BIRDS OF NANTUCKET
The Harrier and the Prince
by Kenneth Turner Blackshaw
The title deals with names for things. It could have been titled, "The Northern Harrier Formerly Known as the Marsh Hawk." This was the first phrase in an article by the Nantucket Conservation Foundation describing this species. It made me think of "The Artist Formerly Known as Prince," who subsequently became known simply as TAFKAP.

Birders have trouble with name changes and many of my birding friends still like to call this bird the Marsh Hawk, the name we used until 1983 when the birding mavens in the sky changed it. Perhaps we could use TNHFKATMH, but no one could ever pronounce it.

Let's talk about this bird. After the Red-tailed Hawk this is the next most likely bird of prey you'll see on Nantucket. Red-tails are the hawks you see perched on telephone poles or "makin' lazy circles in the sky" as mentioned in the title song from the musical "Oklahoma."

Northern Harriers can make lazy circles themselves but generally choose not to. Mostly we see them flying close to the ground, teetering back and forth on wings stretched up in a shallow vee, looking closely for the small rodents that make up most of their diet.

Roger Tory Peterson's guide tells us, "Note white rump. A slim hawk."

Peterson always had a way of getting to the crux of field identification. Northern Harriers vary from quite brown all over to silvery white with black wingtips but Peterson's six words provide a constant key for identifying them regardless of color.

Birders like to use their birding yardsticks to describe size and harriers are just a bit larger than the American Crow. That is the standard for a 20- inch length. Their wings stretch out to more than four feet making them look much larger. Their size also varies greatly due to the fact that in birds of prey the males are smaller and the females are larger. In falconry, male hawks are called tiercels, a French word meaning one-third smaller, and that ratio also applies to our Northern Harriers.

Most harriers we see are brown. Adult males are gray with black wingtips but it takes three years for that plumage to develop and the majority don't live that long. Wisdom comes with age, and if a harrier is successful in avoiding pitfalls like flying into electric wires or eating poisoned rodents, it may live ten years or more. An old male Northern Harrier can look almost white.

This species is considered "threatened" in Massachusetts. In this part of the world it favors a habitat that is also threatened - sandplain grasslands and coastal heathlands. Nantucket at one time had large amounts of this type of territory. Not that it was natural but the huge flocks of sheep that used to be raised here kept everything mowed down. The sheep are gone and scrub oak and pine are taking over.

In an effort to recreate this habitat and allow more harriers to thrive, the Nantucket Golf Club partnered with the Nantucket Conservation Foundation and the Massachusetts Audubon Society on a fifty-year program beginning in 1996. This consists of brush cutting and also prescribed "controlled" burns to recreate a more open habitat. An example of this can be seen looking north along the 'Sconset Road between the 4th and 5th milestones, an area Nantucketers now refer to as the Serengeti.

Although we see Northern Harriers year-round on our island, the cast of characters changes with the seasons. Our winter harriers spend the summer in Canada and our summer breeding birds depart for the southern U.S. during the cold months.

In April and May male harriers can be seen performing spectacular courtship flights. Starting hundreds of feet up they power dive to a few feet off the ground before soaring up over and over again, often turning somersaults at the high points. These flights are punctuated by their whistled calls.

Perhaps it was a sight like this that caused Aristotle to provide the name we still use for the scientific genus of all harriers, Circus. This refers to a circling flight pattern that harriers generally avoid. But clever Aristotle was probably thinking of vertical circles rather than horizontal ones.

Recently as many as 70 nests have been found here. They are ground nesters, generally choosing to build in tiny clearings amid dense scrub oak tangles. Harriers adjust clutch size up to six eggs according to food availability. They take four weeks to hatch and another four or more to gain flight. Nantucket's feral cat population is a limiting factor on nesting success.

As you travel the open areas outside of Nantucket Town, watch for these large long-winged birds of prey coursing our moors, flashing their white rump patches.

George C. West creates illustrations for these articles.

The Maria Mitchell Association sponsors bird walks on Tuesday and Thursday mornings at 6:30 a.m. and Saturday mornings starting at 8 a.m., from the corner of Vestal and Milk Streets. There is a fee for non-members.

To hear about rare birds, or to leave a bird report call the Massachusetts Audubon hot line at 1-781-259-8805. I