Chapter 8

Four days later I set out alone, to try my luck with the riddle. As I entered the clearing, the hummer was seen at his post, and my suspicions fastened upon a small wild apple-tree, perhaps twenty rods distant. I went to examine it, and presently the bird followed me. He perched in its top, but seemed not to be jealous of my proximity, and soon returned to his customary position; but when I came back to the apple-tree, after a visit to a clump of oaks at the top of the hill, he again came over. I could find no sign of a nest, however, nor did the female show herself, as she pretty confidently might have been expected to do had her nest been near by. After this I went to the edge of the wood, where I could keep an eye upon both trees without being myself conspicuous. The sentinel spent most of his time in the ash, visiting the apple-tree but once, and then for a few minutes only. I stayed an hour and a half, and came away no wiser than before. The nest, if nest there was, must be elsewhere, I believed. But where? And what was the object of the male's watch?

My curiosity was fully roused. I had never seen or heard of such conduct on the part of any bird, and the next forenoon I spent another hour and a half in the clearing. The hummer was at his post, as he always was. We had never to wait for him. Soon after my arrival he flew to the apple-tree, the action seeming to have no connection with my presence. Presently he went back to the ash, and drove out of it two intruding birds. A moment later two humming-birds were there, and in another moment they flew away in a direction opposite to the apple-tree. Here, then, was a real clue. The birds were probably our sentinel and his mate. I made after them with all speed, pausing under such scattered trees as had been left standing in that quarter. Nothing was to be found, and on my return there sat the male, provokingly, at the top of the apple-tree, whence he soon returned to the ash. A warbler entered the tree, and after a while ventured upon the branch where the hummer was sitting. Instead of driving her away he took wing himself, and paid another visit to the apple-tree,--a visit of perhaps five minutes,--at the end of which he went back to the ash. Then two kingbirds happened to alight in the apple-tree. At once the hummer came dashing over and ordered them off, and in his excitement dropped for a moment into the leafy top of a birch sapling,--a most unnatural proceeding,--after which he resumed his station in the ash. What could I make of all this? Apparently he claimed the ownership of both trees, and yet his nest was in neither! He sat motionless for five minutes at a time upon certain dead twigs of the ash, precisely as our female was accustomed to sit in her apple-tree. For at least seven days he had been thus occupied. Where was his mate? On the edge of the wood, perhaps. But, if so, why did I hear nothing from her, as I passed up and down? Again my hour and a half had been spent to no purpose.

Not yet discouraged, I returned the next morning. For the three quarters of an hour that I remained, the hummer was not once out of the ash-tree for five minutes. I am not sure that he left it for five minutes altogether. As usual, he perched almost without exception on one or other of two dead limbs, while a similar branch, on the opposite side of the trunk, he was never seen to touch. A Maryland yellow-throat alighted on one of his two branches and began to sing, but had repeated his strain only three or four times before the hummer, who had been absent for the moment, darted upon him and put him to flight. A little afterward, a red-eyed vireo alighted on his other favorite perch, and he showed no resentment. The day before, a warbler had sat on the same branch which the yellow-throat now invaded, and the hummer not only did not offer to molest him, but flew away himself. These inconsistencies made it hard to draw any inference from his behavior. During my whole stay he did not once go to the apple-tree, although, for want of anything better to do, I again scrutinized its branches. This time I _was_ discouraged, and gave over the search. His secret, whatever it might be, was "too dear for my possessing." But my fellow-observer kept up his visits, as I have said, and the hummer remained faithful to his task as late as July 15th, at least.

Some readers may be prompted to ask, as one of my correspondents asked at the time, whether the mysterious sentry may not have been the mate of our home bird. I see no ground for such a suspicion. The two places were at least a mile apart, as I have already mentioned, and woods and hills, to say nothing of the village, lay between. If he was our bird's mate, his choice of a picket station was indeed an enigma. He might almost as well have been on Mount Washington. Nor can I believe that he had any connection with a nest found two months afterward in a pitch-pine grove within a quarter of a mile, more or less, of his clearing. It was undoubtedly a nest of that season, and might have been his for aught I know, so far as the mere fact of distance was concerned; but here again an intervening wood must have cut off all visual communication. If his mate and nest were not within view from his ash-tree perch, what could be the meaning of his conduct? Without some specific constraining motive, no bird in his normal condition was likely to stay in one tree hour after hour, day after day, and week after week, so that one could never come in sight of it without seeing him. But even if his nest was in the immediate neighborhood, the closeness and persistency of his lookout are still, to my mind, an absolute mystery. Our female bird, whether she had eggs or offspring, made nothing of absenting herself by the half hour; but this male hardly gave himself time to eat his necessary food; indeed, I often wondered how he kept himself alive. Is such a course of action habitual with male hummers? If so, had our seemingly widowed or deserted mother a husband, who somewhere, unseen by us, was standing sentry after the same heroic, self-denying fashion? These and all similar questions I must leave to more fortunate observers, or postpone to a future summer. Meantime, my judgment as to the male ruby-throat's character remains in suspense. It is not plain to me whether we are to call him the worst or the best of husbands.

ROBIN ROOSTS.

"From every side they hurried in, Rubbing their sleepy eyes." KEATS.

Of all the nearly eight hundred species of North American birds, the robin is without question the one most generally known. Its great commonness and wide distribution have something to do with this fact, but can hardly be said to account for it altogether. The red-eyed vireo has almost as extensive a range, and at least in New England is possibly more numerous; but except among ornithologists it remains a stranger, even to country-bred people. The robin owes its universal recognition partly to its size and perfectly distinctive dress, partly to its early arrival in the spring, but especially to the nature of its nesting and feeding habits, which bring it constantly under every one's eye.

It would seem impossible, at this late day, to say anything new about so familiar a bird; but the robin has one interesting and remarkable habit, to which there is no allusion in any of our systematic ornithological treatises, so far as I am aware, although many individual observers must have taken notice of it. I mean the habit of roosting at night in large flocks, while still on its breeding grounds, and long before the close of the breeding season.[14]

[14] Mr. William Brewster has been aware of this habit for twenty-five years, but, like myself, has never seen it mentioned in print. He devotes to it a paper in _The Auk_ for October, 1890, to which I am happy to refer readers who may wish a more thorough discussion of the matter than I have been able to give. My own paper was printed at the same time, in _The Atlantic Monthly_, and had been accepted by the editor before I knew of Mr. Brewster's intention to write. References to a roost in Belmont, Mass., discovered by Mr. Brewster six years before, are frequent in the following pages.

Toward the end of summer, two years ago, I saw what looked like a daily passage back and forth of small companies of robins. A friend, living in another town, had noticed similar occurrences, and more than once we discussed the subject; agreeing that such movements were probably not connected in any way with the grand southward migration, which, so far as we could judge, had not yet commenced, but that the birds must be flying to and from some nightly resort. The flocks were small, however, and neither of us suspected the full significance of what we had seen.

On the 19th of July, 1889, the same friend informed me that one of our Cambridge ornithologists had found a robin roost in that city,--a wood in which great numbers of birds congregated every night. This led me to keep a sharper eye upon my own robins, whom I had already noticed repeating their previous year's manoeuvres. Every evening, shortly before and after sunset, they were to be seen flying, now singly, now by twos and threes, or even by the half dozen, evidently on their way to some rendezvous. I was suspicious of a rather distant hill-top covered with pine-trees; but before I could make it convenient to visit the place at the proper hour, I discovered, quite unexpectedly, that the roost was close by the very road up and down which I had been walking; an isolated piece of swampy wood, a few acres in extent, mostly a dense growth of gray birches and swamp white oaks, but with a sprinkling of maples and other deciduous trees. It is bounded on the further side by a wet meadow, and at the eastern end by a little ice-pond, with a dwelling-house and other buildings beside it, all within a stone's throw of the wood.

This discovery was made on the evening of July 25th, and I at once crossed a narrow field between the wood and the highway, and pushed in after the birds. It was too dark for me to see what was going on, but as I brushed against the close branches the robins set up a lively cackling, and presently commenced flying from tree to tree before me as I advanced, though plainly with no intention of deserting their quarters. The place was full of them, but I could form no estimate of their number.

On the following evening I took my stand upon a little knoll commanding the western end of the wood. According to my notes, the birds began to arrive about sunset,--but this was pretty certainly an error,--and though I did not undertake an exact count until the flight was mainly over, it seemed likely that at least three hundred passed in at that point. This would have made the total number twelve hundred, or thereabout, on the assumption that my outlook had covered a quarter of the circuit. After the flight ceased I went into the wood, and from the commotion overhead it was impossible not to believe that such a calculation must be well within the truth.

The next day was rainy, but on the evening of the 28th I stood by the shore of the pond, on the eastern side of the wood, and made as accurate a count as possible of the arrivals at that point. Unfortunately I was too late; the robins were already coming. But in fifty minutes, between 6.40 and 7.30, I counted 1072 birds. They appeared singly and in small flocks, and it was out of the question for me to make sure of them all; while I was busy with a flock on the right, there was no telling how many might be passing in on the left. If my observations comprehended a quarter of the circle, and if the influx was equally great on the other sides (an assumption afterward disproved), then it was safe to set the whole number of birds at five thousand or more. Of the 1072 actually seen, 797 came before the sunset gun was fired,--a proportion somewhat larger than it would have been had the sky been clear.

On the afternoon of the 29th I again counted the arrivals at the eastern end; but though I set out, as I thought, in good season, I found myself once more behind time. At 6.30 robins were already dropping in, notwithstanding the sky was cloudless. In the first five minutes eighteen birds appeared; at sunset 818 had been counted; and at 7.30, when I came away, the figures stood at 1267. "The robins came more rapidly than last night," I wrote in my notebook, "and for much of the time I could keep watch of the southeastern corner only. My vision then covered much less than a quarter of the circuit; so that if the birds came as freely from other directions, at least five thousand must have entered the wood between 6.30 and 7.30. As long as it was light they avoided passing directly by me, going generally to the left, and slipping into the roost behind some low outlying trees; though, fortunately, in doing this they were compelled to cross a narrow patch of the illuminated western sky. I suspect that the number increases from night to night. Between 6.40 and 7.30, 1235 birds came, as compared with 1072 last evening."

Two days afterward (July 31st) I went to the western end of the wood, and found the influx there much smaller than on the opposite side; but I arrived late, and made a partial count only. After sunset 186 birds were seen, whereas there had been 455 entries at the eastern end, two nights before, during the same time.

Thus far I had always been too late to witness the beginning of the flight. On the evening of August 1st I resolved to be in season. I reached the border of the pond at 5.15, and at that very moment a single robin flew into the wood. No others were seen for eighteen minutes, when three arrived together. From this time stragglers continued to appear, and at 6.30 I had counted 176. In the next ten minutes 180 arrived; in the next five minutes, 138. Between 6.45 and 7, I counted 549; then, in six minutes, 217 appeared. At 7.25, when I concluded, the figures stood at 1533 birds. For about twenty minutes, as will be noticed, the arrivals were at the rate of thirty-six a minute. Throughout the thickest of the flight I could keep a lookout upon only one side of me, and, moreover, the gathering darkness was by that time making it more and more difficult to see any birds except such as passed above the dark tree line; and from what went on just about me, it was evident that the number of arrivals was increasing rather than diminishing as my count fell off. There seemed to be no good reason for doubting that at least two thousand robins entered the wood at the eastern end.

Two nights later I stationed myself in the meadow southwest of the roost. Here I counted but 935 entries. The movement appeared to be fully as steady as on the opposite side, but as darkness came on I found myself at a great disadvantage; a hill occupied the background, giving me no illuminated sky to bring the birds into relief, so that I could see only such as passed close at hand. Of the 935 birds, 761 came before seven o'clock, but it was reasonably certain that the flight afterward was nearly or quite as great, only that I wanted light wherewith to see it.

On the evening of August 4th I went back to the eastern end, and as the sky was perfectly clear I hoped to make a gain upon all my previous figures. But the fair weather was perhaps a hindrance rather than a help; for the robins came later than before, and more in a body, and continued to arrive long after it was impossible to see them. I counted 1480,--53 less than on the 1st.

I attempted no further enumeration until the 18th. Then, in an hour and ten minutes, 1203 birds were seen to enter the roost at the eastern end. But they arrived more than ever in flocks, and so late that for much of the time I missed all except the comparatively small number that passed in my immediate vicinity. Many were flying at a great height,--having come from a long distance, as I inferred,--and sometimes I knew nothing of their approach till they dropped out of the sky directly over the wood. On this occasion, as well as on many others,--but chiefly during the latter part of the season,--it was noticeable that some of the robins appeared to be ignorant of the precise whereabouts of the roost; they flew past it at first, and then, after more or less circling about, with loud cackling, dived hurriedly into the wood. I took special note of one fellow, who came from the south at a great altitude, and went directly over the wood. When he was well past it he suddenly pulled himself up, as if fancying he had caught a signal. After a moment of hesitation he proceeded on his northerly course, but had not gone far before he met half a dozen birds flying south. Perhaps he asked them the way. At all events, he wheeled about and joined them, and in half a minute was safe in port. He had heard of the roost, apparently (how and where?), but had not before visited it.

This count of August 18th was the last for nearly a month, but I find a minute of August 27th stating that, while walking along the highway on the westerly side of the roost,--the side that had always been the least populous,--I saw within less than two minutes (as I calculated the time) more than eighty robins flying toward the wood. Up to this date, then, there could not have been any considerable falling off in the size of the gathering. Indeed, from my friend's observations upon the Belmont roost, to be mentioned later, it seems well-nigh certain that it was still upon the increase.

Toward the close of August I became interested in the late singing of several whippoorwills, and so was taken away from the robins' haunt at the hour of sunset. Then, from the 5th to the 13th of September, I was absent from home. On the night of my return I went to the shore of the pond, where, on the 1st of August, I had counted 1533 entries. The weather was favorable, and I arrived in good season and remained till the stars came out, but I counted only 137 robins! It was plain that the great majority of the congregation had departed.

As I have said, there was little to be learned by going into the wood after the robins were assembled. Nevertheless I used frequently to intrude upon them, especially as friends or neighbors, who had heard of my "discovery," were desirous to see the show. The prodigious cackling and rustling overhead seemed to make a deep impression upon all such visitors, while, for myself, I should have had no difficulty in crediting the statement had I been told that _ten thousand_ robins were in the treetops. One night I took two friends to the place after it was really dark. All was silent as we felt our way among the trees, till, suddenly, one of the trio struck a match and kindled a blaze of dry twigs. The smoke and flame speedily waked the sleepers; but even then they manifested no disposition to be driven out.

For curiosity's sake, I paid one early morning visit to the roost, on the 30th of July. It would be worth while, I thought, to see how much music so large a chorus would make, as well as to note the manner of its dispersion. To tell the truth, I hoped for something spectacular,--a grand burst of melody, and then a pouring forth of a dense, uncountable army of robins. I arrived about 3.40 (it was still hardly light enough to show the face of the watch), and found everything quiet. Pretty soon the robins commenced cackling. At 3.45 a song sparrow sang, and at the same moment I saw a robin fly out of the wood. Five minutes later a robin sang; at 3.55 another one flew past me; at four o'clock a few of the birds were in song, but the effect was not in any way peculiar,--very much as if two or three had been singing in the ordinary manner. They dispersed precisely as I had seen them gather: now a single bird, now two or three, now six, or even ten. A casual passer along the road would have remarked nothing out of the common course. They flew low,--not as if they were starting upon any prolonged flight,--and a goodly number alighted for a little in the field where I was standing. Shortly before sunrise I went into the wood and found it deserted. The robin is one of our noisiest birds. Who would have believed that an assembly of thousands could break up so quietly? Their behavior in this regard may possibly have been influenced by prudential considerations. I have said that many of them seemingly took pains to approach the roost indirectly and under cover. On the westerly side, for example, they almost invariably followed a line of bushes and trees which runs toward the roost along the edge of the meadow, even though they were obliged sharply to alter their course in so doing.

All this time I had been in correspondence with my friend before referred to, who was studying a similar roost,[15]--in Belmont,--which proved to be more populous than mine, as was to be expected, perhaps, the surrounding country being less generally wooded. It was a mile or more from his house, which was so situated that he could sit upon his piazza in the evening and watch the birds streaming past. On the 11th of August he counted here 556 robins, of which 336 passed within five minutes. On the 28th he counted 1180, of which 456 passed within five minutes,--ninety-one a minute! On the 2d of September, from a knoll nearer the roost, he counted 1883 entries.

[15] This roost was discovered by Mr. William Brewster, in August, 1884, as already mentioned.

This gathering, like the one in Melrose, was greatly depleted by the middle of September. "Only 109 robins flew over the place to-night," my correspondent wrote on the 25th, "against 538 September 4th, 838 August 30th, and 1180 August 28th." Two evenings later (September 27th) he went to the neighborhood of the roost, and counted 251 birds,--instead of 1883 on the 2d. Even so late as October 9th, however, the wood was not entirely deserted. During the last month or so of its occupancy, the number of the birds was apparently subject to sudden and wide fluctuations, and it seemed not unlikely that travelers from the north were making a temporary use of the well-known resort. It would not be surprising if the same were found to be true in the spring. In April, 1890, I saw some things which pointed, as I thought, in this direction, but I was then too closely occupied to follow the matter.

How early in the season does this nightly flocking begin? This question often presented itself. It was only the middle of July when the Cambridge roost was found in full operation, though at that time many robins must still have had family duties, and some were probably building new nests. Next summer, we said, we would try to mark the beginnings of the congregation.

My own plans to this end came near being thwarted. In December I was dismayed to see the owner of the wood cutting it down. Happily some kind power stayed his hand when not more than a third of the mischief was done, and on the 29th of June, 1890, while strolling homeward along the highway, listening to the distant song of a veery, I noticed within five or ten minutes seventeen robins making toward the old rendezvous. On the following evening I stood beside the ice-pond and saw one hundred and ninety-two robins enter the wood. The flight had begun before my arrival, and was not entirely over when I came away. Evidently several hundreds of the birds were already passing their nights in company. In my ignorance, I was surprised at the early date; but when I communicated my discovery to the Belmont observer, he replied at once that he had noticed a movement of the same kind on the 11th of June. The birds, about a dozen, were seen passing his house.