Curious about their recent appearance, I examined other BBS survey data from the northwestern United States, Canada and Alaska to see when nuthatches were first recorded in these surveys. I found that the data indeed suggest a northward expansion of nuthatches into Alaska from Canada during the past 20 years.

Breeding bird surveys have been conducted in northwestern states and Canadian provinces since 1968, with red-breasted nuthatches reported in Washington and in neighboring British Columbia in very first surveys. But nuthatches were not reported on a BBS in the more northern Yukon Territory until 1974.

Eleven years later in 1985 nuthatches were first reported on a BBS in Alaska. Furthermore, reports of nuthatches doubled in Washington in 1981, rapidly increased in British Columbia in 1990, in the Yukon in 1993, and in Alaska from 1994 through 1996, the same period we first began recording them on the Kenai refuge. Observers in Kachemak Bay and at Hope first reported them in 1992 and 1993, respectively.

Some of these increased reports may have been due to more observers and routes added each year, but the years of first reports suggest a northward expanding population. Nuthatches thus appear to be a relatively new breeding species on the Kenai Peninsula, perhaps nesting here only during the last decade or two.

It is remarkable that one can witness the establishment of a new species in an area within one's lifetime. With predicted trends in global warming, however, we may see more unfamiliar species arriving on the Kenai Peninsula in the future. Let's hope that they are all as benign as nuthatches!

Since nuthatches nest in cavities in trees, I have over the years attempted to attract nuthatches to nest boxes near our house. These attempts have always been unsuccessful; nuthatches apparently rarely use nest boxes, preferring to construct their own cavities in trees.

This spring I was rewarded with an unexpected event; a pair of red-breasted nuthatches reared their young in an old birch snag at the edge of our yard. At first I thought they were merely storing food behind some loose bark about eighteen feet high on the far side of the snag. Then I discovered that they were already busy excavating a cavity where a large branch had broken off during a previous windstorm. Even more surprising was the fact that the wood they chose was solid and hard, not decayed and soft, at least at the surface.

Starting around March 15, the nuthatches began removing "BB"-sized or smaller bits of wood at a rate of about one piece every five seconds, hour after hour. Later, as they moved deeper into the center of the snag, the rate of wood removal slowed. After removing tiny pieces of wood for at least 35 continuous days, the nesting cavity appeared to be completed by April 18. A very rough calculation suggests that they made somewhere between 3,700 to 10,000 "wood removal actions" to excavate the cavity deep inside the birch snag.

Incubation appeared to have started by at least May 7, when I observed the male bringing food to the female inside. The nuthatches were very pugnacious and drove away any other bird that came within 20 feet or more of their nesting cavity.

I have read that red-breasted nuthatches line their cavity entrance with sticky sap or resin to ward off predators, but at this stage I could see no resin around the cavity entrance. I thought this might not always occur. Then by May 14 until at least May 19, I observed the nuthatches bringing small bits of sap and resin and smearing it around the entrance to the cavity. By the time they completed this phase of protecting their eggs and young, the thick clear sap could be seen running a couple of inches down the tree trunk from the cavity entrance. At an observed rate of one sap trip per one to five minutes, I roughly estimate that lining the cavity entrance with sap required 600 to 3,000 trips.

Ted Bailey is a retired Kenai National Wildlife Refuge wildlife biologist who has lived on the Kenai Peninsula for over 27 years.