Part 9

one of the most abundant and characteristic species. Along the shores of the rivers and creeks generally, wherever the black willow (Salix niger) grew, a few pairs were sure to be found. Among the button-bushes (Cephalanthus occidentalis) that fringed the margin of the peculiar long narrow ponds scattered at frequent intervals over the heavily timbered bottoms of the Wabash and White Rivers, they also occurred more or less numerously. Potoka Creek, a winding, sluggish stream, thickly fringed with willows, was also a favorite resort; but the grand rendezvous of the species seemed to be about the shores of certain secluded ponds lying in what is known as the Little Cypress Swamp. Here they congregated in astonishing numbers, and early in May were breeding almost in colonies. In the region above indicated two things were found to be essential to their presence, namely, an abundance of willows and the immediate proximity of water. * * * So marked was this preference, that the song of the male heard from the woods indicated to us as surely the proximity of some river, pond, or flooded swamp, as did the croaking of frogs or the peep of the Hylas.

Dr. Chapman (1907) writes of this bird in its haunts:

The charm of its haunts and the beauty of its plumage combine to render the Prothonotary Warbler among the most attractive members of the family. I clearly recall my own first meeting with it in the Suwanee River region of Florida. Quietly paddling my canoe along one of the many enchanting, and, I was then quite willing to believe, enchanted streams which flowed through the forests into the main river, this glowing bit of bird-life gleamed like a torch in the night. No neck-straining examination with opera-glass pointed to the tree-tops, was required to determine his identity, as, flitting from bush to bush along the river's bank, his golden plumes were displayed as though for my special benefit.

Dr. Lawrence H. Walkinshaw (1938) says that the golden swamp warbler "nests rather abundantly along southwestern-Michigan rivers. * * * Winding streams, bordered densely with oak, maple, ash, and elm, shallow ponds with groups of protruding willows and flooded, heavily shaded bottom-lands are favorite nesting habitats for the Prothonotary Warbler (Protonotaria citrea). Such habitats occur along the banks of the Kalamazoo River and its tributary the Battle Creek River in Calhoun County, Michigan."

Territory.--The males arrive on the breeding grounds a few days or a week before the females come and immediately try to establish their territories, select the nesting sites, and even build nests. Dr. Walkinshaw (1941) writes:

The Prothonotary Warbler is a very strongly territorial species. When a male takes possession of a certain area he continually drives off all opponents if he is able. At certain areas in Michigan I have watched these birds battle intermittently for two or three days, usually for the same bird house, one male finally taking possession. In addition I have observed them to drive off House Wrens (Troglodytes aedon), Black-capped Chickadees (Penthestes atricapillus) and Yellow Warblers (Dendroica aestiva). * * * The male Prothonotary Warbler selects the territory, selecting the nesting site before he becomes mated for the first nest, but thereafter both birds inspect the new nest sites.

On observations made near Knoxville, Tenn., Henry Meyer and Ruth Reed Nevius (1943) found that--

three males established territories. Male I arrived April 14. By the next day he was singing on an area 550 feet long and for the most part not more than 200 feet wide. It included three kinds of habitats: (a) a grassy terrace on which several nesting boxes were located, (b) river banks densely covered with small trees and bushes, and (c) a small open orchard which constituted the connecting link between the terrace and the river bank. Male II arrived on April 18 and occupied a narrow territory along a brook confined by wooded slopes and which contained two lotus ponds. The area was about 400 feet long and 100 feet wide. A nesting box was on a stake above one of the ponds. Male III appeared May 5 in the terraced area being claimed by Male I. During the day, the 2 males sang energetically and flew often only a few inches apart. Male I maintained his territory and Male III disappeared.

There were a number of nesting boxes on the area that the males investigated, carrying nesting material into some of them while they were waiting for the females to arrive. The mate of the first male came on April 20, and--

on this day this pair communicated by their full call-note. Twice the male was seen pursuing the female rapidly in a small semi-circle and pausing, called a soft, full note which was later heard only when the two sexes were together.

The mate of Male II came April 22, four days after the latter's arrival.

Combat with other species found within the territories of these birds was observed. Combat with the Bluebird was most frequent but one or more indications of opposition was noticed with the Flicker, Downy Woodpecker, Acadian Flycatcher, Tufted Titmouse, Robin, and Cardinal.

The males sing persistently and energetically from the time that they arrive on their territories, hoping to attract their mates, but they are not always successful, especially in regions where the species is rare or not very common, and their nest-building brings no occupant. Edward von S. Dingle writes to me that, at Summerton, S. C., a male prothonotary warbler built a nest in a low stub, but no female was ever seen. He sang frequently and remained in the vicinity for several weeks. And Frederic H. Kennard, in far-away Massachusetts, mentions in his notes that he saw one and watched it for several days, June 16-20, 1890. "He sang loudly and clearly and sweetly, and seemed to like a particular place by the side of the river, for when I returned later in the day, he was still there, on the other side of the river." On June 19, he watched him for half an hour. He was always in the same locality. On a later search, no nest or no mate could be found.

Courtship.--Brewster (1878a) gives the following full account of this performance:

Mating began almost immediately after the arrival of the females, and the "old, old story" was told in many a willow thicket by the little golden-breasted lovers. The scene enacted upon such occasions was not strikingly different from that usual among the smaller birds; retiring and somewhat indifferent coyness on the part of the female; violent protestations and demonstrations from the male, who swelled his plumage, spread his wings and tail, and fairly danced around the object of his affections. Sometimes at this juncture another male appeared, and then a fierce conflict was sure to ensue. The combatants would struggle together most furiously until the weaker was forced to give way and take to flight. On several occasions I have seen two males, after fighting among the branches for a long time, clinch and come fluttering together to the water beneath, where for several minutes the contest continued upon the surface until both were fairly drenched. The males rarely meet in the mating season without fighting, even though no female may be near. Sometimes one of them turns tail at the outset; and the other at once giving chase, the pursuer and pursued, separated by a few inches only, go darting through the woods, winding, doubling, now careering away up among the tree-tops, now down over the water, sweeping close to the surface until the eye becomes weary with following their mad flight. During all this time the female usually busies herself with feeding, apparently entirely unconcerned as to the issue. Upon the return of the conqueror her indifference, real or assumed, vanishes, he receives a warm welcome, and matters are soon arranged between them.

Nesting.--The prothonotary warbler and Lucy's warbler are the only two American warblers that habitually build their nests in cavities, usually well concealed. The normal, and probably the original, primitive, nestling sites are in natural cavities in trees and most nests are still to be found in such situations today. The prothonotary is not at all particular as to the species of trees, nests having been found in many kinds of trees, although perhaps a slight preference is shown for dead willow stumps. Nor is it particular as to the size or condition of the cavity, or its location, though quite often choosing one over water or near it. The height above the ground or water varies from 3 feet or less to as much as 32 feet but there are more nests below 5 feet than there are above 10, the height of the majority being between 5 and 10 feet. The size and shape of the cavity are of little concern; if the cavity is too deep, the industrious little birds fill it with nesting material up to within a few inches of the top; sometimes a very shallow cavity is used, so that the bird can be plainly seen from a distance as it sits on the nest. The old deserted holes of woodpeckers or chickadees are favorite nesting sites; the entrances to these have often been enlarged by other agencies, or are badly weathered. In very rotten stumps, the warblers have been known to excavate partially or to enlarge a cavity.

The nests built by the males in early spring, referred to above, are probably rarely used as brood nests and might be classed as dummy nests. The family nest is built almost entirely by the female, with encouragement and a little help from her mate, who accompanies her to and from the nest and in the search for material; much of the soft, green moss used extensively in the nest is often obtainable from fallen logs and stumps in the vicinity.

Brewster (1878a) mentions a nest taken from a deep cavity that "when removed presents the appearance of a compact mass of moss five or six inches in height by three or four in diameter. When the cavity is shallow, it is often only scantily lined with moss and a few fine roots. The deeper nests are of course the more elaborate ones. One of the finest specimens before me is composed of moss, dry leaves, and cypress twigs. The cavity for the eggs is a neatly rounded, cup-shaped hollow, two inches in diameter by one and a half in depth, smoothly lined with fine roots and a few wing-feathers of some small bird."

In Dr. Walkinshaw's (1938) Michigan nests, "moss constituted the bulk of the nesting material in nearly all cases, completely filling the nest space whether it was large or small. On top of this the nest proper was shaped and a rough lining of coarse grape-bark, dead leaves, black rootlets procured from the river-banks, and poison-ivy tendrils was added. Above this a lining of much finer rootlets, leaf-stems, and very fine grasses was used."

In addition to the materials listed above Meyer and Nevius (1943) mention hackberry leaves, hairs, pine needles, horsehair, and cedar bark in their Tennessee nests. They say that from 6 to 10 days were required for nest construction, and that from 3 to 5 days more elapsed before the first eggs were laid. Their four nests were all in bird-boxes; one was in an orchard over plowed ground, one over a lotus pond in a wooded ravine, and two were over lily pools near buildings.

Dr. Walkinshaw (1938) publishes a map showing the location of 21 nesting boxes along the winding banks of the Battle Creek River, in Calhoun County, Mich., and writes: "Of the 28 nests found during 1937, 19 were in bird-houses over running water, 6 were in stubs over water (2 of which were over running water), and the other 3 were in natural holes back from the river bank. Of 44 nests found from 1930 through 1937, excluding the 21 in bird-houses, six were over running water in old woodpecker holes, one in a bridge-support in a slight depression, and nine in natural holes over standing water. Seven were in old woodpecker holes from two to a hundred and sixty feet back from the river-bank."

Many and varied are the odd nesting sites occupied by prothonotary warblers. Dr. Thomas S. Roberts (1936) writes:

The vagaries of this bird in choosing artificial nesting-places are shown by the positions of the following nests. On the La Crosse railroad bridge: in a cigar-box nailed on the engine-house on top of the draw; on one of the piers; in a metal ventilator-cap four inches in diameter, that had fallen and lodged just at the point where the draw banged against the pier, and close under the tracks; in a shallow cavity in a piece of slab-wood nailed to a trestle-support close under the road-bed of the railroad; these all far out in the middle of the Mississippi River. Still others are: in a Bluebird box on a low post by a switching-house and busy railroad platform; in a cleft in a pile in the river; in a tin cup in a barn, to reach which the birds entered through a broken pane of glass; in a pasteboard box on a shelf in a little summer-house; in an upright glass fruit jar in a house-boat; and other similar situations. In most cases the birds had to carry the nesting-material long distances, especially to the places on the bridge.

John W. Moyer (1933) relates an interesting story that was told to him by people living in a farm house along the Kankakee River. A pair of these warblers built their nests and raised their broods for three consecutive seasons in the pocket of an old hunting-coat, hung in a garage; each year the man cleaned out the nest and used the coat in the fall, and the next spring the birds used it again. M. G. Vaiden tells me of a similar case.

Nests have been found in buildings, on beams and other supports. Louis W. Campbell (1930) reports two on shelves in sheds, one in a small paper sack partly filled with staples and another in a coffee can similarly filled. Nests in cans in various situations have been found a number of times, and others have been reported in a tin pail hung under a porch, in a mail box, in a box on a moving ferry boat, in a Chinese lantern on a pavilion, and in an old hornets' nest.

Dr. Walkinshaw writes to me: "At Reelfoot Lake, Tenn., during July, 1940, I found 8 nests of the prothonotary warbler, all built a few feet above the water in small natural holes in cypress knees. Evidently these are regular late-summer nesting sites." The knees were farther under water earlier in the season. Most of his 76 Michigan nests were over water, or less than 100 feet from it; but 10 were 300 or more feet away from it and 2 were over 400 feet away. M. G. Vaiden tells me of a pair that nested in the tool box of a log-loading machine that was in daily operation, hauling logs.

Eggs.--From 3 to 8 eggs have been found in nests of the prothonotary warbler, from 4 to 6 seem to be the commonest numbers, 7 is a fairly common number, and at least 3 sets of 8 have been reported; in the J. P. Norris series of 70 sets are 34 sets of 6, 15 sets of 7, and 2 sets of 8.

The eggs vary in shape from ovate to short ovate, and they are more or less glossy. The eggs are undoubtedly the most striking of the warblers' eggs, with their rich creamy, or rose-tinted cream, ground color, boldly and liberally spotted and blotched with "burnt umber," "bay," "chestnut brown," and "auburn," intermingled with spots and undertones of "light Payne's gray," "Rood's lavender," "violet-gray," and "purplish gray." There is quite a variation in the amount of markings, which are generally more or less evenly scattered over the entire egg; some are sparingly spotted and blotched, while others are so profusely marked as almost to obscure the ground color (Harris).