Nature Watch: Diving Into Winter Waterfowl

About the author: Steve Ellis is a naturalist and Land Trust member who enjoys sharing his love of the natural world. His blog series, “Nature Watch,” will appear each month in “Habitchat,” chronicling native plants and wildlife you can expect to see during that particular time of year. We thank Steve for sharing his passion, illustrating the importance of island conservation.

Overview

Over thirty species of waterfowl – swans, geese and ducks – are drawn to the hospitable environment of Greater Puget Sound in the winter months. About half of these are diving ducks, those that make their living underwater. Some may begin arriving as early as late August, having migrated from breeding areas in Alaska and Canada, frozen out of the lakes, ponds and rivers they summered on. Most come to forage for invertebrates such as clams, crabs and marine worms.

Long-tailed Duck is a species that seeks bottom-dwelling invertebrates. Named for the males’ elegant tail feathers, they can dive to a depth of 200 feet. Though at times they may be seen close to shore, they’re usually out of sight, far offshore.

The most abundant divers are probably the Surf Scoters, one of three related scoter species. These can be seen from many local beaches, diving for mussels and clams. Scoters work larger invertebrates through the water until one shell breaks, exposing the bird’s meal. Smaller mussels are swallowed whole, and the scoters’ powerful digestive system grinds the shells into little bits.

Scores of Surf Scoters can sometimes be seen in Penn Cove. Some will stay through the ensuing year; these are most likely last year’s young that chose to forego the migration to interior Alaska and Canada.

Another widespread diver is the Bufflehead, North America’s smallest duck. They nest in tree cavities found along northern lakes and rivers. It’s nearly impossible to visit a local beach in February and not see at least one of these dapper black-and-white ducks.

Fish are also on the menu for some divers. Mergansers, in particular, vie for fish with other waterbirds such as loons, cormorants and grebes. Prey species range from schooling fish such as herring and surf smelt to bottom-dwellers including sculpins and gunnels.

In late winter and early spring, scoters and goldeneyes feast on the ultra-nutritious roe deposited during herring spawning. This food source is particularly important to female divers as they prepare not only for migration but also egg-laying and incubation.

Diving duck courtship begins in January and continues through February. Rearing up from the water and head-nodding are two displays performed by male Buffleheads and goldeneyes in hopes of attracting a mate, and they often vigorously chase after rival males.

By late April, most diving ducks have flown north to coastal areas of Alaska and British Columbia. They gather there to wait for spring to overcome the snow and ice covering their chosen summer territories.

Red-breasted Merganser by Craig Johnson.

Fauna: Red-breasted Merganser (Mergus serrator)

Red-breasted Merganser is one of the most common species of our fish-eating, diving ducks.

About the size of a Mallard, Red-breasted Mergansers are known for their serrated bill, designed for holding slippery fish. Males have greenish heads that sport a divided, shaggy crest and a wide white band at the neck. Females have a reddish-brown head and crest. Both sexes are grayish above and light below; white patches on the dark wings are easily observable during flight.

They breed in Canada and Alaska – I once nearly stepped on a nest hidden in deep grass near a river in western Alaska. Their migration south is rapid, and they can hit flying speeds of over 80 miles per hour.

Mergansers employ four methods of catching fish. In Line Abreast Herding, several birds advance together to push prey toward the shore to trap them. They may beat their wings on the water to hurry the fish along. In Individual Search, a single bird swims while repeatedly submerging the head, a method usually used in shallow water. Shallow Diving involves probing for prey among rocks, mostly done in less than six feet of water, while Deep Diving can take the bird 20 feet down and may last over a minute. The main prey species in our area are sculpins, herring, and surf smelt.

By late February, Red-breasted Mergansers will be coming together in ever-enlarging flocks that will depart our waters in April. Look for them close to shore in kelp beds or far from the beach. They’re occasionally found on larger lakes and in the Skagit River, but their preference is for saltwater.

Bull Kelp washed ashore at Keystone Farm and Forest Preserve.

Flora: Bull Kelp (Nereocystis luetkana)

Though bull kelp resembles a plant and engages in photosynthesis, it’s really a type of algae known as brown seaweed. This alga has two distinct life phases and usually lives just one year, though a few survive for a second.

Mature kelp is the phase that’s most familiar. A holdfast is attached to a rock on the seabed. A long stipe or stem grows from the holdfast to the water’s surface. It supports long blades or fronds that lie on the surface, kept from sinking by an air-filled float.

Reproduction begins in the fall when, unlike plants, spores are released from the undersides of the kelp fronds. These drop to the ocean floor to start a new generation. Bull kelp is capable of astonishing growth rates; research shows kelp in Puget Sound may add 5½ to 7 inches daily.  Starting in March, lengths of 80 feet are attained in one season.

Winter storms dismantle much of the kelp “forest,” piling it onto the beaches.

The importance of bull kelp can’t be overstated. Kelp forests protect shorelines by moderating the impact of waves.  Countless invertebrates inhabit the stipes and fronds, and many fish species seek shelter there or come to find prey. When beached, kelp fragments are consumed by beach hoppers and flies. Some bull kelp remains attached to their rocks in winter, providing sanctuary for small fish, while mergansers and other fish-eating birds search for prey under the fronds.

Bull kelp inhabits rocky sea beds with strong to moderate wave action. The exposed waters off Fort Ebey State Park support a large bull kelp forest.

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