No. 18.

BIOLOGICAL SERIES No. 6.

ADDITIONAL NOTES

то

Summer Birds of Flathead Lake,

WITH SPECIAL REFERENCE TO

SWAN LAKE

RY

PERLEY MILTON SILLOWAY,

Principal Fergus County Free High School, Member American Ornithologists Union.

Author of "Some Common Birds," "Summer Birds of Flathead Lake," Etc.

WITH INTRODUCTION BY MORTON J. ELROD.

PREPARED AT THE UNIVERSITY OF MONTANA BIOLOGICAL STATION, BIGFORK, MONT.,
UNDER DIRECTION OF MORTON JOHN ELROD.

University of Montana, Missoula, Montana, U. S. A.

1903.

"INDEPENDENT PUBLISHING COMPANY, HELENA, MONTANA."

Introduction.

The notes presented in this bulletin, when added to the bulletin "Summer Birds of Flathead Lake," University of Montana Biological Series No. 1, include the work on ornithology during the summers of 1900, 1901, 1902 and 1903. Three seasons having been spent in the Mission Mountains, on the Flathead Indian Reservation, and along the shores of Flathead lake, it was thought best to extend the observations in the summer of 1903. Prin. Silloway was therefore recommended to spend a portion of the time in the vicinity of Swan lake.

This lake is a beautiful sheet of water, cradled between two ranges of mountains, with wooded slopes to the water's edge. It is primitively wild, with miles of woodland, interspersed occasionally with open glades.

Only a few hardy pioneers have entered the region. The birds have thus not been molested by man, and a visit to the region gave opportunity for study not heretofore made.

The illustrations here given are as faithful a portrayal of the region about Swan lake as can be made with the camera. Plate LIII shows the region to the southeast, with the Mission range in the background. The mountain slopes to the low summits are covered with a dense forest. Bordering the lake may be seen a fringe of willows, back of which are the cottonwoods and alders, and lastly the conifers. A large area bordering the water is swampy, shown in Plates LIV and LV. It is exceedingly difficult to get around in this region. Plate LVI shows the location of the lake with regard to the mountains, while Plate LVII shows a large portion of the wooded valley south of and above the lake. With the excep tion of a section of country including the lower portion of the lake as shown in Plate LV all of the country shown in the photographs is in the Lewis and Clarke forest reserve.

The notes here presented by Prin. Silloway contain several important features worthy of special mention. One point is the calamity that often befalls the old birds or the young. Another is the fact that birds occupy unfinished nests, which contain eggs. This latter may be due to the laziness or shiftlessness on the part of the mother, or to her inexperience, which prevents rapid working, or to the destruction of a first nest. The finding of a nest of the Willow thrush, which ordinarily builds close to the ground, six and one-half feet up in a tree, will be of interest to students of animal intelligence, as illustrating the change of habit due to environment. The region overflows annually. Irregular habits of nidification were also found in the cedar waxwing. Indeed, the notes so carefully prepared show quite plainly great individuality in the construction of the nests.

Since Bulletin Biological Series No. 1, Summer Birds of Flathead Lake, is out of print it is considered advisable to print a list of the summer birds thus far discovered, which is appended. This list therefore includes all the summer birds which have been observed about Flathead lake, numbering 137.

MORTON J. ELROD.

Missoula, Mont., Sept. 19, 1903. 10354

Further Notes on the Summer Birds of Flathead Lake.

The following notes are based upon observations made from May 30 to July 30, 1902. The first three weeks of June were spent at the head of Swan lake; the remainder of the time was given to observation in the immediate vicinity of the Biological Station. As a supplement to the notes made during the seasons of 1900 and 1901, which were reported in the bulletin entitled "The Summer Birds of Flathead Lake," issued under the direction of the University of Montana Biological Station, these further notes are deemed worthy of publication. Several important species, overlooked in the previous seasons, were noted in 1902; and as a complete record of our observations for the region is desirable, the notes herein given will serve to fill out somewhat that which was lacking in the larger bulletin. As previously stated, no attempt has been made to furnish a complete list of the birds of the Flathead region, but simply to report such observations as were made by our party during the collecting season; hence no authorities have been cited. It is merely intended to furnish a record of personal work that may be helpful to other observers.

SWAN LAKE.

Among the many little lakes which lend interest and beauty to the Mission, Swan, and other ranges of our Montana mountains, Swan lake is worthy of consideration because of many delightful features. It is an expansion of Swan river, or the Big Fork, the outlet of the lake into the river being about eight miles overland from the Biological Station, in a direction somewhat south of east. A very poor road, generally overflowed during the time of high water in the spring, but tolerably passable at other times, leads from the Station to the foot of the lake. Another road, generally in ordinary condition, follows a course around the bend of Swan river to the northward, thus furnishing access to the lake at all times, the distance over this road being about fifteen miles.

In its origin the lake bed is probably the result of glacial action, whereby in remote ages an irregular furrow was ploughed by the moving ice-mass. The situation is between the northern end of the Mission range and the southern end of the Swan range, and nearly parallel to the eastern shore of Flathead lake. From the tops of the Mission summits between the two lakes, both can be easily seen, the separating crests being not more than five or six miles in breadth.

Swan lake is said to be about twelve miles in length, and the average width is at least half a mile. The contour of the lake is formed by several successive slightly cresentic bays or enlargements. At its head it opens out into a nearly circular area about two miles in diameter, above which lies a large submerged region in the spring, though later it