Unusual winter brings unusual birds

Southeast Wild

Posted: Friday, February 16, 2001

Except for the last week, the winter of 2000-2001 in Southeast Alaska has been noteworthy for the lack of snow and cold weather.

Although a bane to skiers and commercial snowplow operators, this balmy winter has probably been very beneficial to the local deer population. On Jan. 7, very mild temperatures even coaxed out a large bat (identified to species as a "big brown bat") near the Peterson Creek trailhead just south of Amalga Harbor, a very rare winter sighting for any bat species in Alaska.

Mild temperatures and snow levels have also had some interesting impacts on overwintering bird populations. For example, wintering shorebirds in the Juneau area seem to be more abundant than normal.

The mild winter has also allowed more gulls than normal to overwinter in the Juneau area.

Mixed in with the common glaucous-winged and mew gulls is one very special visitor from Siberia - an adult slaty-backed gull. This species has never been seen before in the Juneau area during the winter, although one or two birds have shown up in August on three occasions (in the last decade) to feed on salmon runs at Sheep Creek and Salmon Creek.

The color of the appropriately named slaty-backed gull contrasts nicely with the light-gray backs of the glaucous-winged gulls which it resembles in size. This cooperative bird has been readily found by Juneau birders in the Lemon Creek area and has been added to the life lists of several local birders. Overwintering slaty-backed gulls are sometimes found in Ketchikan so it is probable that this bird is a stray drawn to the other gulls flocking to the Lemon Creek area.

Bird feeders or other foods provided by man can also provide resources enabling bird species to linger over in mild winters such as this. For instance, a "red" fox sparrow probably from central Alaska has been overwintering at a North Douglas feeder. This "red" form contrasts sharply in color with the local "sooty" form of fox sparrow which breeds abundantly in Sheep Creek and Gold Creek valleys.

Normally, the "red" form of this species is a very scarce fall migrant which passes through Juneau in November. The mild winter has induced this bird to stay put since Nov. 18, 2000. Similarly, at least two white-crowned sparrows are choosing to overwinter at another feeder in Auke Bay.

Warblers are a group of very colorful small bird species which are known for their diversity of migrations which often range over thousands of miles. Alaska provides breeding habitat for a number of warbler species; however, they generally have migrated out of the state by the end of September with a few lingering into mid-November.

Warblers have never been seen on the Juneau Christmas Bird Count held in late December, although a yellow-rumped and Townsend's warbler have been seen in the few days around the count day. In January 2001, however, downtown Juneau hosted both a yellow-rumped and an orange-crowned warbler. The only previous January warbler record for Juneau was a yellow-rumped warbler found at a feeder on Jan. 23, 1990, during subzero weather.

The distribution of these two overwintering warblers is very interesting as they appear to be taking advantage of a very limited micro-habitat where they can find insects supplemented with perhaps a few berries. Often the orange-crowned warbler could be found foraging for long periods of time in the same pine tree, an exotic species to the Juneau area. The yellow-rumped warbler also appeared to prefer foraging in bushes and shrubs introduced to Juneau for their aesthetic qualities.

In the same area of downtown Juneau, at least one ruby-crowned kinglet could also be found this January, another species which is found very rarely in the winter. Without the habitat modifications introduced by man, it seems unlikely that these species would overwinter here even in this mildest of winters.

Although this mild winter is perhaps most notable to birders because of some of the unusual species, it also appears that numbers of some other common overwintering species are below normal.

The number of scoters, loons, and murres (a common seabird) all seem to be down from those found in a normal winter. It is unknown if they also stopped to overwinter further north or are simply using other nearby habitats. Due to the remoteness of the seacoast, much needs to be discovered about the distribution of overwintering waterfowl and seabirds along the west coast of North America.

Paul Suchanek is a member of Juneau Audubon Society. The Great Backyard Bird Count began today and continues through Monday. To join in, log onto http://birdsource.cornell.edu/, then check back to learn what species other feeder counters have seen.

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