Page:Life Histories of North American Diving Birds.djvu/27

Rh season. It was almost impossible to count or even to estimate the number of western grebes in this colony, for the nests were scattered over a wide area among the reeds or bulrushes (Scirpus lacustris), and many of them were beyond our reach in water too deep to wade; there were certainly hundreds, and perhaps over a thousand of them. The nests were floating in water 2 feet deep or more and consisted of compact masses of rubbish, dead and rotten reeds, mixed with a few green flags, and plastered with soft slimy vegetable substances. They were generally anchored to growing bulrushes in plain sight, but some were well concealed from view in thick clumps. They were built up from 3 to 5 inches above the water and measured from 18 to 25 inches in diameter, the inner cavity being from 7 to 9 inches in diameter. We were surprised to find the bodies of a large number of these grebes lying dead on or near their nests, during both seasons, and were unable to account for it; sometimes two bodies were found at one nest. Muskrats were quite common in this slough, and a pair of minks had a den on the island; perhaps the latter may have indulged in a midnight massacre. In another deep-water slough, near Crane Lake, we found a small colony of 12 or 15 pairs of western grebes nesting among the cat-tail flags (Typha latifolia), where the nests were often well concealed in thick clumps.

Although they were not so shy and retiring about their breeding grounds as the other grebes, I was never able to surprise a western grebe on its nest until one cold, rainy day when I waded into the slough and saw the birds sliding off their bests all around me, swimming away almost under my feet and bobbing up unexpectedly near me; the sun came out soon afterwards and I longed for my camera; I tried to repeat the experience later but never succeeded. Apparently they sit more closely in wet weather, but under favorable circumstances do not find it necessary. Evidently both sexes assist in incubation. They seldom, if ever, cover the eggs with the nesting material as other grebes do. I once flushed a female ruddy duck from a clump of bulrushes, but a careful search revealed nothing but grebes' nests and later I took from a grebe's nest two eggs of the western grebe and an egg of the ruddy duck. The smaller grebes also occasionally lay an egg in a western grebe's nest.

In North Dakota the western grebes breed abundantly in some of the sweetwater lakes, generally in deep water and often among the tall canes and wild rice which grows 8 or 10 feet high. The extensive marshes of tall canes (Phragmites communis) bordering the Waterhen River in Manitoba form a safe and almost inaccessible breeding resort for this species where large numbers find a congenial summer home. The water in these marshes is too deep to 55916–19–Bull. 107.–2