They look like hunched-over men in black suits. You see them working the shoreline. Black with long red bills. Their stocky bodies bent forward. Occasionally stopping to prod the sand and perhaps eat a morsel. Then moving on.
This is the oystercatcher, a New Zealand shoreline bird. The name, however, is a bit of a misnomer, at least for the birds here in New Zealand, since many of them here never catch or eat oysters.
Oystercatchers are a genus of birds (Haematopus) found on shorelines world-wide; they range in length from about 15-20 inches. They feed off a variety of shellfish and other prey along the ocean or inland along mudflats. The name oystercatcher was coined in 1731 for all members of this genus because of the similarity to a bird found on the oyster banks of the Carolinas in the United States.
The first European to describe the New Zealand oystercatcher was Joseph Banks, Captain Cook’s famed botanist, who in 1769 described shooting several birds ‘black with red bills and feet’, an inauspicious start to a bird which at least at one time has been threatened with extinction.
There are two main species of oystercatcher in New Zealand (plus a less common variety on the nearby Chatham Islands).
The South Island pied oystercatcher (Haematopus finschi) is black and white in color with a red bill and red eye-ring. They are the more common of the two varieties and are generally found inland on the South Island along rivers and in bogs. They migrate to the North Island in the winter. In 1994 there were estimated to be around 112,000 of this species.
The variable oystercatcher (Haematopus unicolor) is found on the shorelines of the North Island. They can be solid black, pied or intermediate in color. According to The Encyclopedia of New Zealand only around 5,000 variable oystercatchers remain.
New Zealand oystercathers generally feed during low tide eating a variety of shellfish and other prey depending on their individual locations.
Also depending on their location, they have evolved slight variations in their bills. A long bill is useful for prying molluscs off rocks and for opening the shells. The oystercatcher either inserts its bill between the gap in the shell and prys the shell open, or if it can’t get the tip in, the oystercatcher will often hammer the shell or make a hole in the shell and extract the prey.
There can be a lot of shells on the beach or in the tidal flats, and many of the shells although closed contain no food; they are empty. Apparently experienced older birds are able to tap the shells to determine if there is something inside, while younger inexperienced birds waste time opening empty shells.
Oystercatchers are generally monogamous and return to the same breeding sites each year. Some pairs have been seen together at the same place for ten or more years. Occasionally, however, each member of a mating couple may separate and winter in different areas before reuniting. Not a bad idea as far as I’m concerned.
“Piping” is an oystercatcher behavior exhibited during courtship or when threatened. The birds will lower their bodies making their bills vertical and run along while making a piping noise.
Oystercatchers don’t build a proper nest for their eggs but rather lay them directly in the sand with little protection. Hence the eggs, like so many other New Zealand birds, are vulnerable to a variety of predators including dogs and beach-goers.
When an intruder approaches a nest, the bird(s) will attempt to chase the intruders away. Walking on a remote beach west of Auckland this summer, an oystercatcher chased me away as I approached an isolated log on the beach, which in retrospect I’m sure hid an egg. The bird first came running at me and then veered off sharply as if wanting me to follow and give chase. Then the bird limped along on the ground, which I later learned was a display at having a broken wing, another attempt to lure predators away. Finally, when I realized what was going on, I left. I took this picture using a zoom lens after the oystercatcher had returned to the log, but still kept a watchful eye on me even from the distance.
Finally, here’s a short video I made of some oystercatchers running along the surf at Pukehina Beach.
1)Image by: 1, 2, 3, 4) Dick Daniels – New Zealand 2, 4) Dick – New Zealand 1, 2) Black variant 3, 4) Mottled variant