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SWALLOW ROOSTS AND SWALLOW MIGRATION
SWALLOWS begin to gather near the shore at Ipswich, as well as elsewhere on our coast, as early as the first of July, and their numbers rapidly increase from day to day. At the end of that month and during August and early September, great multitudes of these interesting birds are to be found in the neighborhood of the sea. In these flocks all four of our common species occur, but by far the most abundant is the tree swallow. Next in numbers comes the barn swallow, and next the bank swallow, although the latter is less common in Ipswich than the eave swallow, which appears to be a rather more exclusive bird, and one that is more apt to keep by itself than to mingle in the large mixed flocks.
From the great numbers of swallows that congregate here in the fall it is evident that many must come from a distance, for there are more than the immediate country would support during the nesting season. It is their annual excursion to the seashore, and although they gather about the neighboring roadsides, pastures and marshes, their favorite resorts are the dunes and upper beaches. Although some of these birds migrate south early in the season, the majority remain together for days or even weeks before starting for their winter homes; yet it is possible that some are constantly leaving, and their places are so quickly taken by others that we do not notice any diminution in their numbers.
Although many of the swallows scatter far and wide in the search for food, yet such is the social disposition of these birds that great flocks are commonly to be found during July, August and early September, even at midday in various of their favorite haunts. Perhaps the most familiar of these haunts, and certainly the most conspicuous to the passer-by, is the roadside. Here they congregate and line fence rails and telegraph wires. Before the extension of the wires to the beach road at Ipswich, the swallows often clustered on the fence rails, but since the erection of these “way-side crucifixes,” as Frank Bolles called telegraph poles, the lowlier perches have been forsaken.
TREE SWALLOWS INVESTIGATING A BIRDHOUSE
NESTS OF EAVE SWALLOWS ON AN OLD BARN
One may see lines of these birds stretching, with but few gaps, on a couple of wires for a mile. Such congregations number several thousand, and all four species may be seen sitting shoulder to shoulder in the most friendly and democratic manner. At times, especially on marsh roads, where there are neither retaining fences nor overhead wires, the swallows cover the ground itself in patches, taking flight reluctantly as the wayfarer advances upon them.
Another favorite resting place by day is in the salt marshes, where the birds cover every available projection such as fence posts, staddles, gunner’s blinds and stranded branches of trees.
Swallows are certainly fond of the water and delight to gather about ponds near the seashore. I have seen as many as two thousand in such a situation in Ipswich. The great majority of these were tree swallows, but here and there a barn swallow and a diminutive bank swallow were to be seen. They were constantly alighting on the bushes, fence wires, and rails, particularly on those that were over the water. Every few moments, with a loud whirring noise from their many wings, they would rise and wheel about in bands, showing first dark and then white, as they turned alternately their backs and their breasts to the observer. Again they would distribute themselves irregularly over the sky, and a little later they would throw themselves at the water with such violence that the surface would be covered with little splashes, as if a bombardment were in progress.
Such exhibitions as this display not only the social and gregarious characteristics of swallows, but also the love of what appears to deserve the name of play. It has been said, as a reproach to their intelligence, that birds do not play when young as do the young of mammals, but the evolutions I have just described seem to show a spirit of enjoyment or play in flight, the natural exercise of birds, just as do spurts of running, or wrestling or butting contests in mammals.
Another interesting trait of these flocking birds is their habit of inspecting holes in posts and trees, and bird-houses that come in their way, as well as of collecting feathers in their bills as they fly. This autumnal revival of the nesting instincts is an interesting trait, and appears to be a common one in birds. Examples of this are the autumnal revival of song, notably in the meadow-lark, bluebird, song and Savannah sparrows, as well as in the barn and tree swallows; of the inspection of nesting localities by bluebirds and phoebes as well as by tree swallows; and of the courtship actions of grouse, sandpipers, plovers and ducks.
Among the apple orchards near the coast at Ipswich are to be found many ancient trees, picturesque veterans, partly killed by the struggles with many winters, storm-beaten and time-worn, yet surprisingly full of vigor in their living branches, as shown by their wealth of blossoms in the spring and of apples in the fall. Among the dead branches of these old trees swallows love to congregate; here they proclaim their presence, even in their absence, by the numerous white droppings that spot the dead branches; here they roost for the night in great numbers. From these dead tree-tops they arise in the early morning with the whirring f many wings, and betake themselves to the roofs of neighboring barns, where they sun themselves, preen their feathers and gossip with one another. These roosts among the orchards may be frequented for many days or weeks before all the birds disappear for the south.
The sand dunes and beaches, however, are the most popular resort of this interesting group of birds. Here they alight on the beach itself, on the smooth expanses in the dunes, or among the bayberry bushes, where the tree swallows gorge themselves with the waxy berries. I once found forty-one of these large berries in the small alimentary tract of a tree swallow. As far as I know this is the only species of swallow that enjoys such an unusual diet, for insects are, of course, the swallow’s favorite prey.
In a thicket of birches among the dunes just to the south of my camp a multitude of swallows spend the nights in the latter part of the summer, and they are interesting neighbors. On one August evening I watched them from the top of a dune. They began to arrive about six o’clock, and the majority came from the west, — from the region of the setting sun, — and flew in a continuous sheet, perhaps a third of a mile wide, skimming for the most part close to the sand, but mounting occasionally high into the sky. As the birds sped by me, they often flew within a few feet or inches, and at times barely grazed the sand. Tree swallows were in the majority, while barn swallows formed perhaps a fourth part of the whole, and there were a few bank but no eave swallows. The characteristic notes of the three species could be heard from time to time, but the birds were for the most part silent, although occasionally a barn swallow would break forth into his always delightful song. The flight was an irregular and wavering one, but the multitudes were intent on their goal, wearied, no doubt, by the day’s work and play. Occasionally two would stop in their onward career, playfully to attack each other in mid-air, and at times, for no apparent reason but as the impulse seized them, a sudden upward or even retrograde movement of all the birds would occur. The sun set at five minutes of seven, but the birds still poured by in the gathering dusk, while the air to the north and west appeared filled with black forms against the luminous yellow haze made by the rays of the departed sun. At ten minutes past seven, already dusk, the birds were pressing’ on in undiminished numbers. Two minutes later they suddenly stopped coming, with the exception of a few stragglers, while a great mass of whirling, twittering birds could be seen over the birch thicket to the south. A minute later, at thirteen minutes after seven, another army of birds was flying south, but the movement ceased at a quarter past seven, although a few belated ones straggled by in the darkness.
At half-past seven I ventured to investigate the roost, which I found to be somewhat over an acre in extent and to consist of small birch trees about fifteen feet high, closely crowded together. The blackness of the undergrowth of ferns was relieved by the numerous white droppings of the roosting birds. In the darkness not a swallow could be seen amid the thick foliage, but a constant conversational twittering revealed their presence. As I entered the grove the noise became greater, and a number of birds above my head took flight. I shook a tree and a frightened mass of swallows flew out with whirring wings. The disturbance, however, was local and soon quieted when I had beaten a hasty retreat.
The morning flight from this roost was certainly an interesting performance. I slept that night on the top of a pointed dune a short distance to the west of the swallows. About four o’clock I heard a few swallows going over, and ten minutes later a large number of these birds sprang suddenly into the clear, cool morning air that was already faintly glowing with the light of the coming sun. Hither and yon they flew in the exuberance of their joy of living, describing irregular curves and partial circles, fluttering their wings rapidly and bursting out into song which proclaimed their identity. The song was that of the barn swallow, and the combined effect of the great multitude of singers was delightful in the extreme. All appeared to be barn swallows, although in the imperfect light identification by sight was difficult. In a few minutes the joyful birds dispersed. Many, still singing, flew over my sandy couch high in the air towards the west, and soon all were gone. The song of the barn swallow is one of the most delightful of our bird songs, yet it is but little known.
For nearly ten minutes only a few scattered swallows were to be seen, when suddenly a great whirring of wings was heard, and the simple song of the tree swallow, poured from a multitude of throats, burst upon my ear. The effect was a pleasing musical jingling, that seemed to shower down from the sky, as many hundreds, perhaps thousands, of tree swallows rose in the air. As they went north and west they flew for the most part lower than the previous band of barn swallows, that now seemed small in comparison. They did not skim close to the cold sand, however, as at night, but were perhaps one hundred feet up. At a quarter f five a mixed flock of about a hundred swallows flew over me as I lay on my dune-top. In this group barn, tree, and bank swallows could all be distinguished. The sun rose out of the sea at eight minutes of five. Another day of hunting and sport!
The southward migration of swallows in the autumn occurs by day. Swallows are not obliged to fly by night, like most of the smaller birds, for two very good reasons. In the first place they are strong and swift flyers, and can accomplish more in half a day than many other birds in a whole one, and secondly they can feed while on the wing. Hence night work is not necessary for them, and the hours of daylight easily suffice for both feeding and travelling.
I have often seen in the fall great numbers of swallows flying leisurely towards the south over the beach and dunes at Ipswich during nearly the entire day. Now they skim close to the white sand, snapping up the surface flies and other delectable insects. Again they mount high in the air, and continue their southward journey, far removed from the earth. Again they alight to feed on bayberries, to rest and converse with each other. In the air they call to each other as they fly, just as do the nocturnal hosts, whose lack of skill on the wing and whose feeding habits, being of the earth or trees, require the extra night hours of labor. These night migrants, although heard, are invisible in the darkness, while the swallows delight the eye with their graceful flights in the full light of day.
A more spectacular migration of swallows I have sometimes observed. Here the resting hosts, moved by a common impulse, or in response to some mysterious signal, mount into the air in irregular circles, at times drifting together and whirling about like masses of smoke, all the time rising higher and higher. When so high that the individual birds can with difficulty be distinguished, they move off towards the south, and with their rapid flight are soon lost to sight. With the evidence of migration so apparent, it is a curious fact that for many years it was believed that swallows retired to the bottoms of ponds in the fall and spent the winter dormant in the mud!