Tuesday, January 18, 2011


When you first encounter a Northern Hawk Owl (Surnia ulula), you will understand why it has two different types of raptors in its name. Clearly an owl because of that big head and forward-facing eyes, nevertheless it has the rakish look of a hawk about it, with long tail, rapid flight, and – of course – diurnal habits.

One of these birds spent the winter of 2010-2011 on Westham Island in southwestern British Columbia, delighting birders and nature photographers by the hundreds. Because of their open perching habits and tameness, Hawk Owls are readily detected where they occur, so it is likely that at least some of the few individuals that make it to peripheral wintering areas are found as observers scrutinize the winter landscape. In my case, it was a wonderful way to start the year - and on a beautiful sunny day!

In the Pacific Northwest, we don’t get veritable invasions in winter, with dozens of Hawk Owls showing up like they do in the Great Lakes region. Nevertheless, at least a few birds make it down to Washington in most winters, and with increasing knowledge of where to look for them, more have been seen in recent years. Breeding has been confirmed at Manning Provincial Park, just north of the border in British Columbia, and suspected at Harts Pass in Washington.

Hawk Owls perch, usually at the very top of a tree or other conspicuous perch (often on utility wires in this day and age), and survey the surrounding semiopen landscape for their prey. Their primary prey is voles, but they are willing to take anything they can subdue from a long list of mammals up to the size of hares and birds up to the size of grouse.

Hawk Owls are not modified like many other owls for auditory hunting. Their two ears are symmetrical, and they don’t have a well-developed facial disk. They must have good hearing, however, as they are occasionally seen to plunge into snow to capture a vole. With long tail and short, rounded wings, they hunt somewhat like accipiter hawks, detecting prey visually and dropping from a perch to move at high speed with rapid wing beats. Most prey is captured at fairly close range, but their distant vision is excellent.

There are other diurnal owls. Most pygmy-owls hunt during the day, small birds their primary prey. Snowy Owls and Burrowing Owls are conspicuous features of open landscapes, although both hunt at night as well. Short-eared Owls can be seen during the day, but much of their hunting is at dusk. The same is true for Great Gray Owls. Hawk Owls, conspicuous on their perches all day long, also tend to hunt more in the afternoon, so hunting in dim light seems to be hardwired in owls.

Bear in mind that owls of the Far North must be able to hunt both day and night, as the days are so long in summer, the nights so long in winter. Fortunately for them, voles are active day and night.

Like many other owls, Hawk Owls nest in natural cavities, for example at the hollow tops of broken-off snags, and holes abandoned by woodpeckers. Their clutch size varies from 3-13 eggs, with a mean of about 7. It is a large and variable clutch size, as is the case with several owl species that seem to depend on voles and lemmings for their reproductive success.

Keep your eyes peeled for the owl that acts like a hawk!

Dennis Paulson

Wednesday, January 12, 2011


When we think of ducks, we may think of familiar white waddling barnyard Pekins, but in fact these waterfowl are among the most strikingly colored birds. Some of them are downright gorgeous. Look at a Wood Duck if you like brilliant iridescence. How about a Long-tailed Duck for a pleasing pattern of black, brown, and white? Or if swatches of pure color attract you, peruse a Cinnamon Teal. Of course it is the males you will be looking at, as females are generally brown; not that they aren’t beautiful in their own ways.

The Northern Pintail (Anas acuta), not the most brightly colored of ducks, is surely the most elegant. The long, swanlike neck of the male of this species contributes to the look of elegance, as do the long, sweeping central tail feathers. The subdued gray and white body and rich dark brown head add patrician colors to the attractive shape. Even the females, somewhat smaller than the males, have longer necks than those of other ducks.

Why the long neck? Well, dabbling ducks often feed by upending in shallow water, their tail up in the air and their head and neck submerged to sample underwater fare such as leaves, buds, and seeds of aquatic plants and a great variety of invertebrates. You can only reach so far with an average-length neck, and over time pintails just outreached the competition by evolving that long neck. By feeding in water too deep for their near relatives, they presumably were able to take advantage of resources unavailable to the others.

But it must be added that most of the feeding done by pintails is in very shallow water or on land, where they take seeds from sedges and grasses. On their wintering grounds, they are very common among the dabbling ducks that feed on marine invertebrates on mudflats as the tide goes out. The long neck also serves them well in those situations, allowing a foraging bird to reach all around it. This adaptable species is one of the most abundant ducks in western wetlands.

As in other temperate-zone ducks, pair bonds are formed in fall and early winter, and you can expect to see pintail pairs from then on until the female has laid her 5-10 eggs. Male courtship consists of ritualized displays and vocalizations, with head up, bill down, and tail up prominent components. That long, slinky tail is surely impressive at this point. Females are impressed by both the intensity of courtship displays and the constant attentiveness of the courting male. Some of the choice may also involve appearance, males with more colorful scapulars and whiter breasts preferred.

Because mortality is heavier on females than males in most ducks, there is a surplus of males in late winter and spring after all the females are paired up. In this and other dabbling ducks, it is common to see groups of males in pursuit of a single female. These pursuit flights can involve up to a dozen males – although usually just a few – and last for many minutes. They may end with a forced copulation when the female is forced down on land, or the female may “escape” only to be harassed by other males that spot her. The female may have to be mated to avoid this.

Prime pintail breeding habitat is a shallow marsh. Because such marshes are subject to disappearance during any extended drought, they come and go in the landscape, and so do pintails. During wet years, they do well, and their numbers increase. During widespread droughts, the opposite is the case. Breeding populations wax and wane and have varied from about 2 million to about 10 million birds in recent decades.

Dennis Paulson
Nature Blog Network