Watchers document annual return

Broad wings, large head and a distinctive under-wing pattern; seeing a hawk fly overhead is exciting, and sometimes confusing.

Imagine watching hundreds of hawks fly by and being able to identify each by species, sometimes age or sex, and even whether the bird has eaten recently. This is how several dedicated hawk watchers spent their spare time in April during the spring hawk migration.

Records are kept documenting the numbers of each species seen each day. Years of observation have determined that migration generally peaks April 10 to 25.

Most of Alaska’s hawks do not winter here. Due to the unavailability of food, they choose to migrate south to warmer and less snowy regions of the country. However, in summer when rearing young, it is more important to move back north where prey is abundant. In the spring, they take advantage of prevailing southerly winds and updrafts over mountains to ease the long flight.

Thus, impressive numbers of hawks are seen at the local hawk watch. The birds fly north, generally following the coastline. One of their regular routes follows the Copper River inland. Reaching the mountains, they funnel up the valley to the Matanuska Glacier and then disperse throughout the state. Near Sheep Mountain, at about Mile 118 on the Glenn, the highway overlooks the valley, creating a perfect spot to view the passing hawks.

The birds will often fly high overhead, sometimes close to the ridge on the north side of the road. On a sunny day, the sun reflects off the snow and illuminates distinguishing features on the underside of the birds’ wings, which aids in identification. The migrants speed from east to west toward their breeding grounds in the Interior. Earliest to arrive are the Golden Eagles and Goshawks, later in April the Osprey and Swainson’s Hawks pass through.

For one weekend at the peak of migration, chosen based on historical flight records, Anchorage Audubon and Mat-Su Birders host a hawk watch event. As many as 100 birders, from beginners to experts, gather to watch and learn about the migrating hawks. The most commonly sighted birds at this time of spring are Harlan’s Red-tailed Hawks and Rough-legged Hawks. In addition, several migratory Golden Eagles pass through, distinguished from the local residents by their westerly flight path. Smaller Sharp-shinned Hawks, Northern Harriers and Merlins zip by.

Expert observers call out the identification as each passes. In some weather conditions the hawks will form kettles, flocks of birds that circle upward in updrafts to catch prevailing high-altitude winds. In 2012, the numbers of hawks were lower than in previous years, with a peak day of 114 birds. But the weather can cause hawks to follow different pathways and observers may not be there at the right time, or a hard winter may reduce survival. So, each year brings an exciting chance to see a spectacular flight.

Hawks are not the only attraction. A resident Hawk Owl is nearly always present, observing the observers. Trumpeter Swans will frequently be seen following the migrating hawks. Birders enjoy the antics of Common Ravens and Bald Eagles. One year a pair of extremely rare Mountain Bluebirds stopped by!

Alaska is not the only location with an impressive hawk migration. Hawk Mountain in Pennsylvania is one of the most visited for fall migration along the peaks of the Appalachians. In Minnesota, Hawk Ridge north of Duluth on Lake Superior funnels hawks in their southerly journey, where they avoid crossing the large expanse of water. In Veracruz, Mexico, millions of Broad-winged Hawks and Vultures travel over the narrow isthmus on their way to and from South America.

When you see a hawk this summer soaring on thermals, hunting from a perch or just passing by, remember the journey this amazing bird has taken to nest and raise a family here in Alaska.

Nancy Wade is member of the Mat-Su Birders and Alaska WildBird Rehabilitation Center. Send birding questions for her column on birding to alaskaflamingo@yahoo.com.