suntan.
With no interest in the sand or the surf, I was instead on my way to a rather ugly mass of rock and concrete called Terugasaki point. During the late summer, this area becomes the unlikely playground for an unusual species of bird called the Japanese green pigeon , or aobato in Japanese. And while pigeons are usually quite commonplace and boring (unless you are Bert on Sesame Street), this brightly colored variety is anything but. Their appearance and behaviour during August and September over this beach is an incredible spectacle.
Oiso station (pictured above) lies near the south-western/Atami end of the Tokaido Line, making it a relatively convenient ride for anyone coming from Tokyo or Yokohama stations. For optimal pigeon watching time, I recommend getting there at around 6 or 7am. When you get there, the station exit faces the ocean and you will need meander your way due south until you get there. If your shoes get wet, you have gone too far.
As you approach the sandy beach, you will find that Terugasaki point stands out like a big pile of misplaced rocks in the water. Make your way there on any late summer morning, and you will likely find a few dozen enthusiastic ojisan (meaning middle aged men in Japanese) photographers too, most of them dwarfed by the telezoom lenses and tripods they carried there. And much like the birds they are watching, this flock keeps together in a tight row formation on the beach, perhaps an unspoken rule to stay out of each others shot and give the rather nervous pigeons enough room to be comfortable. I had brought a modest telezoom, a 80–400mm Nikkor, so I set up somewhat sheepishly on the edge of the group and waited for the first flock of pigeons to fly in from the mountains behind us.
A videographer friend who accompanied me set up his slow motion camera on the walkway above the adjacent concrete breakwater. While he got some great footage on that day, the rough seas that he witnessed the following week resulted in a far more dangerous visit for the pigeons, as you can see:
Oiso is a breeding ground for aobato where they usually hide out in the forested mountains just up from the beach. So it’s puzzling to witness a flock descend from the safety of the green mountains to loiter on the rocky shores as the waves crash in, very often right on top of them.
So why do they do it? Incredibly, they’re thirsty for sea-water.
Here is a quote from Bird Research News a few years back that attempts to explain the strange phenomenon:
It is convincing to assume that Japanese Green Pigeons drink salty water to maintain the osmotic pressure of the body fluid through keeping a balance between sodium and potassium in the body. It is explained that Japanese Green Pigeons ingest sodium by drinking seawater because their diet consists primarily of fruits containing a large quantity of potassium. However, this theory has not been physiologically demonstrated yet. Every year at Terugasaki Point, some of the pigeons fall victim to high waves, which suggests that seawater drinking is a physiologically indispensable behavior for the pigeons at the risk of their life. 
Whatever the reason these birds come to the seaside, the town of Oiso is certainly happy to have them. Aobato have become a rather cute local mascot that you can see posterized all over the quiet coastal town, and on its website too.
As I moved around Terugasaki Point, I noticed there was an occasional buzz of excitement and pointing to the sky. At first, I didn't think it was anything special. But it turned out that another unexpected admirer had come to find the green pigeons, but it was looking for a little more than a pretty show. A falcon was combing the area, hungry to snatch a straggling bird from the flock for a quick meal, and eventually he managed to separate one bird from the group and close in for the kill:
I will spare you the details of how this epic air chase ended, but suffice it that the next five minutes were no fun for the pigeon. The folks at Bird-research.jp tell me that they've seen many online reports of such falcon attacks on pigeons in Oiso, including this one captured on video. You may click though to that video at your own discretion.
At around mid-morning, at 10am or so, many of the photographers began to pack up their stuff and go home. I stuck around for another hour, but it was clear that flocks were flying by less frequently. I suspect this wasn't because of the falcon attack, but maybe more attributable to the increasing morning heat.
For anyone planning an outing to Oiso to see these pigeons first hand, I highly recommend coming in the early morning too. Not only is this prime pigeon-watching time, but it also gives you some time to wander around the town on your way back to the station. The highlight for me was when I stopped into a relatively new Oiso Geihinkan restaurant, a wonderful villa on the hill near (pictured below) that serves great Italian food in a gorgeous setting at a reasonable price . And while they have a wonderful lunch menu, I confess that after witnessing the gory drama above the beach that morning, I really only wanted a salad.
 I feel strange calling them "green pigeons. As you can see from the photos throughout this article, they are very much yellow.
 From Bird Research News, September 28, 2011 (PDF).
 If you keep left when coming to the beach from Oiso station, you’ll pass it on your way to the beach.