Birds of wetland and reef: Gray Duck and Reef Heron
Two very different birds depend on Samoa's shallow water habitats. One is the familiar matu'u, or Pacific Reef-Heron, a bird that is seen nearly every day by anyone visiting Samoa's shoreline. The other is Samoa's only duck, the toloa or Gray Duck, a bird that is so rare that most young Samoans have probably never seen one.
It comes as a surprise to some people that we don't have more kinds of ducks in Polynesia. After all, ducks like water, and we've got plenty of that, right? Well, we've got plenty of salt water, but very few lakes, marshes, or large streams of fresh water. Almost all ducks prefer fresh water, and even the few kinds of “sea ducks” eat mostly seagrass and other plants that aren't found around Samoa's coral reefs. Therefore, there aren't many suitable homes for toloa in American Samoa. These suitable homes are the fresh and brackish (fresh/saltwater mix) water wetlands.
“Wetlands” is a word that we've been hearing a lot lately. It refers to areas of land that are permanently or periodically flooded or submerged in shallow water. So much wetland habitat has been lost in the United States, primarily through draining and filling, that strict federal laws have been passed protecting wetlands. Locally, the Coastal Zone Management Program is responsible for protecting our remaining wetlands, which serve vital roles as nurseries for fish and crabs, natural water purification and recharge areas, sites for taro production, and homes for rare plants and wildlife. There used to be extensive mangrove (togo) swamps bordering Pago Pago Bay, but these were filled in long ago, before the negative environmental consequences of such activities were understood. The largest remaining wetland areas here are the pala lagoons in Nu'uuli and Leone and the marshes and Pala Lake on Aunu'u Island. There are also many other small but important wetlands remaining in both Tutuila and Manu'a.
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| All illustrations on this page used with permission from Dick Watling from “Birds of Fiji, Tonga and Samoa” and “Birds of Fiji and Western Polynesia” (Pacificbirds.com). |
All of these areas were once home to toloa. However, as wetlands were filled in and as shotguns became available, this once-popular game bird became rarer and rarer. During a major survey of Samoan birds in 1986, not a single toloa was seen, leading to the concern that this bird might be extinct in American Samoa. Happily, this is not the case. A few toloa still live in the territory, mostly on Aunu'u, where the village leaders have taken an active role in protecting their ducks. This bird, and the wetlands it depends upon, need our continued protection if it is ever to recover to healthy population levels.
The toloa is a “dabbling duck”. This means that it doesn't dive under the water to feed, but rather tips down, with its tail in the air and its neck stretching under the water, to reach the plants and small insects and snails that it feeds on. Although it sometimes swims in the sea, it does not feed there, and, like most ducks, it does not eat fish.
One interesting thing about the toloa is that is doesn't always nest near the water. It may build its nest in tall dense grass, or place it in a low tree hollow. Five to ten pale green eggs are laid. The journey of the young ducks from the nest to the safety of the water is a dangerous one, and usually only one or two ducklings make it.
The toloa is a great wanderer. The bird is found across a huge geographic area, extending from Indonesia to French Polynesia, and south to New Zealand and Australia. The toloa is a strong, fast flier, and commonly flies between islands. It seems likely that the small population on Aunu'u, which was apparently absent in the late 1980's, may have recolonized American Samoa from western Samoa, where the duck is slightly more common. This gives us reason to hope that the toloa may return to areas that it formerly used, if the wetlands are preserved, and the duck is protected from hunting. So ... if you see a toloa, consider yourself lucky, and please don't disturb it. Perhaps one day Samoa's special duck will once again be a common sight.
The
matu'u, or Pacific Reef-Heron, is a common sight today. With its
long legs and long neck, often curved in an S-shape, the matu'u
is one of Samoa's most recognizable birds. One interesting fact about
the matu'u is that it comes in two color forms, either dark gray
or pure white, although almost all the matu'u in Samoa are dark
gray. In other areas, particularly atolls like Swains Island or Rose Atoll,
almost all the matu'u are white. It seems that in Polynesia the
dark forms are found on volcanic islands, with dark lava rocks, while
the white birds occur on atolls with white sandy shorelines. In many other
parts of its range, however, including Fiji, both white and gray forms
occur commonly in the same area. The reason for the matu'u's two
color forms remains a unclear.
The matu'u is the master spear fisherman of the bird world. It stalks slowly across the reef flat, scanning for the slightest movement, and then throws its long neck forward as fast as lightning, catching its prey with its long sharp beak. It feeds on a wide variety of reef creatures, including fish, crabs, and snails.
Although the matu'u usually makes its living feeding on the coral reef, it also uses the freshwater wetlands of Samoa. Mangrove areas like the Nu'uuli Pala are frequent feeding sites, and the birds will also hunt for food in freshwater streams. These rainforest stream valleys are the matu'u's favored nesting areas, where the herons build their large nests high in the trees. Some matu'u also nest on offshore islets, and have even been reported to nest on ledges in caves. Usually three pale green eggs are laid.
Strict protection of Samoa's wetlands is essential if the toloa is to regain its place among our familiar native birds and if the matu'u is to continue to be a common resident of our shoreline villages. Please help spread the message that landfills kill a very important part of Samoa's natural environment - our wetlands.
Pepper Trail, DMWR