ALWAYS IDENTIFIABLE: A Mallard, a Common Loon and a Red-necked Grebe, all sleeping in the characteristic posture of their families. (Illustrations not to scale.) Art by David Sibley
For birdwatchers, winter is a time to stand on frozen shores and struggle to identify distant waterfowl. This means focusing on beak shape, head shape, body proportions, and behavior, among other things. It is understandable that you will be discouraged when you meet a sleeping bird because all of these characteristics will be partially or completely hidden. On the bright side, a sleeping waterfowl reveals other useful terrain marks, and in some cases is easier to identify than an awake bird.
Even if part of the head is hidden on a sleeping bird, what you can see is still helpful. An awake bird is constantly moving – preening, stretching, alert, relaxed, courting, training, diving, etc. The shape of the head changes as the feathers are raised and lowered with the bird’s mood and activity. A sleeping bird is just sleeping. His head shape remains the same.
Distinguishing between the Greater Scaup and Lesser Scaup, or Barrow’s Goldeneyes and Barrow’s Goldeneyes, can be easier when they are sleeping, simply because their head shape is then more consistent and reliable. On a broader level, sleeping postures can help distinguish different families of waterbirds.
The posture of a sleeping duck is familiar to everyone. Ducks turn their heads 180 degrees, place their beaks in their back feathers and rest there. When birds sleep on water, they seek maximum buoyancy and tend to float high in the water with their tails up. This change is particularly visible in diving ducks, such as scoters or mergansers. When active, these species walk low in the water with their tails flat on the surface. If you’re used to seeing them like this, it can be confusing to see their high, rounded backs and raised tails when they sleep.
Loons, like ducks, place their beaks in their back feathers to sleep, but even when sleeping they have a very low profile with their heads resting flat on their shoulders.
Grebes have a unique sleeping posture. Unlike other birds, they do not turn around. They simply rest their neck on their back and tuck their beak along the neck. This creates an entirely different silhouette than ducks or loons and instantly identifies the bird as a grebe.
Cormorants simply never sleep while swimming.
Distant waterfowl are difficult to identify, but don’t ignore sleeping birds. They could reveal clues that you won’t see when they’re awake.
This article first appeared in the November December 2019 issue of BirdWatching magazine. Subscribe now.
