It was the markedly dovelike coo which first introduced me to this species. With William Brewster I was at the Fresh Pond marshes, listening for the repetition of some strange calls which had excited the curiosity of Cambridge ornithologists, and which proved to belong to a Florida Gallinule,[[B]] when we heard the soft notes of a Least Bittern, who soon rose from the marsh near by. A few days later the Bittern was found in full song—if the coo be its song—in the marshes of Presque Isle in Erie Bay; but it must be confessed that a desire to secure specimens of this, to me, strange bird left no opportunity to study its habits, and the species was not again observed until June, 1898, in the northern part of Cayuga County, New York. Here, under the guidance of an observing local ornithologist, Mr. E. G. Tabor, an encounter was had with a Least Bittern which made a unique page in my experience as a bird student.
[B]. See Brewster, Auk, vol. viii, 1891, p. 1.
It was on the border of Otter Lake, where the Least Bitterns nest in small numbers in low bushes, or a mass of drift, or more often in the fringe of cat-tails. The trail of a boat through the reeds and empty nests, which before had held from three to five eggs, marked the ill-directed work of the boy oölogists whose misspent zeal has resulted in such a vast accumulation of eggshells and such an absence of information about the birds that laid them. A visit to a more distant part of the lake, where even thus early in the year the cat-tails were five feet above water of over half that depth, saved the day, as far as Least Bitterns were concerned. Paddling close to the reeds, a practiced eye could distinguish the site of a Bittern’s nest, when the nest itself was invisible, by the bowed tips of the reeds which the bird invariably bends over it.[31] The object of this habit is perhaps to aid in concealing the eggs from an enemy passing overhead—a Crow, for example—an attack by boat evidently not being taken into consideration.
Certainly our appearance was in the nature of a surprise to a pair of birds who had just completed their platformlike nest and were apparently discussing future steps in their domestic affairs.
32. Least Bittern’s nest; reeds parted to show eggs.
As we approached, the female, who even before the eggs are laid seems to have the home love more strongly developed than the male, bravely stuck to her post, while the male marched off through the reeds in the manner which has been described as so remarkable. When he paused, with either foot grasping reeds several inches apart or clung to a single stalk with both feet, he resembled a gigantic, tailless Marsh Wren.
33. Least Bittern on nest mimicking its surroundings.
The actions of the female were interesting in the extreme. Her first move was an attempt at concealment through protective mimicry—a rare device among birds. Stretching her neck to the utmost, she pointed her bill to the zenith, the brownish marks on the feathers of the throat became lines which, separated by the white spaces between them, might easily have passed for dried reeds, and the bird’s statuelike pose, when almost within reach, evinced her belief in her own invisibility.[33], [34]