Oh, To Be a Northern Shoveler

Northern Shovelers were actively feeding on Central Pond at Union Bay in Seattle, Washington.

Their heads were underwater; occasionally, their eyes came above the surface, but mostly they stayed down. Somehow, they were getting breaths, but I couldn’t see how. True, their nostrils are near the base of the bill, and maybe only an instant is needed. These ducks, two males and a female, were swimming fast. The body plumage said Northern Shoveler. The males had cinnamon-brown sides, white in front and behind the cinnamon patch. The heads appeared black, showing, though, as green when the light was right, and their backs dark. The female was streaked brown and light, like so many female ducks. But I hadn’t seen their bills, those large spatula-like projections. Ornithologists created the genus Spatula for these and their three close relatives in honor of that bill.

I’d come to the Union Bay Natural Area at UW’s Horticulture Center to look for them and see if I could watch them feed on this April morning. During spring in Seattle, shovelers are often on the Central and Carp ponds. Most would be paired by this time and traveling as a unit or in small feeding groups. Finally, one raised its head entirely out of the water and showed that humungous projection. I always think that bill should cause them to fall over, but its structure makes it surprisingly light, and I suspect they have strong neck muscles. 

A pair of Northern Shovelers swim in a tight circle while feeding.

They use their bill to filter out food. These birds suck water through the front of their beaks and push it out through the lamellae on the sides. They specialize in small nektonic invertebrates, which is the scientist’s way of saying swimming critters. Probably, Daphnia and many other minute things fill the water column in these shallow ponds. These shovelers swam in straight lines, occasionally doing turns, moving their heads up and down in jerky motions. A few weeks ago, pairs were swimming in tight circles. That behavior probably stirs the crustaceans and other invertebrates, seeds, and microscopic vegetation up from the bottom, making them better for filtering. We’d had strong winds in the last couple of days, and the water column was probably well mixed. 

A female Northern Shoveler opens her mouth wide to show the lamellae that allow her to filter out microscopic organisms from the water column.
The fine lamellae on the bill of this female Northern Shoveler allow her to filter out small crustaceans and other microscopic food items from the water column.
A group of Northern Shovelers swim in an oval. Each is stirring the bottom with their feet and the one following can filter any food items stirred up.
Northern Shovelers swim in a wide oval, following the one in front to catch the stirred-up water.

Once, a year ago, on Carp Pond, I watched some shovelers swim in an oval. The oval swimming, as well as the circling, are cooperative feeding techniques. It is an ingenious way of working together, everyone benefits. They can exploit the stirred-up food items by following, filtering out the good pieces. For example, we filter out noodles and vegetables from soup by pulling a spoon full along the side of the bowl and letting the liquid drain out. These ducks suck in a mouthful of soupy pond water and then use their tongue to push the water out through their built-in sieve. 

A male Northern Shoveler actively preens while a female takes an bath in the water beyond him. These are probably paired for the coming breeding season.

At the eastern end of Carp Pond, I found a shoveler pair actively preening. The female floated in the water, using her bill to pull through the body, wing, and tail feathers, occasionally taking a vigorous splashing bath. The male stood on a log, using his bill to work all its feathers. This log must be a favorite perch for ducks. A week ago, a female shoveler had her bill tucked under back feathers on one end, two Green-winged Teal were preening in the middle, and a drake shoveler was on other end. 

I find it amazing that the skin on these ducks is dry. Water doesn’t get to their skin even when swimming. The tight barbules on each feather vein act like Gore-Tex, and the weaves are so close that water droplets can’t get through. The layers of feathers and the coating they put on their feathers make the plumage waterproof. A drop of crude oil on the plumage negates all this and allows water to seep through the plumage, reaching the skin. Birds that encounter an oil spill will vigorously try to preen off the oil. The oil is toxic, but often they die of hypothermal because of the water that reaches their skin, chilling them. Just a dime-size dot of oil may spell their death.

A male Northern Shoveler actively preens while a female sleeps. Two Green-winged Teal also care for their feathers while resting on the log at Union Bay.

Birds spend a lot of time each day taking care of their feathers. Probably, these two were well fed and preparing for an afternoon nap, if not the night. Once they felt they had thoroughly cleaned and straightened their feathers, it would be time to sleep. We do something similar before bed each night.

Anuran Chorus at Stossel Creek

Pacific Tree Frogs were in full chorus, and a few American Bullfrogs added to the performance. The marsh system along Stossel Creek provides ideal habitat for these species.

The frogs were in full chorus. Swamp stretched across the valley for a hundred yards and for a half-mile along Stossel Creek. A mixture of willows and grasses grew in the wetlands, and then a pond opened downstream from this spot. The loudness and diversity of their songs made me think that hundreds were singing simultaneously. These were Pacific Tree Frogs Pseudacris regilla, and I was trying to absorb that a tiny anuran, less than 2 inches long, could make that much sound.

They also go by the name Pacific Chorus Frog and hearing this choir made me think that chorus frog might be a better name. When one male begins to sing, any nearby male will jump right in and try to outsing the other. Each puffs out its vocal sack as it puts forth the song. This was not an organized chorus with all of them singing together, but rather each male was trying to out-compete the next. If he succeeds, a female may come his way. He needs to sing louder or differently to entice her to pay attention to him. 

In the distance, I noticed the deeper and more resonating call of an American BullfrogLithobates catesbeianus. This introduced species is a severe problem in Washington. The Washington Department of Fish and Wildlife has listed it as an invasive species. Bullfrogs grow to be big. With their legs stretched out, they can be up to ten inches long and are voracious predators, eating anything they can catch. They were natives in Western Pennsylvania, and I searched for them along the shoreline of ponds near my parent’s farm. 

At fifteen minutes into my recording, a lull of ten seconds happened. Perhaps, one male needed a break to catch a snack, and all the rest followed, but I suspect it was more likely that one sensed a possible predator nearby, and they went silent. Eventually, one male frog couldn’t resist and croaked. The rest then started back up. Barred Owls are common in these lowland forests of the Pacific Northwest and will hunt these frogs. 

Tree frogs need to breed, though; these anurans sing even if it exposes them to the risk of being eaten.