HARVARD UNIVERSITY LIBRARY OF THE Museum of Comparative Zoology [ 9- THE WILSON BULLETIN A Quarterly Magazine of Ornithology H. Lewis Batts, Jr. Editor Editorial Advisory' Board George A. Bartholomew Andrew J. Berger William W. H. Gunn Raymond A. Paynter, Jr. William A. Lunk Robert A. Norris Kenneth C. Parkes Volume 71 19.59 Published by THE WILSON ORNITHOLOGICAL SOCIETT >V() (1 4 (i 0 i; AW 0 3 .fc U W ^ March 1959 VOL. 71, No. 1 PAGES 1-104 Hi ; mr.v Wbt Wifeon iPulletm Published by ®lje Alteon ©rnittolosical ^ocietp at Kalamazoo, Michigan The Wilson Ornithological Society Founded December 3, 1888 Named after Alexander Wilson, the first American ornithologist. President— Lawrence H. Walkinshaw, 1703 Wolverine-Federal Tower, Battle Creek, Michigan. First Vice-President— Harold F. Mayfield, River Road R.F.D., Waterville, Ohio. Second Vice-President-Phillips B. Street, Route 1, Chester Springs, Pennsylvania. Treasurer — Ralph M. Edeburn, Dept, of Zoology, Marshall College, Huntington 1, West Virginia. Secretary — Aaron M. Bagg, Farm Street, Dover, Massachusetts. Membership dues per calendar year are: Sustaining, $6.00; Active, $4.00. The Wilson Bulletin is sent to all members not in arrears for dues. The Josselyn Van Tyne Memorial Library The Josselyn Van Tyne Memorial Library of the Wilson Ornithological Society, housed in the University of Michigan Museum of Zoology, was established in concurrence with the University of Michigan in 1930. Until 1947 the Library was maintained entirely by gifts and bequests of books, reprints, and ornithological magazines from members and friends of the Society. Now two members have generously established a fund for the purchase of new hooks; members and friends are invited to maintain the fund by regular contributions, thus making available to all Society members the more important new books on ornithology and related subjects. The fund will be administered by the Library Committee, which will be happy to receive suggestions on the choice of new books to be added to the Library. William A. Lunk, University Museums, University of Michi- gan, is Chairman of the Committee. The Library currently receives 65 periodicals as gifts and in exchange for The Wilson Bulletin. With the usual exception of rare books, any item in the Library may be borrowed by members of the Society and will be sent prepaid (by the University of Michigan) to any address in the United States, its possessions, or Canada. Return postage is paid by the borrower. Inquiries and requests by borrowers, as well as gifts of books, pamphlets, reprints, and magazines, should be addressed to “The Josselyn Van Tyne Memorial Library, University of Michigan Museum of Zoology, Ann Arbor, Michigan.” Contributions to the New Book Fund should be sent to the Treasurer, Ralph M. Edeburn, Dept, of Zoology, Marshall College, Huntington 1, West Virginia (small sums in stamps are acceptable). A complete index of the Library’s holdings was printed in the September 1952 issue of The Wilson Bulletin and each September number lists the book titles in the accessions of the current year. A brief report on recent gifts to the Library is published in every issue of the Bulletin. The Wilson Bulletin The official organ of The Wilson Ornithological Society, published quarterly, in March, June, September, and December, at Kalamazoo, Michigan. The subscription price, both in the United States and elsewhere, is $4.00 per year, effective in 1959. Single copies, $1.00. Subscriptions, changes of address and claims for undelivered copies should be sent to the Treasurer. Most back issues of the Bulletin are available (at 50 cents each for 1950 and earlier years, 75 cents each for 1951—1958) and may be ordered from the Treasurer. I ^ i ^ u I®*" publication, books and publications for review should be addressed to the Editor. Exchanges should be addressed to The Josselyn Van Tyne Memorial Library, Museum of Zoology, Ann Arbor, Michigan. Entered as second class matter at Lawrence, Kansas. Additional entry at Ann Arbor, Mich. ^ The Allen Press, Lawrence, Kansas pTcot^p. zo MAR 2 7 191 HP.1 OHlfe THE WILSON BULLETIN A QUARTERLY MAGAZINE OF ORNITHOLOGY Published by The Wilson Ornithological Society Vol. 71, No. 1 March 1959 Pages 1—104 CONTENTS Black-throated Trogon, Painting by Don R. Eckelberry facing page Life History of the Black-throated Trogon Alexander F. Skutch A Field Study of Temperature Regulation in Young Least Terns and Common Nighthawks Thomas R. Hoicell Observations on the Fulvous Tree Duck in Louisiana Brooke Meanley and Anna Gilkeson Meanley Comments on “Species Recognition” with Special Reference TO the Wood Duck and the Mandarin Duck William C. Dilger and Paul A. Johnsgard Variation in the Songs of the Rufous-sided Towhee Donald ]. Borror Observations on Territorial Behavior of Least Flycatchers David E. Davis Notes on the Nesting of Selected Species of Birds of the Sonoran Desert D^nsley General Notes LEG-MUSCLE FORMULAE AND SYSTEMATICS Andrew J. Berger TUFTED TITMOUSE FEEDING ON A SHREW Richard C. Fleming SCISSOR-TAILED FLYCATCHER IN NORTHERN MINNESOTA Gordon W. Gullion and Bruce A. Brown INTERACTION BETWEEN A FERAL PARAKEET AND HOUSE SPARROWS Thane S. Robinson YELLOW-BREASTED CHAT PARASITIZED BY TICK Don BleitZ FOSTER-FEEDING AND POLYGAMY IN THE PURPLE MARTIN William E. Southern NEW BIRD RECORDS FOR ST. CROIX, VIRGIN ISLANDS G. A. Seaman NESTING CONCENTRATIONS OF LONG-EARED OWLS IN COCHISE COUNTY, John J. Stophlet John S. Tomer ARIZONA A PALM WARBLER IN OKLAHOMA Ornithological News JossELYN Van Tyne Memorial Library Ornithological Literature , Y William H. Behle, The Bird Life of Great Salt Lake, reviewed by Thane b. Robinson; L. L. Snyder, Arctic Birds of Canada, reviewed by 1 . B. Hofsluml. 5 D 19 33 46 54 73 86 9.3 94 9.5 95 95 % 96 97 99 100 102 103 jVBAByyw -jjj* BLACK-THROATED TROGON {Trogon rufus] Male (fop) and female. From a tempera painting by Don R. Eckelberry. LIFE HISTORY OF THE BLACK-THROATED THOGON BY ALEXANDER F. SKUTCH ON Barro Colorado Island in Gatun Lake, in the middle of the Isthmus of Panama, I found my first two nests of the Black-throated Trogon ( Trogon rufus ) , in 1935. Both were destroyed by predators before the eggs hatched. Four years later, in the Valley of El General in southern Costa Rica, I found my third nest, which met a similar fate. In most of the succeeding years I have studied birds in the same region, where these trogons are not uncommon, and I have encountered five additional nests. With the exception of one which I did not see until the young were almost feathered, only the last was successful. This was situated on our farm in El General in April, 1958, and enabled me to round out a study begun 23 years earlier. The present paper is, then, a report of observations gathered over nearly a quarter of a century. The slowness of their accumulation is to be attributed to the diffi- culty of finding the nests of the majority of the birds that dwell in tropical rain-forest, and the discouragingly small proportion of these nests that yield living young. Appearance and Range One of the smaller members of its family, the Black-throated Trogon has a total length of about nine inches, of which w ell over half is accounted for by its long tail. The male’s predominant color is bright metallic green, which covers all the upper surface of head and body and likewise the chest. Golden reflec- tions play over his glossy back. His lores, cheeks, chin, and throat are black; his lower breast, abdomen, and under tail-coverts bright orange-yellow. His central tail feathers are bluish-green with black tips, the outer ones white with narrow black bars. His wing-coverts are finely vermiculated with black and white, so that at a distance they appear gray, while the primaries are largely black. Each large, deep brown eye is surrounded by a prominent ring of pale blue, naked skin. His bill, waxy yellow when viewed in the sunshine, is of a tint so pale that in the shade it appears white. His short legs and toes aie blackish. On head and body the female is mostly brown, with yellow on her lower breast, abdomen, and under tail-coverts. Her black-tipped central tail feathers are cinnamon-rufous, of a shade far brighter than her back; while the outer ones are white, narrowly barred with black. A wide white crescent behind and a narrower one in front of each dark brown eye give her an appearance of alertness. Her bill is gray, with black on the culmen and tip of the upper mandible, and her feet are dark. (The colors of the featherless pans are taken from notes made at nests on Barro Colorado Island and in El General.) o 6 THE WILSON BULLETIN March 1959 Vol, 71, No. 1 This lovely trogon ranges from eastern Honduras through southern Central America to the Guianas and Brazil. It inhabits not only the rain-forests of the Caribbean lowlands of Central America but also the drier and more open woodlands of the Pacific side north of the Gulf of Nicoya. In the rain-forests of El General, on the Pacific slope south of the Gulf of Nicoya, it is resident and breeds up to about 2500 feet above sea level; I can find no definite record of its presence anywhere much higher than this. I did not once meet it in the course of a vear and a half of intensive bird-watching on the northern side of the basin of El General around 3000 feet. At this altitude it is replaced by the Collared Trogon [Trogon collaris), and in this region the two species appear not to overlap vertically. Habitat and Food 1 have most often met the Black-throated Trogon perching solitary in the heavy forest, well above my head but far below the crowns of the great trees. Rarely another adult was in view. Of the four trogons on our farm — the others being the Massena Trogon (T. massena). the Violaceous Trogon [T . violaceus), and the White-tailed or Baird’s Trogon {T. viridis) — the Black- throated stays lowest. Although the other three sometimes wander and even nest outside the forest, in pastures and plantations with scattered trees, this shade-loving species seems never to venture beyond the shelter of continuous woodland. Like other members of its family, it perches very upright, with its tail pointing almost straight downward. It remains long in one spot, then suddenly darts out, plucks an insect from the foliage while hovering on wing, and carries it to the same or another perch to eat it. It sometimes takes berries or other small fruits in the same spectacular fashion ; but it eats fewer of them than some of the other trogons, as I judge by the absence from its nest of the regurgitated seeds that accumulate abundantly in the chambers of the White- tailed Trogon, the Massena Trogon, the Quetzal [ Phmomachrus mocino), and other species. Voice The call of the Black-throated Trogon consists of low, weak, mellow notes delivered in series of two, three, or less often four: cow coiv, or cow cow cow, that of the female even weaker than that of the male. Of the associated trogons of the Central American lowlands, the Black-throated most resembles in voice the Violaceous Trogon, whose notes are of the same character but more force- ful, and delivered more rapidly in longer series, perhaps a dozen together — a performance far more vigorous and spirited than that of the Black-throat. The call of the White-tailed Trogon, which also consists of soft, melodious notes, is easily distinguished by their acceleration and rise in pitch as the long series Al<*xan(ler V. Skulcli BLACK-THROATED TROGON 7 proceeds, to end in a sort of roll. The voices of the Massena Trogon and the Citreoline Trogon, [Trogon citreolus) stronger and harsher than those of the foregoing species, are not readily confused with them. The Black-throated Trogon’s call closely resembles that of its highland representative, the Collared Trogon, and to a less degree that of the Mexican Trogon [T. niexicanus) . When alarmed, or when cautiously approaching their nest. Black-throated Trogons of both sexes voice low churring and rattling notes, which sound something like krrrr, krrr-ret, or krrr-re-ek. As it utters these notes, the bird rather slowly raises its tail until it stands almost upright, then lowers it at about the same speed — a movement which makes the black-barred, white under surface of the tail flash out conspicuously. A less frequent utterance consists of low, clear, beautifully modulated notes, mingled with the subdued, melancholy cote’s grouped in twos and threes, which I heard once in June from a male who perched in sight of my blind. The male Black-throated Trogon presents the unexpected contrast of glittering plumage, which one associates with such active, spirited birds as hummingbirds and jacamars, and calm, subdued demeanor, expressed by dignified upright carriage, long motionless perching, and low, shrinking, almost melancholy notes sparsely used. The Nest In the sunny month of January, as the dry season becomes well established in El General, all the trogons in its forests call with increased frequency. Sometimes two male Black-throated Trogons call against each other, but even in rivalry their notes are low and subdued. Occasionally one dashes toward his opponent, who avoids contact by retreating. I have never seen trogons fight. As with nearly all the forest birds, I have not succeeded in learning how territories are delimited and pairs formed. The cavities used for nesting are carved into decaying wood by both sexes. In El General, I found a pair beginning to excavate a hole as early as February 11, but the work proceeded slowly, with long intervals of neglect, and was not finished until about the end of March; it was April 10 before I found an egg in the hole. All the nests that I have seen have been dug into slender, upright stubs of dicotyledonous trees far advanced in decay, or in one instance in a dead part of the trunk of a small living tree. Often the trunk is so weak that in studying the nest one must take great care not to cause its collapse. My eight nests ranged from 4 feet 4 inches to 12 feet above the ground. Half of them were between 5 and 8 feet. Tlie lowest was almost 3 feet below the top of a stump 7 feet high and 6 inches in diameter. The Black-throated Trogon appears consistently to avoid massive dead trunks such as are chosen by White-tailed Trogons and Massena Trogons for their more deeply carved chambers. 8 THE WILSON BULLETIN ^^ar(•ll 1959 V,)l. 71, No. 1 The Black-throated TrogonN nest cavity is hardly more than a shallow niche, with most of the front open. The opening is usually roughly pear-shaped, widest near the bottom, but exceptionally widest at about mid-height, and usually its outline is rather irregular. Often the edges are jagged. The five doorways of which I have measurements ranged from 4Yj to 6^2 inches in height and from 2% to 2% inches in greatest width. The excavations extended from IU4 to inches below the lowest part of the opening, but most were more than 2 inches deep. The transverse diameter of these little hollows ranged from 3 to 4 inches; usually it was about 3% inches. In this shallow depression the eggs rest and the nestlings grow up. The back and sides of the cavity slope forward and inward to meet the narrow top of the doorway, so that the whole niche is 6V2 to 8 inches high. This upward extension of the excavation provides a place for the parents’ long tails, which are turned upward and slightly forward above their backs as they incubate and brood. One exceptional nest, situated at the very top of a slender stump 12 feet high, had the usual entrance in the side, but this was confluent with an opening in the top of the stub, so that the eggs were exposed to the sky. No lining is ever taken into this roughly carved chamber in a rotten trunk, hut the eggs rest upon the few particles of loosened wood which remain on the bottom. The Eggs Of my eight nests, one had, when found, a single egg, which disappeared within two days; probably it was freshly laid and would have been followed by another if the nest had not been pillaged. Each of the remaining seven nests (five in El General and two on Barro Colorado) contained two eggs or nest- lings, and this is the number found in two additional nests reported from Barro Colorado by Eisenmann (19.52:28). Carriker (1910:559) also found a nest with two eggs at El Pozo de Terraba in southwestern Costa Rica. One of my nests contained a single egg when found, soon after midday on May 29, and the second was laid between 1:45 p.m. on May 30 and 10:45 a.m. on May 31. In another nest, the second egg was laid between 9:00 a.m. and 5:15 p.m. of the same day. The eggs are bluntly ovate and white, with slight gloss. The measurements of seven average 27.6 by 22.0 mm. Those showing the four extremes measured 29.4 by 23.0, 26.2 by 23.8. and 27.0 by 20.2 mm. In El General, two nests from which the nestlings left on May 2 probably contained an egg at the very end of March. In two other nests eggs were laid in April, and in two, in May. In one of these the set was not complete until May 31. My two nests on Barro Colorado contained eggs when found in early Aj)ril. For this locality Eisenmann records another nest with eggs in April, and one in which a nestling hatched about June 21. Carriker’s nest at El Pozo Alexander F. Skiitch BLACK-THROATED TROGON 9 de Terraba contained eggs on June 21. Thus, the few available records indi- cate that in southern Central America the Black-throated Trogon begins to lay at the end of March, while the latest nestlings are fledged in early July. Incubation At noon on April 8, 1935, I entered a blind in front of my first nest on Barro Colorado Island, without disturbing the male trogon, who was then covering the two eggs. As we sat quietly through the afternoon, 1 could see his head rising just above the rounded bottom of the opening in the tottering stub, and sometimes the brilliant green feathers of his neck were ruffled over the rim. For hours he sat almost motionless; but the monotony of the long watch was broken when a Blue-crowned Wood-Nymph Hummingbird {Thalurania furcata), and then a Dusky-capped Flycatcher (Myiarchus tuberculifer) , sunned them- selves in a patch of brilliant sunshine that found its way through the forest canopy to fall upon a prostrate trunk just outside my right window, both in the same spot and attitude, lying flat with spread wings and outfluffed plumage. Later, when the sun was low, a band of seven collared peccaries {Pecari tajaca) walked in single file in front of the blind. Soon after their passage, the male trogon began to call in an undertone from the nest, a low, mellow cow cow cow, repeated again and again. After three minutes I heard the soft call of his mate. Then he started to leave the nest, but paused resting on the rim of the aperture. After a minute or so in this position, he darted out and promptly vanished among the trees. Then his mate went at once to the nest and clung upright in front of the door- way while she scrutinized her surroundings. After a brief survey, she climbed inside, turned around, and settled on the eggs, facing outward. This was at 5:26 p.m. Here she remained until, by 6:45, I could no longer see her and I stole away in the dusk. At 6:00 the next morning, when the light was still dim in the woodland, I resumed my watch. Despite the slowly increasing light, I failed to see the trogon in the nest, and I began to fear that she liad been frightened away in the night. But she was only sitting very low, perhaps still sleeping, for when the light grew stronger her head became visible above the doorsill. Nothing noteworthy happened until 9:09, when the female called cow cow cow in a low voice and the male called with similar notes from among the trees. After they had exchanged a number of calls, the female moved forward to rest in the doorway with much of her yellow belly showing outside. For several minutes she delayed here while she and her mate called back and forth. Finally, at 9:13, she flew away; and after the usual survey made while clinging upright before the entrance, the male went in at 9:19 and turned around to settle in the nest facing outward — the usual position. He sat steadily until I ended by watch at noon, and he was still present at 3:45 and 4:20 in the afternoon. Thus in the course of 24 hours the female had taken one long session, from 5:26 in the evening until 9:13 the next morning, and the male had incubated all the rest of the time. On April 15, 1958, I made, with my wife’s help, an all-day record at a nest with two eggs, in the forest near our house in El General. At 5:35 a.m. I entered the blind in the dusky underwood, and as it grew light I detected the white crescents before and behind the eyes of the sitting female, then gradually the rest of her head. At a little before 7 :00, the male arrived and called with churring and rattling notes, krrr-rek and krrr-re-ek, several times repeated. Then he changed to a low cow cow cow as his mate very slowly pushed forward into the doorway, looking around as she did so. At 7 :01 she darted off, and two minutes later the male entered. Although he stayed continuously at his post through the morning and early afternoon, he sat rather restlessly, frequently rising up to lower his head into the bottom of the cavity. He did this by turning sideways in the niche or even completely around, until his yellow belly filled the lower part of the doorway. 10 THE WILSON BULLETIN March 1959 Vol. 71. No. 1 while his black-barred, white outer tail feathers occupied its upper portion, or sometimes projected slightly outside. He then seemed to be standing on his head, and his reversed position apparently made it easier for him to reach the eggs in the narrow niche; hut whether he turned or merely examined them, 1 could not see. He woidd maintain this posture for a minute or two, rarely longer, then settle down in his usual position, head outward, eyes and bill just above the lower edge of the doorway, tail ascending above his back against the outward-sloping rear wall of the niche. If his tail had been just a little longer, it would have projected through the opening into the outer air, as happens with the far longer feathers of the male Quetzal’s train. At 2:34 p.m., when the sky was darkly overcast, a Violaceous Trogon called cow cow cow cow cou) .... loudly overhead, and this apparently stimulated the Black-throated Trogon to call in his lower notes from the nest, where he had been sitting all day. After more calling while he rested on the doorsill, he flew to a neighboring branch and continued his cow cow cow. From 2:38 to 3:23 the eggs remained unattended, while rain began to fall. At 3:23 the female, after repeating a long, low rattle over and over, raising her tail above her back each time she did so, entered to resume incidration. Soon after 4:00 the shower stopped and the sun began to penetrate the clouds. 1 was certain that the female, sitting quietly, had settled down for the night; but, to my great surprise, the male returned at 5 :03, apparently called her out, and at 5 :08 went to the doorway, lowered his head as though to feed nestlings, then entered to incubate. He remained there only 17 minutes, for at 5:2.5 the female came back and resumed incubation. As the light grew dim, and she became invisible, 1 left. The male had sat continuously for 7 hours 35 minutes, and again for 17 minutes late in the afternoon. Not counting the few minutes the eggs were left uncovered whenever the parents changed over, they were unattended for only one period of 45 minutes in the course of the day. The female sat all the rest of the day, and through the night. Except for the male’s short session late in the afternoon, this pair had followed the pattern of incuhation that I had found to be typical of the lowland trogons: two change-overs in each period of 24 hours, the male sitting for six to eight hours in one long stretch each day and the female the remainder of the time — a schedule which closely resembles that of incubating pigeons and doves. The male’s brief evening session seemed pointless in a bird that incubates for hours at a stretch, and 1 resolved to watch again to learn whether it was habitual with him. My first opportunity came two days later, when I entered the blind at 4:30 on a darkly clouded afternoon, while the female was silting. 1 did not have long to wait for the male, who arrived at 4:42, and after seven minutes of krrr-ing and coic-ing finally persuaded his mate to make way for him. Then he promptly went to the nest, holding in his hill some small object that 1 could barely discern in the dim light. Clinging in front of the doorway, he lowered his head into the hollow' as though feeding nestlings. After a while he entered, still holding the morsel, but presently he rose up, turned around until his yellow belly was in the doorway and his tail stuck up into the air, and seemed to be offering the food again. .Soon he settled down in the usual incubating posture, still with food in his bill. In 14 minutes his male reluined and repealed her rattling call until, after five minutes, he gave up the nest to her. As well as I could see, he swallowed the morsel while she called. I could detect nothing in her hill, nor did she lower her head into the nest as though offering food to nestlings. After she had settled down, 1 put her off to see whether perchance a Alexamlcr F. Skutch BLACK-THROATED TROGON 11 nestling liad hatclied since my last inspection, but two eggs were reflected in the mirror that 1 held over the doorway. By 10:40 the following morning (April 18), however, one had hatched. The male’s proffer of food to unhatched eggs was not unprecedented in my experience, and elsewhere (Skutch, 1953:10-17) I have given a number of examples of such “anticipatory food-bringing.” Possibly, even as early as our all-day watch on April 15, three days before hatching, the male had heard the tapping or weak calls of the imprisoned chicks making their first feeble attempts to break out of their shells. Perhaps this was responsible for his frequent turning in the nest, standing on his head, and inspecting the eggs beneath him. His return late in the afternoon of April 17 was evidently to attend chicks rather than to incubate eggs; and probably this was true of his similar return two days earlier, although I did not then notice — or look for — food in his bill. The female 2:ave no indication that she was aware that the eggs were about to hatch; in my experience, female birds anticipate the nestlings less often than males. In addition to the two long watches, I have records of 72 visits, at various times of day, to nests containing eggs. The latest hour of the morning at which I ever saw a female covering eggs was 11:25, at one of the nests on Barro Colorado, but it is most unusual to find her present after 9:00. The earliest hour at which I found a male in the nest was 7 :00. My latest record of the presence of a male is 5:26 p.m., and my earliest of the female’s afternoon return is 3:00 p.m. When the female continues to incubate as late as 11:00, her mate may have come to replace her so early in the morning that she would not relinquish the nest to him, and he went off and stayed away a long while. At least, I have seen this happen in the Collared Trogon (Skutch, 1956:359— 360 ) . Black-throated Trogons sit closely and have remained on their eggs watching me set up a blind eight or ten yards in front of them, an operation which often involves much movement and noisy clearing away of undergrowth. Fre- quently, too, I have been able to enter or leave a blind, or to remove it, without chasing away the incubating male or female. But the fact that they sit stead- fastly while one sets up a blind does not mean that they would enter the nest if one watched without concealment. Perhaps they remain firm in the presence of an intruder because their departure would betray the location of their nest if he had not already noticed it; and for the same reason, they hesitate to approach the nest if a man or other animal capable of harming it is in view. At the nest which I discovered when newly begun on February 11, 1942, 1 did not see an egg until April 10. I had not visited the nest the preceding day, so it might well have been laid earlier. The second egg was deposited on April 11. One egg vanished in the course of incubation. The remaining one was 12 THE WILSON BULLETIN March 1959 Vol. 71, No. 1 chipped in the afternoon of April 27 but did not hatch until two days later, on April 29. Thus the incubation period was at least 18 days, and possibly a little longer if the surviving egg was the first rather than the second of the set. This may be compared with the Mexican Trogon’s incubation period of 18 or 19 days (Skutch, 19421. The Nestlings The newly hatched trogon has pink skin devoid of all down or visible rudi- ments of feathers, and its eyes are tightly closed. The pin feathers grow out rapidly, and when six days old the nestling bristles with them. By the tenth day they have become so long that they almost cover the nestling’s upper parts; except for a few feather-tips, the plumage is still tightly ensheathed. But 24 hours later, at the age of 11 days, the nestling is fairly well clothed with freshly expanded plumage. The rectrices, however, are still wholly enclosed in their sheaths, and this is also true of manv of the feathers of the crown. A day later the plumage of the crown has expanded and the rectrices are escaping their sheaths. When 13 days old, the young trogon is completely feathered on head, upper parts, and breast. Except for the large roundish spots on the wing- coverts and the huffy-brown rather than yellow of the abdomen, it rather closely resembles its mother in its rich brown attire. Like her, it has prominent white crescents behind and in front of each eye; these are joined by a narrower rim of white above and below the orbit, hut on her the crescents are not confluent. Its bill is dark gray with lighter base and tip, and the feet flesh colored. A day or two later, at the age of 14 or 15 days, the young trogon leaves the nest. On April 19, 1958, I watched from 6:30 to 11:30 a.m. at the nest in which the two nestlings had hatched on the preceding day. They were brooded constantly by both ])arents sitting alternately, except for the brief intervals taken up by the change-over and the delivery of food. The male, who was in the nest, when I arrived, sat for 3 periods of 49, 79, and 120 minutes, making a total of 248 minutes. The female brooded only twice, for 17 and then 7 minutes, or a total of 24 minutes. The remainder of the 5 hours, 28 minutes in all, was occupied by change-overs and the slow process of feeding the nestlings. On its arrival to replace its mate on the nestlings, each of the parents behaved much as it did when it came for its turn at incubation, calling with either soft notes or churrs and rattles, or with a combination of the two. This was continued for several minutes, until at last the luooding partner bestirred itself and slowly left the nest, sometimes after calling softly in answer to the other, l^ach time that a parent returned it brought an insect or some unrecognizable object of food, usually small and green. Once the female came with a winged insect surprisingly large as a meal for a day-old nestling. After the departure of Alexander F. Skutch BLACK-THROATED TROGON 13 its mate, the newly-arrived parent would cling upright in front of the doorway, its tail pressed against the trunk and head lowered into the cavity, and would patiently deliver the morsel. This usually took about two to four minutes, although eight minutes were occupied by the female in giving the very large insect to a nestling. The meal over, the parent climbed through the doorway and turned around to brood facing outward, just as it had incubated. In the five hours the two nestlings were fed as many times, twice by the male and thrice by the female, who brought a meal at the very end of this period. Since, as far as I could see, a parent brought only one article at a time, the most equitable division would have given no more than three insects to one nestling and two to the other. On April 24, when the two nestlings were six days old, 1 again watched from 6:30 to 11 :30 a.m. The morning was cloudy and cool, but the still featherless youngsters were left exposed nearly as much as they were covered. The female brooded twice, for 35 and later for 32 minutes, the male, only once, for a long session which had lasted 96 minutes when I went away and left him sitting. The female brought two green insects, which had been well mashed, but were so big that the nestlings, doubtless cold and sluggish from long exposure, did not succeed in swallowing them. Finally she ate them herself, twisting her head and neck from side to side as she forced the larger one down with an effort. The male brought three morsels, all of which the youngsters seemed to eat. The parents evidently did most of their hunting well up in the trees, for each time that they came I first heard their voices from above me, before they dropped to a perch in sight of the blind. I next watched at this nest from 6:30 to 11:30 a.m. on April 29, when the two youngsters were 11 days old. On this sunny morning they were not brooded at all. Tbe male came seven times with as many insects, most of which were very large and green, although one was brown. As formerly, to deliver a meal he clung upright before the df)orway, his tail usually spread just enough to reveal a little of the white outer feathers with their black bars. But now he did not have to hend his head into the cavity, for with a loud sizzling noise the nestlings reached up w'ell above the lower edge of the doorway to take their meals. One of them once spent about two minutes forcing down the large insect it had received. Not having glimpsed the female during the morning, 1 watched for her again in the evening. The youngsters now rested with their heads visible in the doorway. The male brought them two more meals between 4:30 and 5:30, making nine feedings in six hours that day. The female did not arrive until 5:45, w'hen the light w'as failing beneath the lofty trees. After calling cow coiv very softly several times, then krrr-re-e-e-e, with the notes more wudely spaced toward the end, she flew to the nest and clung in front of it; but 1 was not sure that she delivered food. Then she entered to brood, sitting vei7 high in the cavity, with much of her yellow^ ventral plumage showing above the low'er edge of the doorway, not merely her head as while she incubated tine eggs. Here she stayed until I left in the dusk. This was the last time 1 saw her. If I had not watched for her to come and brood her nestlings that night, I shoidd have inferred from her failure to feed them on that and later days that some accitlent had befallen her. When I entered the blind at 12:20 p.m. on May 1, both of the nestlings, now' well feathered, were looking through their doorway. Their white eye rings made them appear bright and alert. In the next four hours the male came 11 times, bringing 11 insects, some so large that the youngsters wuth difficulty forced them down. For half an hour rain fell 14 THE WILSON BULLETIN Marcli 1959 Vol. 71, No. 1 rather hard, hut neither parent hrooded the nestlings. Neither came to cover them at nightfall. Next morning, May 2, 1 resumed my watch as it grew light. The male first brought food at 5:43, and by 6:00 he had given the nestlings four meals, after which he came more seldom. z\t about half-past six, a nestling rested with its breast against the lower edge of the doorway. Soon it grew restless, preened, and stretched its wings. Then for a while it drowsed with closed eyes, to he aroused when the male arrived with more food. After this meal, at 8:14, the nestling jumped up to perch on the doorsill — the first time I saw it there. It now began to utter rhythmically a low, soft note, which 1 could hardly hear above the voices of the cicadas. It preened, then drowsed. After a while, the other nestling tried to push its head through the doorway beside it. At 9:04 the male flew up with an insect in his hill, alighted on a low branch about 20 feet from the nest, and churred as usual. The nestling thereupon flew from the doorway toward him, going well for a few yards, hut falling when it tried to alight on a twig. The male darted toward it as it fluttered to the ground close in front of the blind. Here it rested behind a fallen palm frond and continued to utter the low, soft note at intervals of a few seconds; the male, perching low and still holding the insect he had brought, voiced alternately churrs and soft cow's. Soon the youngster flew again, rising a few feet hut dropping to the ground about five yards from its starting point. Presently it was out of sight, and, although 1 heard its low notes for nearly half an hour more, 1 never saw it again. Only 14 days old, it seemed small and weak to face the perils of the tropical forest. The youngster in the nest, not the one who had just flown out. was given the insect which the male had. The stay-at-home also received the next meal, an insect so large that six minutes were required to gulp it down. But the male perched low and called softly many times, as though encouraging the fledgling to rise from the ground. After this feed- ing, at 9:40, he remained away from the nest for four hours, no doubt attending the youngster who had now wandered beyond my sight and hearing. From 1:40 to 4:15 obser- vations were suspended; hut at the latter hour the second nestling was still in the nest, with the male close by. Soon the young trogon began to utter soft monosyllables such as the other had voiced just before it flew; and until it left it kept up this utterance much of the time, now loufler and now softer, at a rate varying from 24 to 28 notes per minute. As with closed hill it delivered each note, its throat swelled out conspicuously, and often it was easier to count the movements of tlie throat than the low notes themselves. At its loudest, however, the nestling’s call resembled the soft cow of the parents and was not difficult to hear. When taking food it made the usual sizzling sound, but it might resume the rhythmic monosyllables even with a partly swallowed insect protruding from a corner of its mouth. In little over an hour that afternoon (4:40 to 5:44), the male brought seven meals to the nestling, which had evidently become very hungry alter a long period of neglect. Sometimes it jumped up high in the nest in its eagerness for nourishment. Next morning we watched from daybreak to 12:15 p.m., hoping to see the other young trogon depart. Before sunrise it began its monotonous calling, ceasing briefly while a squirrel passed close by the nest. Later, when the great dry frond of a chonta palm (Iriarlea) crashed down loudly close by, it crouched in the bottom of the nest and remained silent for about 20 minutes. But it was calling loudly and persistently when the male arrived with the first meal of the day at 7:27, two hours after daybreak. By 9:02 it had been fed four times and was feeling strong enough to flap its wings and preen vigor- ously. Then followed a long interval of fasting and persistent calling, until at 11:49 the male brought an insect, then another, 9 minutes later. The spacing of these meals sug- gested that the male trogon was attending his youngsters alternately, first feeding the one Alexaiuler F. Skutcii BLACK-THROATED TROGON 15 off in the forest until it was satisfied, then bringing a number of insects in fairly rapid succession to the one in the nest. There is no reason to suppose that the fledgling who had gone out of sight was receiving food from the female. When 1 left the blind at 12:15 p.m., the second youngster had not once stood in the doorway, and was resting so quietly in its niche that 1 thought it would stay until the next day. But when 1 returned at 4:10 it had gone. If, as is probable, the young trogons left the nest in the order of their hatching, the first was about 14 days old, the second very close to 15 days, at the time of their departure. Although the first flew from the doorsill just after the male alighted on a neighboring branch with food, the male did nothing which 1 could interpret as an attempt to urge it out. Nor did the parent, as far as I could see, make the least effort to lure the laggard fledgling from the nest, during the period of more than a day that it remained alone. As has nearly always been the way in my experience, the departure of the first youngster was spontaneous, and that of the second probably so. Of the seven nests of the Black-throated Trogon that I found while, or before, they contained eggs, this alone was successful. In the only other nest that I have known to produce fledged young, they were nearly feathered when I first saw them. After the nestlings’ departure, a heavy deposit of waste material covered the bottom of the nest; the parents had never in my presence done anything to cleanse it. The dark mass was already well disintegrated, and the only recognizable objects were a number of yellowish maggots and a few hard parts of insects, including a beetle’s elytron, a leg resembling that of a grasshopper, and a long antenna. Some days earlier, before the nestlings flew, I had removed from beside them the empty exoskeleton of a large green insect, which now had some maggots in it. From the head to the tip of the long ovipositor this insect measured 4% inches, and to the tip of the wings it was 2% inches. The stout body was about 2 inches long. A number of the insects that I saw the parents carry to the nest appeared to be as big as this, and some even longer. Their size explains the infrequency of the feedings through most of the nestling period. I never detected a fruit in a parent’s bill when it visited the nest, and I searched in vain for a regurgitated seed. All the evidence indicated that the nestlings’ diet consisted wholly of insects, which are also the chief food of the adults. Although at this nest the female stopped bringing food at some time between the nestlings’ sixth and eleventh days, not all female Black-throated Trogons are so neglectful. At a nest which I kept under observation in 1942, the single nestling vanished when it was 10 or 11 days old. In the late afternoon of the eleventh day after it hatched, I found both parents close by the devastated nest, the male with a long-winged green insect in his hill, the female with some smaller article of food in hers. Later, I saw her cling in front of the empty niche, as though offering a meal to a nestling. The bringing of food to nests from which the young have recently been taken, or in which they lie dead, is 16 THE WILSON BULLETIN Marcli 1959 Vol. 71, No. 1 not unusual among birds. I have seen it in the Citreoline Trogon (Skutch, 1948:144), the Collared Trogon (Skutch, 1956:364), and a number of birds in other families. This persistence in food-bringing ensures that weak young, or those which have fallen from the nest, will not he neglected. Still, the female parent’s neglect of older nestlings was not without precedent in my experience with trogons. A female Quetzal gradually lost interest in her family, and to her mate fell the whole care of the two young during their last five or six days in the nest, and doubtless also after their departure (Skutch, 1944:227). A male White-tailed Trogon was the sole provider for a nestling through most of its 25 days in the nest. Both the Quetzal’s and the White-tailed Trogon’s nests were late in the season; and it seemed that the defection of these females, if indeed the female White-tailed Trogon remained alive, might be attributed to the waning of parental impulses as the breeding season approached its end. But this explanation could hardly apply to the female Black-throated Trogon, whose nest was one of the earliest of the kind that I have known. I can think of just one condition in which the female’s abandon- ment of her brood would be adaptive rather than maladaptative: if there were an excess of males, and she left her first mate in charge of the brood in order to rear another family with a new mate. But this is merely a suggestion, unsupported by observations. Acquisition of the Adult Plumage The nestling plumage is described in detail by Ridgway (1911:782), who also describes males in transitional plumage, without, however, giving any information about the period when this is worn. In El General, I have seen young males in transitional plumage in January and April. Since in this region the breeding season, as far as is known, extends from the end of March to June, the young males that I met in April were probably about a year old; and because they still bore the marks of immaturity when others of their kind were nesting, it is also probable that they would not breed until about two years old. Although the males of certain species of birds nest in transitional plumage, all of the males of this and other kinds of trogons that I have seen attending nests wore the resplendent attire of full maturity. The three young males of whose plumage I have descriptions showed that the dorsal surface of the body acquires the glittering green of maturity well in advance of the ventral surface, the wings, and the tail. On the one that I met on January 4, 1948, the upper jiarts were largely green; hut the sides of the head, front and sides of the neck, and the breast were mostly brown, with some green in the center of the breast. The belly was yellow. The remiges and rectrices resembled those of the adult female; hut the eye-ring was bluish and the hill greenish-yellow, somewhat as in the adult male. On April 11, 1954, 1 Alexander F. Skutc'h BLACK-THROATED TROGON 17 saw a young male whose plumage was similar to that just described, except that the tail contained some short green feathers, just growing out. A male of which I wrote a description on April 23, 1957, had the largely brown head and breast mottled with green, and the tail was farther advanced than in the pre- ceding individual. I could detect just one long, brown feather in its center, and otherwise it resembled that of the adult male. His wings, too, were, as far as I could see, much like those of the adult male. In these males in transitional plumage, a whitish bar separated the brown of the breast from the yellow of the abdomen ; and this is of interest because such a bar is a permanent feature in the plumage of certain closely related species, including the Collared Trogon and the Mexican Trogon. Summary In Central America, the Black-throated Trogon is confined to the forests below about 2500 feet above sea level. Its diet consists largely of insects plucked from the foliage while the bird hovers in the air. Its mellow notes are low and weak. Some pairs begin to prepare their nests early in February, but laying seems not to start before the end of March, while the latest young are fledged in June or early July. Two white eggs are laid in a shallow, unlined niche carved into the side of a decaying, often tottering, slender trunk, at heights of four to 12 feet above the ground. The female incubates from the late afternoon until the following morning, and the male sits through most of the day, often taking one long session of about eight hours’ duration. One male returned in the evening after his mate had replaced him on the nest, and the second time that this unusual behavior was witnessed he brought food and offered it to the eggs, then almost ready to hatch. In one instance, the incubation period was 18 days or a little more. The nestlings, sightless and perfectly naked at hatching, are feathered at the age of 11 or 12 days and leave the nest when 14 or 15 days old. They are brooded and fed by both parents. Their food appears to consist wholly of insects, many of them so large that they can scarcely be swallowed. The rate of feeding is usually slow, during the first week about once in two hours for each member of the brood ; but after a period of neglect, a single older nestling received seven meals in little over an hour. One female ceased to feed her nestlings between their sixth and eleventh days, although she brooded them by night until they were 12 days old. But another female — and also a male — brought food to the nest after the disap- pearance of their single nestling, which would then have been 11 days old. 18 THE WILSON BULLETIN Marcli 1959 Vol. 71, No. 1 In their first plumage, males resemble females. They have been seen in transitional plumage in April, when they could hardly have been much less than one year old. Apparently they do not breed until about two years of age. Literature Cited Carriker, M. a., Jr. 1910 An annotated list of the birds of Costa Rica including Cocos Island. Ann. Carnegie Mas., 6:314-915. Eisenmann, E. 1952 Annotated list of birds of Barro Colorado Island, Panama Canal Zone. Smith- sonian Miscel. Coll., 117 (5) :l-62. Ridcway, R. 1911 The birds of North and Middle America, Part V. U. S. Nat. Mas. Bull., 50;xxiii + 859 pp. Skutch, a. F. 1942 Life history of the Mexican Trogon. Auk, 59:341-363. 1944 Life history of the Quetzal. Condor, 46:213-235. 1948 Life history of the Citreoline Trogon. Condor, 50:137-147. 1953 How the male bird discovers the nestlings. Ibis, 95:1-37, 505-542. 1956 A nesting of the Collared Trogon. Auk, 73:354-366. EL QUIZARRA, SAN ISIDRO DEL GENERAL, COSTA RICA, JUNE 21, 1958 A FIELD STUDY OF TEMPERATURE REGULATION IN YOUNG LEAST TERNS AND COMMON NIGHTHAWKS BY THOMAS H. HOWELL The Study of temperature regulation in young birds dates l)ack at least to the time of Edwards ( 1824 1 , who divided nestlings into two groups — those able to maintain a more or less constant body temperature soon after hatching (precocial ), and those that are unable to do this, so that their body temperature varies with that of the environment ( altricial ) . The terms in parentheses above are usually used to designate the two groups, but nidifugous (young able to leave the nest site shortly after hatching) and nidicolous (young restricted to the nest and dependent on parental care) are often employed as equivalents of precocial and altricial, respectively. Birds that nest on the bare ground are frequently assumed to be precocial, but there are very few published studies on such species that include measurements of body temperatures of the young. The present study was undertaken in the hope of adding to the limited data available on this subject. Most of the information presented here was obtained in July, 1955, at Grand Isle, Jefferson Parish, Louisiana. This locality is on the coast of the Gulf of Mexico about 100 miles south of New Orleans. Some additional data were obtained at Los Angeles, California, in August, 1956. The two species studied were the Least Tern [Sterna albijrons) and the Common Nighthawk [Chorcleiles minor) . At Grand Isle both these species lay their eggs on sand or bare ground, and tbe young may be exposed alternately to intense solar heat and to cooler periods brought on by frequent tbunder- storms. Tbe terns are strictly diurnal, and although the nighthawks may be active at any time of the day they are primarily crepuscular and nocturnal in this region during the hottest part of the summer. These two species, although different in most respects, are similar in the type of nest site utilized; it therefore seemed that a comparison of the adaptations of their young to similar environmental conditions would be of interest. All body temperatures listed are esophageal, in degrees C., and were taken with a quick-registering mercury thermometer unless otherwise noted. I am aware of the shortcomings of mercury thermometers as compared to thermo- couples, but the field investigator usually has no choice but to use the former. Therefore, body temperatures recorded may not be as precise as possible but they are consistent and adequate for comparisons between the two species. Environmental temperatures were also taken with the same quick-registering mercury thermometers unless otherwise noted and are in degrees C. It was often desirable to have black-bulb temperatures as a measure of the intensity of solar radiation. “Black-bulbs” were improvised from the black cardboard 19 20 THE WILSON BULLETIN March 1959 Vol. 71, No. 1 tubing of the thermometer case or from a small glass test tube thoroughly blackened with camphor smoke. When held around the mercury bulb of the thermometer, both these “black-bulbs” gave almost identical results. Obviously the readings are not as accurate as those obtained with meteorological equip- ment, but like the body temperatures they are consistent throughout this study and thus have some comparative value. Least Tern On July 1, 1955, I located 15 nests with eggs of this species at Grand Isle in a large level expanse of white sand mixed with shell fragments. As July is late in the breeding season of the Least Tern in this region, these sets of eggs were almost certainly not the first clutches. The nesting area was roughly rectangu- lar and was surrounded on three sides by marsh and bordered by a bayou on the fourth. There was virtually no vegetation and no shade anywhere in the nesting area. No other species were nesting there, hut flocks of Black Terns {Chlidonias niger) and Laughing Gulls (Larus atricilla) were frequent visitors. Unfortunately, there was little nesting success in this colony. Eight nests were destroyed by children who followed my footprints across the sand, and several others were raided by raccoons from the surrounding marsh. Laughing Gulls apparently preyed on both eggs and young. However, I was able to get some data on a few very young nestlings from three of the nests. I attempted to take temperatures of the nestlings as soon as possible after the brooding parent departed, and I then remained by the nest and took temperatures of the young at regular intervals during their continued exposure to the environment. It was not always possible to tell how soon after departure of the parent the first temperature was recorded, for most of the adult birds in the colony took wing as I approached the edge of the area. In such instances I could record only that the time unhrooded was something greater than the number of minutes that elapsed between sighting an unhrooded nest and taking the temperature. The results obtained from five nestlings on five different occasions are summarized in Table 1. It will be noted that body temperatures in one- and two-day-old nestlings varied through about 8°C., but did not rise above 42.5°C. in these or in a three-day-old nestling, even though black-bulb and ground temperatures rose above this figure. Presumably the nestlings regulated their body temperature more effectively at the high than at the low end of the scale, and I was able to get additional information on this point in August, 1956, by subjecting nestling Least Terns to heat and cold stress under laboratory conditions. Two nestling terns were found in a breeding colony at Playa del Rey, Los Thomas K. Howell TEMPERATURE REGULATION 21 Table 1 Environmental Temperatures and Body Temperatures (in °C.) of Five Least Tern Nestlings One to Three Days Old (Each column represents separate, nonconsecutive records) Time since parent left > 5 min. y> 5 min. > 3 min. > 5 min. >5 min.^ Ground 31.0 42.5 29.5 30.2 49.5 Black-bulb 28.4 44.0 night 28.5 43.0 Air 29.5 28.5 1 day old 36.2 42.5 37.2 34.2 2 days old 42.5 38.2 35.0 42.2 3 days old 42.5 ^Extremely conservative estimate of time. Angeles, on August 1. One appeared slightly smaller and younger than the other ; the smaller one was more white and the larger one more yellow in color. The letters (W ) and (Y) are used to distinguish these two young birds in the following discussion. I estimated that (W) was no more than one day old and that (Y) was two days of age at most. Deep esophageal temperatures taken immediately after the brooding parent left were 40.5 (W) and 41.5°C. (Y) ; during the following hour, these body temperatures (unbrooded) varied only between 40.0 and 41. 2°C. (W) and 40.8 and 42. 5°C. (Y) at an air temperature (with 5 m.p.h. wind) of 27 to 29°C., a blackdmlb temperature of 35.5°C., and a ground temperature of 33 to 36.5 °C. A few hours later I returned to the nesting colony and took the two nestlings to the laboratory. They each weighed 5.7 grams, and after about 30 minutes at ambient temperatures of 24 to 30°C., their body temperatures (taken at 4 p.m. ) were 33.5 (W) and 35.2°C. (Yl These and other temperatures recorded in the laboratory were measured by a thermocouple. At 4:30 p.m. both birds were placed in a cold chamber at an ambient temperature of 10°C.; this declined gradually to 5.5°C. The laboratory results are shown in Eigure 1. At 4:26 p.m., when the birds were at their lowest body temperature, both were capable of slow movement and (Y) cheeped faintly. The young birds were returned to their nest at 5:03 p.m., and a parent bird settled down to brood them almost immediately. The next day f returned to this nest and found (W ) but not (Y) . The body temperature of (W) was 41.6°C. within two minutes after the departure of the brooding parent. When taken to the laboratory again, ( W) weighed 6.1 grams, an increase of 0.4 gram over the previous day. At the lalioratory room temperature of 23.0°C., the body temperature of (W) dropjied to 36.4°C. in about 20 minutes. At this time, 3:57 p.m., (W) was placed in an insulated chamber at an air temperature varying between 43 and 45°C.; results are shown in Figure 2. 22 THE WILSON BULLETIN March 1959 Vol. 71, No. 1 It will be noted that during the first six minutes there was a rise of 4.1 °C. in body temperature. During the following 16 minutes the bird maintained a fairly constant body temperature, but after that a rise to higher levels commenced. However, the body temperature remained below that of the surrounding air for the entire 38-minute period. Fig. 1. Responses of Least Terns of approximate ages of one (W) and two (Y) days to low and moderate ambient temperatures. The bird was visibly affected by the high ambient temperature after five minutes of exposure, for it began to call, hop about, and pant. From this time on the bird seemed to be in a state of increasing distress. Its beak was kept open and its whole body trembled with the effort of violent panting. The respiratory rate was too rapid for an accurate count, and there seemed to he an erythemia of the linings of the mouth and pharynx. The bird was removed from the 4.S°C. test chamber after 38 minutes and was exposed to ambient temperatures of 23 to 27°C. for the next 35 minutes, during which time it was being returned to its nest. When replaced in the nest at 5:10 p.m., the bird’s body temperature had dropped to 35°C.; a ]iarent bird came and settled down to brood the young one as soon as I walked away. These data indicate that very young nestling Least Terns show considerable lability of body temperature (a range of at least 24°C. ) hut that they are capable of regulating effectively for at least 38 minutes under severe heat stress. Thomas R. Howell TEMPERATURE REGULATION 23 Comparative information was ol)taine(l on a juvenile Least Tern of an estimated age of two w'eeks. This bird was fully fledged and able to fly, but after two flights of about 40 and 15 yards, respectively, it appeared to be exhausted and w'as captured by band. Its body temperature at the time of capture was 39.2°C., and it weighed 37.6 grams. Tlie bird was placed in a closed chamber at an ambient temperature of 20 °C. and subsequently at 10°Ci. ; its body temperature at the start of the experiment was 37.6°C. Results are shown in Figure 3. M I NOTES Fig. 2. Response of Least Tern of approximate age of two days to continuous ambient temperatures of 43 to 45°C. Data on House Wren nestling of similar w'eigbt is replotted from Baldwin and Kendeigb (1932:118). M INUTES Fig. 3. Response of Least Tern of approximate age of twm w'eeks to varying aml)ient temperature. 24 THE WILSON BULLETIN Marcli 1959 Vol. 71, No. 1 Although this juvenile regulated well at moderately cool ambient temper- tures, it showed a drop in body temperature below the usual adult level when subjected to somewhat greater cold stress. The young tern was captured about two hours before the experiment began, and as I did not feed it the bird was without food for at least two hours and perhaps much longer. It may have been running out of energy reserves by the time it was subjected to the ambient temperature of 10° C., and its slow recovery to higher body temperatures supports this suggestion. However, it flew from my hand when I returned it to the nesting colony, and it was last seen running rapidly for cover. Nighthawk This species lays its two eggs on the bare sand at Grand Isle, but the nest site is usually among small tufts of vegetation where the concealing coloration of the adults and young is most effective. The vegetation provides small patches of shade, hut not enough to shield the parent bird or to cover the sand between adjacent clumps of grass, especially during the middle of the day when solar heat is most intense. July is late in the breeding season of night- hawks in southern Louisiana, and I was not able to find any newly hatched nestlings. The youngest birds I could find were two of an estimated age of five and six days — the estimate based on camparison with photographs of nestlings of known age given in Bent (1940). These young birds were kept under observation for seven days, and additional data were obtained from two others of ages estimated at 15 to 16 days and from a juvenile nighthawk about 24 days old. As with the Least Terns, I attempted to take temperatures of the young as soon after the departure of the brooding parent as possible and then at regular intervals while the young were unbrooded. In my limited study, I found that the young up to at least 15 days of age were brooded during the entire day. I did not find them brooded during the early part of the night, but no observa- tions were made later than about three hours after sunset. The brooding parent left the young only when closely approached, and the bird invariably departed with an “injury-feigning” type of flight, as described by Tomkins (1942). The adult nighthawk flopped away with extremely labored wingbeats and with the tail hanging vertically; often the bird collapsed a few yards away with wings and tail spread and mouth gaping. This behavior was a good indication that the parent had just left its young and was quite useful to me in locating them. As I was primarily concerned with getting temperatures of the young immediately, I did not attemjjt to identify the sex of the brooding parent each time. However, when such identification was made the bird was a female. The body temperatures of young of different ages under various conditions of ex|)osure are given in Tables 2^. Thomas H. Howell TEMPERATURE REGULATION 25 Table 2 Environmental Temperatures and Body Temperatures (in °C.) of Two Young Common Nighthawks 5 to 6 Days Old 6 to 7 Days Old (Consecutive (Consecutive (Consecutive Observations) Observations) Observations) Time since parent left 2 min. -f- 15 min. (/) 1 min. -|- 15 min. 1 min. -|- 7 min. w > 3 min. Ground 40.0 40.0 a a 31.5 31.5 41.0 41.0 a o Black-bulb — 30.0 30.0 41.5 41.5 30.6 Air 33-34 33-34 0) 29.5 29.5 35.5 35.5 “ 29.5 Bird No. 1 39.5 42.0 b 38.5 36.5 39.8 44.0 38.0 Bird No. 2 38.5 41.0 H 38.5 37.0 40.5 43.0 ^ 38.0 Table 3 Environmental Temperatures and Body Temperatures (in °C.) of Two Young Common Nighthawks 7 to 8 Days Old (Consecutive Observations) (Consecutive Observations) Time since parent left 1 min. -T 6 min. 0) f/) 1 min. + 15 min. -j- 15 min. + 15 min. Ground Black-bulb 42-43 38.2 42-43 38.2 Q O 31.5 29.0 29.0 28.5 28.5 Air Bird No. 1 40.5 43.0 0) E 38.5 37.0 36.4 27.2 34.8 Bird No. 2 40.5 43.5 1— 38.2 36.8 37.0 36.8 (active) Table 4 Environmental Temperatures and Body Temperatures (in °C.) of Two Young Common Nighthawks 10 to 1 1 Days Old 1 1 to 1 2 Days Old 1 5 to 16 Days Old (Consecutive Observations) (Consecutive Observations) Time since parent left 1 min. + 15 min. 1 min. 15 min. + 6 min. > 5 min. Black-bulb 37.5 34.0 39.0 39.0 Air 31.0 31.5 32.0 32.0 28.0 (nigbtl Bird No. 1 39.4 42.0 39.5 42.5 37.8 Bird No. 2 39.0 41.5 39.5 41.5 41.8 38.2 26 THE WILSON BULLETIN March 1959 Vol. 71, No. 1 Although the youngest nighthawks were five to six days old, their body temperature at this and more advanced ages was more labile than that of the younger Least Terns under natural conditions. The nestlings of these two species would not normally be exposed to very cold conditions, but the differ- ence in their response to heat is noteworthy. After only seven minutes exposure to hot, direct sun (black-bulb temperature 41.5°C. I, nestling nighthawks six and seven days old experienced a rise in body temperature to 43 and 44°C. Even after 38 minutes exposure to an ambient temperature of 43 to 45 °C., a two-day-old Least Tern did not reach this level of body temperature. The young nighthawks showed great distress at the elevated body temperatures, and I have little doubt that they would have died if left exposed for 15 or 20 minutes longer. A body temperature of about 46°C. is lethal for the House Wren {Troglodytes aedon) (Baldwin and Kendeigh, 1932), and as I did not want to risk having the young nighthawks reach this level and perish I left after the seven-minute interval. A parent bird immediately returned and brooded the young, and they evidently suffered no lasting ill effects. On the following day similar results were obtained, but equally hot environmental conditions did not occur at later stages in the growth of the young and the highest body temperatures subsequently recorded were not over 42.5°C. The lowest body temperature recorded was 34.8 °C., after 45 minutes exposure of an eight-day-old bird to an ambient temperature of 27 to 28°C. Gular flutter in response to heat stress was noted in nighthawks of all ages. The behavior of the nestlings is important with regard to temperature regu- lation. The five- and six-day-old nestlings were able to run about, although not very rapidly. When the parent was flushed and the young were closely approached, the latter usually ran off for a short distance and then stopped. This running appeared to be essentially undirected, and a nestling was just as likely to come to rest in an open, unshaded spot as in a more concealing and shaded location. If disturbed again or if apparently uncomfortable from exposure, the birds again moved off but often to an equally “unsatisfactory” exposed location. By the time the young were about 11 and 12 days old, however, their movements were much better directed. I was unable to keep them exposed to sun for more than 15 minutes, for after this time they went more or less directly to a nearby patch of shade and remained there unless chased out. These observations indicate that nestlings under about 12 days of age would not he likely to survive unless closely brooded by a parent. Their body tem- perature regulation is probably not adequate to cope with exposure to normal extremes of heat for more than a few minutes, and they are unable to reach shelter except by chance. By about 12 days of age their temperature regulation is still imperfect, hut the birds are able to seek shade when exposed to intense 1 honias K. Howell TEMPERATURE REGULATION 27 solar heat. After an age of about 15 days is reached the young may not he continuously brooded; their body temperature regulation has presumably improved although data on this point are not available. However, 1 was able to obtain the following information on a bird of slightly more advanced age. A juvenile nighthawk of an estimated age of 24 days was captured on July 23; it was evidently exhausted after two flights of about 50 yards each and was caught by hand after the second one. This bird was then exposed (with inter- vening rest periods ) to cold stress in a refrigerator and to heat stress by tethering it in full sun. It was then confined in the dark at about 30°C. for 24 hours, making a total of at least 29 hours without food. The results are given in Table 5, and except for a slight drop in body temperature when first sub- jected to cold and a slight rise after exposure to heat, the various experimental conditions seemingly had little effect; only the drop to 37.5°C. might be considered outside the usual limits of fluctuation. The bird was given food and water at the end of the darkness-starvation period and released in apparently good condition. It seems likely that body temperature regulation in young birds over three weeks old is essentially as effective as that of adults. Table 5 Environmental Temperatures and Body Temperature (in °C.) of a Young Common Nighthawk, Estimated Age 24 Days Conditions: Exhausted after two flights 20 min. rest 1 5 min. in refriger- ator 30 min. rest; 30 min. in refrigerator 30 min. rest; full sun 1 6 min. + 15 min. + 13 min. + 14 min. + 24 hrs. without food Black-bulb 39.0 39.0 29.0 Air 28.5 28.6 12.0 12.0 31.0 31.0 27.2 30.5 Body 38.8 39.0 37.5 39.4 41.4 41.5 41.0 40.0 39.5 One other point of possible interest with regard to survival of young night- hawks may be mentioned here. The nesting areas of this species at Grand Isle are inhabited by swarms of the salt marsh mosquito {Aedes soHcila?is) , and the hordes of these voracious insects sometimes made prolonged data-gathering by a human observer an impossibility. However, although the youngest night- hawk nestlings had conspicuous areas of bare skin showing along the apteria, I never saw a mosquito alight on a young bird or even hover around one. Probably the nestlings could not survive such locations if they were subject to attack by the more common species of mosquitoes. Discussion Body temperatures of nestling gulls (Larus sp. ) under various environ- mental conditions have been studied by Barth (1951), Bartholomew and Dawson (19.52, 19.54), and Behle and Goates (1957). Abdulali (1940) 28 THE WILSON BULLETIN Marcl) 1959 Vol. 71, No. 1 reported mortality of nestling Least Terns (S. a. albifrons) after 15 to 20 minutes of exposure to hot sun, but this observation was incidental to a photographic study and neither ambient nor body temperatures were recorded. I know of no published records of body temperatures of young Least Terns of either Old or New World populations. The observations of Barth (1951) on young Larus canus are closely com- parable to those reported here. Barth found body temperatures to range from 16°C. to 44.2°C., depending on age and environmental conditions. After 34 minutes of exposure to ambient temperatures from 41 to 43°C., a four-day-old bird reached a body temperature of 45.3°C. and died. The next highest body temperature reading, 44.2°C., was reached by an o)/^-day-old bird after 10 minutes of exposure to an ambient temperature of 47°C. ; the body temperature was not lethal in this instance. Barth concludes that the young gulls are better able to tolerate low ambient temperatures than high ones but that the capacity for regulation is better under the latter conditions. The results reported here on the Least Tern are generally in accord. However, the Least Tern breeds primarily in warm climates where ambient temperatures as low as those occurring in some high latitude gull colonies do not occur. It appears that very young Least Terns regulate at least as well at high ambient temperatures as somewhat older nestling gulls. As ambient temperatures high enough to constitute a threat to the survival of young Least Terns may be expected to occur during their breeding season, it is not surprising that this species apparently has evolved more effective regulation of body temperature under heat stress. It may be noted that the small size of the Least Terns as compared with gulls means a relatively larger body surface, and this makes even greater the problem of heat loss when the air and/ or substrate temperatures are higher than the body temperature. Bartholomew and Dawson (1952 ) recorded temperatures of young Western Gulls ( Larus occidentalis ) of ages varying from those in pipped eggs to at least two weeks old. Even in pip})ing young that were unbrooded for 45 minutes, the body temperatures were no less than 32.3°C. at an air tempera- ture of 27°C. In contrast, a hatchling Least Tern did not regulate as well as this at ambient temperatures that were slightly higher (Table 6). In this instance the relatively greater body surface of the small tern would tend to increase heat loss to a cooler environmental temperature. Behle and Goates (1957) studied young California Gulls {Larus califor- nicus) from the pipped egg stage up to about 21 days of age. The ambient temperatures and the duration of time unbrooded differed from those to which the Least Terns were subjected, and the data cannot be closely compared. Incompletely hatched California Gulls at air temperatures from 29 to 33°C. had body temperatures between 36 and 37°C.; this seems to indicate better Tliomas H. Howell TEMPERATURE REGULATION 29 capacity for regulation than in the Least Tern (Table 6 ) at a slightly later and drier stage, but the time unbrooded was not known for the young gulls and the comparison is thus of doubtful value. Table 6 Environmental Temperatures and Body Temperature (in °C.) IN A Newly Hatched Least Tern (Consecutive Observations) (Consecutive Observations) Age 4 hrs. + 15 min. (U 17 hrs. d- 15 min. -(- 15 min. Ground 34.8 34.8 a o 26.6 26.6 26.6 Black-bulb 34.0 35.8 Q) 30.5 29.5 29.5 Air 31.6 £ j— 27.8 28.6 28.5 Body 39.5 36.0 35.8 31.0 30.2 Rolnik (1947 ) studied the effects of cold on the young of several species of gulls and other birds nesting on arctic islands in the Barents Sea. He found that a one-day-old Kittiwake (Rissa tridactyla) weighing 38.5 grams went from a body temperature of 36°C. to 19.8°C. after 75 minutes at an air tem- perature of 6.5°C. In contrast, the 5.7 gram Least Terns studied by me took only 23 minutes to reach body temperatures of 18.5 and 19.8°C. under very similar conditions (Eig. 1). Here again, the small size of the tern nestlings is undoubtedly important in accounting for this difference in rate of cooling. Rolnik also described a state of “apparent death” in nestlings at body tem- peratures of 9 to 15°C. from which the birds fully recovered when warmed. His interesting experiments deserve to be repeated, especially with temperate and tropical charadriiform species. Data on body temperature regulation of altricial birds of a size comparable to young Least Terns are given by Baldwin and Kendeigh (1932) and by Dawson and Evans (1957). Baldwin and Kendeigh give weights of young House Wrens at four days and at 11 days as 4.6 and 10.4 grams, respectively; presumably young wrens at age five to seven days would weigh about five or six grams and thus approximate the weight of the young terns. Baldwin and Kendeigh (1932:118) show the response of a seven-day-old wren to high air temperature. These data are replotted on Figure 2, illustrating the relatively poor regulatory capacity of the young wren as compared to that of a young tern of similar size. Dawson and Evans (1957) give figures on body temperatures of young Field Sparrows iSpizella pusilla) and Chipping Sparrows (S. passerina) at air temperatures of 10 to 40°C. Three-day-old sparrows of these species are comparable in weight (mean weights 5.9 and 5.5 grams, respectively) to the youngest Least Terns. The body temperature of the sparrows at age three days 30 THE WILSON BULLETIN Marcli 1959 Vol. 71, No. 1 appears to vary almost directly with the air temperature hut remains slightly above it, especially at the higher end of the scale where the difference is on the order of 5°C. The nestling terns showed much greater capacity for tempera- ture regulation than this. In summary, it appears that young Least Terns regulate their body tem- perature as well or better than young gulls of similar age in response to high ambient temperatures, somewhat less effectively than gulls in response to low ambient temperatures, and, of course, much better than altricial nestlings of similar age and size at either high or low ambient temperatures. However, if one compares age from beginning of incubation in the terns and in the altricial sparrows, it is evident that the latter achieve essentially complete homeothermy in a shorter period of time. The incubation period of the Least Tern is about 21 days whereas that of the Lield and Chipping Sparrows is 11 to 12 days. The sparrows achieved homeothermy at 7 to 10 days after hatching or about the 18th to 21st day after the start of incubation (Dawson and Evans, 1957) ; the newly-hatched Least Tern, at a “total age” of 21 days, is quite imperfectly homeothermic. It is equally evident that young nighthawks are not precocial in a strict sense although they exhibit some characteristics of that condition. They are covered with down on hatching and are active at an early stage; indeed, they are nidifugous although not fully homeothermic. This raises the question of whether the order Caprimulgiformes can be called either precocial or altricial, whether some members of the order are definitely one or the other, or whether an intermediate condition prevails throughout the group. There is no unanimity in the literature on this order. The Heinroths (1924-33 ) regard the ground-nesting species as semiprecocial and the tree-nesting types ( such as Nyctibius) as altricial. Witherby ei a/. (1938 ) consider the “young helpless” ; A. 0. Gross (Bent, 1940:221) says of the Common Nighthawk that “on the first day the young are able to stand upright and are very active at the time of hatching.” Weller (1958) supports this observation, and Pickwell and Smith (1938) describe hatchling Lesser Nighthawks iChordeiles acutipennis) as fully able to move about. Similar comments are found in Bent (1940) with regard to the young of other North American caprimulgids such as Caprimul- gus carolinensis (p. 151), C. vociferus (p. 169), and Nyctidromus albicollis (p. 201). Aldrich (1935) found nestling Poor-wills { Phalaenoptilus nuttaUii) to be active, but Brauner (1952) reported that in three-day-old Poor-wills the body temperature went as low as 20.3°C. at an ambient temperature of 12.6°C. after a little over two hours unbrooded. In view of the great lability of body temperature under certain conditions in the Poor-will and in the Lesser Night- hawk (Marshall, 1955), it is likely that extensive further investigation of temperature regulation in both nestlings and adults of any caprimulgiform Thomas K. Howell TEMPERATURE REGULATION 31 species would be worthwhile. The almost complete absence of temperature data on nestlings makes any generalization tenuous, but it appears that the young of some caprimulgiforms look and act like precocial nestlings but lack the degree of homeothermy associated with that condition. Summary Young Least Terns [Sterna albifrons) and Common Nighthawks [Chordeiles minor) were subjected to heat and cold stress under field and laboratory conditions and their responses in terms of body temperature were recorded. Very young Least Terns are imperfectly homeothermic; they regulate body temperature less well at low air temperature but better at high air temperature than gulls of similar age, and their capacity for temperature regulation is much better than that of altricial nestlings of similar size. Young Common Night- hawks are even more imperfectly homeothermic, and they appear to be intermediate between the precocial and altricial conditions. Literature Cited Abdulali, H. 1940 The sun as a mortality factor among young birds. Jour. Bombay Soc. Nat. Hist., 41 :433-434. Aldrich, E. C. 1935 Nesting of the Dusky Poor-will. Condor, 37 :49-55. Baldwin, S. P. and S. C. Kendeich 1932 Physiology of the temperature of birds. Sci. Publ. Cleveland Mus. Nat. Hist., 3:1-196. Barth, E. K. 1951 Body temperature of the young of gulls [Laras). Nytt Magasin for Natur- videnskapene, 88:213-245. Bartholomew, G. A. and W. R. Dawson 1952 Body temperatures in nestling Western Gulls. Condor, .54:58-60. 1954 Temperature regulation in young pelicans, herons, and gulls. Ecology, 35:466- 472. Behle, W. H. and W. a. Goates 1957 Breeding biology of the California Gull. Condor, 59:235-246. Bent, A. C. 1940 Life histories of North American cuckoos, goatsuckers, hummingbirds and their allies. IJ.S. Nat. Mus. Bull., 176:viii -f- 506 pp. Brauner, J. 1952 Reactions of Poor-wills to light and temperature. Condor, 54:152-159. Daavson, W. R. and E. C. Evans 1957 Relation of growth and development to temperature regulation in nestling Field and Chipping Sparrows. Physiol. Zoo/., 30:315-327. Edwards, W. F. 1824 De Tinfluence des agents physiques stir la vie. Paris. Heinroth, 0. AND M. Heinroth 1924-33 Die Vogel Mitteleuropas. Berlin. 32 THE WILSON BULLETIN March 1959 Vol. 71, No. 1 Marshall, J. T., Jr. 1955 Hibernation in captive goatsuckers. Condor, 57:129-134. PlCKWELL. G. AND E. SmITH 1938 The Texas Nighthawk in its summer home. Condor, 40:193-215. Rolnik, V. V. 1947 The phenomenon of “apparent death” by birds. Zool. Zhur., 26:345-350. Tomkins, I. R. 1942 The “injury-feigning” behavior of the Florida Nighthawk. W'ilson Bull., 54:43- 49. 'Vt ELLER, M. W. 1958 Observations on the incubation beliavior of a Common Nighthawk. Auk, 75:48- 59. WiTHERBY, H. F., F. C. R. JOURDAIN, N. F. TiCEHURST AND B. W. TuCKER 1938 The handbook of British birds. Vol. II. London: H. F. and G. Witherhy. DEPARTMENT OF ZOOLOGY, UNIVERSITY OF CALIFORNIA, LOS ANGELES, JULY 30, 1958 OBSERVATIONS ON THE FULVOUS TREE DUCK IN LOUISIANA BY BROOKE MEANLEY AND ANNA GILKESON MEANLEY The Fulvous Tree Duck {Dendrocygna bicolor) is a locally common breeding bird of the rice fields of southwestern Louisiana. The “Mexican Squealer,” “Yankee Duck,” or “Canard Yankee,” as it is variously known to the Cajun rice farmer, is probably more closely associated with this cultivated marsh type than is any other bird. In Louisiana the tree duck nests only in rice fields, as far as can be ascertained; no breeding records for it have been reported from the coastal marshes, though it is found there regularly before and after the nesting season. The first authentic nesting records of this species in Louisiana were reported by Lynch (1943) for August 13, 1939. He found several nests in Acadia Parish rice fields and made notes on nesting habits. The status of the Fulvous Tree Duck in this area before the introduction of rice culture is conjectural. Early occurrence records coincide fairly closely with the introduction of rice culture shortly after the Civil War. Lynch {ibid.) says that “it is not impos- sible that rice culture made possible the extension of the nesting range of this bird into Louisiana, since most of this region had been prairie prior to cultiva- tion.” Since information on the Fulvous Tree Duck in this area is scant, we made a study of its ecology and local distribution during 1955, 1956 and 1957. Observations were made in all rice-producing parishes but were centered mainly in Evangeline and Jefferson Davis parishes, where the greatest con- centrations occur during the nesting season. Nesting densities in two large areas were estimated by counting the number of paired birds that regularly visited certain feeding fields. In one study tract, the number of pairs occupying nesting fields was determined by census. The search for nests occupied considerable time because of the difficulty of locating them in dense stands of rice, which were often over five feet high. Earmers helped locate several nests. Habitat preferences were appraised by surveys of various areas where the ducks were known to occur. Information on depredations upon crops was obtained through inspections of rice fields where Fulvous Tree Ducks had been feeding. U. S. Fish and Wildlife Service field reports provided additional material on this subject. Distribution and Populations In seasons other than the breeiling period, the Fulvous Tree Duck has been reported from marshlands of the coastal parishes extending from the Missis- sippi River to the Texas border. Lowery ( 1955) reported that it was known to occur within the state during every month of the year except February. 33 34 THE WILSON BULLETIN Marcli 1959 Vol. 71, No. 1 Before rice planting begins in Marcli and April, many Fulvous Tree Ducks concentrate in the fresh-water marshes of Vermilion and Cameron parishes. On the Lacassine Refuge, in Cameron Parish, the preferred marsh type is a fairly uniform stand of “Paille Fine” or maidencane (Panicum hemitomon) containing many small ponds (Fig. 1). Watershield [Brasenia Schreberi) is abundant in most of these ponds (Fig. 2 ) . Fig. 1. Coastal Marsh liabitat in Cam- Fig. 2. Pond of watersliiekl in “Paille eron Parish, Louisiana. “Paille Fine” domi- Fine” marsh, nant vegetation. In the spring, the first rice fields occupied by Fulvous Tree Ducks are in the area bordering the coastal marshes and extending inland about 20 miles. As these lower rice fields are being planted, flocks of the birds loaf and feed in the native marsh throughout the day and fly into the fields to continue their feeding at night. Fish and Wildlife Service personnel estimated that in May, 194.5, 5000 tree ducks were operating between the Lacassine Refuge marsh and adjacent newly-sowm rice fields. A progressive movement of tree ducks into the northern tier of rice-pro- ducing parishes occurs as the young rice plants in these interior areas attain a height of eight or ten inches. By the end of April, when the earliest rice is a foot high, most Fulvous Tree Ducks are pretty well dispersed over the rice country in the vicinity of their breeding grounds. The breeding range extends into all rice-producing parishes of Louisiana, with the exception of a small area located in the extreme northeastern section of the state. Principal nesting areas lie north and northeast of the Lacassine Wildlife Refuge in Jefferson Davis, Acadia and Evangeline parishes. The Meanley and Meanley FULVOUS TREE DUCK 35 greatest nesting concentrations appear to be in the northern part of the rice belt (Fig. 3) rather than in rice fields adjacent to the coastal marsh. This may be because rice usually is planted first in the northern part of the rice belt; drainage is better in that area and the farmer can prepare his seed bed earlier. We attempted to determine nesting densities in two localities in which tree ducks seemed to be most abundant. At Mamou, in Evangeline Parish, approxi- mately 20 paiis nested in a five-square-mile area; while at Roanoke, in Jefferson Davis Parish, approximately 13 pairs were in a five-square-mile area. Nesting densities for small areas may be considerably higher, as several pairs often nest in a single field. One rice farmer located six nests in several contiguous rice fields, comprising 400 acres, on his farm near Mamou. Fligh nesting densities in these areas may be related to the fact that they are almost due north of the Lacassine Refuge marsh, one of the important concentration points before and after the nesting season. Following the nesting season, in late August and early September, tree ducks begin moving into large ponds, lakes, openings in mature rice fields, and flooded rice stubbles. At Mamou, a favorite gathering area is a shallow 200- acre lake. On September 17, 1955, we observed 140 tree ducks on this lake. 36 THE WILSON BULLETIN March 1959 Vol. 71, No. 1 On September 27, 1955, approximately 500 were recorded feeding in rice stubbles and potholes in mature fields at Roanoke. Claude Lard, manager of the Lacassine Wildlife Refuge, reported that the tree duck occurs on the refuge throughout most of the year, but reaches its peak population between the latter part of August and the end of September. He recorded a flock of 3000 birds during this period in 1954 (letter of August 19, 1955). In 1955, tree ducks had moved southward out of the northern rice-producing parishes by October 15. This movement was coincident with the first cold wave of the season and with termination of the rice harvest. To our knowledge, the latest fall flight occurred the evening of November 2, 1955, when 200 tree ducks flew over Bayou Lacassine in the direction of an inundated field of rice stuhble. Winter records in the coastal marshes are fairly numerous and include the following: four on November 25, 1956, at the mouth of the Mississippi River ( R. Beter, personal communication) ; 400 on a 1940 Christmas count at the Lacassine Refuge (U. S. Lish and Wildlife Service files) ; 500 in the marshes at Chenier au Tigre, on the southwest coast of Vermilion Bay, between Decem- ber 8 and 18, 1925 (A. M. Bailey, 1928) . Winter recoveries of banded and recaptured birds at Avery Island were reported by E. A. Mcllhenny as follows: Banded September 18, 1937 September 14, 1940 September 27, 1941 September 27, 1941 Recaptured December 11, 1937 December 30, 1942 1944-45 hunting season December 14, 1942 Wintering populations such as those mentioned above are not recorded from Louisiana every year; it is the opinion of several wildlife biologists and game enforcement officers who work in the coastal marshes that most of the tree ducks migrate southward to Mexico in winter. At present, however, there are no banding records to support this view. Nesting Ecology Extensive areas of rice fields form the optimum nesting habitat of the Lulvous Tree Duck on the Louisiana prairies. Fields heavily infested with weeds appear to be preferred over purer stands. In several localities, tree ducks were observed both feeding and nesting in the same weedy rice field; in certain other areas, a single weed-infested field was selected for feeding only. Among the more common herbaceous weeds occurring in Louisiana rice fields are: signal grass [Brachiaria exteusa), knot grass {Faspoluin dislichuin) , bull paspalum [ Paspahim Boscianum) , jungle rice {Echinochloa colonum), barnyard grass {Echiuochloa crusgalli) , Walter’s millet {Echinochloa Walteri), sedge (Cyperus spp.), mud plantain {Heteran- thera lirnosa), and smartweed [Polygonum spp.). Meanley and Meanley FULVOUS TREE DUCK 37 Nests were situated either on rice field levees or between levees over water. Six of eight nests we found were located over water between levees. These nests were attached to growing plants. The floors of the nests were several inches above the water level, which generally is fairly constant in rice fields. Rice [Oryza saliva) , the dominant plant of the area, is the principal material used in construction of most nests. In two nests we found rice plants which had been pulled up by the roots. Some late nests had the ripening grainheads of rice woven into them. One early nest was constructed entirely of signal grass. This nest was found in a pure stand of signal grass, which had crowded out the rice over an area of about a quarter of an acre. Most nests had a canopy of vegetation pulled over them (usually after the clutch was complete ) , and several were equipped with ramps leading to the rims. One nest had an S-shaped ramp four feet long. The depth of this nest from ground to top of rim was 11^4 inches and the inside width at top was 12% inches. None of the nests contained down. Nesting associates of the Fulvous Tree Duck in Louisiana rice fields, in order of relative abundance, are: Redwinged Blackbird {Agelaius phoeniceus ) , Purple Gallinule [Porphyrula martinica) , King Rail {Rallus elegans). Least Bittern [Ixobrychus exilis), and Long-billed Marsh Wren {Telrnatodytes pahistris) . These nesting associates usually nest in May, June and July, but there are also August records for each. Breeding Activities When tree ducks arrive in the spring, the ponds and rice stubble are already occupied by paired Blue-winged Teal [Anas discors) . Most tree ducks feed, sleep and move about in groups, although individuals or odd numbers of birds may freely leave one group for another. It seems that some tree ducks pair after their arrival on the breeding grounds. During this early period, small groups engage in eccentric flights. Two, three, or four ducks will fly about in unison, in a flight that is characterized by much twisting, turning and sharp hanking from side to side. On one occasion we observed three males (identified by their calls) following a female on the ground. The female maintained a three- to ten-foot lead, but if the males stopped following, the female moved closer to them until they began to follow again. Whenever a calling female flew over a field, many males standing on the ground immediately answered the call. Nesting begins about the middle of May, or as soon thereafter as the rice is high enough to provide nesting cover. The earliest record for Louisiana, as far as can be ascertained, is of a nest with one egg found at Maniou on May 25, 1956. At Mamou we also found a nest with six eggs on June 8, 1956; one with six eggs on June 23, 1956; and one with five eggs on July 8, 1957. At 38 THE WILSON BULLETIN March 1959 Vol. 71, No. 1 Elton, a nest with five eggs was located on July 4, 1955, and one with 23 eggs on July 16, 1955 (Eig. 4). Nesting may occur even later, for three downy young, approximately 30 days old, were banded on September 17, 1955. Fig. 4. Nest of 23 eggs of Fulvous Tree Duck in mature rice field at Elton, Louisiana, July 17, 1955. The nest we discovered at Mamou on June 8 eventually contained 13 eggs, which is about average clutch size for the Fulvous Tree Duck. Clutches in several nests found by Lynch [ibid.) varied from 10 to 15 with an average of 13. “Dump nests” are not uncommon with this species, as exemplified by the nest of 23 eggs, referred to above. W. L. Daw'son ( 1923 ) describes such a nest in California that contained 62 eggs. We flushed three adult birds from within five feet of a nest containing nine eggs. The day before it contained only sev^en. Johnstone (1957) found the incubation period for captive birds to be 26 days. Tbe following observations on wild birds also indicate an incubation period of approximately that length: Nest A contained six eggs when it was first located on June 8; it had nine eggs on June 9, and 13 on June 15; several eggs were pipped on July 5; three had hatched by July 6. Nest B had a single egg when it was found on May 25; it contained eight eggs on June 1; on this date the eggs were placed under a domestic hen, and they hatched 24 days later. Apparently both the male and female share in most phases of nesting activity. Pairs were seen flying together over rice fields throughout the nesting rhey were frequently observed flying together to and from their nests season. Meaniey and Meaniey FULVOUS TREE DUCK 39 and were often observed together with their brood. Delacour (1954) suggests that the male probably spends more time at the nest than the female. Notes on Development of Young A downy young (female) raised in captivity lost its egg tooth on the fourth day (Fig. 5). At 35 days, quills on wings and tail appeared (with feathers showing at tips of quills) . At the same time, the legs began changing color from olive-green to blue-grey, very nearly the adult color. At 40 days the juvenal plumage began to appear on the upper back, flanks and front of the neck (Fig. 6). At 60 days, a remnant of the downy cheek stripe was still present, and nearly complete juvenal plumage had developed, except for rectrices and remiges. At 63 days the cheek stripe was completely gone, and initial flight occurred. Weights of this young female were as follows: Age in days 4 6 8 33 60 365 Weight in grams 28.4 32.3 34.7 223.8 523.0 654.0 Two ducks in breeding condition weighed 747.7 grams (male) and 771.4 grams (female). This pair was collected from a rice field at Roanoke, Louisiana, on May 30, 1956. 40 THE WILSON BULLETIN March 1959 Vol. 71, No. 1 Late of Nests and Young Nesting success of first attempts may not be high, for only three of the 10 we observed were successful. Renesting undoubtedly compensates for this low figure. The early nests are particularly vulnerable to destruction and theft by farm hands, who find them in the course of “rogueing” rice fields for undesirable weeds during late June and July. On many farms this operation consists of a rather systematic coverage by a crew of boys and men walking abreast throughout a field. A few farmers detest the tree ducks so much that the nests are destroyed whenever they are found, as are the nests of the Purple Gallinule. More often, however, the eggs are gathered and placed under a harnyard hen. Upon hatching, the young ducks usually seem to adapt readily to their surroundings. In 19.5.5, we saw ducklings of 15 different broods in 14 barnyards. Some of these young ducks die at an early age, or are eventually eaten, while others are kept as novelties. During the summer of 1955, a farm hoy showed us two dead hroods of downy young, which drowned in heavy rainstorms before they were a week old. Lortunately for the tree duck, there is a considerable period following the “rogueing” operation when there is relatively little human activity in the rice field. Nesting attempts at this time are more likely to be successful than those made earlier. Raccoons { Procyon lotor) , opossums [Didelphis marsupialis) , skunks I Mephitis mephitis ) and domestic dogs wander in rice fields and on rice field levees and may destroy some nests or young. The broken eggs we saw in one nest probably had been destroyed by a raccoon. One young tree duck was found dead on a highway bordering a rice field. Man is, however, the principal decimating factor. Since the rice harvest begins in late July, and some ducks are still nesting through August, a few nests may be destroyed each year by the combine. The eggs in a nest we studied at Elton, Louisiana, began hatching on August 6, 1955, just four days before harvesting operations began. Loods Lrom field observations and stomach examinations (see Table 1) it is obvious that rice is an important food in water-planted fields near the coast. Seeds of this cultivated plant comprised 78 per cent of the food of 15 tree ducks collected and examined by Imler (1944). These ducks were collected from newly sown fields in April and May of 1944. In the late summer and fall rice appears to he less imjjortant in their diet, even though it is again abundantly available either in the stuhhle or standing in unharvested fields. There was only a trace of rice in the gullets and gizzards of five birds and in 100 droppings collected in late summer and fall; instead, weed seeds formed the bulk of the food. Meanley ami Meanley FULVOUS TREE DUCK 41 Table 1 Foods of the Fulvous Tree Duck in Louisiana (Based on 200 Droppings and 20 Gizzards) SPRING Dry-planted fields Water-planted rice Upper Rice Belt^ Fields near Coastal Marsh- ( 1 00 droppings) ( 1 5 gizzards) Per Cent Per Cent Fimbrystilis sp. 65 Oryza saliva 78 Paspalurn distichum 25 Brasenia Schreberi 11 Eleocharis sp. 10 Misc. weed seeds Oryza saliva trace ( Setaria, Paspalurn, Caperonia, Ranun- culus) 11 EARLY FALL Rice stubbles and mature rice fields^ Rice stubbles and (Gizzards and gullets of mature rice fields^ 5 birds) ( 1 00 droppings) Per Cent Per Cent Paspalurn distichum Echinochloa colonum and P. Boscianum 50 and E. W alteri 45 Cyperus rotundus 30 Paspalurn distichum 30 Echinochloa colonum Oryza saliva 15 and E. W alteri 20 Misc. sedges and grasses 10 ^ Rice drilled or disked into dry soil. 2 Field flooded and sown by airplane. 3 Evangeline and Jefferson Davis parishes. The importance of rice in the spring diet may reflect the relative scarcity of weed seeds during that period. It is true, however, that some weed seeds are available at the time rice is sown, particularly in pasture fields that were in rice the previous year. Weed seeds are available also in the native marsh where the ducks forage during the early part of the planting period. The gullets of two tree ducks collected from wet pastures at Roanoke, Louisiana, on May 30, 19.56, were crammed with the seeds of knot grass, signal grass, and Walter’s millet. Seeds of watershield, which are commonly found in the native marsh, formed 11 per cent of the food contents of 15 tree ducks collected by Imler {ibid.) in April and May. In late summer and early fall, grassy spots in rice fields provide excellent foraging sites. The panicles of several acjuatic plants such as knot grass, signal grass and jungle rice, extend just high enough above the surface of the water to be convenient for feeding ducks. When foraging for food in deeper waters, such as ponds or small impound- ments, tree ducks feed by “tipping.” On occasion, they also make short dives in which their entire bodies disappear under water. In shallow water, they poke their heads and necks beneath the surface without tipping (Fig. 7) . 42 THE WILSON BULLETIN Marcli 1959 Vol. 71, No. 1 Fig. 7. A typical feeding posture of Fulvous Tree Duck. Depredations The Fulvous Tree Duck is often charged with depredations upon newly sown rice fields in the spring and on the maturing fields in late summer and early fall. Damage in the spring usually occurs in fields that were flooded at the time of sowing. If the weather is warm, the rice sprouts in four or five days, and the field is then drained for a few days before being flooded again for the summer. As this first draining takes place, tree ducks. Blue-winged Teal, Redwinged Blackbirds and Boat-tailed Crackles {Cassidix rnexicanus ) flock to the mud flats and shallow pools to feed on the sprouting seeds. Tree ducks ordinarily feed in these fields at night. In late April, they usually depart from the coastal marshes at about 8:00 p.m. for their journey to the rice fields. On bright nights they could be observed in this flight and were seen to he moving fast and usually in small, tight flocks of 30 or 40 birds. Tree duck damage in sjiring is confined to a few fields in the rice belt, both because of the relatively small jiopulation of birds and the limited area of water-planted rice. Personnel of the Branch of Game Management and Branch of Wildlife Research. U. S. Fish and Wildlife Service, made a study of tree duck depreda- Mcanley and Meanley FULVOUS TREE DUCK 43 tions in Louisiana rice fields in 1944. Reports (Iinler el al., 1944; and Davis et al., 1944 ) of these investigations showed that in limited sections tree ducks may take nearly all of the seed, while over most of the area their feeding will result only in a thinning of the stand. Ducks destroyed as much as three per cent of seeds in some 30 per cent of the fields which contained water-planted rice. It was assumed that more seed would have been taken if the fields had been entirely unj^rotected by the farmer. Actual crop damage was not nearly as severe as suggested by the destruction of the seed in the spring. For in the fall evaluation it was found that in most fields where the rice seed had been nearly cleaned up, the rice plants had stooled out and filled in the gaps. The reappraised damage thus was estimated to be one half of one per cent. In early fall, after nesting is complete, tree ducks continue to feed in fields of ripening grain and in stubble fields that still have water on them. The seeds of grasses, sedges and other aquatic plants that grow in rice fields form the major food during this period. Nevertheless, many farmers contend that flocks of tree ducks feed mostly on the ripening rice, or otherwise damage the rice by opening up and enlarging potholes. An inspection of these potholes revealed that many of them are a result of the nesting of the Purple Gallinule. In many places where a gallinule builds its nest, the rice is knocked down for a radius of 5 to 10 feet and numerous potholes develop. Certain open pond areas in rice fields also may be the result of poor cultural methods. Ducks frequent these potholes primarily to forage for grass seeds, and do occasionally enlarge them somewhat. J. J. Carroll (1932), in writing about depredations in Texas, presented another view on this matter. “In July and August when the rice is in ‘the milk,’ that is to say when the kernels are soft and juicy, this duck wreaks havoc in the rice fields. The plant is bent over by the weight of the bird’s body and the ‘head’ containing the grains completely nibbled off. When it is taken into account that a flock of a thousand or more may descend into a field in one night some idea may be gained of the heavy damage resulting. The largest numbers are to be seen in the late fall just before the southward migration.” In July, 1957, we observed over 200 tree ducks in a rice field across the road from the Texas Rice-Pasture Experiment Station, a few miles west of Beau- mont. The director of this station informed us that he was not aware of any depredations and had not received a single complaint. In early October, 1955, we spent two days at Roanoke, Louisiana, observing a flock of 500 tree ducks that were working through rice fields and stubbles in an area of approximately five miles. While contingents of this flock occasionally alighted in openings in mature rice fields, most of the feeding and loafing took place in one flooded stubble field. Although from three to five per cent of the rice remained in the 44 THE WILSON BULLETIN March 1959 Vol. 71, No. 1 stubble after the harvesting operation, several birds collected from this flock had been feeding only on weed seeds. In mid-August, 1956, when most of the rice fields had been harvested in the vicinity of Mamou, Louisiana, a flock of some 150 tree ducks shifted their activities to a field in the “milk” stage of development. A thorough inspection of this field failed to reveal any damage to rice plants by the ducks. They were feeding entirely within the numerous grassy pools that were located in the field. Several days prior to harvesting, rice fields are drained to facilitate the combine operation. The progressive draining of the fields results in drying up of most of the stubble by mid-fall, and the ducks then return to the coastal marsh. It would he impossible to estimate the number of tree ducks that are shot during the rice planting and ripening periods. Since the majority of rice fields are sown by drilling (a practice which does not attract the tree duck) rather than by water planting, illegal shooting is confined to relatively few areas in the spring. Some farmers make a regular practice of shooting these birds in an attempt to “protect” their fields. No duck is more easily killed as it circles within range over the gunner’s head. It is fortunate for the tree ducks that most of them migrate southward prior to the opening of the waterfowl hunting season. Acknowledgments We are grateful to Mr. Morton M. Smith of the Louisiana Wildlife and Fisheries Commission for assistance in the field work; to Mr. Claude Lard, formerly manager of the Lacassine National Wildlife Refuge, for his search of refuge files; to Mr. Royston R. Rudolph, formerly refuge biologist, Sahine and Lacassine National Wildlife refuges, for information based on his field experiences in the coastal marshes; and to Dr. Frank L. Hoskins of Greenville, North Carolina, Dr. A. C. Martin, Mr. Robert E. Stewart and Dr. Lucille Stickel of the Patuxent Research Refuge for their review of the manuscript. Summary The Fulvous Tree Duck is a locally common breeding bird of the rice fields of southwestern Louisiana. Observations made in 1955, 1956 and 1957, showed that this species was probably most abundant in the vicinity of Mamou, Evangeline Parish, and Roanoke, Jefferson Davis Parish. Tree ducks arrive in the rice country as the rice is planted in the spring and usually depart following fall harvest. A few winter in the coastal marshes. The nesting period extends from late May well into August. Thirteen and 20 pairs were found nesting in two separate five-square-mile areas. All nests observed were in rice fields. Clutch size in several nests found by John J. Lynch averaged about 13 eggs. A clutch of 23 eggs was probably a dump nest. Several Aleanley and Mcanley FULVOUS TREE DUCK 45 investigators have reported incubation periods varying from 24 to 26 days. Nests were constructed of rice or other plants that occurred in the rice fields; they usually had a canopy and ramp; none was lined with down. Renesting compensated for some first attempt losses. Depredations on rice plantings sometimes occurred in spring in water-planted rice fields. Favorite foods were seeds of grasses and sedges found in rice fields. Flocks totalling 3000 were occasionally seen in the fall on the Lacassine Wildlife Refuge. Literature Cited Bailey, A. M. 1928 Notes on winter birds of Chenier an Tigre, Louisiana. Auk, 45:271-282. Carroll, J. J. 1932 A change in distribution of the Fulvous Tree Duck {Dendrocygna bicolor helva) in Texas. Auk, 49:343-344. Davis, W. T., P. W. Close and R. H. Imler 1944 Fnlvous Tree-dnck depredations on rice in Louisiana. Report in files of U. S. Fish and Wildlife Service. Dawson, W. L. 1923 The birds of California (Vol. 4). San Diego, Los Angeles and San Francisco: South Moulton Co., 2122 pp. Delacour, j. 1954 The waterfowl of the world (Vol. 1). London: Country Life, Ltd., 284 pp. Imler, R. H., H. C. Gascon and C. L. Horner 1944 Fulvous Tree-duck depredations in rice in Louisiana. Report in files of U. S. Fish and Wildlife Service. Johnstone, S. T. 1957 On breeding of whistling ducks. Avic. Mag., 63:23-25. Lowery, G. H. 1955 Louisiana birds. Baton Rouge: La. State Univ. Press, 556 pp. Lynch, J. J. 1943 Fulvous Tree-duck in Louisiana. Auk, 60:100-102. PATUXENT RESEARCH REFUGE, LAUREL, MARYLAND, AND LINTHICUM HEIGHTS, MARYLAND, FEBRUARY 24, 1958 COMMENTS ON “SPECIES RECOGNITION” WITH SPECIAL REEERENCE TO THE WOOD DUCK AND THE MANDARIN DUCK BY WILLIAM C. DILGER AND PAUL A. JOHNSGARD IT is well known that closely related, sympatric species have evolved species- specific features which serve to minimize the possibility of “wrong” choices being made during pair formation. The amount of evolution of such species- specific features is roughly proportional to the deleterious effects of the “wrong” choices made in species recognition. Of course, if upon initial contact, the forms interbreed too freely panmixia will occur and both will eventually lose whatever genetic identity they may have had. On the other hand if, by the time of contact, the forms have incidentally developed differ- ences sufficient to serve automatically as isolating mechanisms from the outset, then the further evolution of such characters will not occur as a result of “mistakes” being made. Thus, it would seem that the post-contact evolution of species-specific features which serve as isolating mechanisms depends upon rather particular conditions involving contacts between forms which find themselves neither impartially interfertile nor completely isolated at the start (see Sibley, 1957, for a thorough discussion of these phenomena). The species recognition features evolved in birds are mainly visual and/or vocal in nature. Either may predominate, depending on the nature of the selection pressures involved and upon the nature of the genetic variability available upon which the selection can exert its influence. Visual recognition will tend to be emphasized by selection in those species in which visual features are most advantageous, and the same may he said for vocal features. The rela- tive advantage or disadvantage is probably determined largely by the ease in which either may be perceived in the physical environment in which pair formation typically takes place (Dilger, 1956). Ducks of the genus Anas, many trochilids, paradiseids, phasianids, etc., probably rely largely on visual species recognition (Sibley, 1957) ; and thrushes of the genus Catharus have been shown to rely most heavily on vocalizations for their species recognition ( Dilger, 1956 ) . The process of evolution of a signal character (visual, vocal, etc.) from a nonsignal origin is termed “ritualization.” This term is used because it is rather descriptive of what happens to a movement as it evolves into having a greater and greater effect as a signal. Ethologists employ this term for the evolution of motor patterns (Blest, 1957 MS), hut it should also apply to the evolution of associated structural features (shape, color, texture, etc. ) which the motor ])atterns accentuate and which accentuate the motor patterns. This course seems reasonable because structural changes toward increasing signal 46 Dilger and Johnsgard SPECIES RECOGNITION 47 function exhibit the same phenomena characteristic of the ritualization of motor patterns. It is necessary to emphasize that the same selective pressures which are responsible for ever refining and rendering more “unmistakable” the male signal characters are also working equally on the releasing mechanisms (RM’s) of the female. These RM’s are responsible for receiving (via the sense organs) the sign stimuli emanating from the male and, depending on the circumstances, translating these signals into varying combinations of effector (muscular and glandular ) actions. Thus the females exhibit as much sexual “dimorphism” as the males do only it is not visible. The evolution of the RM ideally “keeps pace” with the continuing refinements of the signal to which it is attuned. In most cases it seems likely that the male signal charac- ters and the female RM’s do evolve roughly apace although it is unlikely that they evolve exactly together because of the probable disparity in the amount of genetic variability in the systems controlling the signal characters and the RM’s. Investigations into the mechanisms of species recognition should not only include consideration of the innate releaser-sign stimulus-RM features briefly discussed above, hut should also include a consideration of possible effects of early experience in regard to various learning processes such as “imprinting” ( Pragung) and allied phenomena. These are undoubtedly of great impor- tance in some instances even though they may not always he as directly controlled genetically as are the purely innate mechanisms. If the critical features of the normal environment which serve as releasers, and which make up the Umwelt for each species, are rather rigid and “predictable” then the animal can “afford” to have its responses “built in,” so to speak, in a rigid manner exemplified by the common releaser-sign stimulus-RM type of response. If, on the other hand, the animal’s Umwelt is a rather plastic one in any regard, then the responses to this type of situation are likely to be learned in some fashion. Different types of learning (see Thorpe, 1951) will prevail, depending on the nature of the situation. Imprinting, characterized by a short “sensitive period” and relative stability once established, seems to be a type of learned response close to a purely innate type of response. It has been long known that if hybrids are desired under laboratory conditions it is easier to obtain them if individuals of one of the two species with which one wishes to work are raised by the other species. Individuals thus reared seem to behave as if they had become imprinted on the foster ])arents and form pair bonds with members of the foster parent species much more easily than otherwise. The senior author has data indicating that this may be true within the genus Agapornis, for instance. Whitman (1919) utilized this technique with various pigeons and may have been the first to 48 THE WILSON BULLETIN March 1959 Vol. 71, No. 1 discover this principle. It is equally well known, however, that in some species this early experience has apparently no effect on future behavioi as far as “choosing” a mate is concerned. The Brown-headed Cowbird { Molothrus ater) and the Cuckoo {Cuculus canorus ) are two examples in which the young are regularly raised by foster parents and which, as adults, have no trouble in choosing mates of the proper species. If imprinting is involved in such cases it would mean that the sensitive period does not occur until the young normally have contact with their own species. At any rate it seems that species recogni- tion, like other behavior features, is dependent upon both innate and learned elements in various relative strengths and combinations, depending upon the nature and the amount of the selective pressures brought to bear. This would naturally vary from species to species. However, it does seem probable that parasitic species are the only ones in which early experience is likely to play no part in rendering the adults more likely to “choose” mates of their own species ( see also Cushing, 1941). The source of selection in developing species recognition features and their attendant RM’s may be any of the many and biologically disadvantageous events attendant upon the formation of interspecific pairs (Dilger, 1956). In addition, it may be of importance to consider the circumstances under which “mistakes” may be made. There seem to be at least two such circumstances. One is a situation where a female is located geographically in such a manner that her own species is relatively rare and a closely related, or even a merely similar appearing or sounding, species is rather abundant. This is a situation that is common where two related species share a rather narrow zone of overlap. This female will display the usual appetitive behavior asociated with a “search” for a mate. The longer she searches in vain the lower her threshold to respond becomes. This threshold may become so lowered that she will eventually respond to the suboptimal stimuli afforded by the next most similar set of sign stimuli, which will most likely be a male of the next most closely related species. Selection may work on such species as this to either restrict its range to areas in which the conflicting stimuli do not exist or to further refine the male signal characters and the female RM’s to function in a signal spec- trum even farther from that of the related species. In this latter case, the related species will also evolve its signal characters and RM’s farther away from its “competitor.” The other situation is where a female has an unspecific set of RM’s resulting from an unfortunate genetic recombination or, possibly, because of a mutation causing her to react unspecifically to male signals. Males may also have unspecific signals caused by the same phenomena. This situation, of course, will he selected against possibly even more strongly as these birds would he j)rone to make “mistakes” chronically in the case of females or he not as likely to attract mates in the case of males. Dilger ami Johnsgard SPECIES RECOGNITION 49 It has been suggested (Sibley, 1957) that those sympatric, closely related species which are polygamous and exhibit short term pair bonds dem- onstrate the most pronounced species recognition signal characters. The reason suggested is that “the combined effects of selection against hybrids and of sexual selection should produce a high degree of species diversity and develop- ment of signal characters in the males” (and a high degree of species diversity and development of the RM’s in the females j . This is quite likely to he true. However, there are many closely related and sympatric species (such as some parrots, for instance ) which are not polygamous and which form pair bonds of long duration — perhaps for many years. These species also evolve highly diverse species characters. If a “mistake” is made by individuals of these species it will tend to be of long duration and will likewise tend to cause a consequent high degree of “damage” to the gene pools involved. Hence, selective pressures brought to bear in these cases would also be very strong ones and would also result in a high degree of species diversity in regard to signal characters and RM’s. The parrot genera Amazona of the New World and Psittacula of the Old World provide likely examples of this. Not oidy does the length of the pair bond seem to have an influence upon the nature of the selective pressures brought to bear, but the time it takes the bond to form is probably of importance as well. Some thrushes, which have a seasonal pair bond, take three to four days to form their pair bonds ( Dilger, 1956 ) , and ducks commonly require several months to form their pair bonds, hut Budgerigars {MelopsUtacus undulatus), which have pair bonds lasting for years, take but a few hours to form them ( Morris, 1956 ) . Budgerigars do not have the problem of existing sympatrically with closely related species, but the thrushes and ducks considered do. In some cases it might be an advantage to have evolved behavior patterns which cause the pair bond to be formed rather slowly where mistakes are likely to be made. The most effective species-recognition insurance may occur in species having strong parental imprinting overlying innate behavior, militating for a long pair bond formation period and highly evolved signal characters with their associated RM’s. These modifications which may evolve as isolating mechan- isms probably occur in various combinations and strengths depending again on the vicissitudes of the selection pressures involved and upon the genetic variability available. From our human viewpoint we naturally tend to think of these as problems of species recognition. However, if we try to project ourselves into the bird s Ihmvelt and regard these problems from its “viewpoint,” a slightly different slant is obtained which may he of use to our thinking. Birds apparently are incapable of having concepts of any kind, including those of “sex, ’ ‘ species, “male,” “female,” etc. The bird’s “problem” becomes one of culminating a 50 THE WILSON BULLETIN Marcli 1959 Vol. 71, No. 1 period of appetitive behavior with the perception of sign stimuli which, in a broad sense, triggers the initiation of a “satisfactory sexual association. It is of value if we are aware of this “bird’s eye view because it may give us a much better idea of what is important to the animals concerned and thus may give us a better idea of how and where selection is working. The majoi leason why birds, like most other animals, make “mistakes is that they do not leact to the total environment but only to those features to which they have evolved to react under particular circumstances. This is why they are so easily misled experimentally by what may seem to many as totally improbable objects (see Tinbergen, 1951) . The observed instances of this are many, hut Lack s (1953) Robins {Erithacus rubecula) , fighting a tuft of red feathers, or Tinbergens 1 1951 ) male sticklebacks [Gasterosteus aculeatus) , reacting aggressively to any red object, have become classic examples. The senior author has found that Wood Thrushes [Hylocichla miistelina) will mount and attempt coition with papier mdche models of Wood Thrushes (Dilger, 1956), and these same birds will react aggressively or otherwise to small cubes and spheres painted brown above and white with black spots below. An apparent evolutionary anomaly is the existence of the Wood Duck [Aix sponsa) and the Mandarin Duck {A. galericulata) . The males of both species seem literally covered from head to tail with the most improbable and compli- cated collection of highly specific releasers that one could imagine, yet these species are not sympatric with any closely related ones or with each other. Like all highly evolved social signals, these are likely to he strongly selected against by predation if they are not even more strongly selected for by the necessity of ready recognition by females of their own species. This would seem to suggest the possible explanation that these species were sympatric with each other or with closely related forms in the near past. However, the only near relative of the Wood Duck which possibly could have been recently sympatric with it is the Muscovy {Cairina moschala) of Mexico, and it is a significant fact that hybrids between these two forms are unknown. Likewise, the Mandarin has possibly been sympatric only with the fairly closely related Pigmy Goose (Nettapus coromandelianiis) , a combination for which hybrids are also unknown. If indeed some closely related form had been sympatric with either the Wood Duck or the Mandarin in the past one would think that selection operating through the effects of predation would have caused the males to tend toward a more cryptic plumage since the time of species separa- tion. This is evidently not the case. Another thought is that ducks of other less closely related genera, and pos- sibly even of other tribes, may be the source of selective pressures if sufficient mistakes in mate choices are made that involve these more distant relatives. There is considerable support for this supposition. The Wood Duck is Dilger and Jolinsgard SPECIES RECOGNITION 51 notorious for forming mixed pairs and has produced hybrids with 26 species of ducks (Johnsgard, MS). Species involved include such unlikely forms as the Common Shelduck [Tadorna tadorna), 16 species of Anas, and five species of Aythya. This would indicate a very high first generation chromo- somal compatibility, exceeded only by the Mallard (Anas platyrhynchos) , which has hybridized with 40 species of Anatidae. It is of significance that the majority of Wood Duck hybrids of known parentage have involved the female Wood Duck, whereas most Mallard hybrids result from the male Mallard copulating with females of other species. The hybrids produced by Wood Ducks and Mandarins are apparently always sterile, and although they have been reported only from birds in captivity, these facts do demonstrate the Wood Duck’s unusual proclivity for mixed pairing. Mandarins, on the other hand, are not known to have hybrid- ized with more than five other species. Paradoxically, the two species of Aix will only rarely, if ever, hybridize with each other. The remarkable findings of Yamashina (1952), which indicate that the Mandarin possesses two less chromosomes than the Wood Duck and other anatines, would provide a logical explanation for sterility in alleged Mandarin X Wood Duck hybrids, and may also explain tbe former’s failure to hybridize with as many species as has the Wood Duck. Even in view of this extensive mixed pairing it is difficult to explain why the males of Aix have evolved such extreme complexities of plumage patterns. The danger of mixed pairs being formed witbin tbe genus Anas, for example, is equally great, and the male dimorphism exhibited here is extensive — not enormous as it is in Aix. Perhaps intertribal pairings are selected against more strongly than are intergeneric ones, but also the elaborate display move- ments of Anas probably substitute in large part for the very elaborate display plumage of Aix. Another, at least partial, explanation may lie in the possible discrepancy between the evolution of the male signal characters and the female RM’s. If for some reason, such as a lack of enough genetic variability, the females were not able to evolve a sufficiently refined set of RM’s rapidly enough, the greatest part of the burden of selective pressures toward species recognition would fall on the males, resulting in the extreme plumage complex we observe at present. Perhaps the fact that Wood Ducks, and especially Mandarins, are crepuscu- lar in their habits (Heinroth, 1910b, and Savage, 1952) is related to the increased danger of predation from visually operating predators attracted by the showy male plumages. Mandarins are in fact even more crepuscular than Wood Ducks. This may be related to their greater elaboration of contrasting male plumage patterns. 52 THE WILSON BULLETIN March 1959 Vol. 71, No. 1 Aix males are also more highly competitive with each other over the atten- tions of females than are most other clucks. In both species, but particulaily the Mandarin, the males congregate around a receptive female and conduct their courtship displays in a highly intense and competitive manner (Lorenz, 1941, and Heinroth, 1910a ). This may indicate that there is a comparatively great amount of competition among the males in displaying the optimal stimuli to a female. Although Mandarins appear to be monogamous with long paii bonds (in the wild at least ) , this initial intraspecific sexual competition and a greatly extended period of display and pair formation must be effective in maintaining the high degree of sexual dimorphism found in this species. This is especially true in the Mandarin, where the choice of a mate lies exclusively with the female (Lorenz, 1941). Selection thus would tend to cause the males to evolve releasers of ever increasing effectiveness. This may perhaps be thought of as an “attempt” to evolve a kind of superoptimal set of stimuli. An additional point of interest is that the males of Aix (especially sponsa) have displays consisting of numerous primitive and simple actions (Lorenz, 1941) which are largely homologous with the elaborate displays of Anas; thus possibly Anas males provide a kind of superoptimal stimulation to the RM’s of Aix females. This may explain the disproportionate frequency of matings with Anas males. It has been proven that birds and other animals will often react more strongly to superoptimal stimuli even though these usually do not occur in nature and are manufactured by the experimenter (Koehler and Zagarus, 1937, and Tinbergen, 1951, for example) . We are greatly indebted to the many helpful suggestions and ideas afforded hy Mr. Robert W. Ficken and Mr. Robert E. Goodwin. Summary Several things are pointed out that should he considered by anyone interested in prob- lems of “species recognition.” These are: 1. The source of selection controlling development of species-specific signals and releasing mechanisms (RM’s) may be ajiy of the disadvantageous consequences of mixed pairing (not necessarily hybridization alone). 2. The term “ritualization” should apply equally to the evolution of morphological features and motor patterns which are being selected for toward increasing signal function. 3. ft should be remembered that the evolution of RM’s proceeds in concert with that of the associated signal characters. 4. Early experience resulting in some form of learning such as “imprinting” may be of considerable consequence in subsequent “species recognition.” 5. The reasons why mistakes may be made in “mate choice” should be considered. For example, genetically “normal” animals may respond to suboptimal stimuli because of abnormally lowered thresholds; or genetically “abnormal” animals may respond with unrefined response capabilities. 6. Sympatric, closely related species which are polygamous and which have short term pair bonds are not the only ones tipon which strong selective pressures exert their influence toward marked development of signal characters and RM’s. Consider closely related, sympatric species with very long pair bonds which are not polyga- Dilger and Johnsgard SPECIES RECOGNITION 53 mous such as some of the parrots, etc. 7. Closely related species which are synipatric may not he the only source of selection toward diverse signals and RM’s. Any species with somewhat similar signal features and RM’s may exert this influence providing that they, of course, are sympatric with the form under investigation. 8. The amount of time taken to form the pair bond as well as its duration is likely to be of importance (Aix, for example). 9. It is useful to try to think of these problems from the “bird’s point of view.” After all, these problems are functions of the animal’s JJmwelt — not ours! Literature Cited Blest, A. D. 1957 MS The concept of ritualisation. Cushing, J. E. 1941 Non-genetic mating preference as a factor in evolution. Condor, 43:233-236. Dilger, W. C. 1956 Hostile behavior and reproductive isolating mechanisms in the avian genera Catharus and Hylocichla. Auk, 73:313-353. Heinroth, 0. 1910a Beobachtungen bei eineni Einbiirgerungsversuch mit der Brautente {Lampro- nessa sponsa [L.]). Jour. /. Ornith., 59:101-1.56. 19106 Beitrage zur Biologie, namentlich Ethologie und Psychologie der Anatiden. Verh. V. Ornith. Kong. (Berlin), 1910:589-702. JOHNSGARD, P. A. 1956 MS Hybridization in the Anatidae and its taxonomic implications. Koehler, 0. and A. Zagarus. 1937 Beitrage zum Brutverhalten des Halsbandregenpfeifers (Charadrius h. hiaticula L.). Beitr. Fortpfl. biol. Vogel, 13:1-9. Lack, D. 1953 The life of the robin. London: Pelican Books, 240 pp. Lorenz, K. 1941 Vergleichende Bewegungsstudien an Anatinen. Jour. ]. Ornith., 89:194—293. Morris, R. 1956 Mating behaviour of the budgerigar. Cage Birds, 110:299-300. Savage, C. 1952 The mandarin duck. London: Adam and Charles Black, 78 pp. Sibley, C. 1957 The evolutionary and taxonomic significance of sexual dimorphism and hybrid- ization in birds. Condor, 59:166-191. Thorpe, W. 1951 The learning ability of birds. Ibis, 93:1-52, 252-296. Tinbergen, N. 1951 The study of instinct. Oxford: Clarendon Press, 228 pp. Whitman, C. 1919 The behavior of pigeons. (Airnegie Inst. IP ash., publ. 257, 3:1-161. Yamashina, Y. 1952 Classification of the Anatidae based on the cyto-genetics. Papers from the coordinating committee Res. Genetics, 3:1-34. THE LABORATORY OF ORNITHOLOGY AND THE DEPARTMENT OF CONSERVATION, CORNELL UNIVERSITY, ITHACA, NEW YORK, FEBRUARY 18, 1958 VARIATION IN THE SONGS OF THE RUFOUS-SIDED TOWHEE BY DONALD J. BORROR CONSIDERABLE variation is known to occur in Rufous-sided Towhee {Pipilo erythrophthalmus) songs (Saunders, 1951), but relatively little is known of the exact nature of the variation. This study was made to learn more of the nature of the variation in the songs of this bird. The collection of tape recordings in the Laboratory for the Study of Animal Sounds, Department of Zoology and Entomology, Ohio State University, includes 71 recordings containing towhee songs (43 from Ohio, 4 from Michi- gan, 13 from Maine, 2 from West Virginia, 3 from North Carolina, and 6 from Florida); these recordings contain a total of 694 songs (Tables 1 and 7). These songs have been analyzed by means of a Vibralyzer ( Borror and Reese, 1953 ), and graphs made of the different patterns found. Most of the record- ings were made by the writer; a few were made by Dr. Carl R. Reese. All the recordings were made with a Magnemite Model 610-E tape recorder, using a tape speed of 15 inehes per second. General Character of Towhee Songs Towhee songs commonly consist of two parts, (1) one or more introductory notes, and (2 ) a trill. A few songs lack the first part, a few lack the second part, and a few are double (introductory notes, a trill, then more introductory notes, then another trill ) . The trill usually consists of a rapid series of similar phrases; occasionally the first note or phrase of the trill is different from the rest, and in rare cases the trill is two-parted ( a few phrases of one type, then a few of another type ) . Each part may vary in the number and character of the notes or phrases it contains. A towhee generally sings at the rate of five to ten songs a minute. Its songs are usually all alike, hut it may occasionally sing songs of one type for a while, and then change to a different type; rarely a bird may sing two types of songs alternately. The largest number of song types recorded from a single bird in a single recording was eight (recording No. 879B, from Florida). Variation in Introductory Notes of Song The introductory notes in the songs studied represented 45 different patterns (plus one other in which there were no introductory notes). These patterns were designated by capital letters, A through TT, and may he classified as follows : 54 D(malcl J. Borror RUFOUS-SIDED TOWHEE 55 I. With no introductory notes (designated as pattern A) II. With one introductory note (12 patterns, B-M) a. The note clear and musical (5 patterns, B-F, Figs. 1, 9-12, and one note like those in Fig. 46) b. The note huzzy (5 patterns, G-K, Figs. 2, 13-17) c. The note with both musical and huzzy elements (2 patterns, L-M, Figs. 18-19) III. With two introductory notes (23 patterns, N-JJ) a. The two notes about the same pitch (5 patterns, N-R, Figs. 3, 20-22, and two notes like those in Fig. 46) b. The first note higher in pitch than the second (12 patterns, S-DD, Figs. 4—6, 23-39) c. The second note higher in pitch than the first (6 patterns, EE-JJ, Figs. 7, 40-45) IV. With three introductory notes (8 patterns, KK-RR) a. The three notes alike (1 pattern, KK, Fig. 46) b. The first two notes alike, the third different (2 patterns, LL-MM, Figs. 47-48) c. All three notes different (5 patterns, NN-RR, Figs. 8, 49-53) V. With four introductory notes (2 patterns, SS-TT) a. The four notes alike (1 pattern, SS, the notes like those in Fig. 46) b. The four notes different (1 pattern, TT, Fig. 54) The occurrence of these introductory patterns in the recordings from different areas is summarized in Table 2. One Introductory Note. — Nearly one-fourth of the introductory patterns found consisted of a single note. When this note was musical, it was steady in pitch (Figs. 1, 9, and 10), slightly up-slurred (Fig. 11), abruptly down-slurred (like the notes in Fig. 46), or down- slurred at the beginning and then steady in pitch (Fig. 12). When it was buzzy, it was up-slurred (resembling the “chewink” call. Figs. 2, 15), or steady in pitch (Figs. 14, 16, and 17). The introductory note in one Ohio pattern (pattern L) was buzzy at the beginning, then musical and nearly steady in pitch (Fig. 18) ; in one Florida pattern (pattern M) it was abruptly down-slurred and then buzzy (Fig. 19). Two Introductory Notes. — Half of the introductory patterns found consisted of two notes. These notes were alike in four patterns (2 from Florida, 1 from Maine, and 1 from central Ohio, Figs. 3, 21, 22, and like two of the notes in Fig. 46), and slightly different in quality but of about the same pitch in one Florida pattern (Fig. 20). The most common type of introduction (12 patterns) consisted of a high-pitched note and a lower-pitched note; in most of these (Figs. 4, 23-32) the first note was shorter and sharper than the second, with the second musical; in a few cases (Figs. 5, 33, and 34) the first note was buzzy; in a few other cases (Figs. 36-39) the first note was complex, containing two dominant frequencies or containing two or more overlapping notes; in one pattern (Figs. 6, 35) the two intro- ductory notes overlapped. Three or Four Introductory Notes. — These patterns made up a little over one-fifth of the total. Most of the introductory patterns consisting of three notes (Figs. 8, 49-53) had these notes different. Twelve of the introductory patterns (excluding pattern A, representing no introductory notes) occurred in the songs of different birds; the occurrence of these patterns is sum- marized in Table 3. One pattern (V, Figs. 27-29) occurred in as many as seven different birds; several patterns occurred in birds from widely separated areas. 56 THE WILSON BULLETIN March 1959 Vol. 71, No. 1 Table 1 Rufous-sided Towhee Song Recordings Studied Recording Song Pattern Figure No.- No. of Songs No. Locality Date Series^ Introd. Trill 342 Bradenton, Florida March 24, 1953 — FF-31 41 83 5 384 Franklin Co., Ohio April 10, 1953 A B F-22 NN-33 (12) 49 (75) (85) 3 2 432 Columbus, Ohio April 29, 1953 — 00-46 50 99 9 457 Reynoldsburg, Ohio May 4,1953 — 00-37 8 8 7 665 Worthington, Ohio May 30, 1953 — 11-44 44 97 10 762 Reynoldsburg, Ohio March 24, 1954 A B C-39 C-47 (10) (10) 92 101 10 1 766 Reynoldsburg, Ohio March 24, 1954 — C-18 1 1 11 786R Columbus, Ohio April 21, 1954 — V-38 (27) 91 9 814B Bradenton, Florida April 6,1954 A B Q-1 Q-4 (3) 3 3 1 21 A A-27 — 80 5 B E-27 (46)3 (80) 1 C 0-27 (46)3 (80) 5 879B Myakka River State Park, Florida April 13, 1954 D E KK-27 N-6 ( 46 ) 20 (80) (59) 1 1 F M-6 19 59 11 G KK-1 46 — 3 H SS-1 (46)3 — 1 912B Greensboro, N. C. April 24, 1954 — PP-15 51 68 8 916B Greensboro, N. C. April 24, 1954 A B Y-1 Y-28 (33) 33 81 1 11 921B Greensboro, N. C. April 24, 1954 — GG-5 42 57 10 1127 Hocking Co., Ohio .June 5,1954 — G-47 13 (103) 8 1262 New Albany, Ohio April 1,1955 — MM-23 48 76 11 1284 New Albany, Ohio April 10, 1955 A B F-21 U-47 12 26 74 (102) 2 7 1296 Columbus, Ohio April 13, 1955 — HH-49 (43) 107 6 1299 Columbus, Ohio April 14, 1955 A B U-32 U-8 25 (25) 84 61 9 8 1433 Worthington, Ohio May 19, 1955 — 11-49 (44) (107) 9 1464 Adams Co., Ohio May 30, 1955 — HH-49 7 7 15 1471 Hocking Co., Ohio .June 5,1955 A B L-1 A-12-2 18 65, 55 3 3 1.550B Lincoln Co., Maine July 19, 1955 — C-26 (10) 79 8 1557B Lincoln Co., Maine July 23, 19.55 A B W-34 W-43 (31) (31) 86 96 3 10 Donald J. Horror RUFOUS-SIDED TOWHEE 57 Table 1 {Continued) Recording Song Pattern Figure No.” No. of Songs No. Locality Date Series’- Introd. Trill 1560B Lincoln Co., Maine July 23, 1955 — B-34 19) (86) 11 1641B Bradenton, Florida March 14, 1956 — Z-3 34 56 1 1649 New Albany, Ohio March 27, 1956 A B LL-24 00-29 47 (50) 77 82 6 10 1728 Reynoldsburg, Ohio April 28, 1956 A B F-1 F-47 (12) (12) 105 1 7 1731 Reynoldsburg, Ohio April 28, 1956 A B JJ-1 JJ-47 (45) 45 (103) 11 2 1734 Reynoldsburg, Ohio April 28, 19.56 — DD-36 38 90 11 1786 New Albany, Ohio May 5,19.56 A B U-24 T-47 (25) 24 (4) 102 2 2 1808 Reynoldsburg, Ohio May 6,1956 — U-24 4 4 11 1823 New Albany, Ohio May 9,1956 A B A-46 A-46-46 — (100) (100) 5 10 1826 New Albany, Ohio May 9,19.56 — EE-14 40 67 6 1955 Reynoldsburg, Ohio May 30, 1956 — C-18 (10) (71) 11 1958 Reynoldsburg, Ohio May 30, 1956 — CC-35 37 88 7 1971 Adams Co., Ohio June 2,19.56 A B E-28 F-22 (12) (12) (81) 75 2 1 1991 Mocking Co., Ohio June 2, 1956 — U-24 (25) (77) 8 2109 Lincoln Co., Maine July 1,19.56 — W-34 30 (86) 11 2112 Lincoln Co., Maine July 1,1956 — C-7 (10) (60) 3 2205 Lincoln Co., Maine July 19, 19.56 — C-7 (10) 60 12 2207 Lincoln Co., Maine July 19, 19.56 A B TT-16 QQ-16 54 52 69 (69) 4 2 2213 Lincoln Co., Maine July 25, 1956 A B C V-30 I-ll 1-30 (28) (2) 2 (2) 64 2 5 2 3 2215 Lincoln Co., Maine July 25, 1956 A B C D C-20 X-34 A-34 C-34 (10) 5 10 73 5 (5) (5) 13 2 1 2 2357 Collier Co., Florida March 21, 1957 — J-41 (16) (94) 8 2390 Collier Co., Florida March 21, 1957 — .1-41 16 94 6 2445 New Albany, Ohio April 11, 1957 — HH-50 (43) no 5 2457 New Albany, Ohio April 16, 1957 — F-50 (12) 111 10 58 THE WILSON BULLETIN March 195h Vol. 71, No. 1 Table 1 {Continued) Recording Figure No.” Song NO. OT No. Locality Date Series^ Pattern Introd. Trill Songs 2458 New Albany, Ohio April 16, 1957 — F-50 (12) (111) 9 2459 New Albany, Ohio April 16,1957 A B HU -50 HH-49 (43) (43) (112) 108 7 2 2460 New Albany, Ohio April 16, 1957 — A A -47 6 6 8 2463 New Albany, Ohio April 16, 1957 — DD-5 39 58 9 2476 New Albany, Ohio April 24, 1957 A B B-18 P-51 9 21 (71) 113 12 2 2486 New Albany, Ohio April 27, 1957 — H-18 14 71 13 2488 New Albany, Ohio April 27, 1957 — AA-47 (6) 104 10 2489 New Albany, Ohio April 27, 1957 — V-53 28 115 5 2497 New Albany, Ohio April 27, 1957 — HH-50 43 112 14 2499 Reynoldsburg, Ohio April 28, 1957 — D-42 11 95 8 2520 Whitehall, Ohio May 1,1957 — U-25 (25) 78 11 2578 Reynoldsburg, Ohio May 7,1957 — V-19 29 72 8 A AA-47 35 103 7 2587 Columbus, Ohio May 10, 1957 B B-46 (9) 100 11 C 1-48 15 106 9 2666 Worthington, Ohio May 18, 1957 — RR-35 53 89 2 2706 Kanawha City, W. Va. May 25, 1957 — S-33 23 85 6 2715 Kanawha City, W. Va. May 25, 1957 A B C-9 C-9-H-17 (10) (10, 14) 62 (62), 70 3 4 2757 Oscoda Co., Mich. May 30, 1957 A B BB-1 BB-13 (36) 36 66 2 5 2770 Oscoda Co., Mich. May 31, 1957 — V-52 27 114 6 2781 Oscoda Co., Mich. May 31, 1957 — V-45 (27) 98 12 2782 Oscoda Co., Mich. May 31, 1957 — K-54 17 116 7 2941 Lincoln Co., Maine July 3,1957 — W-50 31 109 10 2945 Lincoln Co., Maine July 13, 1957 — W-10 (31) 63 10 3000 Lincoln Co., Maine July 14, 1957 — V-34 (28) (86) 12 A R-34 22 87 3 3002 Lincoln Co., Maine July 14, 1957 B W-40 32 93 4 C W-1 (32) — 1 1 Series are designated only in recordings containing songs of two or more patterns. 2 Numbers in parentheses represent figures of this pattern, but were made from a song in another series. ® Patterns E, O, and SS are like pattern KK (Fig. 46), but contain one, two, and four notes respectively, instead of three. Donald J . Borror RUFOUS-SIDED TOWHEE 59 Table 2 Occurrence of the Introductory Patterns in Towhee Songs Number of Patferns Pattern Groupi- Central Ohio Southern Ohio Michigan Maine West Virginia North Carolina Florida Total" I 1 1 1 1 1 a 4 1 2 1 1 5 11 b 2 1 1 1 1 1 5 c 1 1 2 a 1 1 3 5 111 b 6 1 2 3 1 1 1 12 c 4 1 1 1 6 a 1 1 IV b 2 2 c 3 1 1 5 a 1 1 V b 1 1 Totals 23 6 3 10 3 3 11 46 'Roman numerals and small letters refer to the groups "Some patterns occur in the songs of birds from differenf "Includes the pattern of no introducfory nofes. in the c! areas. assification outlined on p. 55. Table 3 Introductory Patterns Occurring in the Songs of More Than One Bird Number of Birds in Which the Pattern Occurred Pattern and Central Soufhern West North Group' Ohio Ohio Michigan Maine Virginia Carolina Florida Total 11 a B 2 1 3 11 a C 2 3 1 6 11 a F 3 1 4 11 b H 1 1 2 11 b 1 1 1 2 111 b U 4 1 5 111 b V 3 2 2 7 111 b W 3 3 111 1) DD 2 2 111 c HH 3 1 4 111 c 11 2 2 IV c 00 3 3 'Roman numerals and small letters refer to the groups in the classification outlined on p. 55; the capital letters refer to individual introductory patterns. 60 THE WILSON BULLETIN March 1959 Vol. 71, No. 1 Variations in the Trill The songs studied contained 53 different trill patterns (designated by num- bers, 1—54, with No. 1 representing no trill) ; there was more variation in the trill than in the introductory part of the song. Even in the songs of different birds considered to have trills of the same pattern, there were minor variations (compare Eigs. 5, 86, and 87; 101-105; 107 and 108; and 109-112) in the trill. The different trill patterns differed in the general character of the phrases (number and types of notes present), their length (or the rate with which they were uttered), their number, and in how the trill began. The first phrase of the trill in 23 of the patterns was different from the remaining phrases, that is, the trill began with an extra note (Figs. 2, 4, 8, 60—63, 65, 66, 68, 75—79, 81, 82, 91, 93, 96, 99-101, 115, and 116) ; this note was sometimes very short (0.05 sec. or shorter), but in most cases it was longer than any of the subse- quent trill phrases, and higher in pitch. The variations in the trill were such that the different trill patterns were not readily classifiable. The phrases contained from one to several notes, and the notes frequently overlapped. Some of the characteristics of the trill pat- terns occurring in the songs of birds from different areas are summarized in Table 4. Songs of a given type sung by a given bird occasionally differed by one or a few phrases in the number of phrases in the trill; these differences were not considered to represent different trill patterns. Songs containing different types of trills often differed considerably in the number of trill phrases they contained, and in the rate with which the phrases were uttered. Table 4 Summary of Trill Characteristics Area No. of Song Series No. of Trills' Trill Phrase Length (in seconds) Number of Trill Phrases Range Series Averages Range Average- Range Average- Central Ohio 48 375 .0.5-.20 .095 ±.004 2-15 2.78-14.32 7.36±0.34 Southern Ohio 7 38 .05-.12 .081±.012 2-10 3.33-10.00 6.29±0.85 Micliigan 4 30 .11-.13 .120±.004 2-6 2.80-5.86 4.69±0.66 Maine 21 143 .03-.13 .072±.006 4-18 4.00-17.42 9.41±0.90 West Virginia 4 17 .06-.12 .088±.016 4-7 5.00-7.00 5.80±0.45 North Carolina 3 29 •04-.08 •063±.012 8-16 8.91-15.38 11.61±L94 Florida 9 65 .05-.17 .092±.012 3-14 3.00-9.90 7.83±0.74 Total 96 697 .03-.20 ,088±.003 2-18 2.78-17.42 7.73±0.31 'This is not quite the same as the number of songs, since some songs had no trill and some had two trills. ''Averages are given plus or minus the standard error of the mean; the figures in the last column are averages of the series averages. Donald J. Borror RUFOUS-SIDED TOWHEE 61 The trill phrases varied in length from 0.03 (pattern 10, Fig. 63) to 0.20 sec. (pattern 48, Fig. 106), and were uttered at rates from 5 to about 35 phrases per second; they varied in number from 2 to 18. The trill phrases in the songs of Michigan birds averaged significantly longer than in birds from Ohio, Maine, and North Carolina; those in the songs of central Ohio birds averaged significantly longer than in birds from Maine. The number of trill phrases averaged significantly greater in the songs of birds from Maine than in the birds from Michigan and West Virginia, greater in the birds from North Carolina than in those from Michigan and West Virginia, and greater in the birds from central Ohio than in those from Michigan. In general, the shorter the trill phrases, the more phrases there were. The trill phrases were generally all of the same pitch; rarely the pitch appeared to fall a little toward the end of the trill, usually because of the dropping out of some of the higher frequencies. The last phrase of the trill was occasionally incomplete. The trill often became less loud toward the end. When the trill began with a high-pitched buzz (for example, pattern 24, Fig. 4), this buzz was much louder than the rest of the trill. Twelve trill patterns (excluding pattern 1, representing no trill ) occurred in the songs of different birds (Table 5). Most of these recurring patterns occurred in only two or three birds; one (No. 47, Figs. 6, 101-105) occurred in six birds. Many of these patterns occurred in the songs of birds in widely separated areas. Table 5 Trill Patterns Occurring in the Songs of More Than One Bird Number of Birds in Which the Pattern Occurred Trill Pattern Central Ohio Southern Ohio Michigan West Maine Virginia North Carolina Florida Total 5 1 1 2 18 3 3 22 1 1 2 24 2 1 3 28 1 1 2 33 1 1 2 34 2 2 35 2 2 46 3 3 47 5 1 6 49 3 1 4 50 2 1 3 62 THE WILSON BULLETIN March 1959 Vol. 71, No. 1 Song Patterns The combination of a particular type of introduction (A to TT I and trill (1 to 54) resulted in a particular song pattern (for example, B-18, K-54, and SS-1) . A total of 93 song patterns were found in the recordings studied. These patterns are most easily classified on the basis of the type of introduction they contained. The occurrence of the 93 patterns in the songs of birds in different areas is summarized in Table 6. Although there were 12 introductory patterns and 12 trill patterns that occurred in the songs of different birds, there were only 5 song patterns that were sung by different birds: (1 ) Pattern L-22, sung by a bird in central Ohio (recording 384, series A) and another in southern Ohio (recording 1971, series B). (2) Pattern U-24, sung by two birds in central Ohio (recording 1786, series A, and recording 1808, Reynoldsburg) and one in southern Ohio (recording 1991). (3) Pattern AA-47, sung by two birds in central Ohio (recording 2460, and recording 2587, series A ) . (4) Pattern HH-49, sung by two birds in central Ohio (recording 1296, Columbus, and recording 2459, series B, New Albany) and another in south- ern Ohio (recording 1464). (5) Pattern HH-.50, sung by two birds in central Ohio^ (recordings 2459, series A, and 2497, and recording 2445 ) . There is a great deal of difference in the song pattern of different birds, and only rarely ( in this study, only 5 of 93 song patterns ) does one find a given song pattern sung by different birds. When the song patterns of different birds are sufficiently different to be distinguishable by ear, the individual birds can be recognized by their songs. The songs of the Llorida birds were somewhat different in character from those of the northern birds; none of the introductory or trill patterns of the Llorida birds (except those of no introduction or trill) occurred in the songs of any northern birds (Tables 3 and 5). Most songs of the Llorida birds are readily distinguishable by ear from those of northern birds. There was an appreciable time interval between the notes of the introduction (when the introduction contained more than one note), and between the intro- duction and the trill. The time interval between the notes of the introduction is shown by the graphs (Pigs. 3-8 and 20—54). The interval between the introduction and the trill (shown only in Pigs. 1-8) varied in the different patterns from 0.04 to 0.30 sec., and averaged 0.12 sec. I There is a slight possibility that these recordings were of the same bird. Recordings 2459 and 2497 were made about fifty yards (and eleven days) apart; 2445 was made about one-tourth mile away, and five days before the first of the other two recordings was made. Donald J. Horror RUFOUS-SIDED TOWHEE 63 Table 6 OCCURKENCE OF ToWHEE SONG PATTERNS Number and Per Cent of Song Patterns' Central Southern West North Pattern- Ohio Ohio Michigan Maine Virginia Carolina Florida Total I 2 1 1 1 5 4.65 14.29 5.00 7.14 5.38 a 11 2 5 2 1 203 25.58 28.57 25.00 66.67 7.14 21.51 u 2 1 1 2 1 7 D 11 4.65 14.29 20.00 10.00 7.14 7.53 1 1 2 c 14.29 7.14 2.15 Tot. 13 4 1 7 2 3 293 30.23 57.14 20.00 35.00 66.67 21.43 31.18 1 1 5 7 a 2.33 5.00 35.71 7.53 K 13 1 4 9 1 2 1 303 1) III 30.23 14.29 80.00 45.00 33.33 50.00 7.14 32.26 7 1 1 1 93 c 16.28 14.29 25.00 7.14 9.68 Tot. 21 2 4 10 1 3 7 464 48.84 28.57 80.00 50.00 33.33 75.00 50.00 49.46 a 2 2 14.29 2.15 b IV 2 4.65 2 2.15 5 1 1 7 c 11.63 5.00 25.00 7.53 Tot. 7 16.28 1 5.00 1 25.00 2 14.29 11 11.83 1 1 a 7.14 1.07 V b 1 5.00 1 1.07 Tot. 1 5.00 1 7.14 2 2.15 Total 43 7 5 20 3 4 14 935 46.24 7.53 5.38 21.51 3.22 4.30 15.05 ^The upper figure is the number of song patterns, and the lower figure is the per cent of the potterns from that area; in the bottom line, under "Total," the per cent is the per cent of all the patterns (93) occurring in the songs of birds from that area. “Roman numerals and small letters refer to the groups in the classification outlined on p. 55. ^One of these patterns occurred in the songs of birds from two different areas. ‘Two of these patterns occurred in the songs of birds from two different areas. "Three of these patterns occurred in the songs of birds from two different areas. The frequencies in the towhee songs studied (excluding harmonics) were for the most part hetween 2000 and 6000 cycles per second. The extremes found were 1800 cycles per second (patterns DD and MM, Figs. 39 and 48) and 9000 cycles per second (pattern 36, Fig. 90) . 64 THE WILSON BULLETIN March 1959 Vol. 71, No. 1 Summary OF THE Table 7 Towhee Recordings Studied Central Number of Ohio Southern Ohio Michigan Maine West Virginia North Carolina Florida Total Birds Recorded! 27 5 2 7 2 3 5 51 Recordings 38 5 4 13 2 3 6 71 Song Series- 51 7 5 22 3 4 14 106 Songs 377 40 32 132 13 30 70 694 Introductory Patterns^ 22 5 3 9 3 3 10 454 Trill Patterns^ 27 7 4 11 3 3 6 534 Song Patterns^ 43 8 5 20 3 4 14 93 ^An estimate; represents a minimum figure. "A song series is a group of songs of a given patfern in a given recording. ^Some of fhese patterns occurred in the songs of birds from more fhan one area. ■* Does not include the pattern of no introducfion or trill. Summary The songs of the Rufous-sided Towhee usually consist of one or more introductory notes and a trill. In 71 tape recordings of towhee songs, from six states ( Ohio, Michigan, Maine, West Virginia, North Carolina, and Florida) and containing 694 songs, there were 45 introductory patterns (plus one of no introductory notes) and 53 trill patterns (plus one of no trill). The introductoi’y patterns contained from one to four notes. The trills contained from 2 to 18 phrases, uttered at rates f 5 to 35 phrases per second. The different introductory and trill patterns were combined in 93 different song patterns (Table 7). The recordings were studied by means of a Vibralyzer. The song patterns were classified on the basis of their introductory notes. Twelve introductory patterns and 12 trill patterns, hut only 5 song patterns, were found in the songs of different birds. The frequencies in the songs ranged from 1800 to 90000 cycles per second, hut in most songs were between 2000 and 6000 cycles per second. There is a great deal of variation in towhee songs, and more variation in the trill than in the introductory notes. It is possible in many cases to recognize individual birds by their song. Plate 1. Audiospectrographs of Towhee Songs. Fig. 1, pattern C-18, 766-1, central Ohio. Fig. 2, pattern 1-30, 2213-4 (C), Maine. Fig. 3, pattern Q-4, 814B-7 (B), Florida. Fig. 4, pattern U-24, 1808-2, central Ohio. Fig. 5, pattern X-34, 2215-4 (B), Maine. Fig. 6, pattern .A.A-47, 2460-1, central Ohio. Fig. 7, pattern HH-49, 1464-1, southern Ohio. Fig. 8, pattern 00-37, 457-1, central Ohio. Numbers following the pattern represent the recording, and the song in the recording, from which the graph was made; letters in parentheses represent the series in the recording. Plate 2. Audiospectrographs of Introductory Patterns in Towhee Songs. Fig. 9, pattern B. 2476-1 (A), central Ohio. Fig. 10, pattern C, 2215-8 (D), Maine. Fig. 11, pattern D, 2499-1. central Ohio. Fig. 12, pattern F, 1284-1 (A), central Ohio. Fig. 13, pattern G, 1127- 2, southern Ohio. Fig. 14, pattern 11, 2486-1, central Ohio. Fig. 15, pattern I, 2587-21 (C), central Ohio. Fig. 16, pattern J, 2390-1, Florida. Fig. 17, pattern K, 2782-1, Michigan. Fig. DonaKl J. Borror RUFOUS-SIDED TOWHEE 65 18, pattern L, 1471-1 (A), southern Ohio. Fig. 19, pattern M, 879B-6 (F), Florida. Fig. 20, pattern N, 879B-5 (E), Florida. Fig. 21, pattern P, 2476-2 (B), central Ohio. Fig. 22, pat- tern R, 3002-2 (A), Maine. Fig. 23, pattern S, 2706-2, West Virginia. Fig. 24, pattern T, 1786-2 (B), central Ohio. Fig. 25, pattern U, 1299-1 (A), central Ohio. Fig. 26, pattern U, 1284-4 (B), central Ohio. Fig. 27, pattern V, 2770-1, Michigan. Fig. 28, pattern V, 2489-1, central Ohio. Fig. 29, pattern V, 2578-4, central Ohio. The recording, song, and series from which each graph was made are indicated as in Plate 1. Plate 3. Audiospectrographs of Introductory Patterns in Towhee Songs. Fig. 30, pattern W, 2109-1, Maine. Fig. 31, pattern W, 2941-1, Maine. Fig. 32, pattern W, 3002-5 (B) , Maine. Fig. 33, pattern Y, 916B-1 (B), North Carolina. Fig. 34, pattern Z, 1641B-1, Florida. Fig. 35, pattern AA, 2587-1 (A), central Ohio. Fig. 36, pattern BB, 2757-1 (B), Michigan. Fig. 37, pattern CC, 1958-2, central Ohio. Fig. 38, pattern DD, 1734-1, central Ohio. Fig. 39, pattern DD, 2463-2, central Ohio. Fig. 40, pattern EE, 1826-1, central Ohio. Fig. 41, pattern FF, 342-3, Florida. Fig. 42, pattern GG, 921B-1, North Carolina. Fig. 43, pattern HH, 2497- I, central Ohio. The recording, song, and series from which each graph was made are indi- cated as in Plate 1. Plate 4. Audiospectrographs of Introductory Patterns in Towhee Songs. Fig. 44, pattern II, 665-2, central Ohio. Fig. 45, pattern JJ, 1731-4 (B), central Ohio. Fig. 46, pattern KK, 879B-27 (G), Florida. Fig. 47, pattern LL, 1649-2 (A), central Ohio. Fig. 48, pattern MM, 1262-1, central Ohio. Fig. 49, pattern NN, 384-4 (B), central Ohio. Fig. 50, pattern 00, 432-2, central Ohio. Fig. 51, pattern PP, 912B-4, North Carolina. Fig. 52, pattern QQ, 2207- 2 (B), Maine. Fig. 53, pattern RR, 2666-1, central Ohio. Fig. 54, pattern TT, 2207-1 (A), Maine. The recording, song, and series from which each graph was made are indicated as in Plate 1. Plate 5. Audiospectrographs of Trill Patterns in Towhee Songs (only the first part of each trill is shown; the remaining phrases in each case are like the ones shown). Fig. 55, pattern 2, 1471-4 (B), southern Ohio. Fig. 56, pattern 3, 1641B-1, Florida. Fig. 57, pattern 5, 921B-2, North Carolina. Fig. 58, pattern 5, 2463-2, central Ohio. Fig. 59, pattern 6, 879B-6 ( F) , Florida. Fig. 60, pattern 7, 2205-1, Maine. Fig. 61, pattern 8, 1299-7 (B) , central Ohio. Fig. 62, pattern 9, 2715-2 (A), West Virginia. Fig. 63, pattern 10, 2945-5, Maine. Fig. 64, pattern 11, 2213-2 (B), Maine. Fig. 65, pattern 12, 1471-4 (B), southern Ohio. Fig. 66, pat- tern 13, 2757-1 (B), Michigan. Fig. 67, pattern 14, 1826-1, central Ohio. Fig. 68, pattern 15, 912B-4, North Carolina. Fig. 69, pattern 16, 2207-1 (A), Maine. Fig. 70, pattern 17, 2715-3 (B), West Virginia. Fig. 71, pattern 18, 2486-1, central Ohio. Fig. 72, pattern 19, 2578-4, central Ohio. Fig. 73, pattern 20, 2215-1 (A), Maine. Fig. 74, pattern 21, 1284-1 (A), cen- tral Ohio. Fig. 75, pattern 22, 1971-2 (B), southern Ohio. Fig. 76, pattern 23, 1262-1, central Ohio. Fig. 77, pattern 24, 1649-2 ( A) , central Ohio. Fig. 78, pattern 25, 2520-2, central Ohio. Fig. 79, pattern 26, 1550B-1, Maine. Fig. 80, pattern 27, 879B-1 (A), Florida. Fig. 81, pat- tern 28, 916B-1 ( B) , North Carolina. Fig. 82, pattern 29, 1649-7 (B) , central Ohio. Fig. 83, pattern 31, 342-3, Florida. Fig. 84, pattern 32, 1299-1 (A), central Ohio. Fig. 85, pattern 33, 2706-1, West Virginia. Fig. 86, pattern 34, 1557B-1 (A), Maine. Fig. 87, pattern 34, 3002-2 (A), Maine. Fig. 88, pattern 35, 1958-2, central Ohio. The recording, song, and series from which each graph was made are indicated as in Plate 1. Plate 6. Audiospectrographs of Trill Patterns in Towhee Songs (only the first part of each trill is shown; the remaining phrases in each case are like the ones shown). Fig. 89, pattern 35, 2666-1, central Ohio. Fig. 90, pattern 36, 1734-1, central Ohio. Fig. 91, pattern 38, 786R-5, central Ohio. Fig. 92, pattern 39, 762-3 (A), central Ohio. Fig. 93, pattern 40, 3002- 5(B), Maine. Fig. 94, pattern 41, 2390-1, Florida. Fig. 95, pattern 42, 2499-1, central Ohio. Fig. 96, pattern 43, 1557B-6 (B), Maine. Fig. 97, pattern 44, 665-2, central Ohio. Fig. 98, pattern 45, 2781-1, Michigan. Fig. 99, pattern 46, 432-2, central Ohio. Fig. 100, pattern 46, 2587-8 (B), central Ohio. Fig. 101, pattern 47, 762-6 (B), central Ohio. Fig. 102, pattern 47, 1786-2 (B), central Ohio. Fig. 103, pattern 47, 2587-1 (A), central Ohio. Fig. 104. pat- tern 47, 2488-1, central Ohio. Fig. 10.5, pattern 47, 1728-1 (B), central Ohio. Fig. 106, pattern 48, 2587-21 (C) , central Ohio. Fig. 107, pattern 49, 1296-1, central Ohio. Fig. 108, pattern 49, 2459-7 (B), central Ohio. Fig. 109, pattern .50, 2941-1, Maine. Fig. 110, pattern 50, 2445-1, central Ohio. Fig. Ill, pattern 50, 2457-1, central Ohio. Fig. 112, pattern 50, 2497-1, central Ohio. Fig. 113, pattern 51, 2476-2 (B), central Ohio. Fig. 114, pattern 52, 2770-1, Michigan. Fig. 115, pattern 53, 2489-1,, central Ohio. Fig. 116, pattern 54, 2782-1, Michigan. The record- ing, song, and series from which each graph was made are indicated as in Plate 1. FREQUENCY IN KILOCYCLES PER SECOND 66 THE WILSON BULLETIN March 1959 Vol. 71, No. 1 jt 3 _ L / r — ~r 1 ,V 4 < iAI0 a k \ T A ' 4 ill* A O T?r 6 1 v_ A X \ \ 4 \ f\ n \ —i 6 4 2 7 _UJ pvj 4- ,1 mmrn A- n ' m . j r fr; 8 to d tih 4tt, Vi 0.0 0.2 0.4 0.6 0 8 time IN SECONDS 10 1.2 Plate 1. FREQUENCY IN KILOCYCLES PER SECOND Donald J. Borror RUFOUS-SIDED TOWHEE 67 Plate 2. FREQUENCY IN KILOCYCLES PER SECOND 68 THE WILSON BULLETIN March 1959 Vol. 71, No. 1 Plate 3. FREQUENCY IN KILOCYCLES PER SECOND Donald J. Borror RUFOUS-SIDED TOWHEE 69 6 4 2 6 4 2 00 53 54 i 0.2 0.4 06 0.8 1.0 1.2 1.4 TIME IN SECONDS Plate 4. FREQUENCY IN KILOCYCLES PER SECOND 70 THE WILSON BULLETIN March 1959 Vol. 71, No. 1 Plate S. FREQUENCY IN KILOCYCLES PER SECOND Ounald J. Borrur RUFOUS-SIDED TOWHEE 71 Plate 6. 72 THE WILSON BULLETIN March 1959 Vol. 71, No. 1 Literature Cited Borror, D. J. and C. R. Reese 1953 The analysis of bird songs by means of a Vibralyzer. Wilson Bull., 65:271-276. Saunders, A. A. 1951 A guide to bird songs (2nd ed.). Garden City: Doubleday and Co., Inc. xiv + 307 pp. DEPARTMENT OF ZOOLOGY AND ENTOMOLOGY, OHIO STATE UNIVERSITY, COLUM- BUS 10, OHIO, DECEMBER 26, 19.57 OBSERVATIONS ON TERRITORIAL BEHAVIOR OE LEAST FLYCATCHERS BY DAVID E. DAVIS \ LTHOUGH the theory of territorialism has been amply studied and reviewed, ji\_ a number of aspects remain to be clarified. This study of the Least Flycatcher [Empidouax minimus) attempts to use information obtained about the breeding sequence to understand certain aspects of the development of territorial behavior. The paper also discusses in some detail the clutch size, hatching and fledging success, and the incubation and feeding behavior for a dozen nests. In particular, this study has emphasized the analysis of the role of the chebec call of the male. Although this call is generally accepted (MacQueen, 1950) as the “territorial song,” the existence of an elaborate flight-song per- formance in the genus (see McCabe, 1951, for detailed description for Traill’s Flycatcher [F. traillii]) presents problems in interpretation. For Hammond’s Flycatcher {E. hammondii) Davis (1954) suggested that the chebec note be called a patrol note and that it “serves to indicate to the female the position of the male.” The present study pursues this problem. The genus [Empidonax) has attracted attention from a number of persons. Bent (1942:174^-260) assembled miscellaneous notes on the various species. McCabe (1951) observed the flight song of Traill’s (Alder) Flycatcher and found that the birds simultaneously performed in the evening an elaborate song which was timed in relation to sunset, and persisted till August 8. MacQueen (1950) described the territories and song of the Least Flycatcher at the University of Michigan Biological Station for three summers. The details of her work will be discussed under each section below. Davis (1954) described the breeding of Hammond’s Flycatcher at the Montana State Uni- versity Biological Station at Flathead Lake for three summers and compared several aspects of six species in the genus. The current report presents the results of observations at the University of Virginia Biological Station at Mountain Lake, Virginia, from June 13 to July 18, 1956. Unfortunately, the birds had already started nesting and thus the inception of breeding was missed. The procedures were essentially to map territories, record behavior in building the nests, determine frequency of attentive and feeding behavior, and count the number of chebec calls. Obser- vations were started at dawn every day from June 14 to July 16. The individual birds were not marked by hands or other devices because it was felt that the birds might desert the nest or area, and because such marks would be very difficult to see in any case. The problem of obtaining statistically adequate data for Least Flycatchers 73 74 THE WILSON BULLETIN March 1959 Vol. 71, No. 1 arises, as it did for Hammond’s Llycatcher. Although about 125 hours of actual observation time were accumulated, when divided among 10 pairs, several periods of the day, and various phases of the nesting cycle, there are only a few observations in each category and thus no useful measure of variability is available for statistical comparison of categories. Thus statistical significance cannot be determined. The result is a description of what was recorded rather than attempts at generalizations concerning the breeding of Least Llycatchers as a species. While the study is therefore deficient in this important aspect, it is considered worthwhile to report the observations because it seems unlikely that a sample of suitable size (perhaps 6000 hours! ) will soon be obtained, and also because these observations may suggest generalizations. The Biological Station is located near Mountain Lake, Virginia, about 50 miles west of Roanoke. It is on Salt Pond Mountain at an altitude of 3800 feet. The forest is basically oak— chestnut (Braun, 1950:232), although the chestnuts have been killed by blight. In addition to white oak [Quercus alba) , which may comprise 50 per cent of the trees, red oak {Quercus borealis), cucumber tree {Magnolia acuminata], pitch pine {Pinus rigida), and sweet birch { Betula lenta) are the most important species. The grounds of the Biological Station have been cleared and present a park-like appearance ( Lig. 1). The flycatchers inhabited this area as well as more dense adjacent areas. Large tracts of apparently suitable dense vegetation lacked flycatchers. Perhaps the Least Llycatchers that lived in the dense vegetation can be con- sidered as overflow from the open area (Lig. 1), and thus do not contradict Breckenridge’s report (1956) that these flycatchers are scarce in dense vegetation. The birds formed a definite colony in the study area. Searches in nearby areas revealed no birds, even in apparently suitable vegetation. Actually there were two parts to the colony. The area of the Station grounds (Part 1) consisted of about 19 acres, and contained nine nests and two pairs that failed to nest. The flycatcher density thus was 22/19, or 1.2 birds per acre. The other area (Part 2) adjoined the Station on the south and bordered the road to Mountain Lake. It consisted of about 9.5 acres. Observations in this area were not as intensive. During the time available only one nest and one fledged brood were found although two other pairs may have been present. On this basis the density was 8/9.5, or 0.8 bird per acre. Colonial distribution has been recorded by a number of observers (Bent, 1942; Kendeigh, 1947:48; MacQueen, 1950). The latter recorded densities of 2.0 to 2.7 pairs per acre, which is much higher than the density here recorded. The other birds present included (in decreasing order of abundance) Robins Davia\ ill K. Davis BEHAVIOR OF LEAST FLYCATCHERS 79 like a butterfly than like a bird. This song is obviously the flight song reported by various authors and described in detail for Traill’s (Alder) Flycatcher by McCabe (1951). The performer is assumed to be a male because all gave chebec calls. The performance occurred between 1950—2010 (sunset at 1912) on each evening observed. Birds in all stages of breeding performed. Observations were made every evening from June 16 to July 5, but the last flight song was observed on June 26. It was impossible simultaneously to observe every bird, and thus some performances were missed. However, it was possible to be in a position to watch and identify several at the same time. It is clear that the birds whose females were building or laying performed most constantly. To compare the frequencies according to the phase of the cycle the number of birds performing may be compared with the chances to observe a bird (which is the number of evenings multiplied by birds in the phase). Males in the building phase performed on 4 of 9 chances; males in the laying phase per- formed on 5 of 6; males in the incubating phase performed on 8 of 33; and in the feeding phase on 2 of 44. On the two evenings when no actual flight was made, several birds started the performance by calling weep, weep and ascend- ing in the tree, but failed to fly up. This performance was never observed in the early morning, although obser- vations were started daily at 0415 when there was less light than at the time of the evening performance. Greetings. — Both the male and female may chatter and twitter when they meet away from the nest or at the nest. Typically the greeting is given when the female comes off the nest during incubation or comes from the nest during feeding of the young. Defense. — During the latter part of the observation time a number of strange birds wandered through the area. Presumably these birds had lost their nest or mate by some accident and were searching for a new place. The owners of the territory met these birds with a series of weep-weep notes, identical to the notes in the flight song, and drove the strangers away. This note in clearly an aggressive note. It was not possible to determine whether the female gave the note. Building Note. — A churr was given by the male and female as she built the nest, hut its function is not known. It was not heard after incubation began. The birds flutter their wings somewhat as they go from branch to branch. Calls of Young. — During the last few days of feeding the young may pro- duce some notes in the nest. However, as soon as the young leave the nest they emit a mellow chip note that apparently serves as a location note to help the adults find them. In one case a young bird gave this call when it was out on a branch near the nest but not after it hopped back into it. 80 THE WILSON BULLETIN March 1959 Vol. 71. No. 1 Territorial Behavior The territorial behavior of the Least Llycatcher very closely resembles the behavior of Hammond’s Llycatcher (Davis, 1954) and other members of the genus: Dusky {E. oberhoheri) , Acadian (E. virescens) , and Western {E. difficilis) (personal observations). The males defend the territory and the females defend a small area around the nest. After the young leave the nest both male and female drive other Least Llycatchers away from the territory even though the young may be outside. The young generally leave the territory. Two broods left one day after hatching, three broods left two days after (but one of them returned to its territory 13 days later), one brood remained in its territory for 12 days, while another remained 13 days. The size of the territory differs among pairs and according to the stage of breeding. Although it is difficult to define the boundaries precisely, in general the male has a territory ranging from 0.35 to 0.55 acre in size. The territories of four males in incubation or laying were 0.33, 0.35, 0.54 and 0.55 acre. Territories of three males during the feeding phase were 0.15, 0.26 and 0.37 acre. One male had a very large territory (2.8 acres), which was reduced to about 0.3 acre during feeding. It is perhaps significant that this bird had a neighbor on only one side of his territory. Another bird, which started nesting late (June 26), had a territory of 0.23 acre bounded on nearly 80 per cent of the periphery by other birds. The female may use part of the male’s territory or have an area of her own to which the brood may go when leaving the nest. The defense of the territory is performed by active fighting. The male defends a larger area than does the female. The function of the various notes in the defense of the territory is not clear. Presumably the flight song is territorial, although it is not performed during the daytime. An integral part of the flight song is the defense note described above as weep-weep. It was performed regularly by the male when driving out an intruder and actually fighting. On 24 occasions a fight between flycatchers was observed, and on 18 the defender used the call. In two other cases an invader used this call. On seven occasions c/iebec’s accompanied the fights but at no greater rate than usual. Twice after severe fights no chehec^s were given. The weep note was given at all stages of breeding, but was more common later, presumably because more strangers were around. While the above evidence suggests that the tveep call is a means of territorial defense, some other evidence does not support this conclusion. On June 25 a pair took up a territory adjacent to another pair that was feeding young. Not until July 1 (second day of incu- bation ) was the weep-weep call heard, although some fights between the males had been seen. However, the number of chehec^s was no greater than normal by either bird. David E, Davis BEHAVIOR OF LEAST FLYCATCHERS 81 The observations cited above do not suggest that the chebec is a territorial song; they show that the weep-weep note is aggressive. However, some other observations agree with the interpretation that chebec is territorial. It is clearly given from a few particular perches that are conspicuous. It may be used in opposition to an adjoining male. The male stops calling chebec when he leaves his territory. But in contrast to this view is the fact that at both nests which were started after observations began, the chebec calls did not reach maximum frequency till the cycle was advanced. In one case the bird was not heard till the day the first egg was laid, even though observations were made in adjacent areas. In the other case the male did not reach the maximum until the sixth day of building (the female started four nests). When the female disappeared ( two cases ) the number of chebec calls increased from 50 to 376 per 15-minute interval. No female was obtained although several were wandering around. Neither of these behavior sequences fits the pattern of conventional territorial song behavior. When fighting against other Least Flycatchers or other species the bird clicks its bill rapidly thus making a loud clatter. The Least Flycatcher was seen to drive Robins, vireos. White-breasted Nuthatches, Cedar Waxwings, Rufous-sided Towhees, warblers and Wood Pewees away from the nest and young. Yellow-shafted Flickers and Hairy Woodpeckers were watched but not attacked. The patterns of fighting described above do not fit the “typical” (Song Sparrow, Indigo Bunting) territorial behavior. In particular the two types of song are peculiar. The current observations agree with the suggestion (Davis, 1954) that the notes (the chebec of the Least Flycatcher and Hammond’s, and the corresponding notes of other species) serve to indicate to the female the position of the male. Similarly the female note (here called whit) indicates to the male the position of the female. The vigorous calling in early morning is not clearly explicable on this basis, but might be an extension of location notes needed in the darkness. It has long been accepted that the function of terri- torial song is to repel aggression and to advertise to the female that a male is present. Perhaps in these flycatchers these functions are each attached to different notes so that there exists aggressive song and advertising song ( position note ) . Nesting Cycle Nest. — The nest is built in a crotch of a small tree or fork of a large tree, or on a lateral limb. Of 14 nests observed, 4 were in a crotch of a white oak sapling (about four inches DBH) and 7 were on a horizontal branch of a large white oak, 2 were on branches of pitch pines and one was on a branch of a sugar maple sapling. The average height was 15.8 feet, distributed as follows: 7 feet, 1 nest; 11-12 feet, 4 nests; 13-14 feet, 4 nests; 15 feet, 2 nests; 27 feet, 1 nest; and 35 feet, 1 nest. One female started four different nests on horizontal branches of large white oaks, all 20-30 feet above the ground. 82 THE WILSON BULLETIN Marcli 1959 Vol. 71, No. 1 The nest is a compact bowl, constructed from plant fibers and lined with some feathers or fluffy plant material. The inside diameter is two inches. The nests were very similar irrespective of location. In only one case was building observed and it may have been abnormal. A female over a period of seven days started four nests. The first was demolished by waxwings and the others were abandoned. Tlie male did not accompany the female on her trips to the nest hut called nearby. Eggs and Young. — Five nests when first observed had eggs. The average clutch was 3.4 and was distributed thus: 2 eggs, 1 nest; 3 eggs, 1 nest; 4 eggs, 3 nests. Three other nests had young when first observed: 4 young, 2 nests; 3 young and 1 unhatched egg, 1 nest. Assuming that none of these latter 3 clutches originally had .5 eggs, the mean clutch size was 3.6. Six nests were inaccessible or destroyed before the contents were observed. One egg in one nest did not hatch and none of four eggs in a late nest hatched. Thus the proportion hatcliing was 24/29 = 83 per cent. This result does not include a nest that was empty when found and was tleserted the following day by the female. Only one young failed to fledge. Thus the proportion was 23/24 — 96 per cent for the seven nests for which data were obtained. The proportion of eggs that produced fledglings was 83/96 80 per cent. The duration of nestling period was obtained in four cases: one of 14 days, two of 15, and one of 16. The period was measured from the day the first young hatched to the day that one of the young left the nest. The time of departure was observed at seven nests. In five cases the young left before 1000. In one case the two young left about 1900, and in one case three left about 1900 and one left the following morning. Independence may not be attained for about three weeks. One brood was still fed by tbe adults at 21 days although the young had been catching insects by tliemselves for five days. All the other broods left the area before the stage of independence was reached. No young were known to have died in the post-fledging period of dependency. Incubation. — The incubation is performed l)y the female alone. This agrees with MacQueen (1950:198) but is contrary to Bent’s opinion (1942:216) that “probably both sexes incubate.” Quantitative data on incubation and brooding are presented in Table 3. The percentage of time on the nest is remarkably constant during the day and during the stages. The only outstanding value is for early morning 0-4-day stage, hut this is merely sampling variability, for most of the data were obtained on one bird on the morning of the day incubation started. The average of the percentages in Table 3 (omitting 28.4 per cent) is 77.1 per cent which can he used as the percentage of time the female is on the nest. Table 3 Percentage of Time Spent Incubating OR Brooding Stage Days Time of day 0430 -0730 0830-1230 1330 -2000 Min. Per Cent Min. Per Cent Min. Per Cent Incubation 0^ 244 28.4 207 75.5 236 81.5 5-9 388 80.0 323 76.3 0 — 10-14 884 82.0 397 73.2 529 78.2 Brooding L5-19 456 77.3 357 74.5 387 72.9 Min. — Total minutes of observation during this time period and stage. David E. Davis BEHAVIOR OF LEAST FLYCATCHERS 83 The duration of inculcation was not obtained for any clutch, but is assumed to he 14 days, although Bent (1942:216) states “the period of incubation is said to be 12 days.” The assumption of 14 days is based on the meager evidence that incubation lasted at least 12 days in one nest and that Davis (1954) found a period of 15 days for one nest of Hammond’s Flycatcher. The male may feed the female while she incubates. At one nest he fed her 11 times in 360 minutes and at another nest 12 times in 128 minutes. The weather was cold and foggy on these days. The eggs in most nests hatched over a period of two days but in one nest during three days. The female continues to brood for several days. She stays on the nest at night at first but when the young become large, she perches on the edge. Feeding. — The male and female feed the young. During the early stages of feeding the male sometimes gave food to the brooding female who then gave it to the young. The sex of the bird could usually he determined by a difference in behavior, checked by the call notes. The male characteristically perched on a small twig to feed the young, whereas the female perched on the nest or in some cases on a different branch. The individual birds were very consistent in their approach. In one case the male changed perches in the last three days apparently because the size of the young made the former perch nnsnitable. Some males called chebec regularly at feeding. Male 1 called 25 times for 99 feedings. Table 4 gives the frequencies of feeding. The data are divided into stages of nestling development by 5-day periods and into three parts of the day. It is apparent that the total rate of feeding increases rapidly and more than doubles from early to late nestling stage. Table 4 Hourly Feeding Rates by Time of Day Stage of nesting Time of day 0430 -0730 0830 -1230 1330- -2000 Min. Rafe Min. Rafe Min. Rate 15-19 days 315 4.8 411 7.5 743 4.8 20-24 days 570 14.0 622 10.6 1029 11.7 25-29 days 727 16.2 701 13.6 1039 14.6 Min. — Total minutes of observation during this time period and stage. The number of young also affects the feeding rate. One nest had two nestlings and the other nests all had four nestlings. The average rate per hour was 7.2 in the nest with two young, and 14.2 in the other nests. These figures include all observations and the distribu- tion by time of day and stage of feeding is comparable. Table 5 gives the percentages of feedings by the male. The sex was identified in 65.6 per cent of 1280 feedings. No trend in proportion of feedings by the male is apparent either by stage of nesting or time of day. The fecal sac was removed by males and females. Within a pair, how'ever, considerable difference in frequency appeared to occur. When the young are 12-13 days old they begin to flap and stretch their wings. In another day they may stand on the rim of the nest and flap their wings very rapidly. On about the 15-16th day they may leave the nest. A bird may hop out to a branch and then come back in. When they leave, they can fly a yard or more. They generally hop gradu- 84 THE WILSON BULLETIN March 1959 Vol. 71, No. 1 Table 5 Percentage of Feedings by Male Time of day Stage of nesting 0430- -0730 0830- -1230 1330- -2000 Feedings Per Cent Feedings Per Cent Feedings Per Cent 15-19 days 22 40.8 50 68.0 38 42.1 20-24 days 91 66.8 55 52.7 no 55.5 25-29 days 164 59.8 199 39.2 111 47.7 Totals Means of percentages 277 55.8 304 53.3 259 47.1 ally upwards till they are about 30 feet up. The young may sit together on a branch to be fed and to sleep. Duration oj Breeding Season. — The date of laying for 12 nests can be approximated by calculation backwards from known dates of hatching or fledging. Assuming 14 days for incubation and 15 for fledging, the laying dates are: May 24 (2 nests), May 31, June 4, 5, 7, 10, 11, 12, 18, 28, and July 2. It is apparent that in 1956 in this area the peak of laying occurred in the first week of June. Presumably the late nests were renesting by birds whose first nest or mate had been destroyed. There was no evidence of a second nesting in this area. No breeding behavior was seen in the territories where a brood had been successfully raised. Furthermore, both male and female care for the young for as much as 20 days after leaving the nest. However, Bent (1940:216) states (without evidence) that two broods are “often, if not regularly” raised in the southern portion of the range. I wish to acknowledge the collection of data by the following students: Edward Daley, Paidine Lorvan, W. J. Pitman, Robert Price, and Alice Walralh. Only observations that were mutually agreed to be reliable were included. Summary During the summer of 19.56, observations of territorial behavior and nesting of the Least Flycatcher {Empidonax minimus) were obtained at the University of Virginia Biological Station at Mountain Lake, Virginia. The birds nested in the oak forest and the park-like grounds of the Station. Most of the 14 nests were in oaks, either in a crotch or on a branch. The average height was 16 feet. The clutch size was 3.6 based on five nests with eggs and three nests with young when found. About 80 per cent of the eggs produced fledglings. The call notes consist of at least eight types. (1) The male position note ichehec) is given at a rate of about 700 per 15 minutes, from 0430-0530 at the time of laying. It declines during the day and the rest of the breeding cycle. It increases in frequency during laying and after disappearance of the female. (2) The female has a note (whit) that appears to have the same function. (3) The alarm (iweep) is given by both sexes. (4) The flight song at dusk is jierformed by the male. (5) Greetings are given when members of David E. Davis BEHAVIOR OF LEAST FLYCATCHERS 85 a pair meet. (6) An aggressive call {weep-weep) is used when fighting with other Least Flycatchers. (7) A special note (churr) is given as the nest is huilt. (8) The young have a location note. Incubation is performed only by the female, who spends about 80 per cent of her time on the nest. Males and females feed the young about equally frequently. The rate of feeding by both birds increased from about six per hour during the first third of the feeding phase to about 15 per hour during the last third. The territorial behavior resembles that of other members of the genus. The males defend an area but the role of the chebec note is not clear. It is given from prominent places within the territory but it is not used when fighting and, in the two cases available, increased in frequency up to the start of incubation. Defense of territory is associated with an aggressive note. Literature Cited Bent, A. C. 1942 Life histories of North American flycatchers, larks, swallows, and their allies. U. S. Natl. Mas. Bull., 179:1-538. Braun, E. L. 1950 Deciduous forests of Eastern North America. Blakiston Co., Pliiladelphia, 596 pp. Breckenridge, W. J. 1956 Measurements of the habitat niche of the Least Elycatcher. IFilson Ball., 68: 47-51. Davis, D. E. 1954 The breeding biology of Hammond’s Elycatcher. Auk, 71:164-171. Kendeigh, S. C. 1947 Bird population studies in the coniferous forest biome during a spruce hudworm outbreak. Dept. Lands and Forests, Ontario Biol. Bull., 1:1-100. MacQueen, P. M. 1950 Territory and song in the Least Flycatcher. Wilson Bull., 62:194-205. McCabe, R. A. 1951 The song and song-flight of the Alder Flycatcher. W ilson Bull., 63:89-98. THE JOHNS HOPKINS UNIVERSITY SCHOOL OF HYGIENE AND PUBLIC HEALTH, BALTIMORE 5, MARYLAND, JANUARY 24, 1958 NOTES ON THE NESTING OF SELECTED SPECIES OF BIRDS OF THE SONORAN DESERT BY M. MAX HENSLEY ^l^HESE miscellaneous data were collected during June and July of 1948, and from February through August of 1949, in a study (Hensley, 1954) of the breeding birds of the intermountain desert plains in Organ Pipe Cactus National Monument, Arizona. Notwithstanding the time interval since the conclusion of that study, it seems likely that the data presented here may be of interest to investigators concerned with the bird species found in this signifi- cant region. The topography, flora, and breeding bird population are given in detail in my earlier report {ibid.) . Acknowledgments I wish to acknowledge the most cordial cooperation of the National Park Service officials who were stationed on the Monument during the time of the study. Mr. William R. Snpernaugh, Superintendent of Organ Pipe Cactus National Monument, and Ranger Glen L. Bean were most helpful. I am also indebted to Dr. S. Charles Kendeigh, Department of Zoology, University of Illinois, and Dr. George J. Wallace, Department of Zoology', Michigan State University, who kindly read the manuscript and offered many pertinent suggestions. Dr. Arthur A. Allen, Laboratory of Ornithology, Cornell University, aided greatly in the final compilation of the data during the original research program. Systematic List Of the 25 representatives of 16 families of birds known to nest in the region, observations on 16 species are presented below. Turkey Vulture (Cathartes aura). — This species was recorded from March 1 through August. One nest with two eggs was discovered on May 31 in a cairn of rocks in a small valley. The boulders were arranged so as to form a chamber, 10 feet in diameter and about 3.5 feet high, with a single small entrance. Red-tailed Hawk (Buteo jamaicensis) . — Eight nests of this resident species were located in saguaros i Cereas giganteus) , hut only one site was suitable for frequent observations. This nest contained two eggs when found on April 1. Both adults shared in the incubation of the eggs and care of the young. The first egg hatched on April 7. On May 19, 42 days later, the young birds were still in the nest hut left within the next two or three days. The food of these hawks consisted mostly of rodents with the round-tailed ground squirrel (Citelliis teredcaudus) the most common species taken. The desert spiny lizard ( Sceloporiis magister) and Clark’s spiny lizard (S. clarki) were both found in this nest. One of the adults was seen flying overhead with a sizable snake dangling from its talons. The heads of the rodents were generally removed before being offered to the young, while the lizards were entire. The most active feeding periods appeared to he during the mid- morning (8 to 9 a.m.) and again around 5:00 p.m. Harris’ Hawk i Parahuteo iinicinctus) . — Two nests of this resident hawk were found in saguaros. Some 10 hours of observations were made at a nest which contained two eggs on April 17. It was placed about 19 feet above ground in a cradle made by two short arms of the cactus. 86 M. Max Hensley SONORAN DESERT BIRDS 87 Both sexes are said to share in incubation (Bent, 1937) hut 1 recorded only the female incubating at this nest on each of three visits. Both eggs hatched on May 4, 17 days alter the nest was found. Two days after hatching one nestling was found dead at the base of the saguaro. The down at this stage was a soft “pinkish buff” color above, fading to white below. On the eighth day the surviving chick had lost the early reddish-colored natal down and appeared completely white. The wing and tail feathers were fully developed within two weeks and at approximately 17 or 18 days the crown, back, and scapulars were covered witli juvenal feathers. The first wing exercising was noticed at this age and food was being left at the nest for the young to pick up unaided. It was not until May 31, when the young bird was 27 days old, that it was seen actively feeding from a carcass left at the nest. Feeding was observed on the fourth and eighth day after hatching. On both occasions the adult tore the food into small pieces which were rapidly picked from her bill by the nestling. Food was brought to the nest two or three times daily, in the early morning, midafternoon, and late evening as a rule. Round-tailed ground squirrels were the only animals recorded being fed and invariably the heads of the rodents were removed prior to feeding. The intestines and skin of the ground squirrels were not fed to the young nestling, but were consumed by the adults at the nest. On three occasions branches of the mistletoe i Phoradendron calif ornicum) were brought to the nest by the adult birds. In the first instance the fledgling picked at the twigs. On the other two occasions the twigs were ignored. So far as is known, vegetative items do not comprise any part of the diet. The young bird left the nest at about five and one-half weeks of age but remained in the vicinity for several more days. Gambel’s Quail [Lophortyx gambelii) . — Twelve pairs of Gambel’s Quail were found nesting in wash areas where adequate cover was available. Nesting of this permanent resident was under way by the latter part of March. The first brood was observed on May 12, when 15 to 20 young chicks were counted with the attending adults. Six pairs were seen with broods ranging from three to 20 cbicks each. White-winged Dove iZenaida asiatica) . — White-wings may be seen almost anywhere during the summer season. The fruit of the saguaro was found to be the most highly favored food and was consumed throughout the ripening period. Also, the fruit of the condalias or wild jujubes {Condalia lycioid.es and C. spatiudata) was consumed. My first White-winged Dove record was April 19, after which the population gradually built up to a peak in May. The first nests were found on June 2, and each contained two freshly laid eggs. The latest date of active nests was July 27, when one nest had two very young nestlings and another contained two eggs. These July records indicate second nestings as they were well toward the end of the breeding season for all species. Only two other nests were still active at this date: a Curve-billed Thrasber with two eggs under incubation and a pair of Gila Woodpeckers with young about ready to fledge. The height of the nesting season for the doves was during the first part of June. Neff (1940) recorded one nest with eggs on August 5. Incubation lasted 14 days (June 7 to 21, date of last egg laid to last egg hatcbed) in one nest and 18 days in another (June 2 to 20). In accordance with Kendeigh (1952), the attentive periods of the adults at these nests lasted for several hours during incubation. The single exchange of incubating birds observed was accomplished in a matter of seconds. Chasing was observed on only one occasion, when a male ( ? ) gave chase to another White-winged Dove which stopped to rest in the nest tree. Of the 26 jiairs observed nesting this was the only instance where this behavior was noted. 88 THE WILSON BULLETIN Marcli 1959 Vol. 71, No. 1 Nest locations varied in height above the ground from 3 to 25 feet with an average of 7.5 feet. Thirteen were placed in palo verde (Cercidiurn microphyllum and C. torreyanurn) (av. 7.3 feet) ; six in ironwood (Olneya tesota) (av. 10.6 feet) ; two in mesqiiite (Prosopis julijlora) (av. 6.5 feet) ; two in catclaw (Acacia greggii) (av. 6.0 feet) ; one in hitter condalia (Condalia globosa) (8 feet) ; and one on a broken sagnaro stump (6 feet). Two of the nests in ironwood trees were placed in chimps of mistletoe and mark the only instances (except one Mourning Dove, Zenaidura macroura) of this plant being utilized as a nest site. The fruiting season for this plant was waning by this time, so the usual attraction of birds to these sites for food was negligible. This food attraction may account for the reluctance of earlier nesting species to utilize the excellent cover afforded by the mistletoe. By late August and early September most of the White-winged Doves had either left the nesting grounds entirely or were moving about seeking out the available food. Ground Dove (Columbigallina passer ina) . — The single nest of this species was found in a dead catclaw tree, partly uprooted and extending out over a large wash. The nest was typically dovelike in appearance hut more sturdily constructed and sparsely lined with grass. It was placed on the main trunk of the tree some six feet above ground and contained two eggs when found on May 30. The first clutch hatched around June 1, and by June 6 feather development was evident on wings and tail. The young fledged by June 15. Thirteen days later the nest again contained two eggs. The second clutch probably hatched on July 1. Ten days later one young was frightened from the nest; the other left a day or two later. The nestling period for the first brood was less than 15 days, and the first bird of the second brood left the nest when it was not over 12 or 13 days of age. Neither the adults nor young were seen later, and this single instance marked the only record for the species during the study. Costa’s Hummingbird (Calypte costae). — A single nest was found in Arch Canyon (Ajo Mountains) on May 1, when it contained one newly hatched young and one egg. It was located in a Palmer’s oak (Quercus palmeri) on the tip of a limb five feet above ground. The nest was placed within six feet of the vertical canyon wall which shaded the structure during the day, except at high noon. The activity at the nest was observed closely for the next three hours and 17 minutes. During this period the female was on the nest during 13 attentive periods ranging in length from one to 25 minutes, averaging 12.7. The 13 inattentive periods were much shorter, lasting from one to five minutes and averaging only 2.6. Fifty minutes after observations started the young bird apparently was fed nectar. After one hour and five minutes (11:06 a.m.) the second egg was Ijroken in half with the young bird still in the larger end. Fifty-three minutes after the first feeding the young bird was fed again, and 28 minutes later the third feeding was administered. By 12:25 p.m., two hours and 25 minutes after the start of the observation, the second bird had emerged. Dur- ing the last hour following the hatching of the second egg, one or both of the nestlings were fed twice, the second feeding coming 25 minutes after the first. In all five feedings were recorded, averaging 59.2 minutes apart. The shells were still in the nest at 1:15 p.m. when observations terminated. Little fear was displayed by the adult, which allowed a hand to he moved within an inch of the nest before she would hop off and hover a foot or two away. All observations were made within three or four feet of the nest. Cila Woodpecker (Centiirus uropygialis) . — Seven nest sites of this permanent resident were observed. One pair was beginning nesting operations on April 13 in a cavity some 30 feet up in an arm of a large saguaro. By April 20 the young birds coidd be heard for M. Max Hensley SONORAN DESERT BIRDS 89 several feet around the nest site. The young of the first brood fledged shortly after May 4, and the second left the nest soon after June 15. Three pairs completed their first nestings around June 6. In two of these cases the second nestings were completed by July 22, and the remaining pair had successfully reared the second brood by July 19. Apparently a single brood was raised by two other pairs, these fledging about May 5 and July 8, respectively. All nest cavities were in saguaros and ranged from 25 to 30 feet above ground. The last active nest was recorded on July 27 with young about ready to fledge. Both sexes assisted in incubation and care of the young as was indicated for several other species of woodpeckers by Kendeigh (1952). Say’s Phoebe {Sayornis saya) . — This species occupies an interesting niche in this region. Four of five nests were found in old wells or abandoned vertical mine shafts. The nests were placed on ledges or in crevices usually about five to seven feet down from the rim of the holes. The only exception was a nest in the garage at Monument Headquarters. In this instance the nest was placed on a support about 12 feet above the floor. This same nest was used during the previous season and for both nestings of 1949. Two clutches of five eggs each were hatched and successfully fledged. The young of the first brood fledged during the first week in April, and after a 10-day interval the second nesting began. The second set of eggs was present on April 25. The species was recorded from March through the month of June. Verdin ( Auriparus flaviceps) . — Of 16 nests found, 14 contained clutches of four eggs, one had five eggs, and the other had three young when discovered. Nests were placed from 2.5 to 7 feet above ground and near the periphery of a tree or bush. Branches extending over washes were commonly selected as nest sites. Palo verde trees provided nest sites for eight pairs, and two each were placed in condalia, catclaw, and cholla cactus {Opuntia fulgida) . The other two nests were in desert hackberry {Celtis pallida) and ironwood. One nest, placed six feet up in a catclaw tree, contained one egg on March 23. By March 27 the full complement of four eggs was present. At this time, during a 71-minute observation period, the female made six trips to the nest carrying feathers. On three occasions the female sang from within the nest in response to the song of the male. The incubation periods lasted from 15 to 17 days and only the female was recorded as performing this duty. Steady incubation did not occur, at least in one instance, until after the clutch was completed. The young stayed in the nest from 15 to 18 days. Three of the pairs were known to raise two broods. Nest construction was first noticed on March 8, and all nests were empty by June 6. Verdins are permanent residents of this area and were recorded throughout the study. Cactus Wren (Campylorhynchus brunneicapillum) . — Twenty-one of 22 active nests observed were in the cholla cactus. The other one was on an arm of a saguaro some 15 feet from the ground. Heights of the nests in the chollas ranged from 3 to 10 feet. Anderson and Anderson (1957) recorded a similar minimum nest height in chollas even though suitable sites at lower heights seemed available in both studies. As pointed out by Huey (1942), Curve-billed (Palmer’s) Thrashers competed with Cactus Wrens for nest sites in this cactus. Incubation lasted 17 days in two nests. In one case the clutch of three eggs was com- pleted on March 29, and on April 16 the nest contained three newly hatched yoxing. Incu- bation dates for the second nest were April 2 to 19, from completion of the set until all were hatched. The nestling period for six of the nests ranged from 17 to 20 days. The egg 90 THE WILSON BULLETIN March 1959 Vol. 71, No. 1 number per clutch was three or four with about equal numbers of each. Three pairs raised a second brood. Nesting activities of this common permanent resident began in late March and continued until late June. Curve-billed Thrasher {Toxostoma ciirvirostre) . — Tw'enty-seven nests of this resident species were observed. All were in cholla cactus and ranged from 3.5 to 9 feet above ground. Nesting operations were under way by late February and continued until early August. Sixteen of the 27 nests contained three eggs, eight had two, two had four, and one had a single egg. Of the five pairs known to have attempted two nestings, three used the same nest for both, but the other two pairs built new nests. The initial attempts of the latter two pairs, however, were unsuccessful. Both pairs had deposited incomplete clutches of two and three eggs for their first nesting before desertion. Three and four eggs, respec- tively, comprised the clutches of the second attempts. Another pair had two eggs in the first clutch and one in the second. Incubation lasted between 13 (May 1 to 14) and 14 (March 7 to 21) days for two nests, and the young stayed in the nest for 17 and 18 days, respectively. The dates refer to the interval between the depositing of the last egg and the hatching of the last young. Bent (1948) gives 13 days as the incubation period and 14 to 18 days for the nestling period. The sexes share in incubation duties, as well as in the brooding and feeding of the young. During a one-hour observation period the male of one pair incubated for 19 minutes and the female, for 30 minutes. In a second pair, watched for two hours, the male incubated a total of 23 minutes; the female, 32 minutes. One egg required two hours and 32 minutes for the hatching process, w'hich occurred between 10:14 a.m. and 12:46 p.m., the warmest part of the day. Black-tailed Gnatcatcher (Polioptila melanura) . — One nest was found on Alarch 19 in tlie final stages of construction. It was placed within the many-branched interior of a small condalia tree 4.5 feet above ground. Both adults w'ere engaged in the building activity. On March 23 the nest contained one egg, and by March 28 the complete clutch of five eggs was present. During a two and one-half hour observation period the male spent 55 minutes on the nest as compared to 19 spent by the female. The incubation period for this clutch was 14 days (March 28 to April 11), with only two of the eggs hatching. The last young fledged in 12 days. During one 60-minute observation period, the young, nine days old, were fed once every 8.5 minutes with both parents participating. On April 25 three fledged broods consisting of two, tliree, and four young were seen accompanied by adults. Gnatcatchers were commonly recorded from March through July. Phainopepla i Phainope[>l(i nitens) . — Eight nests were located as follows: four in palo verde, two in catclaw, and one each in condalia and mesquite. They were placed from 4 to 15 feet higli and were usually in the outer third of the tree. No nests were found in mistletoe, a common site according to Bent (1950) ; they w'ere, however, always in the vicinity of a plentiful supply of these berries. Rand and Rand (1943) noted that the tree containing a nest usually had mistletoe berries growing as well. In my study most nests W'ere placed in trees without mistletoe, but always adjacent to ones with the parasite. Only the male was recorded in nest-building activities. One individual ceased his labors only to help his mate chase an intruding female from the vicinity. The female continued the chase and on another occasion gave chase alone to an intruding female. Rand and Rand (ibid.) recorded similar chasings by the female. M. Max Hensley SONORAN DESERT BIRDS 91 Six of the nests found contained two eggs, and the other two held three each. The first nest was under way hy March 10 and the last young left a nest shortly after May 30. The incubation period at two nests was 14 days (March 28 to April 11, and April 6 to 20) . The young remained in these nests for 17 and 19 days. Only the female was seen to feed the young during an hour and 17 minutes of watching at one nest. The principal food of this species in the nesting season appeared to be the red berries of the mistletoe, and as soon as the young had grown large enough to eliminate the seeds they w'ere fed almost exclusively on these fruits. Some Phainopeplas apparently winter in this region for they have been recorded in every month of the year by Monument officials. They were common throughout my stay in the area. Loggerhead Shrike (Lanins ludovicianus) . — The single nest, found on April 19, contained six eggs. It was in a thick clump of dead mistletoe seven feet np in a palo verde tree. The eggs hatched between April 19 and 24, and the young had fledged hy May 4. No other individuals were seen. House Finch (Carpodacus mexicanus) . — All of the 12 nests found were located in cholla cactus at heights varying from three to eight feet above ground. The first nests of this resident species were discovered on March 28, and active nesting continued until the end of June. Clutch sizes varied from three to five eggs; nine nests had four. Length of incubation in two nests was found to he 12 days (March 29 to April 10) and the young remained in the nest 15 to 16 days. Evenden (1957), in a study made in Cali- fornia, similarly found an average clutch size of 4.4 eggs for 25 completed nests, an average incubation period of 13.17 days, and an overall average nestling period of 15.1 days in 11 nests. In my study, the only case of parasitism by the Brown-headed Cowbird (Molothrus ater) was recorded in a nest of this species. On May 4, four eggs (second clutch) w’ere present in this particular nest. Five days later a cowbird egg was in the place of one of the finch eggs which was found broken on the ground below. The House Finches deserted this nest before the eggs hatched. Few records of this species being parasitized by the cowbird are available. Apparently Hanna (1933) and Robertson (1931) have recorded the only other known instances of parasitism in this species. Summary During the summers of 1948 and 1949, 25 species of birds, representing 16 families, were known to nest in Organ Pipe Cactus National Monument, Arizona. Observations of 16 of these species are here briefly discussed, including information concerning nest sites, incubation, adult behavior, and breeding periods. Literature Cited Anderson, A. H. and A. Anderson 1957 Life history of the Cactus Wren. Part I: winter and prenesting behavior. Condor, 59:274-296. Bent, A. C. 1937 Life histories of North American birds of prey. fL 5. Na/. Mas. Bull., 167 :viii 409 pp. 92 THE WILSON BULLETIN Marcli 1959 Vol. 71, No. 1 1948 Life histories of North American niitliatches, wrens, thrashers, and their allies. U. S. Nat. Mas. Bull., 195 :xi + 475 pp. 1950 Life histories of North American wagtails, shrikes, vireos, and their allies, f/. S. Nat. Mus. Bull., 197:vii + 411 pp. Evenden, F. G. 1957 Observations on nesting behavior of the House Finch. Condor, 59:112-117. Hanna, W. C. 1933 House Finch parasitized by the Dwarf Cowbird and Black Phoebe nests occupied by House Finch. Condor, 35:205. Hensley, M. M. 1954 Ecological relations of the breeding bird population of the desert biome of Arizona. Ecol. Moriogr., 24:185-207. Huey, L. M. 1942 A vertebrate faunal survey of the Organ Pipe Cactus National Monument. Trans. San Diego Soc. Nat. Hist., 9:353-376. Kendeigh, S. C. 1952 Parental care and its evolution in birds. III. Biol. Mono., 22 :v + 356 pp. Neff, J. A. 1940 Notes on nesting and other habits of the Western White-winged Dove in Arizona. ]our. Wildl. Mgt., 4:279-290. Rand, A. L. and R. M. Rand 1943 Breeding notes on the Phainopepla. Auk, 60:333-341. Robertson, J. M. 1931 Some changes in the bird life of western Orange County, California. Condor, 33:204-205. DEPARTMENT OF ZOOLOGY, MICHIGAN STATE UNIVERSITY, E. LANSING, MICHIGAN, OCTOBER 13, 1958 GENERAL NOTES Leg-muscle formulae and systematies. — Nearly 90 years have passed since Alfred 11. Garrod described differences in the thigh muscles which he thought would aid in determin- ing the relationships among birds. His muscle formulae have become an integral part of the technical diagnoses of the families and orders of birds. Garrod’s contribution in this regard was, indeed, a most significant one, but Hudson (1937. Amer. Midi. Nat., 18:1-108) demonstrated over 20 years ago that Garrod’s formulae may be misleading because they often do not report adequately the similarities or dissimilarities in the thigh musculature, that is, the formulae are incomplete. Nevertheless, many contemporary writers continue to use Beddard’s (1898) The Structure and Classification of Birds (or equally outdated references) as their source for myological data in order to support a thesis or to enlarge a technical diagnosis. In certain instances the addition of such formulae is merely padding; it has no real significance. The opportunities for further work on avian myology are unlimited. For example, in addition to all of the genera that have never been studied at all, we need to have data on the complete appendicular myology of most of the genera that were studied in the past, in order that we may know more about the similarities and dissimilarities in their myology, including especially the muscles that Hudson proposed be added to the leg-muscle formulae. I believe that muscle formulae can continue to be a useful part of the technical diagnosis but only if the formulae are enlarged. Hudson’s excellent suggestions for expanding Garrod’s original formulae were based on a study of representatives of North American bird families. If we think in terms of world birds, however, I believe that the addition of several other muscles would make the formulae even more meaningful. I would like to emphasize, however, that a muscle formida is only a substitute for knowing the complete appendicular myology. Perhaps the chief value in expanding the formulae is to call attention to those muscles that seem to exhibit the greatest variability among birds, and thereby to insure that authors will comment specifically on the presence or absence of those muscles when describing the anatomy of a given genus or species. When the author of an anatomical paper does not mention a particular muscle, one cannot be sure whether the muscle is absent or whether the author did not feel that it was important to refer to the muscle, simply because it is not one of the formidae muscles. I have discussed M. iliacus at some length in a paper still to be published. I propose that M. iliacus be added to muscle formulae and that the presence of the muscle be indi- cated by adding “E” to the formula. 1 propose, further, that two other muscles be added. M. plantaris (“F”) is absent in the Accipitridae, Pteroclidae, Psittacidae, Strigidae, Apodidae, and Bucerotidae. M. poplitens (“G”) is absent in the Psittacidae, Apodidae, Aceros undulatus, Picidae, and in all passerine birds thus far studied. So little has been published on the total myology of the pelvic appendage, however, that it hardly seems necessary to say that we have no idea wliether or not these two muscles are absent in all members of the Apodidae, for example, or in how many additional families or genera the muscles may be absent. Mitchell (1913. Proc. Zool. Soc. London: 1039-1072) described M. peroneus longus and M. peroneus brevis in representatives of many families of birds. Either muscle may be absent in some birds. Hudson did not feel that it woidd be wortbwliile to add these muscles to the formulae, and I agree with him, but probably for different reasons. There are several other muscles about which so little is known that we have no way of predicting whether or not it would be advantageous to add them to the formulae. For example, M. flexor hallucis brevis is absent in Gavia, Uria, and in some, but not all, passerines. M. 93 94 THE WILSON BULLETIN March 1959 Vul. 71, .No. 1 extensor hallucis longus is absent in Gavia, Podiceps, and Uria. M. extensor proprius digiti 111 is absent in such distantly related birds as Fregata, Grus, Tyrannus, Corvus, and Stiirnus. M. adductor digiti 11 is absent in Pediocetes, some cuckoos, Colaptes, Dendro- copos, Tyrannus, Paradisaea, Corvus, Fregilupus, Sturnus, Aplonis, Artamella, Vireo, Junco, etc. Is M. extensor brevis digiti IV absent in all woodpeckers and passerines? The full muscle formula as found in a galliform bird, for example, would be ABCDEFGXYAmV. We may tabulate these as follows; Code Letter Name of Muscle A Piriformis, pars caudofemoralis {— femorocaudal) B Piriformis, pars iliofemoralis (= accessory femorocaudal) C Iliotrochantericus medius D Gluteus medius et minimus ( = ‘'piiiformis” of Fisher) F Iliacus (= “psoas” of Fisher)^ F Plantaris G Popliteus X Semitendinosus ( = “flexor cruris lateralis” of Fisher) Y -\ccessorius semitendinosi Am Andiiens V Vinculum between the tendons of Mm. flexor perforatus digiti HI and flexor perforans et perforatus digiti HP ^M. iliacus of Fisher equals M. iliotrochantericus anterior of Hudson and Berger. “If should be noted that the vinculum mentioned by Garrod, Forbes, Beddard, and Gadow usually pertains to the band that connects the tendons of Mm. flexor hallucis longus and flexor digitorum longus and which is found in most non-passerine birds. The vinculum of the formula above is far more variable among birds. When the information above is available for all families of birds, we shall have a much better understanding of the significance of muscle formulae in determining the relation- ships among birds. I grant that this is a sizable list of symbols, and that the skeptic might counter with the statement that anatomists soon will propose that the entire alphabet be used in muscle formulae. However, I submit that systematists might better ignore muscle formulae entirely than to continue to use only Garrod’s abbreviated formulae of AXYAm and ABXYAm. — Andrew J. Berger, Unh'erslty of Michigan Medical School, Ann Arbor, Michigan, November S, 1958. Tufted Titmouse feeding on a shrew. — On February 20, 19.58, in the backyard of my parents’ home in Van Buren County, Michigan, 1 watched a Tufted Titmouse {Pams bicolor) eating bits of flesh which it picked from a Masked Shrew iSorex cinereus) during a heavy snowfall. The bird had lodged the little mammal in a forked branch of a small shruh just above the ground and was holding it there by one foot while clinging to the branch with the other. As 1 approached to a distance of about 10 feet the bird flew to a nearby apple tree with the shrew in its bill and continued feeding. 1 was not able to determine whether the titmouse had captured the mammal alive or found it dead. An examination of pertinent literature failed to disclose any mention of this species including small mammals as part of its diet. Perhaps the greater than average snowfall had created a decline in the availability of the regular food supply and caused the bird to turn to such an unusual meal. — Richard C. Fi.eming, LH6 E. Battle Creek Street, Gales- burg, Michigan, May J5, 1958. March 1959 Vi)l. 71. Ni). 1 GENERAL NOTES 95 Scissor-tailed Flycatcher in northern Minnesota. — On October 23, 1958, we collected a Scissor-tailed Flycatcher {Miiscivora forficata) near the northeast corner of the Forest Research Center, 1260 feet elevation, about three miles west of Cloquet, Carlton County, Minnesota. This bird, a male with double-layered skull, proved to be moderately fat, weighing 51.0 grams, and having testes 3 mm. long. The skin has been deposited at the Minnesota Museum of Natural History, Minneapolis (MMNH no. 14562). The occurrence of the bird in this area was coincident with the arrival of Snow Buntings {Plectrophenax nivalis) and Northern Shrikes (Lanius excubitor) from the north. This record appears to constitute the fourth reported occurrence of this species in Minnesota, and the first occurrence verified by an extant specimen. Earlier records t Roberts, 1932. "Birds of Minnesota,” 2:11) are based on a bird collected near New London in the central part of the state prior to 1912, but subsequently lost ; a sight record of a bird, ‘'about two miles north of the Iowa line — ” south of Lakefield, June 5, 1930; and two sight records of a single bird (Kelly, 1958. Flicker, 30:57) on the south shore of the Lake of the Woods in extreme northern Minnesota on July 3 and 7, 1957. — Gordon W. Gullion and Bruce A. Brown, Forest Research Center, University of Minnesota, Cloquet, Minnesota, November 25, 1958. (Paper No. 992, Miscellaneous Journal Series, Minnesota Agricultural Experiment Station, St. Paul 1, Minnesota.) Interaction between a feral parakeet and House Sparrows. — An escaped Austra- lian Shell Parakeet (probably Melopsittacus undulatus) was observed with a flock of approximately 30 House Sparrows (Passer domesticus) on the campus of Western Michi- gan University. I saw the pale-blue parakeet feeding with and flying with a flock of sparrows on four occasions in the month of Novemher, 1958. In none of these instances was there any sign of interspecific strife between the parakeet and the sparrows; seem- ingly, the parakeet was well-integrated into the aggregation. On two other occasions 1 saw the parakeet separate from, but near, a flock and observed its interaction with individual sparrows. On the first occasion a male sparrow detached itself from the flock of sparrows feeding on the ground, flew approximately 50 feet, and attacked the parakeet where it was perched alone in a low shrub next to a campus building. The parakeet flew and was chased some 20 yards hy the sparrow before it returned to the flock. On the second occasion a female sparrow flew and ran at the parakeet when both parakeet and sparrows were feeding on the lawn ; in this case the parakeet was searching and feeding alone some 20 feet from the closely-packed, feeding sparrows. Seemingly, the sparrows tolerated the parakeet when it was a part of the aggregation, but treated it in a hostile manner when it was not a part of the flock. — Thane S. Robinson, Department of Biology, Western Michigan University, Kalamazoo, Michigan, December 2.3, 1958. Yellow-breasted Chat parasitized by tick. — While banding with Dr. Paul Fluck at Washington Crossing Park during the early part of May, 1958, we captured a Yellow- breasted Chat (Icteria virens) which had a tick, much enlarged with blood, attached to its neck. The tick was removed and identified by Dr. Fred Truxal, entomologist of the Los Angeles County Museum, as an Ixodes muris of the family Ixodidae. This tick has been recorded from several mammalian hosts, but not from birds. These recorded hosts are of the following genera: Blarina, Peromyscus, Microtus, Ondatra, Rattiis, and Zapus. — Don Bi.eitz, Bleitz Wildlife Foundation, 1001 North McCadden Place, Los Angeles 38, Califor- nia, July 28, 1958. 96 THE WILSON BULLETIN March 1959 Vol. 71, No. 1 Foster-feeding and polygamy in the Purple Martin. — While conducting homing experiments with Purple Martins (Progne subis) in the vicinity of the University of Michigan Biological Station, Cheboygan County, Michigan, in the summer of 1958, I trapped, color marked, and released 16 adult martins at distant points. When periodically checking for the return of these homing birds I also observed behavior at the nests. Female 14 was trapped at 3:30 p.m., July 11, and was released near Sleeper Lake, Luce County, Michigan, at 9:00 p.m. the same day. She did not return to the nest until the afternoon of July 13. In her absence the female occupying the nest directly above made several trips to Female 14’s nest with food for the young. This female also continued to care for her own young. Perhaps the begging notes of the young in the nest below induced her to bring food. Number 14’s mate was also feeding his young. He accepted this help and did not attempt to drive away the assisting female. When Female 14 returned, the assisting female ceased this behavior and cared solely for her own brood. This was my only observation of foster-feeding, although 14 females were taken from the colony for periods of a few hours up to approximately three days. I also recorded an instance of possible polygamy. Females 9 and 10 were removed from the colony for homing trials. The nest compartments of these two birds were side by side. During their absence, a single male cared for both broods of young. Often he brought several insects to the nests and fed some to each brood. Sometimes all of the food was given to one brood of young and a fecal sac removed. No challenging martin came to either of these nests. Female 9 was absent from the nest for eight hours and No. 10 was gone for 25.5 hours. The male was successful in his attempt to care for two broods because young fledged from both nests. — William E. Southern, Museum of Zoology, University of Michigan, Ann Arbor, Michigan, October 8, 1958. New bird records for St. Croix, Virgin Islands. — To that increasing list of migratory warblers recorded from St. Croix, Virgin Islands, must now be added yet another, the Yellowthroat ( Geothlypis trichas) . At dawn on April 4, 1958, a clear, loud and unknown witchity-wichity-witchity came from a tree outside my window. Upon investigation of this new call a small bird was seen to fly a short distance away to a scrub thicket. “Squeaking” soon brought the singer within gunshot, and I collected it. Since this warbler was badly mutilated, the skin was forwarded to Mr. James Bond, at the Philadelphia Academy of Sciences, for corroboration of my identification. In a letter dated August 24, 1958, Mr. Bond wrote: “Your specimen is an immature male in the process of acquiring adult breeding plumage. Although recorded from Tobago, it is the easternmost record from the Antilles.” With few exceptions the birds added to the list of new records from the Virgin Islands have been small and insignificant creatures, unobtrusive in drab autumnal anonymity. .Six tall Glossy Ibis {Plegadis falcinellus) , feeding in a small, fresh-water pond located at Williams (West End), .St. Croix, were neither small nor difficnlt to identify. These ibis were first olxserved on the morning of September 15, 1958. By October 2, only three birds could he found. These were observed almost daily until October 10, when another attempt to obtain a specimen scared them away. They took off in a northwesterly direction and were not again seen. The only previous record for this ibis from the Virgin Islands is one by John Furth (James Bond, in litt.), who reported it from Krum Bay and Stumpy Bay, St. Thomas. No dates are given. — G. A. Seaman, Post Office Box 474, Christiansted, St. Croix, U. S. Virgin Islands, November 20, 1958. March 1959 Vol. 71, No. 1 GENERAL NOTES 97 Nesting concentration of Long-eared Owls in Cochise County, Arizona. — On April 16, 1956, I found a nest of the Long-eared Owl, (Asio wilsonianus) , on the John Sala ranch, about 12 miles north of Toinhstone, Cochise County, Arizona. Between April 16 and June 8, 1956, six nests of owls of this species were found witliin a diameter of 3 miles. The elevation of the ranch at the mouth of Granite Springs Canyon is 5190 feet; it lies in the foothills on the south slope of the Dragoon Mountains. The predominant vegetation consists of grasses with scattered yuccas and mesquite; there is an extensive area of live oaks west of the ranch house and along Granite Springs Ganyon. All nests were found in this live oak area. The nests used by the owls were apparently old ones of Ravens (Corvus corax) or Cooper’s Hawks ( Accipiter cooperii) . The nesting area is in the Grassland Sub- zone of the Upper Sonoran Life Zone, as delimited roughly by the 4000- to 5000-foot elevation. The first nest (April 16) was situated approximately 50 to 55 feet up in an Emory oak (Quercus emoryi) in oak woods along the dry stream bed near the mouth of Granite Springs Ganyon. Besides the dominant Emory oaks, trees consisted of Arizona white oak, (Quercus arizonica) , velvet ash, (Fraxinus velutina) , and a scattering of Arizona walnut iJuglans major), western hackberry (Celtis reticulata) , western box-elder (Acer Negundo var. interius) , and alligator juniper (Juniperus deppeana) . Thick grape tangles near the nest were used by the owls as a roosting place. A Gooper’s Hawk nested in an oak about 100 feet from the owls’ nest. Nests of Black-chinned Hummingbirds (Archilochus alexandri) and the Common Bushtit ( Psaltriparus minimus) were observed in the vicinity. The owls’ nest found on April 16 held three downy young which were standing up and stretching their wings. An adult lay on the edge of the nest. It did not flush as I moved about underneath. On April 27, the young were still in the nest. By May 6, the nest was empty; and on May 8, one young was perched near the nest, and the other two in nearby trees. On May 28, the young were still about the nest and were flying well, but on June 5, the family could not be located. Nest no. 2 was found on April 23, about one-fourth mile down Granite Springs Canyon from the first. It was 18 or 20 feet up in an Emory oak in an isolated clump of oaks on a high bank above the stream bed. There were three young in the nest and one smaller dead one under the tree. This nestling was probably only a week old or less because it still retained its egg tooth. This chick (a female) was prepared as a study skin, and is now in the collection of Ur. Allan R. Phillips. On April 27, when I climbed a nearby tree to photograph the nest, one young jumped from the nest to the ground. After photographing this bird, I placed it up about seven feet in the nest tree; it eventually reached the nest. On May 2, the nest was empty, and several days later the young were located in nearby oaks. Nest no. 3 w'as located on May 3, approximately 20 feet up in an Emory oak in a wash with a scattering of oaks, mesquite (Prosopis julijlora) , (Yucca sp.), and heargrass (Nolina microcarpa) in the vicinity. A dead adult Long-eared Owl and one small live downy young were on the ground beneath the nest. I placed the young owl in the tree but it did not survive. The other parent was not seen. Nest no. 4 was situated in an isolated group of oaks in a little valley in the grasslands. This nest was about a mile and one half from Nest no. 2. It was 20 feet up in an Emory oak and contained four downy young on May 10. When I first approached the nest an adult flushed from the nest and flew to the ground where it uttered the characteristic cat calls and flapped its wings. It also dived at me every time I neared the nest. These were the only adults of the six pairs that behaved in this manner. A Cooper’s Hawk nested in 98 THE WILSON BULLETIN March 1959 Vol. 71, No. 1 an oak some 200 feet from the owls’ nest. On several occasions the hawk was seen to leave its nest and chase the owls as they flew about. This was the only friction noted between the two species. On May 15, while I was climbing the tree to photograph the young, two of them jumped from the nest, one landing on a lower limb, the other on the ground. I later placed this latter nestling up in the tree with the other young owl. The wing feathers of this nestling were slightly over two inches out of their sheaths, and the tail measured one inch from the sheaths. The black facial disks were beginning to turn brown. On May 21, the nest was empty, and none of the young could be found. It was not until June 8 that an adult and the four young were flushed from a roost in a nearby oak. Nest no. 5, located on May 10, was 18 to 20 feet up in an Emory oak in a group of oaks in a wash. It was about a mile or more from Nest no. 3. Three young were flushed from adjoining oaks, and on May 18, there were four adult-sized young in a tree near the nest. The nest was much smaller than the other owl nests, being about the size of a Roadrunner’s {Geococcyx calif ornianus) nest. On June 8, I found Nest no. 6, 15 feet above ground in an Emory oak in a clump of oaks along a wash. An adult and two large young were in nearby trees. During the study, I collected about 73 Long-eared Owl pellets that were found under roosts near the nests. I am much indebted to Mr. John R. Mikita, Department of Zoology, University of Arizona, for analyzing this material for me. The following species were identified in the pellets: Species No. of Individuals Notiosorex crawfordi, Desert Shrew 7 Thomomys bottae. Valley Pocket Gopher 2 Perognathus flaviis. Silky Pocket Mouse 8 Perognathus penicillatus. Desert Pocket Mouse 11 Perognathus sp. 193 Dipodoniys merriami, Merriam Kangaroo Rat 19 Dipodomys ordi, Ord Kangaroo Rat 7 Dipodomys sp. 5 Reithrodontomys niegalotis. Western Harvest Mouse 4 Peroniyscus erernicus. Cactus Mouse 10 Peromyscus sp. 14 Onychoniys torridus. Southern Grasshopper Mouse 33 Neotoma albigula, White-throated Wood Rat 1 Bird (“a small junco-type”) 1 In the western United States, concentrations of nesting Long-eared Owls have been reported for California and Utah, but not for Arizona (Bent, 1938. U. S. Nat. Mas. Bull., 170:155-156). In fact, this owl has previously been considered a rare breeder in Arizona. Seven of the nine other known breeding records are for southeastern Arizona (Pima and Cochise Counties). The Long-eared Owl has an extended nesting season in Arizona. The previous records indicate this as well as my owm observations. Two examples will suffice: Dr. Mearns collected a female from a “Cienega” 10 miles west of Camp Verde in north-central Arizona on IThruary 20, 1886, which according to his MS., “was about to lay eggs.” A. J. van Rossem writes (19.36 Trans. San Diego Soc. Nat. Hist., 8:134) of a “family of these owls in tlie mesquite (Lower Sonoran Zone) along the dry stream bed at Bates Well. The young were nearly full grown, hut partly in juvenal plumage. One specimen, a juvenal male, was collected on June 23, 1932.” March 1959 Vol. 71. Ni). 1 GENERAL NOTES 99 In a habitat dissimilar to the Emory oak situation, C. M. Palmer, Jr., of Tombstone, found a nest near Lewis Springs on April 27, 1955. The nest was in a mesqnite and held three downy young. The vegetation was creosotebush and black brush association. He found another nest on March 23, 1957, in a desert hackberry in a dry wash, about eight miles north of Tombstone, but he gave no details of the contents of this nest (Letters, March, 1957). The nesting season of the owls in 1956 was lengthy. The family of Nest no. 2 were out of the nest on May 2, while Nest no. 3 held a downy young on May 3. The young of Nest no. 4 were still in the nest on May 10; on the same date, the young of Nest no. 5 were on the wing. In the vast plains and mountains of Arizona, the Long-eared Owl might easily be over- looked when we consider the fact that ornithologists are a rarity in the region. More intensive field work in the nesting season would probably reveal more nests. Two factors which seem to me to account for the concentration of owls in this small area were the availability of many nesting sites and the apparent abundance of small mammals. I wish to thank Dr. Allan R. Phillips for his criticism of the manuscript and for the early records; C. M. Palmer, Jr. for his records; John R. Mikita for analyzing the pellets; and Mr. and Mrs. John P. Sala for their many kindnesses to me while I was at their ranch. Without their combined help, this study would not have been completed. — John J. Stophlet, 2612 Maplewood Avenue, Toledo 10, Ohio, January 13, 1958. A Palm Warbler in Oklahoma. — On April 26, 1958, I collected a specimen of the Palm Warbler (Dendroica palniarum) in a wooded section of Bird Creek bottom land, three miles northeast of Tulsa, Tulsa County, Oklahoma. I found the bird preening in a small tree approximately five feet above the ground. It was alone and was not singing. Nice (1931. Publ. JJniv. Okla. Biol. Surv., 3) lists the Palm Warhler as a rare transient in eastern Oklahoma, noting that no specimen had been taken in the state at that time. I have found no record of a specimen taken here since then. In this male the testes were somewhat enlarged, 3 mm. in diameter. It was moderately fat with measurements as follows: wing length (chord), 66 mm.; tail length, 52 mm.; length of exposed culmen, 12 mm. The pre-nuptial molt of the head and throat region was in progress. Several bright yellow feathers on the throat were sheathed. On the basis of plumage color, it appeared to belong to the western race {Dendroica palmarum palmarum ) . This was verified by Dr. George M. Sutton at the University of Oklahoma Museum of Zoology where this specimen is now No. 3355. — John S. Tomer. 4045 East 27th Street, Tulsa, Oklahoma, September 10, 1958. ORNITHOLOGICAL NEWS The 1959 meeting of the Wilson Ornithological Society will be held in Rockland, Maine, June 11-14, at the Farnsworth Museum. This is the first New England meeting of the Wilson Society, and it is being held at the invitation of the Portland Society of Natural History, the Farnsworth Museum, and the Maine Audubon Society. Co-chairmen of the local committee are: Christopher M. Packard (Director of the Portland Society of Natural History) and Wendell Hadlock (Director of the Farnsworth Museum). Preliminary plans for the program include a Wood Warbler Symposium, led by Dr. George M. Sutton; a Migration Symposium, led by Chandler S. Robbins; and a Banding Symposium, led by James Baird. It is hoped that the Migration Symposium may present the first films showing radar observations of North American migrants. Plans also include a sea trip to Matinicus Rock to observe puffins and other sea birds. There will also be a field trip to Mt. Desert Island. Further details will be mailed to members in due course. Meanwhile, advance inquiries regarding the Rockland meeting may be addressed to: Mr. Christopher M. Packard, Portland Society of Natural History, 22 Elm Street, Portland, Maine. The Wilson Ornithological Society is indebted to Don R. Eckelberry for making avail- able the painting of the Black-throated Trogon from which the frontispiece was reproduced. The next annual meeting of the American Ornithologists’ Union (A.O.U.) will be held at the Saskatchewan Museum of Natural History, Regina, August 25-30, 1959. Mrs. A. C. Bent has presented the library of her late husband, Arthur Cleveland Bent, to the University of Massachusetts. The library will he housed as a memorial unit in the new nine-million-dollar Science Center currently under construction. The section of the Science Center containing the reading room should be opened by February, 1960, and the library should be available for use by interested ornithologists soon thereafter. It is planned to keep adding to the library to make it a ‘‘living” memorial to Mr. Bent. The University of Oklahoma Biological Station announces a new course in Animal Behavior (Zoology 309) to be offered during the 1959 summer session. The field and laboratory phases of this course will emphasize the local fauna. This will be a three- credit-hour course designed for upperclass and graduate students. The Biological Station is situated on Lake Texoma in south-central Oklahoma. There is a rich vertebrate and invertebrate fauna in this area available for behavior studies. Research programs in animal behavior by the staff, graduate students and private investigators at the Biological Station have involved all classes of vertebrates and some invertebrates. The necessary facilities and equipment for field and controlled behavior studies are available or can he obtained. Persons interested in this course or in the Biological Station should write to Dr. Carl D. Riggs, Director, University of Oklahoma Biological Station, Norman, Oklahoma. 100 March 1959 \ ol. 71. No. 1 ORNITHOLOGICAL NEWS 101 The Division of Biological and Medical Sciences of the National Science Foundation announces that the next closing date for receipt of liasic research proposals in the life sciences is May 15, 1959. Proposals received prior to that date will he reviewed at the summer meetings of the Foundation’s advisory panels and disposition will he made approximately four months following the closing date. Proposals received after the May 15, 1959, closing date will be reviewed following the fall closing date of September 15, 1959. Inquiries should be addressed to the National Science Foundation, Washington 25, D. C. WILSON SOCIETY MEMBERSHIP COMMITTEE The Wilson Society membership is not growing, and the society officers solicit the aid of all members in correcting this situation. If you know of any good prospects, please send their names to the committee member from the appropriate state. Where the state is not represented, names may be sent to the chairman. With the 1959 convention in Maine, we have hopes of increasing the New England membership, and names from this region are particularly desired. James Baird, Norman Bird Sanctuary, Third Beach Rd., Newport, R. I. Frederick M. Baumgartner, Dept. Zoology, A and M College, Stillwater, Okla. James R. Beer, Dept. Zoology and Economic Entomology, Univ. of Minn., St. Paul, Minn. Holly Reed Bennett, 2457 Orchard St., Chicago 14, 111. Elizabeth M. Boyd, Mt. Holyoke College, S. Hadley, Mass. Edward Louis Chalif, 37 Barnsdale Rd., Short Hills, N. J. Thomas Ross Chell, 1220 Beck Lane, Lafayette, fnd. Charles L. Conrad, 137 N. 11th St., Wheeling, W. Va. Nicholas J. Cuthbert, Dept. Biology, Central Michigan College, Mt. Pleasant, Mich. Stephen W. Eaton, St. Bonaventure Univ., St. Bonaventure, N. Y. Frank N. Egerton, 2420 Mayview Rd., Raleigh, N. C. Robert S. Ellarson, Dept. Wildlife Management, Univ. of Wis., Madison. Wis. J. H. Ennis, Cornell College, Mt. Vernon, la. Earl W. Farmer, 611 N. 4th St., -Steubenville, Ohio G. E. Grube, State Teachers College, Lock Haven, Pa. Charles W. Hamilton, 2639 Fenwood Rd., Houston 5, Tex. Douglas A. Lancaster, Museum Zoology, La. State Univ., Baton Rouge, La. Benjamin B. Leavitt, Dept. Biology, Univ. of Florida, Gainesville, Fla. L. R. Mewaldt, Dept. Natural Science, San Jose State College, San Jose, Calif. Lawrence R. Penner, Dept. Zoology and Entomology, Univ. of Conn., Storrs, Conn. Jennie Riggs, 2005 Capers Ave., Nashville, Tenn. John P. Rogers, Wildlife Bldg., Univ. of Missouri, Columbia, Mo. Stephen W. Simon, Blue Mount Rd., Monkton, Md. Doris H. Speirs, “Cobble Hill,” RD No. 2, Pickering, Ontario Howard Young, Wisconsin State College, La Crosse, Wis., Chairman NEW LIFE MEMBER Mrs. Robert V. D. (Kay F.) Booth, a member of the Wilson Ornithological Soci- ety since 1949, resides with her husband and two boys in Painesville, Ohio. Along with many family activities she finds the time to talk before adult and youth groups on bird study and conservation, to band birds, and to participate in the work of the Blackbrook Audubon Society (recently President) and the Cleveland Audubon Society (formerly Editor of the Cleveland Audubon Bulletin-, now Vice-President and one of the bird walk leaders) . She enjoys attending annual meetings of the Wilson Society, as well as those of the American Ornithologists’ Union and Cooper Ornitho- logical Society to which she belongs. In 1954 she attended the Eleventh Interna- tional Ornithological Congress in Switzer- land. JOSSELYN VAN TYNE MEMORIAL LIBRARY gifts have been recently received. Erom: The following Andrew J. Berger — 1 reprint Whitney Eastman — 6 reprints Norman L. Eord — 1 pamphlet Jack P. Hailman — 2 journals, 5 reprints, 2 mimeographed papers Karl W. Haller — 1 book Frank A. Hartman — 6 reprints Fr. Haverschmidt — 2 reprints J. J. Hickey — 1 pamphlet Stuart Houston — 8 reprints Leon Kelso — 2 journals Karl Lagler — 2 pamphlets James Landing — 5 journals, 4 reprints Mrs. Raymond Law — 1 book T. Lebret — 3 reprints Malcolm Lowther — 2 books, 12 journals, 20 reprints \V . L. McAtee — 1 pamphlet Mrs. Margaret M. Nice — 15 reprints Coran Nordstrom — 1 reprint Peabody Museum — 4 reprints William H. Phelps — 1 reprint Thomas L. Quay — 6 reprints Paul Slud — 1 book William E. Southern — 1 reprint Paul A. Stewart — 1 journal, 1 reprint, 1 mimeographed book Robert W. Storer — 60 journals, 3 reprints, 1 pamphlet Texas Ornithologists’ Society — 3 newslet- ters Harrison B. Tordoff — 1 phonograph record George Willoughby — 66 journals Wisconsin Conservation Department — 1 pamphlet Wisconsin Society for Ornithology — 11 journals, 17 reprints Lhiiversity of Wisconsin, Department of Wildlife — 2 reprints Howard F. Voung — 1 reprint Richard L. Ziisi — 76 journals 102 ORNITHOLOGICAL LITERATURE The Bird Life of Great Salt Lake. By William H. Behle. University of Utah Press, Salt Lake City; 1958: 91/2 X 6% in., (12) + 1-203 pp., 43 figs., 28 tables. $4.50. The reader who buys by title alone will be surprised when he opens this hook. The subtitle, ‘‘The life history, ecology and population trends of the California Gulls, White Pelicans, Double-crested Cormorants and Great Blue Herons, together with an account of the Bear River Migratory Bird Refuge,” is more indicative of the contents of the book than is the title. As the subtitle suggests. Professor Behle’s hook is principally a presentation of informa- tion concerning the natural history of four species of colonial-nesting birds found on islands in Great Salt Lake. This information comes from some 25 years of field work by Behle, and others, in the area, and an exhaustive review' of the literature. Following an account of each of the islands studied, the California Gull is treated extensively under such headings as geographic range, seasonal status, flight, time of nest- ing, nests, egg laying, incubation and behavior at nesting sites, dispersal of young, migration of adults, the plumage cycle, homing instinct, etc. There then follows a similar, but less extensive, section on the White Pelican. The Double-crested Cormorant and the Treganza Great Blue Heron are each treated in a brief chapter. The small breeding population of Caspian Terns is considered briefly, as are a few of the birds occurring on the waters and shores of the lake. A list of birds, other than those that nest in colonies, is presented for each of the islands included in the study. The chapter on the Bear River Refuge includes a check-list of 198 species and subspecies of birds recorded at the Refuge by its personnel. An excellent list of literature cited by the author follows the text. There is no index. Objections concerning the book are few, and of minor significance. Tbe maps (Figures 2, 24, and 43) have no scale of miles, and Oklahomans may feel slighted by the omission of their state from the map on page 91. Particular figures, most of which are excellent half-tones, are difficult to find due to the omission of page numbers from the list of illustrations. Behle’s use of “nuptial plumage” may draw some criticism; he points out that the California Gull reaches maturity in three years, but he speaks of nuptial plumages in the first and second years. The book is to be recommended to those interested in the avifauna of Great Salt Lake and its environs, and particularly to those interested in the natural history of gulls, peli- cans, cormorants and herons. — Thane S. Robinson. Arctic Birds of Canada. By L. L. Snyder. University of Toronto Press, Toronto, 1957 : 6 X 914 in., X -J- 310 pp., illus. $4.75. This book has far more to offer than the title and the author’s precise delineation of its scope might indicate. It is a fascinating guide to a fascinating group of birds, and the information contained within its pages is of value to amateur or professional ornithologists whether they visit the arctic regions or not. Even the author’s appraisal of the book as being not one having appeal as a literary companion would not be true if it weren’t for tbe interminably long passages that perhaps reduce the number of pages, but make it bard to keep one’s eyes open. In the introductory chapter the author has established the limits of the Canadian Arctic as defined by him, given the objectives of the text, discussed the process of identification through elimination, provided a key to the orders of birds of the Canadian Arctic, made a 103 104 THE WILSON BULLETIN Marcli 1959 Vol. 71, No. 1 broad classification of arctic habitats and the birds most likely to be found in these habitats, and has written a short but well-done summary of the nature of arctic birds. While the order key is little affected, I personally object to using other than a dichotomous means of separation. Ilis separation of the Gruiformes, Charadriiformes, and Galliformes is done by a triplet rather than a couplet method. There are nine orders covered in the main body of the text and each family discussed under these orders is given a general discussion on features that distinguish the particular family. Here will be found information, though aimed primarily at the amateur, that will often provide quick reference for the professional. Following the general discussion, each species is described under tbe following categories: additional names, status (general, arctic, migratory), habitat, characteristics and remarks. A most interesting feature useful to visitors of arctic regions has been the inclusion of the Eskimo names for each bird species. The section on characteristics often occupies three or four pages and includes features seldom found in identification guides. This section describes the appearance of the adidt in the field and when held in the hand. It describes tbe young in the field, in the hand, and also in the down. The eggs and the nest are also detailed. The remarks section is primarily devoted to problems of classification and distribution. In addition to the main text there is an appendix list of bird species that are not characteristic of the Canadian Arctic, but whose occurrence is occasional, a fairly complete glossary, a partial bibliography of some 52 titles, and a good index. Tbe publishers are to be congratulated on the appearance of the book and its freedom from typographical errors, and a review would be incomplete if mention was not made of the illustrations that are of the usual high quality that we have come to expect from T. M. Shortt. — P. B. Hofslund. This issue of The Wilson Bulletin was published on March 11, 1959. Editor of The Wilson Bulletin H. LEWIS BATTS, JR. Department of Biology Kalamazoo College Kalamazoo, Michigan Editorial Advisory Board George A. Bartholomew William A. Lunk Andrew J. Berger Robert A. Norris William W. H. Gunn Kenneth C. Parkes Raymond A. Paynter, Jr. Suggestions to Authors Manuscripts intended for publication in The Wilson Bulletin should be neatly type- written, double-spaced, and on one side only of good quality white paper. Tables should be typed on separate sheets. Before preparing these, carefully consider whether the material is best presented in tabular form. Where the value of quantitative data can be enhanced by use of appropriate statistical methods, these should be used. Follow the A. 0. U. Check-List (Fifth Edition, 1957) insofar as scientific names of United States and Canadian birds are concerned unless a satisfactory explanation is offered for doing otherwise. Use species names (binomials) unless specimens have actually been handled and subspecifically identified. Summaries of major papers should be brief but quotable. Where fewer than five papers are cited, the citations may be included in the text. All citations in “General Notes” should be included in the text. Follow carefully the style used in this issue in listing the literature cited. Photographs for illustrations should be sharp, have good contrast, and be on glossy paper. Submit prints unmounted and attach to each a brief but adequate legend. Do not write heavily on the backs of photographs. Diagrams and line drawings should be in black ink and their lettering large enough to permit reduction. Authors are requested to return proof promptly. Extensive alterations in copy after the type has been set must be charged to the author. A Word to Members The Wilson Bulletin is not as large as we want it to be. It will become larger as funds for publication increase. The Society loses money, and the size of the Bulletin is cut down accordingly, each time a member fails to pay dues and is put on the “suspended list.” Postage is used in notifying the publisher of this suspension. More postage is used in notifying the member and urging him to pay his dues. When he does finally pay he must be reinstated on the mailing list and there is a publisher’s charge for this service. The Bulletin will become larger if members will make a point of paying their dues promptly. Notice of Change of Address If your address changes, notify the Society immediately. Send your complete new address to the Treasurer, Ralph M. Edeburn, Dept, of Zoology, Marshall College, Hunt- ington 1, West Virginia. He will notify the printer and editor. f Plan now to participate in The Fortieth Annual Meeting to be held at The Farnsworth Museum, Rockland, Maine June 11-14, 1959 Sponsors: Portland Society of Natural History Farnsworth Museum Maine Audubon Society LiSSAHy JUN 251959 VOL. 71, No. 2 June 1959 u lARVARD jirasiTY rALriliS lUO-ZOD PuUetm Published by ^i)e Alteon (^rnitt)olosical S>ocietp at Kalamazoo, Michigan The Wilson Ornithological Society Founded December 3, 1888 Named after Alexander Wilson, the first American ornithologist. President — Lawrence H. Walkinshaw, 1703 Wolverine-Federal Tower, Battle Creek, Michigan. First Vice-President — Harold F. Mayfield, River Road R.F.D., Waterville, Ohio. Second Vice-President — Phillips B. Street, Route 1, Chester Springs, Pennsylvania. Treasurer — Ralph M. Edeburn, Dept, of Zoology, Marshall College, Huntington 1, West Virginia. Secretary — Aaron M. Bagg, Farm Street, Dover, Massachusetts. Membership dues per calendar year are: Sustaining, $6.00; Active, $4.00. The Wilson Bulletin is sent to all members not in arrears for dues. The Josselyn Van Tyne Memorial Library The Josselyn Van Tyne Memorial Library of the Wilson Ornithological Society, housed in the University of Michigan Museum of Zoology, was established in concurrence with the University of Michigan in 1930. Until 1947 the Library was maintained entirely by gifts and bequests of books, reprints, and ornithological magazines from members and friends of the Society. Now two members have generously established a fund for the purchase of new books; members and friends are invited to maintain the fund by regular contributions, thus making available to all Society members the more important new books on ornithology and related subjects. The fund will be administered by the Library Committee, which will be happy to receive suggestions on the choice of new books to be added to the Library. William A. Lunk, University Museums, University of Michi- gan, is Chairman of the Committee. The Library currently receives 65 periodicals as gifts and in exchange for The Wilson Bulletin. With the usual exception of rare books, any item in the Library may be borrowed by members of the Society and will be sent prepaid (by the University of Michigan) to any address in the United States, its possessions, or Canada. Return postage is paid by the borrower. Inquiries and requests by borrowers, as well as gifts of books, pamphlets, reprints, and magazines, should be addressed to “The Josselyn Van Tyne Memorial Library, University of Michigan Museum of Zoology, Ann Arbor, Michigan.” Contributions to the New Book Fund should be sent to the Treasurer, Ralph M. Edeburn, Dept, of Zoology, Marshall College, Huntington 1, West Virginia (small sums in stamps are acceptable). A complete index of the Library’s holdings was printed in the September 1952 issue of The Wilson Bulletin and each September number lists the book titles in the accessions of the current year. A brief report on recent gifts to the Library is published in every issue of the Bulletin. The Wilson Bulletin The official organ of The Wilson Ornithological Society, published quarterly, in March, June, September, and December, at Kalamazoo, Michigan. The subscription price, both in the United States and elsewhere, is J4.00 per year, effective in 1959. Single copies, $1.00. Subscriptions, changes of address and claims for undelivered copies should be sent to the Treasurer. Most back issues of the Bulletin are available (at 50 cents each for 1950 and earlier years, 75 cents each for 1951—1958) and may be ordered from the Treasurer. All articles and communications for publication, books and publications for review should be addressed to the Editor. Exchanges should be addressed to The Josselyn Van Tyne Memorial Library, Museum of Zoology, Ann Arbor, Michigan. Entered as second class matter at Lawrence, Kansas. Additional entry at Ann Arbor, Mich. The AUen Press, Lawrence, Kansas MUS. CBMP. ZOt llifiARr JUN25195! THE WILSON BULLETIN A QUARTERLY MAGAZINE OF ORNITHOLOGY Published by The Wilson Ornithological Society HARVARD HNiVERSITV Vol. 71, No. 2 June 1959 Pages 105-200 CONTENTS Specimens of Woodpeckers from Central Texas Photograph facing page 107 Interspecific Relations of Woodpeckers in Texas Robert K. Selander and Donald R. Giller 107 The Utilized Territory of the Ovenbird Judith Stenger and J. Bruce Falls 125 The Songs of the Grasshopper Sparrow Robert Leo Smith 141 Foot-stirring Feeding Behavior in Herons Andreiv ]. Meyerriecks 153 Display Behavior of Bufflehead, Scoters and Goldeneyes at Copulation M. T. Myres 159 Food Habits of Nesting Cooper’s Hawks and Goshawks in New York AND Pennsylvania Heinz Meng 169 Notes on the Nesting of Turdus leucomelas IN Surinam F. Haverschmidt 175 Notes on Certain Grouse of the Pleistocene Alexander W etniore 178 A Pleistocene Avifauna from Rock Spring, Florida Glen E. Woolfenden 183 General Notes THF. BEHAVIOR OF TWO CAPTIVE OSTRICHES AT A BURNING LEAF PILE William G. Comvay 188 STRIFE OVER A NESTING SITE BETWEEN DOWNY AND RED-HEADED WOODPECKERS R. G. Schwab and J. B. Monnie 190 PILOT BLACK SNAKE AND NESTING PILEATED WOODPECKERS Lawrence KHliain 191 THE PLIGHT OF THE BLUEBIRD IN MICHIGAN George J. W'allace 192 THE POISONING OF MEADOWLARKS WITH INSECTICIDES Daiule N. Griffin 193 BLUE JAY FEEDING ON TERMITES .. Donald H . Laitwre 193 A LATE RECORD FOR NORTHERN PHALAROPE IN WEST VIRGINIA George A. Hall 194 OBSERVATIONS AT A GOSHAW'K NEST IN NORTHWESTERN MONTANA _ Lloyd Parrott 194 198 Ornithological News JossELYN Van Tyne Memorial Library 200 Specimens ot wno.lpeckers from cemral Texas m .lorsal (above) and lateral (below) view. From lelt to rigl.l, male ami female Cenmm nnrf/rons, male and female C. cmolmus, anrl female Mehinerpes erythrocephalus. INTERSPECIFIC RELATIONS OF WOODPECKERS IN TEXAS BY ROBERT K. SELANDER AND DONALD R. GILLER Concrete information on ecologic relations of closely related species is in- frequently reported, especially in this country. A small number of docu- mented cases of interspecific territorialism in birds is known (see review by K. E. L. Simmons, 1951; also. Pitelka, 1951; Legg and Pitelka, 1956; Dixon, 1950, 1954), but many additional data will be needed before the full signifi- cance of this phenomenon, with respect to species’ distribution, numbers, and evolution, can be evaluated. This paper is a preliminary report of studies on territorial and other rela- tions of three woodpeckers in the Austin region, central Texas. The subjects are the Red-bellied Woodpecker [Centurus carolinus), Golden-fronted Wood- pecker {Centurus aurifrons) , and Red-headed Woodpecker {Melanerpes ery- throcephalus) . The data herein reported were gathered, more or less irreg- ularly, over a period extending from spring, 1957, to spring, 1958. Relations of C. carolinus and C. aurifrons The following notes on the systematic and ecologic relations of C. carolinus and C. aurifrons are prompted in part by a recent suggestion (Brodkorb, 1957) that the two may be conspecific. This is not the case, as they are sympatric without interbreeding in central Texas. Distribulion. — Centurus carolinus ranges west to central Texas and is re- placed in the west and in the Panhandle by C. aurifrons. Apparently nowhere is there extensive overlap in ranges, but at least locally in south-central Texas they are sympatric. At Austin, Travis County, overlap is limited to a zone not more than 20 miles in width, and the two species may regularly be seen together only within the limits of the city itself. We have little to add at this time to G. F. Simmons’ detailed account (1925) of the local distribution of these wood- peckers in the Austin region, which includes all of Travis County and parts of adjacent counties. The reader is also referred to G. F. Simmons’ book for accounts of physiography, climate, and vegetation of the region. Climatically, Austin is intermediate between semi-arid regions to the south and west and mesic regions to the east. There is a marked east-west faunal and floral “break” in the Austin region, discussed by Blair (1950) . Contact and hybridi- zation between the eastern Tufted Titmouse ( Pants bicolor bicolor ) and a black- crested race {P. b. atricrislatus) occur in the same region in which ranges of the Centurus woodpeckers overlap (Dixon, 1955). C. carolinus is common throughout Austin and in the region to the east, es- pecially in forest and woodland on the floodplain of the Colorado River; but, rarely has it been recorded even a few miles west of the city. In Austin, C. aurifrons is comparatively uncommon and localized in distribution, but pairs 107 108 THE WILSON BULLETIN June 1959 Vol. 71, No. 2 may regularly be found in several places in the southern and western parts of town, as at Barton Springs; and it occurs in small numbers in central and east- ern Austin, as in the City Cemetery a few blocks east of the campus of the Uni- versity of Texas. West and, especially, south of Austin it is moderately com- mon. At San Antonio, 80 miles south-southw^est of Austin, it is common, and there are no records of carolinus (Attwater, 1892:235) . Both species are permanent residents in the Austin region. There is probably an influx of C. carolinus from the north in the winter, at wdiich time it is more common than in the summer in timber on the floodplain of the Colorado River. However, the local distribution of both species is, by and large, similar in all seasons. Neither species appears to be in the process of extending its range in Texas. Even the local distribution and relative abundance of these species in the ■Austin region apparently have not changed to any great extent within the last 33 years. Many of the specific localities for carolinus and aurifrons mentioned by G. E. Simmons in 1925 are those in which the species are found at the pres- ent time. As the city of Austin continues to expand, a decrease in numbers of aurifrons may be expected as tracts of mesquite, juniper, and oak are cleared west and south of town. Morphologic Differences between Species. — In central Texas hoth species of Centurus are closely similar in size (Table 1) and in general appearance (frontispiece). The only conspicuous difference is in the color and pattern of the head. In the male C. carolinus the entire dorsal surface of the head is red; in the male C. aurifrons the nasal region is yellow, the nape is golden yellow, and a coronal patch of red is surrounded by gray. In the female car- olinus the nasal region and nape are red, whereas these are yellow in aurifrons. In females of hoth species the coronal region is gray. The abdominal region is washed with red in carolinus; the belly may or may not have a suffusion of yellowish in specimens from eastern parts of the state ( Burleigh and Lowery, 1944 I . This region is washed with yellow or golden yellow in aurifrons. There are also some minor differences in pattern of the upper tail coverts and inner wehs of the central rectrices (see frontispiece). Both species vc^y geographically in Texas. A series of C. aurifrons from the Texas Panhandle and Harmon County, Oklahoma, at the northern limit of the species’ range, is considerably larger in all dimensions than birds from central and southern Texas. Specimens from Oklahoma have been referred to C. a. incanescens (A. 0. U. Check-list, 1957:317), a race named from Brewster County, western Texas, and distinguished from C. a. aurifrons of southern Texas and Mexico on the basis of minor color and pattern differences. How- ever, specimens from Brewster County are small like those from central- southern Texas. Variation in size apparently was not considered by Wetmore Selander and Ciller WOODPECKER RELATIONS 109 (1948) in his review of geographic variation in Centurus aurijrons, but it is apparent that there is a north-south cline in size in Texas, which may or may not be concordant with dines of variation in color and pattern. Table 1 Measurements (in mm.) of Woodpeckers from Texas No. ADULT MALES Wing Tail Bill Tarsus C. aurijrons^ 8 137.0 (132-140) 82.0 (76-85) 27.06 (24.9-28.8) 24.70 (24.0-26.0) C. aurijrons- 8 129.7 (128-132) 77.1 (76-79) 25.80 (24.2-27.0) 22.20 (20.2-23.2) C. carolinus^ 6 129.0 (126-132) 76.4 (70-80) 24.35 (23.2-25.3) 21.22 (19.7-21.8) M. erythrocephalus 3 140.0 (137-143) 80.0 (78-82) 22.93 (22.1-24.0) 22.10 (21.9-22.3) ADULT FEMALES C. aurijrons^ 1 134 80 27.6 23.2 C. aurijrons- 6 127.8 (125-132) 73.7 (69-77) 23.48 (22.2-25.1) 22.53 (21.7-23.7) C. carolinus^ 4 125.7 (124-128) 73.3 (70-76) 23.30 (22.2-25.3) 19.90 (19.4-20.5) M. erythrocephalus 1 141 72 22.5 22.8 ^ Texas Panhandle and Harmon Co., Oklahoma. - Central— southern Texas from Travis County south. “Central Texas from Travis County east to Anderson County. Specimens of C. carolinus from Austin and Houston southward reportedly are paler than those from northeastern Texas and have been distinguished ra- cially, as C. a. harpaceus, by Koelz (1954) . Habitat Occurrence. — Throughout its range in Texas, and also extensively in northern Mexico, C. aurijrons inhabits xeric vegetation types in which mes- c|uite is often a dominant element. At Uvalde, Uvalde County, and at Pearsall, Frio County, aurijrons is a common resident in mesquite woodland. In Palo Duro Canyon, northern Texas, it occurs in riparian cottonwoods and mesquite flats on the floodplain of the Prairie Dog Town Fork of the Red River. Char- acteristic habitat of this species south and north of Austin is a mixed oak, large mesquite, and juniper formation on gravel ridges extending from the Bal- cones escarpment for several miles into the black prairie soils east of Austin (see Dixon, 1955, Fig. 9 and p. 169) . We have one record of aurijrons in this vegetation five miles east of Austin. In this formation carolinus is rarely found. C. aurijrons also frequents pecan groves and other open situations on flood- plains, and in small numbers it is found in live oaks, elms, and other mesic types in residential districts in Austin, especially where these are adjacent to stands of mesquite, deciduous oak, and juniper. C. carolinus, in contrast, inhabits mesic formations, frequenting “dead trees, preferably in heavily timbered bottom lands or swampy woods; open deciduous or mixed coniferous woodlands with very large trees [including pecan groves]; heavy woods of oak and elm along rivers and creek bottoms; shade trees and dead trees in town” (G. F. Simmons, 1925:133). 110 THE WILSON BULLETIN June 1959 Vol. 71, No. 2 The marked difference between the species in habitat occurrence functions in the overlap zone to limit contact and, at the same time, competition between them. It should be emphasized that these ecologic differences are shown else- where than in the zone of overlap. There is no conspicuous narrowing of habi- tat range in the Austin region. The overlap in habitat occurrence is sufficiently extensive, however, to warrant the hypothesis that either species would, in the absence of the other, occur in greater density in the overlap zone. Considering the fact that populations of aurifrons have managed to adapt to mesic and humid habitats in Mexico, it is perhaps surprising that the distribution of the Texas population stops abruptly in the Austin region, unless, of course, the presence of carolinus prevents further extension of range. Behavioral Differences. — The two woodpeckers are much alike in behavior, as far as we have determined. C. aurifrons is warier than C. carolinus and there- fore less easily approached and observed ; it is decidedly more shy in the vicinity of its nest. Loraging habits seem to be identical in the two species. In the Austin region their breeding seasons coincide (G. E. Simmons, 1925). The vocalizations are described by G. E. Simmons (op. cit.). Both species have the same repertoire of calls, but those of aurifrons are louder and harsher, and on this account easily recognized. The pulsed “location” call, used pri- marily to “advertise” territory in the breeding season, and the common warn- ing cha note of the two species are compared in Fig. 1; other calls are equally similar. The “location” call of aurifrons is less precisely tuned and slightly higher-pitched than that of carolinus, and it ends less abruptly. Lack of Interbreeding. — Considering the ecologic and morphologic simi- larities of C. carolinus and C. aurifrons, it is indeed surprising that they do not at least occasionally interbreed. However, in the past two years we have carefully noted the composition of dozens of pairs, and, invariably, the mem- bers have been of the same species. Moreover, we have seen no individual evi- dencing mixed ancestry, although, of course, hybridization in these morpho- logically similar species might be difficult to detect. The possibility that the color and pattern differences are controlled by a unifactorial genetic mechanism has been considered. If this were the case, interbreeding could occur without inter- gradation of characters in the hybrids; hut it seems unlikely that this same mechanism would control voice and behavioral differences as well. Some speci- mens of aurifrons have one or more red or orange feathers in the nape, but this does not necessarily indicate hybridization. The same character occurs in many (perhaps all) yellow-naped populations of aurifrons and is no more marked or frequent in sjjecimens from Travis County than in those from west- ern Texas and northern Mexico. To sum up, we have found no evidence of cross-pairing or hybridization be- tween members of the two ])o])ulations, hut the nature of the reproductive iso- 1000 C.P^. 1000 C.P.S. 1000 C.P^. Selander and Ciller WOODPECKER RELATIONS 111 8- 7- 6H ■' 5- 4- 3- 2- t 0- EO 1.2 TIME IN SECONDS Centurus caroHnus 2.4 8H TIME IN SECONDS Centurus aurifrons TIME IN SECONDS Centurus carol inus Centurus aunfrons FIG. 1. Sound spectrographs of calls of male Centurus woodpeckers from central Texas. Above, "location" calls; below, warning calls. Intensity of markings is proportional to energy involved at the frequency level. (The thin line near 5000 c.p.s. in the graphs of C. aurifrons calls resulfs from a signal in the tape recorder itself.) 112 THE WILSON BI LLETIN June 1059 Vol. 71, No. 2 lating mechanism remains to be determined. Differences in vocalizations seem hardly great enough to function alone as an effective isolating mechanism. At present practically no information concerning sexual behavior in these species, or, for that matter, in any other species of the genus, is available. A thorough study of courtship and mating behavior is indicated, but this mig ht be a diffi- cult undertaking. It appears that in both species many birds remain paired throughout the year. G. F. Simmons (1925:133) notes that carolinus “fre- quently spends the winter about trees where it will nest the following spring. . . .” It is possible that pair bonds are maintained for several years or for life. If so, opportunity to study the critical stage of pair formation will be limited. It may be noted in passing that these facts bear on the problem of reproduc- tive isolation, since the probability of the occurrence of a “mistake” in pair- ing, leading to hybridization, depends on the absolute number of pair bonds formed. In species in which pairing occurs each spring, opportunities for “mistakes” are obvously greater than in species in which a bird pairs only once or a few times in its life. Moreover, the formation of lasting pair bonds is usually preceded by long courtship or “engagement” periods, which also tend to reduce the chances for hybridization ( Alayr, 1942). Territorial Relations. — Observations by one of us (Selander) on the gen- eral spatial relations of the two species and of several interspecific conflicts in 1956 suggested that they held mutually exclusive territories. Subsequent ob- servations confirmed this suspicion, and in the spring of 1957 the territorial relations of two pairs were studied in some detail. The study area was at the Deep Eddy housing project of the University of Texas in western Austin (Fig. 2). Observations were made almost daily from March 25 to May 11, 1957, and occasionally thereafter through May, 1958. Alovements of the woodpeckers were plotted on maps, and the records are sum- marized in Fig. 3. The pair of C. carolinus nested in a chinaberry tree approximately 75 yards from a deciduous oak tree in which the pair of C. aurijrons nested. Both nests were about 15 feet above the ground. The territories of both species extended well beyond the limits of the area shown in Fig. 3. As observations of movements accumulated, it soon became apparent that a rigid, sharply defined line of division was maintained between territories of the two species. No tree in the study area was frequented at the same time by both species without conflict. Even in the absence of their neighbors, the pairs were reluctant to cross the territorial boundary. The territorial hoiiiulary was well established when oiir study began, and conflicts were infrequently seen. On March 28, tbe male aurijrons penetrated tbe carolinus territory to point “A” in Idg. 3; immediately be was attacked by the male carolinus and driven back to his territory. Again, on April 6, the male aurijrons entered the other species’ territory. Sclander and CiilJer WOODPECKER REEATIONS 113 Fig. 2. Above: View of territory of C. carolinus at Deep Eddy study area, taken facing nortli from position “A” in Fig. 3. Below: .Study area at Walker Ranch. Nest- tree of A/, erylhrocepholus is just left of large mesquite; that of C. carolinus is on the far right. 114 THE WILSON BULLETIN June 1959 Vol. 71, No. 2 Fig. 3. Study area at Deep Eddy housing project, Austin, showing interspecific terri- torialisin in Centurus. X’s indicate records of C. aurifrons; dots represent records of C. carolinus; where there is more than one record for a location, the number is indi- cated. The territorial boundary is indicated by the dashed line. The two males fought in three different trees near point “A,” and the aurifrons finally re- treated to his territory, flying to the nest-tree. On April 2.5, the female aurifrons entered carolinus territory. This time the female carolinus responded, a fight ensuetl, and the female carolinus chased the female aurifrons hack across the territorial boundary. C. carolinus less frecpiently trespassed on C. aurifrons territory. On May 11, however, the male carolinus flew very near to the ground from his nest-tree to the tree at position “B.” It “hid” behind the tree for two minutes, peeked around one side or the other at the nest-tree of aurifrons, then flew toward the aurifrons nest-tree, where the male and female were perched. Both the male and female aurifrons attacked the male carolinus as he flew toward the tree. The female soon returned to the nest-tree, hut the male continued to at- tack, driving the male carolinus to position “C,” at which point he circled back and re- turned to the nest-tree. The retreating male carolinus continued on to his own nest-tree. On March 29. the male carolinus entered aurifrons territory, where he fought with another male carolinus at position “D,” and again within his own territory at position “E.” The latter individual held a territory east of the study area. The pair of aurifrons was foraging off the study area at the time of this invasion. Displays atul calls used in inlerspecific lerrilorial defense did not differ in any way from those employed in ititraspecific encounters of the same type. In the spring of I95d, the territory of the pair of aurifrons at Deep Eddy was Seiander and Giller WOODPECKER REEATIONS 115 expanded to include that part of the territory of carolinus shown in Fig. 3. On April 19, the two males engaged in a vigorous fight in the carolinus nest-tree, following which carolinus retreated from the area. Subsequently, the pair of aurifrons raised a brood in the same hole used by carolinus in the previous year. Relations of C. carolinus and M. erythrocephalus In April, 1958, an unexpected opportunity to study ecologic relations of C. carolinus and a third species of similar size (Table 1), Melanerpes erythro- cephalus, was provided. This woodpecker, like C. carolinus, with which it is sympatric in southeastern Canada and the eastern United States, reaches its southwestern distributional limit in central Texas at Austin. Formerly a fairly common summer resident in the Austin region (G. F. Simmons, 1925:131), it is now rare. There have been no more than a half-dozen records of this species in Travis County in the last 10 years. It is possible that withdrawal of M. erythrocephalus from central Texas was related to the long drought that ended in the spring of 1957 (Blair, 1958). Now that environmental conditions are again “normal” in this region, it will be interesting to see if it returns in any numbers. On April 17, we were directed by Mr. Wyle Hord to the territory of a pair of erythro- cephalus on the Walker Ranch, along the Colorado River about two miles east of Austin IFig. 4) . According to Mr. Hord, the pair was first seen l)y him in the spring of 1957. The birds nested successfully in 1957 and wintered there in 1957-58. A fledgling was seen near the nest-hole on August 7 by Mr. Fred S. Webster and Dr. C. H. Brownlee. Webster, who has been one of the most active observers in tlie central Texas region for the past six years, informs us that this is the only breeding record of tliis woodpecker in the Austin region that has come to his attention. He suspects, however, that a few additional pairs may he found along the Colorado River between Austin and Bastrop. Occasionally, lone birds have been seen in winter along Onion Creek, a few miles southeast of Austin, and along the Colorado River. Fortunately, a nesting pair of carolinus was located in the same area, permitting study of the territorial relations of the two species 1 Fig. 4) . Observations were made at the Walker Ranch from April 17 to 23 and on May 1. Activities of the erythrocephalus centered about a small, dead cottonwood tree adjacent to a small corral and a mesquite tree in a grassy meadow (Fig. 2). Several holes had been drilled in the cottonwood, including one “active” hole about 15 feet above the ground which the birds occasionally entered and in which at least one roosted at night. They were not incubating at the time of our study, hut we saw some courtship behavior and it was obvious that they were preparing to breed; copidalion was noted on May 1. On the same tlay a third indivitlual of erythrocephalus appeared and was attacked and driven from the terri- tory by the pair. Apparently this species breeds somewhat later, on the average, than does C. carolinus (Bent, 1939). Movements of the birds were recorded and mapped (Fig. 4) over a period of about eight hours on three different days. The birds often visited the nest-tree and also spent a good deal of time in the adjacent grove (T tall cottonwoods, to which they almost invariably retreated as we approached the nest-tree. 4 hey also visited cottonwoods and hackherry trees along the river; and on April 18 the pair led for one-half hour in a large cottonwood 116 THE WILSON BULLETIN June 1959 Vol. 71, No. 2 only 25 yards from the nest of caroliniis. The pair of the latter species nested in a dead limb of a cottonwood which was larger than that used by erythrocephalus. The nest-hole was 15 feet above the ground, and the opening faced north. The nests of the two species w'ere 80 yards apart. erythrocephalus. Letters identify trees, as follows: A, ash; C, cottonwood; If, hack- herry; .M, mesqtiile; P, pecan; R, retania. The i)air mend)ers of caroliniis were feeding young, making repeated visits to the nest with insects. They foraged over a much larger area than did the erythrocephalus. It will he seen in Fig. 4 that caroliniis visited the large pecan tree to the north of the erythrocepha- lus nest-tree and also the southern part of the grove of cottonwoods and a line of hackberry trees along the river. Sometimes they flew' south across the river to forage in trees located several hundred yards from I heir nest. On three occasions the male caroliniis passed within a few feet of the nest-tree of the other species, while one or both of the latter were present. Sclamler and Giller WOODPECKER RELATIONS 117 but no interspecific conflict was seen. Ae noted, liowever, tliat carolinus did not forage in the grove of cottonwoods east of the erythroceplialus nest-tree, although several times they flew through the grove on their way to forage in trees beyond the study area to the north. In summary, it seemed evident even from our limited series of oltservations that the territorial relations of C. carolinus and M. erythroceplialus were de- cidedly different from those of the former species and C. aurifrons. Their ter- ritories overlapped broadly and no interspecific conflict was noted. Experiments with Dummies. — In an attempt to investigate factors involved in species recognition, we have performed a series of experiments in which dummy woodpeckers (study skins) were placed at various points in the terri- tories of pairs of woodpeckers and the ensuing responses recorded. Not all of these throw light on the problem of interspecific territorialism, but they are none the less of some interest. On May 8, 1957, a male dummy C. aurifrons was wired to a limb one foot below the nest- hole of the pair of C. carolinus that was being studied at Deep Eddy. Immediately the fe- male carolinus attacked the dummy, striking it repeatedly with her hill for a period of 45 minutes. The great majority of her blows were directed at the head, particularly the eye region. Her attack stopped only when we approached the tree to retrieve the dummy, which was by then all hut torn to pieces. The male made only a few passes at the dummy and left the tree a few minutes after it was placed in position. The next day. May 9, we attached both male and female dummies of carolinus to the nest-tree of the pair of aurifrons, placing them within two or three feet of the nest-hole. At once both male and female aurifrons attacked the dummies, with the first blows being directed male to male and female to female. In this particular case, the male was much more aggressive than the female. The latter seemed apprehensive and alternately pecked at the dummy and retreated. After 15 minutes the head of the male dummy was detached and fell to the ground. Nonetheless, the male continued his attack on the headless dummy for another five minutes and then directed his response toward the female dummy; hut he continued to make occasional passes at the headless dummy. Again the majority of blows were directed at the dummies’ heads. Ten minutes after the head was knocked from the male dummy, both dummies were re- moved from the nest-tree and placed on a telephone pole 40 yards from the nest-tree. The dummies were attacked in their new positions, hut with lessened intensity, and the attacks were not so long sustained. The same type of experiment was performed by placing a dummy male aurifrons on a post within the territory of the carolinus. As in the previous experi- ment, the dummy was attacked with less intensity than when it was placed on the nest-tree. The results of our work with dummies were not unexpected in view of our previous observations on territorial behavior. Subsequent tests with other pairs of carolinus have shown that the female of this species takes a more active part in defense of the nest-hole area against the dummies than does the male. The same pattern of behavior may he seen when one approaches the nest-tree of a pair of carolinus in which eggs or young are present. The female usually remains in the nest-tree calling excitedly, whereas the male almost invariably flies to a distant tree, returning only when the intruder has departed. 118 THE WILSON BULLETIN June 1959 Vol. 71. No. 2 A second test with aurijrons also confirmed our first, to the effect that in this species the male is more aggressive in encounters at the nest-hole than is the female; hut additional testing is needed. The fact that attacks were usually directed at the heads of the dummies sug- gested that this part of the body alone supplies at least the important sign stim- uli releasing aggressive behavior. This was confirmed by wiring the head of a dummy female carolinus two feet above the nest-hole of a pair of carolinus in a mesquite tree on the University of Texas campus on April 6, 1958. The female came to the nest-tree, suddenly flew to an adjacent stand of cottonwoods, and returned in company with the male. The male flew to the head and pecked it violently ( Lig. 5 I , and the female soon joined him in the attack. After about 10 minutes, the forepart of the dummy’s head, including the bill, came loose, and the male flew off with it in his bill. To our surprise, the female continued her attack on the remnants of the head, a ball of cotton used to stuff the dummy and a tuft of red feathers on the coronal and occipital regions. Her attack con- tinued for several minutes but ceased abruptly when her blows dislodged the few remaining feathers. Shortly thereafter, the male returned and investigated the “remains”; then he entered the nest-hole, presumably to incubate, and the female foraged in the nest-tree. These observations suggest that the red feathers of the head are of paramount importance in releasing aggressive behavior. We have not pursued the problem further, but it is clear that the response to the head alone is fully as strong as to the entire dummy. Despite the fact that the pair of M. erythrocephalus did not behave aggres- sively toward C. carolinus, even when the male of the latter species flew within a few feet of their nest-tree, they readily attacked dummies of that species placed near their nest-hole (Lig. 6). When presented simultaneously with dummies of carolinus and their own species, they usually directed their initial attack at the latter, hut the defense of the nest-tree against the carolinus dummy was vig- orous. These tests help account for the fact that the pair of carolinus avoided perching in the vicinity of the nest-tree of erythrocephalus. Discussion In a recent review of interspecific territorialism in birds, K. E. L. Simmons (1951:407 I has suggested that the term be confined to cases in which “a terri- tory holder of one sjiecies exhibits persistent aggressive behaviour to an in- truding bird of a second species, showing to it some, if not all, of the reactions usually forthcoming in intraspecific encounters.” Lurther, he suggests that the aggression should be related to the territory as a whole and not merely to a jiarticular part of it, thus excluding contests between hole-nesters at nest-sites. We are in general agreement with Simmons in this regard. Conflicts between hole-nesting species competing for roosting or nesting sites frequently involve Selander ami Ciller WOODPECKER RELATIONS 119 Fig. 5. Male carolinus attacking head of male dummy C. caroliniis near nest-hole. species which do not hold exclusive territories. The relations of C. aurifrons and C. caroliniis, however, satisfy all criteria for interspecific territorialisin. The case is unusual in that the territories are mutually exclusive; in their ter- 120 THE WILSON BULLETIN June 1959 Vol. 71, No. 2 ritorial relations, the two woodpeckers behave as if they were a single-species population. Where the two species of Centurus occur together, competition for space and nesting sites is manifested in interspecific territorialism. Lack of signifi- cant differences in feeding and nesting habits and in timing of events of the annual cycle would seem to preclude the possibility of their coexistence, ex- cept in a narrow contact zone where there is complex inter-digitation of vege- tation types. Reproductive isolation is complete, but the species have so far failed to evolve ecologic adjustments that would permit extensive sympatry. In the case of Centurus carolinus and Melanerpes erythrocephalus, sympatry is possible because the necessary ecologic adjustments have been made, and it appears that they do not show interspecific territorialism. There are obvious differences between these species in foraging habits and habitat occurrence. Our observations show that erythrocephalus feeds regularly not in the manner of “typical” woodpeckers but by “flycatching.” The relatively longer wing and tail of this species (Table 1 ) may be related to this trait, which has also been noted by several other writers, including G. L. Simmons (1925:132), Skinner ( fide Bent, 1939:201 ) , and Nauman (1930 ) . Studies of stomach con- tents by Beal (1911) reflect differences in foraging habits in the two wood- peckers. He notes that erythrocephalus “eats very few beetle larvae or other grubs, or ants that live in wood or other places of concealment. Apparently it is not so fond of pecking wood as are the other species [of woodpeckers] . . . .” In our experience, carolinus “flycatches” only occasionally, and all lines of evidence point to the conclusion that erythrocephalus obtains significantly less of its food by foraging over trunks, branches, and leaves than does the other species. In the course of our studies in April, we rarely saw erythrocephalus dig or probe into bark, whereas carolinus fed almost exclusively in this fashion. Typically, erythrocephalus fed by perching in exposed positions atop large pecan or cottonwood trees and darting out some 20 to 40 yards to catch large flying insects, some of which were beetles. We watched one or both individuals repeat this action for periods of up to an hour, and Nauman (1930) calculated that one bird, which was feeding a fledgling, made five to seven sallies per minute, catching a calculated 600 flying insects in the course of an hour. Be- tween sallies, the birds often perch crosswise in the manner of passerines, and the head is turned from side to side as they j)eer about for insects. Some in- sects are swallowed immediately after a bird returns to its “lookout” perch, but larger ones are usually wedged in crevices (typically in stumps), smashed, and picked apart. This discussion is not intended to suggest that erythrocephalus feeds ex- clusively in this manner. The sj)ecies also drills into wood and, especially in the fall and winter, feeds on beechnuts, berries, acorns, seeds, and other vege- Selander and Ciller WOODPECKER RELATIONS 121 Fig. 6. M. erythrocephalus attacking male dummies of its own species (above) and C. crirolinus t below) . 122 THE WILSON BULLETIN June 1959 Vol. 71, No. 2 table food (Beal, 1911); in addition, it reportedly (Bent, 1939:199) takes both eggs and young of some small passerines. The fact that erythrocephalus tends to frequent more open situations than does carolinus may be related to differences in feeding habits. In any event, it is probably important in permitting the two species to coexist. Bent (1939: 195 I regarded erythrocephalus as “essentially a bird of open country and not in any sense a forest dweller,” and other naturalists quoted by Bent have noted its preference for open groves, “old burns,” and other similar situations. Our observations and those of G. L. Simmons (1925:131) in Texas agree fully with these reports. Simmons noted the preference of erythrocephalus for edges of woodlands, orchards, groves, and clearings in open woods, and that of carolinus for heavily wooded bottomlands. At the Engeling Wildlife Manage- ment Area, Anderson County, Texas, in November, 1956, we found erythro- cephalus somewhat less numerous than carolinus and confined to a partly burned stand of trees bordering a meadow, whereas carolinus was generally distributed throughout the oak forest. Even in the study area at Walker Ranch, a preference of erythrocephalus for open situations was apparent, as evidenced, for example, by the location of the nests of the two species (see Eig. 4) . Since tlie foiegoing was written, Kilham (1958a, 1958b, and 1958c) has puldislied three important articles dealing with the biology of C. carolinus and M. erythrocephalus in Mary- land. Among his significant findings are the following: Pairs of C. carolinus disband in late summer, and nesting, which begins in April, is preceded by a long period of courtship and pair bond reinforcement beginning in January. Individuals of M. erythrocephalus hold- ing small winter territories in woodland defended their areas and acorn stores against C. carolinus and a variety of other species of birds. Summary Interspecific relations of three woodpeckers of approximately equal size were studied in central Texas. The closely related, morphologically similar Red-bellied Woodpecker (Centurus carolinus) and Golden-fronted Wood- pecker iCenturus aurifrons) are sympatric in a narrow zone in the Austin region. Within this overlap zone, differences in habitat occurrence limit con- tact and competition; but both species occur in the city of Austin, where they hold mutually exclusive territories. Eeeding and nesting habits are similar in the two species, as are vocalizations and displays. Reproductive isolating mech- anisms, the nature of which are unknown, have evolved, but the species have not made ecologic adjustments which would j^ermit extensive sympatry. The territorial relations of a pair of C. carolinus and a pair of Red-headed Woodpeckers {Melanerpes erythrocephalus) were studied. Their territories overlapped broadly, and interspecific antagonism was not observed. It is sug- gested that differences in foraging habits and habitat occurrence are important factors permitting extensive sympatry of these species. Selamler and Ciller WOODPECKER RELATIONS 123 The reactions of nesting woodpeckers to dummies were tested. Both carolinus and aurifrons attacked dummies of their own or of other species placed in their nest-trees or elsewhere in their territories. The head of a carolinus dummy was as effective in releasing aggressive behavior in carolinus as was the entire dummy. Dummies of carolinus and erythrocephalus placed near the nest-hole of erythrocephalus were attacked with approximately equal vigor. Literature Cited Attwater, H. P. 1892 List of birds observed in the vicinity of San Antonio, Bexar County, Texas. Auk, 9:229-238, 337-345. A. 0. U. Check-list Committee 1957 Checkdist of North American birds (5th ed.). American Ornithologists’ Union, Baltimore, 691 pp. Beal, F. E. L. 1911 Food of the woodpeckers of the United States. U. S. Dept. Agric., Biol. Surv. Bull., 37 : 64 pp. Bent, A. C. 1939 Life histories of North American woodpeckers. U. S. Nat. Mus. Bull., 174: 334 pp. Blair, W. F. 1950 The biotic provinces of Texas. Texas Journ. Sci., 2:93-117. 1958 Changes in vertebrate populations under conditions of drought. Cold Spring Harbor Symp. Quant. Biol., 22:273-275. Brodkorb, P. 1957 Birds. Pp. 361-613 in Blair, W. F., et al.. Vertebrates of the United States. McGraw-Hill Book Co., Inc., New York. Burleigh, T. D., ano G. H. Lowery, Jr. 1944 Geographical variation in the Red-bellied Woodpecker in the southeastern United States. Occas. Papers Mus. Zool., Louisiana State Univ., no. 17:293-301. Dixon, K. L. 1950 Notes on the ecological distribution of Plain and Bridled Titmice in Arizona. Condor, 52:140-141. 1954 Some ecological relations of chickadees and titmice in central California. Condor, 56:113-124. 1955 An ecological analysis of the interbreeding of crested titmice in Texas. Univ. Calif. Publ. Zool, 54:12.5-206. Kilham, L. 1958a Pair formation, mutual tapping and nest hole selection of Red-hellied Wood- peckers. /1//A'. 75 :318-329. 1958h .Sealed-in winter stores of Red-headed Woodpeckers. Wilson Bull.. 70:107-113. 1958c Territorial behavior of wintering Red-headed Woodpeckers. Wilson Bull.. 70: 347-358. Koelz, W. N. 1954 Ornithological studies. II. A new subspecies of Red-hellied Woodpecker from Texas. Contr. Inst. Reg. ExpL, 1:32. Legc, K., and F. a. Pitelka 1956 Ecologic overlap of Allen and Anna Hummingbirds nesting at Santa Cruz, California. Condor, 58:393-405. 124 THE WILSON BULLETIN June 1959 Vol. 71, No. 2 Mayr, E. 1942 Systematics and the origin of species. Columbia Univ. Press, New York, 334 pp. Nauman, E. D. 1930 The Reddieaded Woodpecker. Bird-Lore, 32:128-129. PiTELKA, F. A. 1951 Ecologic overlap and interspecific strife in breeding popnlations of Anna and Allen Hummingbirds. Ecology, 32:641-661. Simmons, G. F. 1925 Birds of the Austin region. Univ. Texas Press, Austin, 387 pp. Simmons, K. E. L. 1951 Interspecific territorialism. Ibis, 92:407-413. Wetmore, a. 1948 The Golden-fronted Woodpeckers of Texas and northern Mexico. W ilson Bull., 60:185-186. DEPARTMENT OF ZOOLOGY, UNIVERSITY OF TEXAS, AUSTIN, TEXAS, MAY 26, 1958 THE UTILIZED TERRITORY OF THE OVENBIRD BY JUDITH STENGER AND J. BRUCE FALLS HANN (1937) showed that the Ovenbird {Seiurus aurocapiUus) strongly exhibits territorial behavior. Since the area defended by the male is used for mating, nesting, and as a feeding ground for adults and young, it exemplifies type A of Nice’s (1941) classification. We studied territories of Ovenbirds in four forest types at the Wildlife Research Station of the Ontario Department of Lands and Forests, in Algonquin Park, Ontario. Observations were carried out during the summers of 1955 and 1956. This paper deals with the extent of the area utilized by a male Ovenbird during the breeding season, some aspects of the way in which it is utilized, and the variations in size which occur in this area as the breeding season progresses. Description of Study Areas Five plots for the study of territories of Ovenbirds were established in four forest types as follows: one plot in aspen, one in a conifer-birch association, two in a mixed hardwood— conifer association, and one in mature maple forest. One of the mixed plots was used only in 1955, and was so similar to the other that it will not be described in detail. The conifer— birch plot was used only in 1956. Each plot was surveyed into a grid of 66-foot squares and the intersections were marked. Areas of plots used varied from eight to 20 acres. Differences in tree species and differences in number, height, and density of canopy layers were used to map study plots into cover types by inspection. Within each cover type circular areas of 33-foot radius were chosen arbitrarily. These samples, which included from eight to 16 per cent of the area in each plot, were used to estimate height, density (percentage of sky obstructed by foliage, not allowing for spaces between leaves), and species composition of each stratum of the forest. In addition, species and diameter at breast height ( DBH ) of all trees more than 1.5 inches in diameter were recorded. Millacre quadrats (6.6 feet square) located at the grid intersections were used to estimate percentage of ground covered by logs and rocks, and by each species in the low vegetation. Brief descriptions of the four main study plots are given below. The per- centage of trees in the canopy made up hy each of the commoner species is included. Aspen Plot. — Upper canopy 93 per cent aspen (Popidus treniuloides, P. grandidentata) . Lower canopy 37 per cent maple (mainly Acer rubriun) , 28 per cent white spruce (Picea glaiica) , and 23 per cent balsam fir {Abies balsamea) . Brush layer denser than in other plots and composed mainly of hazel (Corylus cornuta) and small conifers. Common ground plants — hnnchberry {Coniits canadensis), bracken {Pleridium aquilinam) , and sarsaparilla (Aralia nudicaiilis) . Leaf litter mainly of broad leaves. 125 126 THE WILSON BULLETIN June 1959 Vol. 71, No. 2 Conifer-birch Plot. — Upper canopy 39 per cent white birch (Betula papyrifera) , 20 per cent aspen, and 32 per cent white pine [Piniis strobus) . Lower canopy 71 per cent balsam fir. Brush of hazel and small conifers. Common ground plants — bracken, bunchberry, sar- saparilla, blueberry (Vacciniiirn angiistifolium, V. myrtilloides) , and grasses. Leaf litter mainly of pine needles. Mixed Plot. — Variable. Parts resemble all other plots. Large areas of mature hardwood and other areas of pure conifer. Upper canopy 37 per cent white birch, 23 per cent red and sugar maples (Acer rubriim, A. saccharurn), and 13 per cent wdiite spruce. A few large specimens of yellow birch (Betula lutea), white pine, and hemlock (Tsiiga canadensis) . Lower canopy, present in only 34 of 42 samples, mainly of balsam fir (36 per cent) , maples (20 per cent) , white spruce (19 per cent) , and white birch (12 per cent) . Brush layer, present in only half the samples, chiefly of hazel, striped maple (Acer pennsylvanicum) , and small conifers. Common ground plants — bunchberry, bracken, sarsaparilla, maple seedlings, dewberry (Rubus pubescens) , and grasses. Maple Plot. — Most complex canopy of any plot, having three layers all dominated by sugar maple, 85 per cent in upper and lower canopy, and 91 per cent of understory. Beech (Fagus grandifolia) , 12 per cent of upper canopy. Some ironw’ood (Ostrya virginiana) in all three canopy layers. Lower canopy and understory present in 10 and 12 out of 17 samples, respectively. Brush present in only three of 17 samples, chiefly of striped and sugar maples. Ground vegetation mainly of tree seedlings — sugar maple, striped maple, and beech. More logs and deeper leaf litter than in other plots. Table 1 shows the height and density of each stratum of the forest in each of these plots. Table 2 shows the composition of the forest. Trees are classified with regard to tolerance (here taken to mean capacity to develop and grow in the shade of and in competition with other trees) following Tourney and Korstian (1947). When study plots are arranged in the order — Aspen, Conifer-birch, Mixed, 11 EIGHT AND Table 1 Density of Each Stratum of Forest in Study Plots Strata Plots Aspen Conifer— birch Mixed Maple Height (feet)^ Upper canopy 45 50 55 85 Lower canopy 25 25 25 35 Understory — — — 17 Brush 8 5 6 4 Ground vegetation 1.5 1.5 1.5 1 Density (per cent covered)' Upper canopy 50 45 65 75 Lower canopy 20 15 20 85 Understory — — • — 40 Brush 50 30 25 25 Ground vegetation 70 70 45 5 Logs and rocks 5 5 10 10 1 Median values are used for height and density. Stenger and Falls OVENBIRD TERRITORY 127 Table 2 Composition of Forest in Study Plots Trees- per acre Saplings'* per acre Species^^ Aspen Conifer birch Mixed Maple Aspen Conifer- birch Mixed Maple Tolerant Sugar and red maple 70 0 46 182 71 0 10 83 Striped maple 0 0 2 5 0 0 7 6 Ironwood 3 0 3 13 0 0 1 17 Beech 0 0 0 19 0 0 0 1 Balsam fir 53 141 58 0 39 79 21 0 Spruce (mainly white) 69 28 43 0 37 8 6 0 Hemlock 0 0 9 5 0 0 0 0 Intermediate Yellow birch 0 0 10 0 0 0 0 0 Pine (mainly white) 1 66 20 0 0 2 1 0 Intolerant Aspen (mainly 378 40 2 0 25 0 0 0 trembling) White birch 10 80 64 0 9 2 2 0 Willow sp. 0 0 0 0 7 0 0 0 Totals 584 355 257 224 188 91 48 107 Per cent composition Tolerant 33 47 62 100 78 96 94 100 Intermediate 0 19 12 0 0 2 2 0 Intolerant 67 34 26 0 22 2 4 0 1 Three species that had fewer than five stems per acre in any plot are omitted. -Trees have DBH over 2V2 inches. 3 Saplings have DBH ] 1/2 to 21/2 inches. Maple, a number of trends are apparent. Height and density of the upper canopy increase while density of brush and ground cover decreases from Aspen to Maple (Table 1). Number of trees per acre and the proportion of trees made up by intolerant species decrease ( Table 2 ) . On the other hand, the proportion of trees belonging to tolerant species increases. A high proportion of saplings is tolerant in all plots. These trends suggest that the plots represent an early stage (Aspen), two intermediate stages (Conifer— birch. Mixed), and a late stage (Maple) in forest development. However, they probably do not represent stages in a single succession. The Aspen and Conifer— birch Plots seem likely to become more coniferous. These stands may he regarded as local representatives of the boreal forest. The Mixed and Maple Plots will likely continue to support mixed or hardwood stands. This is not surprising since Algonquin Park lies in a transition zone between the boreal forest and the northern conifer-hard- 128 THE WILSON BULLETIN June 1959 Vol. 71, No. 2 wood forest (as described by Brown and Curtis, 1952), and stands of both types are found on different sites within the area (Halliday, 1937). Method Used to Study Territory Territorial disputes between male Ovenbirds were observed from the time the birds arrived on the breeding grounds until after the young had left the nest. Most encounters consisted of chasing and vocalizing (call notes and songs ) or only vocalizing, although physical contact was occasionally observed. Disputes were fewer, shorter, and less vigorous as the breeding season advanced. Not enough territorial disputes were observed to outline the area defended by any individual, i.e., to measure territory in the strict sense. Instead, all locations where a male was observed were plotted and used to estimate the area utilized by that bird. Many of these locations were esti- mated when a bird was heard singing. Occurrence of song distinguished males from females which are similar in plumage but do not sing. A few birds were marked with colored bands, hut individual males were identified chiefly by differences in their songs. Tape recordings were useful for verifying identifications. Detailed analyses of songs will be published elsewhere. Nine males were studied in 1955, and 13 in 1956. One observer watched a bird, taking care not to disturb it. When the bird was located, its position was marked on a map, and the height at which it was observed was recorded. Locations on the map were numbered consecutively. Each bird was studied one day a week, which amounted to eight or nine times during the breeding season in 1956. Lewer observation periods were completed in 1955. The observation period each day extended from 4:15 to 5:45 a.m. E.S.T. in 1955, and from 5:15 to 9:30 a.m. E.S.T. in 1956. Total Territory Utilized During the Breeding Season All locations where each male Ovenhird was observed from the arrival of its mate until its young left the nest were mapped as in Lig. 1. Lor each bird most of the points formed a comjDact group, but a few points ( about five per cent) lay well outside this group. In order to determine the total utilized territory, the five per cent of points that were most isolated were rejected in all cases. Peripheral points of the remaining group were joined to form a polygon having no indentations (Lig. 1)- Three of the birds (M 26, M 27, M 30) were not observed in certain open areas that lay within the polygons, and these areas were subtracted in finding the area of the total utilized territory. Areas were obtained from the maps using a comjiensating planimeter. Points obtained during the premating period were excluded because there was sometimes a shift in the location of a territory when the female arrived. Points obtained after the young left the nest were excluded for two reasons. In the first place, the family grouj) breaks up (Hann, 1937), and it is doubtful Stcnger and Falls OVENBIRD TERRITORY 129 whether most males still exhibit territorial behavior. Secondly, young birds were apparently not cognizant of the boundaries of the adult’s territory and sometimes wandered beyond, in which case the male went beyond the boundary to feed them. A LOCATIONS ABOVE GROUND Fig. 1. Total utilized lerrifory of M 20. Locations where the hird w'as oliserved are shown. The total utilized territory as determined above is not necessarily identical with the area that a bird will defend if called upon to do so. However, it is an estimate of the area used during the breeding season by a male exhibiting territorial behavior. It is the segment of the environment in which most of the activities associated with the reproductive cycle are performed. Distribution, of activities. — Locations where male Ovenhirds were seen or heard did not appear to be concentrated anywhere hut were scattered through- out the total utilized territory. Data for M 20 shown in Eig. 1 are typical in this regard. Most points represented locations where a hird sang in the trees but no particular song posts were used repeatedly. Prolonged vocalization occurred in any part of the territory where there were trees (usually deciduous) 130 THE WILSON BULLETIN June 1959 Vol. 71, No. 2 of a suitable height (Lig. 1). The Ovenbird feeds almost entirely on the ground ( Stenger, 1958), and nearly all observations of a bird on the ground represented feeding activity. When these observations are plotted separately ( Lig. 1 ) they too are seen to be scattered throughout the territory. Unforested areas that appeared to be similar to each other were used by some birds hut not by others. Large open areas of bracken and grasses in the Aspen Plot were not used by M 26 and M 27, whereas M 23 and M 24 in the Conifer-birch Plot were observed to use similar areas. M 30 in the Maple Plot did not utilize an open wet area. The total area utilized by a female was not determined. However, a female was sometimes observed in company with a male or was flushed from its nest and could then be followed. Lemales were not observed beyond the boundaries of their mates’ territories. However, they did not appear to take an active part in defense of the territory. The nest was located within the total utilized territory although often near the edge. Buffer zone. — When total utilized territories of neighboring birds are drawn on a map there is usually a buffer zone (Williamson, 1956) between them. An example is shown in Lig. 2 where all the territories except those of M 4 and M 5 were separated by approximately 60 feet. In the Maple Plot, where territories were largest, the buffer zone was about 100 feet wide. Sometimes there appears to be considerable overlap between adjacent territories as illustrated in the Mixed Plot in 1956 ( Lig. 3 ) . This results from shifting of territories during the breeding season; territories utilized by adjacent birds on any one day were always well separated. Most of the points rejected in the estimation of total utilized territory oc- curred in the buffer zone. When a bird was observed in the buffer zone it either did not sing at all or gave one or two weak songs. These observations suggest that Ovenhirds recognize the boundaries of their territories since they behave differently in the buffer zone than inside the total utilized territory. Extent of the total utilized territory. — All the birds that were studied occupied fairly compact territories approximately circular or oval in shape (Ligs. 1—3). The size of these areas varied considerably as shown in Table 3. The total utilized territories of M 5 and M 7 were smaller when they were unmated than when they were mated. When birds renested (this occurs only when the first attempt at nesting fails) they occupied larger territories in two cases (M 5, M 32 ) and a smaller territory in one case (M 28 ) than during the first attempt at nesting. They did not change location, however (Lig. 3). 3 he greatest differences in size of territory occurred among different forest types. Considering first nesting attempts in 1956, for the 11 birds for which comparable data are available (omitting M 7 and M 32), the average sizes of territories in the different plots are: Aspen 1.8 acres; Conifer-birch 2.2 acres; Mixed 2.4 acres; and Maple 3.3 acres. The same trend is shown in 1955 Stenger and Falls OVENBIRD TERRITORY ]31 for the Aspen, Mixed, and Maple plots. It was pointed out in the section dealing with study areas that when the plots are placed in this order they show a number of trends in the structure and composition of the forest. Thus, territory size increases as canopy height and density increase, as brush and ground vegetation decrease, and as the forest changes from an early serai stage with many intolerant trees, to a late stage in development characterized by fewer but more tolerant trees. These trends are quite marked when the territories in different plots are compared, but do not hold in every case within plots. These features of the habitat may affect the behavior of the birds, or may determine differences in the supply of food available to Ovenbirds, or both. The relationship between available food and size of territory is con- sidered in a separate paper ( Stenger, 1958 1 . Height of the territory. — The space occupied by a bird is a volume rather than an area and has a measurable height. It can be argued that a more accurate account of territory might be attained by comparing volumes. This Fig. 2. Total utilized territories in Mixed Plot in 1955. 132 THE WILSON BULLETIN June 1959 Vol. 71, No. 2 would necessitate measuring the height of each territory. Greater height might compensate for smaller area or height might be related to area in some other way. The height of the space occupied by a male Ovenbird was estimated by finding the average height of the highest 25 per cent of points where the bird was observed. Analysis of data from territories of nine Ovenhirds showed that the vertical extent of activity was a little less than the height of the densest layer of the forest canopy. This resulted from the fact that Ovenhirds usually sang from the lower branches of the canopy. The vertical extent of activity was not clearly related to the area of the territory. Height values were less \ariable than areas of territories and did not compensate for them. Thus, if Stenger and Falls OVENBIRD TERRITORY 133 volumes were calculated from these dimensions, they would he more variable than the corresponding areas. These results, together with the fact that this species feeds and nests on the ground, indicate that, for the Ovenbird, the area of the total utilized territory is more meaningful than the volume of space occupied. V.ARIATION IN Size OF Table 3 Total Utilized Territory AMONG Forest Types Forest type 1956 1 X O O Bird Territory (acres) Bird Territory (acres) First nest Renest Aspen M 15 1.0 M 28 1.5 1.1 M 26 1.9 M 27 2.1 Conifer-birch M 24 2.1 M 20 2.2 M 23 2.2 Mixed M 5^ 0.8 M 5 2.7 3.6 M 9 1.6 M 31 2.2 M 4 1.7 M 3 2.4 M 7 2.0 M T 1.8 M 10 2.1 M 32 1.5- 3.4 M 2 2.8 Maple M 12 3.9 M 30 2.5 M 13 4.3 M 29 4.0 1 Unmated. 2 Based on observations on only two days. Changes in Utilized Territory as the Breeding Season Advances A distinction can he made between the total utilized territory for the breeding season and the area utilized on one day. Changes in the area utilized daily may be observed as the breeding season advances. The observation-area curve as a means of estimating utilized area. — Odum and Kuenzler (1955) used the observation-area curve as a standard method of measuring size of territory for comparative purposes. After each 10 con- secutive observations were mapped, they plotted the area outlined by all the observation points against the total number of observations. At first, the area increased as more observations were included, hut later the curve leveled off. Odum and Kuenzler selected as a standard, for comparison of different territories, the area obtained when there was less than one per cent increase in area for each additional observation. This method has been modified and extended for the treatment of Ovenbird 134 THE WILSON BULLETIN June 1959 Vol. 71, No. 2 data. Instead of mapping the location of a bird every five minutes, as Odum and Kuenzler did, all different locations where a bird was observed were recorded. This resulted in approximately 12 to 15 locations per hour. Points were plotted on the observation-area curve after each five consecutive observations. In the present study there were a number of days when the birds were inactive. On such days, the number of locations visited by a bird were too few to reach the level portion (or the level of one per cent change) of the observation-area curve. Since the area utilized can change substantially from one day to the next in the case of the Ovenbird, there seemed to be no justification for combining observations made on different days and in different weeks. In order to reach the one per cent level on the observation- area curve, 60 or more locations were usually required and this number was obtained only two or three times for each bird during the breeding season. It was relatively easy, however, to obtain 30 to 40 locations on any one day. As few as 20 locations were sufficient to estimate the slope of the initial portion of the observation-area curve. This slope was estimated by calculating a line of best fit to the points on the initial portion of the curve. The slope of the initial part of the observation-area curve is proportional to the area reached at the level portion of the curve. This is shown in Lig. 4, in which slopes of the initial portions of the curves are plotted against the final areas for all those occasions when the level portion of the curve was attained (at least the last three points at the same level). Points on the level portion of a curve were excluded in calculating the slope. The relationship shown in Lig. 4 means that the rate of increase in area per observation is greater when the area is larger, and suggests that successive locations at which an Ovenbird is observed may be farther apart when the bird visits a larger area. This was tested by measuring the distances between consecutive observation points and comparing the mean distance obtained with the area reached at the level portion of the observation-area curve. Lig. 5 shows that distances between points were greater when the area utilized was larger. Thus, there is a reasonable basis for relating the slope of the initial portion of the observation-area curve to the final area reached by the curve. This relationship was used to estimate the areas utilized by Ovenbirds on days when only enough data were obtained to calculate the slope of the initial portion of the curve. A line of best fit was calculated for the data in Lig. 4. Given a slope value, a corresponding area can he read from this graph or calculated from the equation of the line, Y = .005 + .0199X. Estimates of utilized area obtained in this way should not be regarded as very accurate in view of the rather wide scatter in Lig. 4. Since the error is likely to he greater if the area is large, no definite values were assigned to Slenger and Falls OVENBIRD TERRITORY 135 AREA IN ACRES Fig. 4. Relation between slope of the initial portion of the observation-area curve and the final area reached by the curve. The line of best fit to these data is shown. Fig. 5. Average distance lietween successive locations at wliich a bird was observed in relation to area utilized. Area utilized is taken to he the area reached at the level portion of the oliservation-area curve. 136 THE WILSON BULLETIN June 1959 Vol. 71, No. 2 estimated areas in excess of four acres. This method made it possible to use data which would otherwise have been rejected as incomplete. Changes in the area utilized by the male during the reproductive cycle. — The duration of the different stages of the breeding cycle were determined for a few Ovenbirds whose nests were found. Where nests were not found young birds were easily discovered after they had left the nest and could be aged approximately. Data on the breeding cycle obtained in this way agreed with the more extensive information given by Hann (1937) ; therefore his time intervals were used to fix approximate dates of the different stages of the breeding cycle for birds where only the young were found. The following is a brief summary of the Ovenbird’s breeding cycle: Prenialing Mating Nest-building Egg-laying Incubation Nestling Young leave nest — period from arrival of male to arrival of female; about 13 days in 1955, and about 18 days in 1956. — a period of variable length from arrival of female until nest- building begins. — 5 days for first nest, 4 days for renesting. — 3 to 5 days, depending on number laid. — 12 days, beginning with second-last egg. — 7 to 9 days. — young leave nest in about 9 days, fly in about 11 days, and are independent about 30 days after hatching. Losing the method outlined in the previous section, the area utilized by each bird in each observation period was estimated and the values obtained were assigned to the appropriate stages of the breeding cycle. These values, expressed as fractions of the total utilized territory, are shown in Lig. 6 for the 11 birds for which the necessary data were available. Since no one bird was studied during every stage of the breeding cycle, all the values obtained in each period were averaged and are shown in the final histogram. In interpreting these histograms, it must be borne in mind that measurements were not made at precisely the same stages for all the birds, even within the main ])eriods of the breeding cycle. Two major peaks in the size of the area utilized occurred during the breeding cycle (Lig. 6), one during the premating and mating periods, and the other during the incubation and nestling periods. During these two jjeak periods the average area utilized by the male in one day was almost as large as the total utilized territory. During the period between these peaks ( nest-huilding and eggdaying I the average area was about half the size of the total utilized territory. These marked variations in area utilized can be explained in terms of the male’s activities. In the premating period, when the area utilized is large, the male establishes his territory. He sings often and encounters with other males are frequent. Six of eight males for which data are available showed an increase in area Slenger and Falls OVENBIRD TERRITORY 137 1st NEST 2nd NEST PPMB B I I N 1st NEST 2nd NEST 1st NEST 2nd NEST AVERAGE DETERMINATIONS Fig. 6. Area utilized in different periods of the reproductive cycle expressed as a fraction of the total utilized territory (T) for each bird. Average values for all birds for each period of the reproductive cycle are given in the final histogram. Periods of reproductive cycle: premating (P), mating (Ml, nest-building (B), egg-laying (E), incidiation (I), nestling (N), and after young bave left nest (L). 138 THE WILSON BULLETIN June 1959 Vol. 71, No. 2 utilized during this period. One bird ( M 23 ) that had an extended premating period showed a decrease in the area utilized following the initial increase. Three males were studied in the period between the arrival of the females and the beginning of nest-building. In this mating period the area utilized by the male was large. Lrom the time the female began building the nest until she started to incubate, the area utilized by the male was small (less than in earlier periods in 6 out of 8 cases ) . In this period the male sings infrequently and is often seen with the female although he does not help build the nest. Copulation takes place mainly in this period (Hann, 1937). During the incubation period, the area utilized once again increased in 10 out of 12 cases. The male does not take part in incubation and is seldom seen with the female at this time. He sings about as often as during the premating period. Most males (8 out of 12) showed a small decrease in area utilized toward the end of this period. During the nestling period the male helps feed the young. He sings infre- quently and is secretive, and is therefore difficult to observe. Adequate data were obtained for only four birds, all of which utilized areas about as large as, or larger than during the incubation period. When the young leave the nest the brood is divided between male and female. In this period some males (5 out of 10) utilized larger areas than previously, whereas others used smaller areas. If there are several young they tend to disperse rather than to stay together. It may be that males tending more than one young utilized a larger area during this period than those tending a single young bird. Thus, the size of the area a male Ovenbird utilizes varies during the breeding season. It is large when he is occupied with territorial defense, advertising song, and food gathering for the young, and small when he spends his time Avith the female and copulation is frequent. While the areas utilized by males change markedly, no conclusions concerning the area utilized by females, or changes in size of defended territories can be drawn from the data presented in this paper. Apparently the Ovenbird is somewhat different from certain other species in regard to changes in size of the territory occupied as the breeding season progresses. Toung (19.31) thought that territories of the Robin (Tiirdus rnigratorius) shrank progressively as the breeding season advanced, while Odum and Kuenzler (19.3.5) found that for a number of species territories were smaller during the nestling stage than during nest-huilding and incubation. Acknowledgments This paper is based on pari of an M. A. thesis presented at the University of Toronto hy the senior author. The project Avas supported hy a grant to J. Bruce Falls from the Stenger and Falls OVENBIRD TERRITORY 139 National Research Council of Canada. Judith Stenger held the Ramsay Wright Scholarship of the University of Toronto. It is a pleasure to acknowledge the co-operation and helpful- ness of Dr. C. D. Fowle and Mr. R. O. Standfield, of the Ontario Department of Lands and Forests, who made facilities available at the Wildlife Research Station in Algonquin Park. We should like to thank Mr. J. C. McLeod for assistance with the field work. The encouragement and helpful advice of Dr. G. F. Bennett are gratefully acknowledged. Dr. J. R. Bray read the section on forest composition and made helpful suggestions con- cerning the presentation of data. Summary Territories of Ovenbirds were studied in four forest types in Algonquin Park, Ontario. Locations where a male was observed were used to estimate its total utilized territory for the breeding season. Birds were observed singing or feeding in all parts of their territories, although some birds did not utilize open areas. Total utilized territories of adjacent males were usually separated by a buffer zone but occasionally overlapped. However, areas used by adjacent males on any one day were always separated. Total utilized territories varied from 0.8 to 4.3 acres, being small in an aspen stand, intermediate in size in conifer— birch and mixed stands, and large in a maple stand. Thus, the size of the territory increased wdth increasing height and density of forest canopy, and with decreasing vegetation near the ground. Unmated birds had small territories. The vertical extent of each bird’s activity was related to the height of the forest canopy where the bird sang, hut not in any regular way to the area of its territory. A method was developed to compare the areas utilized by male Ovenbirds on different days during the breeding season. The area utilized was large during the premating and mating periods, smaller during nest-huilding and egg-laying, and large again during the incubation and nestling periods. Thus, the area utilized by a male Ovenbird is large when he is occupied with territorial defense, song, and feeding the young, and small when he is often with the female and copulation is frequent. Literature Cited Brow n, R. T., and J. T. Curtis 1952 The upland conifer-hardwood forests of northern Wisconsin. Ecol. Monogr., 22:217-234. Halliday, W. E. D. 1937 A forest classification for Canada. Canada, Dept, of Northern Affairs and Nat. Resources, Forest Research Div., Bull. 89:1-50. Hann, H. W. 1937 Life history of the Oven-bird in southern Michigan. Wilson Bull., 49:145-237. Nice, M. M. 1941 The role of territory in bird life. Anier. Midi. Nat., 26:441-487. 140 THE WILSON BULLETIN June 1959 Vol. 71, No. 2 Odum, E. P. and E. J. Kuenzler 1955 Measurement of territory and home range size in birds. Auk, 72:128-138. Stenger, J. 1958 Food habits and available food of Ovenbirds in relation to territory size. Auk, 75:335-346. Toumey, j. W., and C. F. Korstian 1947 Foundations of silviculture upon an ecological basis (2nd ed., rev.). John Wiley and Sons, New York. 468pp. Williamson, F. S. L. 1956 The molt and the testis cycle of the Anna Hummingbird. Condor, 58:338-367. Young, H. 1951 Territorial behaviour in the Eastern Robin. Proc. Linn. Soc. N.Y., 5:1-37. DEPARTMENT OF ZOOLOGY, UNIVERSITY OF BRITISH COLUMBIA, VANCOUVER, B.C.; AND DEPARTMENT OF ZOOLOGY, UNIVERSITY OF TORONTO, TORONTO, ONTARIO, CANADA, APRIL 23, 1958 THE SONGS OF THE GRASSHOPPER SPARROW. BY ROBERT LEO SMITH IN the spring of 1944 I began a four-year, life-history study of the Grass- hopper Sparrow {Ammodrarnus savannarum) near Reynoldsville, Jefferson County, Pennsylvania. This paper deals with the songs; a second paper will cover the ecology and life history of the species. The male Grasshopper Sparrow possesses three primary forms of vocaliza- tions that I have designated the Grasshopper Song, the Sustained Song, and the Trill; and the female one, the Trill. Others (Eaton, 1914:292; Saunders, 1951: 254; Todd, 1940:630; Walkinshaw, 1940:56) have observed that the male sang at least two different songs, but apparently they attached little significance to this. After one summer of observations I was aware that each song more or less served a definite purpose and was characteristic of a particular period in the breeding cycle. Attention was given to this problem during the following seasons with emphasis on ( 1 ) the relationship of the songs to territorial estab- lishment, mating and nesting; (2) the behavior of the birds while singing; and (3) the responses elicited in rival males and females. During 1946 and 1947 a daily account was kept of the singing of 12 differ- ent males for a total of 14 individual records. Weather conditions, the differ- ent songs given during the day by each male, and song in relation to the time of day were recorded. In late summer when song diminished, observations be- gan before dawn and concluded at dark in order to include any occurrence of song during this period. Description of the Songs Grasshopper Song. — The most familiar of all the songs of the Grasshopper Sparrow is the one from which the bird derives its name, the Grasshopper Song. It is one to three seconds in duration and possesses an insect-like quality which has been likened to the stridulations of the long-horned grasshopper (Conoceph- alus ) . The song has two variations, common to all individuals, and are repre- sented as follows: Tup zeeeeeeeeeeeee Tip tup a zeeeeeeeeeee To the ear the Grasshopper Song is remarkably consistent. There does not appear to be the wide individual variations in song found in many fringillids. Extensive spectrographic studies probably would prove otherwise. I have met, however, with two outstanding exceptions. In the first instance the individual consistently sang a song that was remarkably similar to that of a cicada {Tibicen sp. ) . In the second instance the bird gave a weak, husky trill with great effort. 141 142 THE WILSON BULLETIN June 1959 Vol. 71, No. 2 I have been able to detect a reedy quality in the songs of other individuals, but this never proved to be a reliable means of distinguishing the individual from neighboring Grasshopper Sparrows. The males sing the Grasshopper Song from a grass stalk, low bush, fence post, 10 to 30 feet up in a tree, or from electric power lines. During the height of territorial establishment this song may be sung up to 220 times an hour. The Sustained Song. — The second vocalization of the Grasshopper Sparrow is more elaborate and more musical than the Grasshopper Song and is subject to more individual variation. The Sustained Song, which may vary from five to 15 seconds in length may be represented as follows; Tip tup a zee e e e e e e zeedle zeee zeedle zeedle zeeeee At times the “grasshopper” introduction is omitted and the song then consists of the last phrase only. The Sustained Song is not confined to perch singing alone. The male often sings it in flight, either alone or while pursuing the female. The male rises out of the grass on quivering wings, delivers this song in a low, fluttering flight and then drops down into the grass again. Even though this song can be heard frequently during the mating and nesting season and during summer evenings, it is surprising how much confusion has developed regarding it. Saunders (1951:254) considered what obviously is the Sustained Song as a post-season elaboration of the typical Grasshopper Song. Todd (1940:630) stated that it probably was a mating song. Eaton (1914:292) stated that Gerald Thayer considered this the true song of the spec- ies. Jouy (1881:58), apparently on mistaken identification, attributed this song to Henslow’s Sparrow [ Passer herhulus henslowii) . He wrote: “Besides their characteristic note of te-wick, they have quite a song which may be fairly represented by the syllables sis-r-r-rit-srit-srit, with the accent on the first and last parts. This song is often uttered while the bird takes a short flight upward; it then drops down again in the tangled weeds and grasses where it is almost impossible to follow it.” This is an adequate description of the Sustained Song of the Grasshopper Sparrow which is often given in flight. Eortunately both the Grasshopper and Henslow’s sparrows nested in the study area. Not once in five years of observa- tions of both species have I heard a Henslow’s Sparrow sing a song that even remotely resembled the Sustained Song of the Grasshopper Sparrow. A similar view was given by Sutton (1928:179-182) . The Trill. — Tbe male possesses still another vocal jjerformance, the Trill, which seems to be confined to mated birds. It is the least common of the vocali- zations and, unless one is frequently afield, it is apt to be missed entirely. Robert Leo Smith GRASSHOPPER SPARROW SONGS 143 Saunders (1951:254) gives a graphic description.: of the Trill, although he does not seem to recognize it as a distinct type of vocalization. Walkinshaw (1940: 59 ) described it as a nesting song. It consists of a series of moderately loud notes on two tones, rapidly given: Ti tu Oi tu Ti i i i i i i i It may be delivered either from a perch or in the grass. The Trill of the Female. — The female Grasshopper Sparrow possesses a vo- calization quite similar to the Trill of the male but it it weaker, suggestive of the Chipping Sparrow’s {Spizella passerina) song and lacks the downward trill: Ti ti i i i i i i i i i It is difficult to observe tbe female singing because, except in courtship flights, she delivers this song while concealed in the grass. On May 21, 1945, I had an excellent opportunity to observe the female uttering the Trill. She appeared in a small bare area in some rather sparse grass near the boundary of a hay and wheat field. Flirting her tail and hopping slowly about in a circle she delivered the Trill. Then she flew into the wheat where she sang it again. The female may sing this trill in answer to the Sustained Song or the Trill of the male, or she may give it without the stimulus of the song of the male. Periods of Song Singing falls into seasonal and daily patterns (Fig. 1). The seasonal distri- bution of song is influenced by the reproductive cycle of the bird; the daily pattern is influenced by the seasonal pattern and by daily weather conditions. Grasshopper Sparrows are in song when they return to their breeding areas in mid-April. The average date over a 5-year period for their arrival on the study area was April 16. The earliest arrival was March 31, 1945, the earliest ever recorded for western Pennsylvania, and the latest arrival was April 21, 1946. The entire population on the study area did not arrive at once, hut built up over a period of a week. During the first days following their arrival the males sang only the Grasshopper Song and confined their singing to the morn- ing hours. As the population increased during the succeeding days, the males sang the Grasshopper Song more and more frequently, until they were heard throughout the day. Within 10 to 14 days after their arrival, the males introduced the Sustained Song. At first each male may sing this song no more than two or three times a day, but within a week he almost replaces the Grasshopper with the Sustained Song for a few days. In general, however, it is given interchangeably with the 144 THE WILSON BULLETIN June 1959 Vol. 71, No. 2 1946: JUNE 10 20 30 JULY 10 20 AUGUST 30 10 20 6M lOM BIRD DISAPPEARED 12M 13M 14M ?)!«’= GRASSHOPPER SONG Inhibited 5-30 songs per day Uninhibited 30-150 songs per day SUSTAINED SONG, Inhibited HjSK Uninhibited Fig. 1. Frequency of song among Grasshopper Sparrows during summer, 1946. Grasshopper Song and is rarely sung for any length of time without interrup- tion by the Grasshopper Song. After pairing all song appears to he inhibited for a few days, but the birds I observed never ceased singing entirely. During the period of egg-laying and incubation, tbe male sings both songs frequently, especially in the early morn- ing and evening, continuing until darkness. Occasionally a bird may sing sporadically throughout moonlight nights. During June, when most Grasshopper Sparrows are feeding young, song wanes. The Sustained Song is heard less frequently during the day and more or less assumes the status of a twilight song. The Grasshopper Song is again the common daytime song; but prior to renesting the Sustained Song becomes conspicuous for several days, then wanes again. By mid-July the Sustained Song has all but disappeared and is sung only occasionally from then until the cessation of song in mid-August. The Grasshopper Song, however, is retained Robert Leo Smith GRASSHOPPER SPARROW SONGS 145 and is sung with diminished vigor and frequency as the summer wears on ( Fig. 1 ) . After pair formation in late April the male introduces the Trill. He gives this infrequently and only on specific occasions. After nesting is completed and the young are on the wing, the male drops the song. The Trill of the female is heard from the time of pair formation to the cessa- tion of nesting. The Grasshopper Sparrow does not have an extended morning awakening song. Upon awakening the bird may remain silent and start to feed, it may utter the chi-ip call note or it may sing the Sustained or Grasshopper Songs. Once the bird commences singing, it interrupts the song sequence frequently with feeding. By mid- July the daily pattern gradually assumes a different character. The Sustained Song is dropped except for a few occasional days when it may be given several times in the very early morning or at evening twilight. Morning song has nearly ceased and daytime song is rarely heard. The cooler tempera- tures of evening and the suspension of feeding activity bring in the twilight song which lasts until darkness comes. At this period the Sustained Song, with its greater carrying power, seems to be the most conspicuous and for this reason has been erroneously described as a post-season elaboration of the regular song of the species. Song may be inhibited by adverse weather conditions. For example, in 1945 spring came exceptionally early. In late March temperatures were in the high 70’s and low 80’s, leaves were opening and the grass was three inches high. As might be expected, the Grasshopper Sparrows returned very early, on March 31. Song increased in volume up to May 1, when cold, wet weather set in. Song nearly ceased. On May 9 the weather cleared, and although the temperature was 30°F., all Grasshopper Sparrows broke into song. Hot, humid weather also has an inhibiting effect on song, but not to the extent of cold, wet weather. Functions of Song The objective study of the function of bird song has suffered from the lack of a suitable definition of bird song. Howard (1920 ) in his pioneer work on territorialism in birds emphasized the advertising function of song. Tinbergen (1939:73) regarded bird song as an utterance “that serves to attract a sex partner, to warn off a bird of the same sex or both.” Nice (1943:144—149) and Fack (1943:28—33) also considered song from this viewpoint. More recently, Moynihan and Hall (1954:50) suggested that the term “song” be confined to those vocalizations with the dual functions of warning rivals and attracting mates. On the other hand, Armstrong (1947:294 ) stated that from a functional point of view no distinction can be drawn between songs and calls. 146 THE WILSON BULLETIN June 1959 Vol. 71, No. 2 Lor the purposes of this paper, and of attempting more clearly to distinguish song from other vocalizations of a bird, song is regarded as a vocal utterance, long or short, simple or complex and species specific, which is given by either sex or both and which functions primarily to repel rivals of the same species, to attract a mate, or both. This definition is exclusive to the point that it eliminates any vocalizations, however complex, which do not serve primarily to attract or repel. At the same time it does not assume that song is exclusively the function of the male. It thus includes the rarer instances of song in female birds. The words “func- tions primarily” do not eliminate the post or pre-breeding season songs of many birds. Other musical utterances not serving to attract or repel should be considered sub-songs and all other vocalizations as calls. The Grasshopper Song. — Its peak occurrence early in the season and its con- sistent appearance in daytime and evening singing up to the complete cessation of song suggest that the Grasshopper Song is territorial in function. The behavior of the bird itself, however, is even stronger evidence that the song is hostile. During territorial establishment the male alternates song with display. In a crouched position with his head lowered between his shoulders ( Lig. 2, A ) , the male raises and flutters one or both wings (Lig. 2, B) . The pri- maries and secondaries are not extended, but the wing is fluttered quickly above the back at the humerus. Then, after hearing the song of his neighbor, the bird stands erect and sings back (Lig. 2, C ) . The song completed, the male again as- sumes the crouched position and flutters his wings. The sequence is as follows: (1) The male stands erect and sings the Grasshopper Song. (2) Song completed, he assumes the crouched position. (3) He flutters one wing or both simultan- eously. (4) He hears rival’s song, and rises to a singing position. (.5) He sings Grasshopper Song. The wing-fluttering of the Grasshopper Sparrow is never accompanied by a song or a call, but is confined to that interval between songs, and is conspicu- ous only during the period of territorial establishment. It seems unusual that this behavior has not been reported by other writers. The only comment on wing-fluttering by the Grasshopper Sparrow that I have found was made by William Brewster (1874) in his unpublished Nantucket journal for July 3, 1874: “. . . I have a new one, namely that the bird frequently quivers its wings like a Bluebird.” Wing-fluttering is closely associated with territorial establishment. Some manner of wing-fluttering occurs in the mating and territorial behavior of a numl)er of passerine species, for example, the Snow Bunting, Plectrophenax nivalis (Tinbergen, 1939:17); the Song Sparrow, Melospiza melodia (Nice, 1943:1.54); the House Wren, Troglodytes aedon (Kendeigh, 1941:21); the European Wren, Troglodytes troglodytes (Armstrong, 19.54:47, 114—117) ; the European Goldfinch, Carduelis carduelis ( Hinde, 1955:720) ; the Canary, Robert Leo Smith GRASSHOPPER SPARROW SONGS 147 Serinus sp, (Hinde, 1955:713—715) ; and the Greenfinch, Chloris chloris ( Hinde, 1955:719). The stimuli for these displays differ from those of the Grasshopper Sparrow. One male has actually invaded or is threatening to in- vade the territory of another; the birds see one another; or often they are face to face. The Grasshopper Sparrows in most instances do not see one another. The males may be hidden from one another by the vegetation or the topography of the field. They do not erect the body feathers. The attitude, however, of the male between songs, the crouched posture with the bill pointed forward, the flutter- ing of the wings, the apparent readiness of the bird to move forward to meet a threat, all strongly indicate that this is a hostile display. During the period of territorial establishment the song of a rival is a sufficient stimulus to release this display. The bird senses the presence of a rival by the sound of his song and manifests this by a hostile display, as if the rival were nearby in the grass. Marler (1956:497) has observed a similar reaction in the Chaffinch (Fringilla coelebs) . The song of the Chaffinch played through a loud speaker induced fierce aggressive display in males. Fig. 2. Attitudes of male during the Grasshopper Song sequence. (A) crouched position. (B) Wing-fluttering. (C) Delivering song. Unfortunately I have never observed among Grasshopper Sparrows a terri- torial dispute that elicited a high intensity intimidation display. If any occurred it happened out of sight in the grass. The only physical encounters I have ob- served during hundreds of hours spent with the species were those after a bird saw another invade its aerial territory. In each instance the bird chased the intruder, then retired to a singing perch, fluttered his wings and sang the 148 THE WILSON BULLETIN June 1959 Vol. 71, No. 2 Grasshopper Song. I have witnessed a number of aerial clashes at disputed ter- ritorial boundaries. In fact, this mode of defense could be the most important, because the deep grass would generally conceal territorial infringement on the ground. Perhaps the Grasshopper Sparrow recognizes the limits of its territory only from a grasstop point of view. The Grasshopper Song, then, serves primarily as an advertising or territorial song. The distribution and occurrence of this song during the season, its tim- ing, and the response it elicits from neighboring males emphasizes this function. It is the first song given by the male in the spring and is delivered from the high- est perch in the territory. It is sung when one male is chasing another from his territory, and is delivered by both when the two retire to their singing posts. At times the Grasshopper Sparrow will deliver the Grasshopper Song while protesting other animal or human intrusion. On occasions male Grasshopper Sparrows protested my presence in their territories. As soon as I left they would return to their singing perches and deliver the Grasshopper Song. The Sustained Song. — The Sustained Song attracts a mate. Its occurrence in the seasonal song cycle, its loudness, and the response it elicits from the fe- male indicate this function. Upon hearing the Sustained Song, the female will answer the male with a Trill (Lig. 3). In turn, the male will respond to the female’s vocalization by answering her with the Sustained Song again, or by flying to her. The function of the Sustained Song cannot be limited to attracting a mate. If that were its sole purpose it should cease upon the arrival of a female, as in the case of the Snow Bunting (Tinbergen, 1939:77 ) . The song, however, is de- livered through the periods of nesting and caring for the young. Lurthermore, it is given with increased frequency just prior to the second nesting. Apparently this song is quite important in maintaining the pair bond throughout the season. The complete Sustained Song with the “grasshopper” introduction is hostile to other males. The first phrase of the song is identical to the Grasshopper Song. This is necessary in the early period of courtship because the territories have been newly settled by the males and the warning function still is of prime importance. The second phrase of the song, however, serves to attract and hold a mate. Later in the season, when territories are well established and the warn- ing is not so imperative, the majority of Sustained Songs lack the “grasshopper” introduction. When one male hears another singing the Sustained Song, he responds not with the Sustained Song hut with the Grasshopper Song. Then both birds launch into a song duel of Grasshopper Songs. The Trill. — The Trill generally is not given by the male until the pair is formed and even then it is usually uttered only in the vicinity of the nest, and only from a perch or in the grass. It may follow one of the other two songs or it may he given alone, often in answer to the female (Lig. 3). It is also given by the male when he is in close proximity to the nest. Robert Leo Smith GRASSHOPPER SPARROW SONGS 149 No Response $ GRASSHOPPER SONG S SUSTAINED SONG The Trill apparently serves as a bond to hold the pair together, and as a sig- nal to both the female and the young that the male is approaching the nest. The fact that the Trill usually is given only by the mated male seems further to sup- port this function. Only once did I hear the Trill given by an unmated male, several of which I have followed through a season. The Trill of the Female. — The Trill is a distinctive vocalization of the female which may or may not be given under tbe stimulus of tbe song of tbe male. Tbe fact that the female Grasshopper Sparrow vocalizes should not be regarded as unusual, but the problem is whether or not this vocalization can be regarded as true song. The manner and circumstances under which the Trill of the female is sung, and its function, indicate that it can be. Just as the male Grasshopper Sparrow can detect the presence of a rival in his territory by the rival’s song, so can he 150 THE WILSON BULLETIN June 1959 Vol. 71, No. 2 detect the presence of a female by some distinctive signal. Herein lies the sig- nificance and the biological importance of the female’s song. When the male sings the Sustained Song, he proclaims his availability to a female. A female bird present on his territory answers with a vocal performance which is loud, species specific, and which advertises her presence to the male. In fact she sings this Trill independent of any song from the male. Hearing the female, the male flies to her. The importance of the female’s song as an attracting mechanism is apparent. The male does not have to see by chance a strange bird in his territory and then challenge it to determine its sex. Because of the nature of the habitat this might be difficult and time consuming. Instead, the song of the female assures that the male will be led to a potential mate, that this potential mate is of the male’s own species and that the male will have the opportunity to find a mate at the proper time in the breeding cycle. The female also gives the Trill when she is approaching, or is in the vicinity of the nest. The primary function of the Trill of the female Grasshopper Sparrow is to declare her presence to the male, to announce her location, to maintain the pair bond, and to signal both the male and the young that she is approaching the nest. Acknowledgments For comments and suggestions I am indebted to Merrill Wood, Charles G. Sibley, Ralph Palmer and the late Josselyn van Tyne. I wish to thank the librarians at the Museum of Comparative Zoology, Harvard University, for their assistance in securing all the notes on the Grasshopper Sparrow from the unpublished journals of William Brewster, and for per- mitting me to examine them. Summary The male Grasshopper Sparrow possesses three primary forms of vocaliza- tions, the Grasshopper and Sustained Songs and the Trill, and the female Grass- hopper Sparrow one, the Trill. The male sings the Grasshopper Song from mid-April to mid-August. The Sustained Song is introduced approximately at the time the females arrive. It is sung w ith diminished vigor until mid-July and only sporadically from then on until the cessation of song in mid-August. The Trill is given from the pe- riod of pair formation to the completion of nesting, as is the Trill of the female. Early in the season song is heard throughout the day. After mating, song is inhibited hut does not cease entirely. During the periods of nest-huilding, incu- bation and care of the young, song is confined primarily to morning and late evening. Song is inhibited by adverse w'eather. J'he Grasshopper Song is the familiar song of the species. It is used pri- marily to inoclaim and defend territory. During the period of territorial estab- lishment the male assumes a crouched, bill-forw^ard position and flutters his Robert Leo Smith GRASSHOPPER SPARROW SONGS 151 wing or wings between songs. This is regarded as a hostile display released hy the song of the rival. The Sustained Song in its entirety consists of a “grasshopper” introduction and a sustained series of melodious notes. After the territories are well estab- lished, the “grasshopper” introduction is usually dropped. The jDrimary func- tion of the Sustained Song is to attract a mate, but the “grasshopper” introduc- tion is hostile in character. A secondary function of the song is to maintain the pair bond. The Trill serves to maintain the pair bond and to signal the mate and the young of the male’s approach to the nest. It apparently is given only by mated males. The Trill of the female advertises the presence of a potential mate in the male’s territory and identifies her species and sex. The Trill also serves to main- tain the pair bond and to signal the male and the young that she is approaching the nest. The male Grasshopper Sparrow responds to the Grasshopper and Sustained Songs with a Grasshopper Song, to the female’s Trill with a Sustained Song or a Trill. There is no response by the male to the Trill of another male. The fe- male responds to the Sustained Song and the Trill of the male with her Trill, hut shows no apparent response to the Grasshopper Song. Literature Cited Armstrong, E. A. 1947 Bird display and behaviour. Oxford Univ. Press, New York. 1954 The wren. Macmillan Co., New York. Brewster, W. 1874 Unpublished journal. Library of Museum of Comparative Zoology, Harvard Univ., Cambridge. Eaton, E. H. 1914 Birds of New York, Vol. 2. Univ. of State of New Y^ork, Albany. Hinde, R. a. 1955 A comparative study of the courtship of certain finches (Fringillidae) . Ibis, 97:706-745; 98:1-23. Howard, H. E. 1920 Territory and bird life. Murray, London. JOUY, P. L. 1881 Description of the nest and eggs of Colurniciiliis heiisloivi obtained near Falls Church, Va. Bull. Nutlall Ornith. Club, 6:57-58. Kendeigh, S. C. 1941 Territorial and mating behavior of the House Wren. III. Biol. Mono., 18(3). Lack, U. 1943 The life of the Robin. H. F. & G. Witherby, London. Mauler, P. 1956 Territory and individual distance in the Chaffinch Fringilla coelebs. Ibis, 98: 496-501. 152 THE WILSON BULLETIN June 1959 Vol. 71, No. 2 Moynihan, M. and M. F. Hall 1954 Hostile, sexual and other social behavior patterns of the Spice Finch {Lonchtira punctidata) in captivity. Behaviour, 7 :S3-76. Nice, M. M. 1943 Studies in the life history of the Song Sparrow II. Trans. Linn. Soc. N. Y., 4: 1-247. Saunders, A. A. 1951 A guide to bird songs. Rev. ed. Douhleday, Garden City. Sutton, G. M. 1928 The birds of Pymatuning Swamp and Conneaut Lake, Crawford County, Pennsyl- vania. Ann. Carnegie Mus., 18:19-239. Tinbergen, N. 1939 The behavior of the Snow Bunting in spring. Trans. Linn. Soc. N. Y. Todd, W. E. C. 1940 Birds of western Pennsylvania. Univ. Pittsburgh Press, Pittsburgh. Walkinshaw, L. H. 1940 Some Michigan notes on the Grasshopper Sparrow. Jack-Pine Warbler, 18: 50-59. DIVISION OF FORESTRY, WEST VIRGINIA UNIVERSITY, MORGANTOWN, WEST VIR- GINIA, MARCH 21, 19.58 FOOT-STIRRING FEEDING BEHAVIOR IN HERONS BY ANDREW J. MEYERRIECKS A PECULIAR type of feeding behavior, described by various authors as “stirring,” “scraping,” “raking,” and so on, has been recorded for several species of herons and other birds (see, for example, Rand, 1956). Briefly, the feeding heron extends one leg and vibrates or quivers it, especially the foot, then stabs at any prey that darts from the disturbance. The purpose of this paper is to describe my observations of this behavior in three North American heron species, and to give several examples of apparent “footedness” (i.e., preference for one foot while foot-stirring) in these same species. My observations concern the Snowy Egret {Leucophoyx thula) , Reddish Egret { Dichromanassa rufescens) , and the Louisiana Heron {Hydranassa tricolor). All three species were observed in Elorida Bay and around the Laguna de la Joyas, near Puerto Arista, Chiapas, Mexico. Additional observations of the Snowy Egret were made on Rulers Bar Hassock, Jamaica Bay, western Long Island, New York, and near Tehuantepec, Oaxaca, Mexico. Use of the Eeet Snoivy Egret. — In Elorida Bay, the clearness of the water and the relative tameness of this species offered exceptional opportunities to see the feet during this behavior. The whole body, particularly the extended leg, vibrates, and these movements seem to impart a stirring motion to the foot. Usually the bird stirs the substrate, but on several occasions I could clearly see individual birds stir the foot above the surface of the mud, not in it. The bright yellow toes of thula are sharply set off from the black legs, and when one of these egrets stirs above the substrate, I get the impression that it is using its foot as a lure. Stirring is probably the best description of the motion of the foot, but at times N. B. Moore’s term “raking” is more appropriate ( Baird et al., 1884). When raking. Snowy Egrets extend one leg, then rake the substrate by short, rapid movements of the toes. 1 saw that this species usually rakes mud, hut it tends to stir aquatic vegetation. Eor example, while using this feeding method on the shallow reefs near Cowpens Cut in Elorida Bay, several Snowy Egrets concentrated on stirring tufts of turtle grass (Thalassia) . When a fish darted from one tuft to another, the egret peered at the tuft, stirred it until the fish moved again, then repeated this procedure until it made a successful strike or moved to a new location. Stirring tufts of turtle grass by thula resem- bles the weed-stirring of the Reef Heron { Demigretta schistncea) seen by Hart- ley (Gibb and Hartley, 1957). However, when feeding in the shallow muds of Dove Creek slough on Key Largo, Florida, Snowy Egrets tended to rake more than stir. Perhaps different 153 154 THE WILSON BULLETIN June 1950 Vol. 71, No. 2 kinds of prey are taken by stirring and raking; however, fish is the only food I have seen Snowy Egrets secure by either method. The usual movements made by a Snowy Egret foot-stirring are “stir-peer- stab” or “stir-stab.” However, one bird stirred continuously for about one minute, then it twirled about with open wings as it chased several fish forced to move by the egret’s activities. Another individual raked the mud of Dove Creek slough until an area of about 100 square feet had been roiled, then the bird ran through the muddied water with open wings, stabbing to the right and left at the harried fish. The Snowy Egret also shows an interesting aerial variant of this feeding method that I call “hovering-stirring.” Sprunt (1936) saw a Snowy Egret hover and pat the surface of the water, while Bond (1934) and Grimes (1936) both observed thula feed on the wing. N. B. Moore (Baird et at., op. cit.) saw a flock of Snowy Egrets feed by hovering over a shoal of minnows, but apparently none of these authors saw the egrets stir the water while feeding. My observations of hovering-stirring were made in Florida Bay, and typically the feeding egret hovered over one spot, dangled one or both legs, then stirred a tuft of grass or some debris until the prey was forced to move. The strike was always made from the hovering position. “Foot paddling,” in which the legs and feet are moved rapidly up and down on the substrate, has been recorded for Leucophoyx thula and Egretta garzetta in the Amsterdam Zoo by Portielje (1928). This behavior is very similar to the paddling of many gulls and waders (see discussion in Tinbergen, 1953 I . I have seen paddling in thula on one occasion (Rulers Bar Hassock, May 15, 1954 ) . A single Snowy Egret was stirring in the manner described, when suddenly it stopped, paddled vigorously for about 20 seconds, then resumed stirring. The paddling movements M'ere clearly distinct from those used in stirring. Reddish Egret. — The foot-stirring of this species differs from that of the Snowy Egret in the following ways: 1) rufescens does not extend its leg forward and vibrate it, but simply vibrates its feet as it wades forward in a normal manner; 2) the foot is not moved in a stirring motion but rather it is scraped or raked over the surface of the mud; and 3) rufescens scrapes both mud and aquatic vegetation, even when hovering (see below). N. B. Moore (Baird et al., op. cit.), commenting on the scraping behavior of rufescens, states that “It is a mode peculiar to this species, and not to he mis- taken for that of any other.” Motion pictures I took of one Reddish Egret using this feeding method clearly show the scraping movements so typical of this species. The foot is moved rapidly back and forth as the bird slowly wades forward, and the toes ajjpear to scrape or rake the substrate. Of the many Reddish Egrets I have watched using this method, none made stirring movements. Andrew J. Meyerriecks HERON FEEDING BEHAVIOR 155 When scraping, rufescens almost always uses the technique “scrape-peer- stab.” Typically, the feeding bird wades forward slowly, scraping as it goes, then it stops and peers intently at the surface of the water, and then it either stabs at some prey or moves on, usually resuming the scraping movements. As mentioned, in areas where tufts of aquatic grass abound. Reddish Egrets move these plants in search of prey by scraping, not stirring. This species also shows the aerial variant “hovering-scraping.” When hover- ing over the water, rufescens is an extremely agile, graceful species as it moves effortlessly from tuft to tuft. The legs of the bird are dangled, and the plants are agitated by scraping motions of the feet. As with the Snowy Egret, rufescens strikes from the hovering position. Although quantitative evidence is lacking, I believe that rufescens uses the hovering method more frequently than thula. Louisiana Heron. — This species resembles the Snowy Egret in that it extends one leg and foot forward and then vibrates it rapidly, thus imparting a stirring motion to the foot. I have never seen tuft-stirring in tricolor, but I did observe that this species always stirs mud, unlike thula, which may stir or rake it. I have never seen hovering-stirring in tricolor. Mcllhenny (1936 ) claims that the Louisiana Heron uses foot-stirring during the winter only, “when the water is cold and their food supply inactive.” This was not the case in the winter of 1955—56 in Florida Bay. All of the stirring observations I made of tricolor were recorded during warm periods, and I was able to see the tiny fish the herons were preying upon moving about quite actively. For example, the air temperature at Cowpens Cut on April 6, 1956, at 1130 hours was 85 degrees F., and the fish sought by the herons were constantly moving about my boat. On this date I watched a Louisiana Heron foot-stir for three minutes. Duration of Foot-stirring Of the three species I have watched, the Snowy Egret uses foot-stirring as a feeding method more often and for longer periods than the other two. N. B. Moore (Baird et ah, op. cit.) also observed that thula uses this technique more frequently than tricolor and rufescens. Table 1 was made by selecting com- parable observations from my field notes. Only those records made of all three species using foot-stirring feeding behavior on the same day in the same place are listed. One bird only was watched during the entire period of observation, and the duration of foot-stirring was recorded with a stopwatch. A glance at Table 1 shows that the Snowy Egret uses foot-stirring for longer periods than do the Reddish Egret and the Louisiana Heron. Table 2 lists observations of foot-stirring in these same three species that are not comparable as to day, place, and so on, hut the data support my belief that Snowy Egrets use this feeding method more often and for longer periods than the other two species. 156 THE WILSON BULLETIN June 1959 Vol. 71, No. 2 The few records I have of feeding success while using foot-stirring (see Tables 1 and 2) show that the method is effective. N. B, Moore {op. cit.) watched a flock of 70 Snowy Egrets on Lehruary 18, 1873, and “scarcely one of this species obtained food without raking for it, numbers being thus engaged at the same time.” All of the successful strikes listed in the tables were made on small fish. Table 1 Duration of Foot-stirring and Feeding Success in Three Species of Herons Species Place and date Florida Bay Chiapas, Mexico December 1 6, I 955 March 11,1 956 March 12, 1956 June 24, 1 956 Leucophoyx Period^ 63 27 19 17 thula Duration" 13 26 15 12 Success^ 3/10 5/9 2/17 1/5 Dichronutnassa Period 150 41 75 8 nifescens Duration 2 3 4 2 Success 1/4 1/8 1/11 0/0 Hydranassa Period 35 57 83 6 tricolor Duration 1 2 1 1 Success 0/0 0/3 1/1 0/0 1 Total period of observation in minutes. " Duration of foot-stirring in minutes. ® Number of successful strikes/total strikes while foot-stirring. Table 2 Frequency and Duration of Foot-stirring and Feeding Success IN Three Species OF Herons’^ Species Number of observations Total observation period in minutes Total duration of foot- stirring in minutes Strike success- Leucophoyx thula 10 319 87 17/62 Dichrornanassa rujescens 5 470 10 4/23 Hydranassa tricolor 4 120 8 4/17 > All of the separate observational periods are combined, as are the duration of foot-stirring and strike success. - Number of successful strikes /total strikes while foot-stirring. Andrew J. Meyerriecks HERON FEEDING BEHAVIOR 157 Rootedness I have the following four records of footedness in herons while using foot- stirring feeding behavior: Snowy Egret, 2 (both right) ; Reddish Egret, 1 (right) ; and Louisiana Heron, 1 (left). All four individuals used the foot indicated for the entire duration of foot-stirring. These clear cut preferences differ from Hartley’s (Gibb and Hartley, 1957) observation of a Reef Heron that used “either foot, but the right more often than the left, to stir tufts of weed to bolt small fishes.” Some Snowy Egrets I watched seemed to “lean” toward the use of one foot during an extended period of foot-stirring, but none of these birds was as clear cut in its preference as those cited. Foot-stirring in Other Herons I found many references to the foot-stirring feeding behavior of various herons, but Rand (1956) mentions only thula and tricolor. Prior to my own observations of rufescens, only those of N. B. Moore (Baird et al., op. cil.) appear to have been available for this species. However, a number of observa- tions of this feeding method have been made in several Old World species of herons. Hartley’s record for the Reef Heron has been mentioned, while White (1946), Hopkins (1948), Koenig (1952), and Hohbs (1957) have seen foot-stirring in the Little Egret {Egretta garzetta) . In Australia, Hopkins (1948) saw this feeding method in the Pied Heron {Notophoyx picata), and Hobhs (1957) observed foot-stirring in the White-faced Heron {Notophoyx novaehollandiae ) . I have never seen foot-stirring in the Common Egret {Casmerodius albus) , and several authors comment on the absence of foot-stirring in this species (e.g., Rand, 1956; Hobhs, 1957). However, Bagg and Eliot (1937), citing the observation of F. A. Stebbins and A. M. Bowen, state that “the Egret [i.e., albus] waded deeper, and when on a muddy bottom would, with the aid of his wings, hop straight up clear of the water and come down with stiff, spread toes, and then scrutinized the ‘roil’ he had caused for dislodged prey. He swallowed several fish.” Although it is not foot-stirring, this observation suggests that some herons may effectively secure food by a feeding method using the legs and feet to disturb the prey without recourse to stirring or scraping. Discussion The bright yellow toes of t/iula and garzetta are sharply set off from the black legs, and both species use foot-stirring feeding methods. This distinctive pattern suggests that it may have evolved in conjunction with this peculiar feeding technique. However, the feet of thula turn a brilliant coral orange during the early part of the breeding season, and the feet are conspicuously displayed at this time (Meyerriecks, 1958). In addition, the feet of garzetta become crimson-pink during the breeding season (Henry, 1955), but the displays of 158 THE WILSON BULLETIN June 1959 Vol. 71, No. 2 the Little Egret are not known in detail. It is possible that the feeding function of this pattern is primary and the display function secondary; however, both functions will reinforce the selection of bright feet. More information on the frequency and duration of foot-stirring in herons is needed before any con- clusions can be made. Literature Cited Bacg, a. C., and S. a. Eliot, Jr. 1937 Birds of the Connecticut Valley in Massachusetts. The Hampshire Bookshop, Northampton. Baird, S. F., T. M. Brewer, and R. Ridgway 1884 The water birds of North America. Vol. I. Little, Brown, & Co., Boston. Bond, R. M. 1934 A partial list of birds observed in Haiti and the Dominican Republic. Auk, 51 :500-502. Gibb, J. and P. H. T. Hartley 1957 Bird foods and feeding-habits as subjects for amateur research. Brit. Birds, 50:278-291. Crimes, S. A. 1936 On an unusual feeding habit of tbe Snowy Egret. Auk, 53:439. Henry, G. M. 1955 A Guide to the Birds of Ceylon. Oxford Univ. Press, London. Hobbs, J. N. 1957 Feeding habits of some water birds. Emu, 57 :216. Hopkins, N. 1948 Birds of Townsville and District. Emu, 47 :331-347. Koenig, 0. 1952 Okologie und Verbalten der Vogel des Neusiedlersee-Schilfgiirtels. Jour. f. Ornith., 93:207-289. McIlhenny, E. a. 1936 Unusual feeding babits of some of the Ardeidae. Auk, 53:439-440. Meyerriecks, a. j. 1958 Comparative breeding behavior of some North American herons. Ph.D. Thesis, Harvard Univ., Cambridge. PORTIELJE, A. F. J. 1928 Zur Etliologie liezw. Psychologie der Silbermbwe, Earns argentntus argentatus Pont. Ardea, 17:112-149. Rand, A. L. 1956 Foot-stirring as a feeding melbod of Wood Ibis and other birds. Amer. Mid. Nat., 55:96-100. Sprunt, a., Jr. 1936 An unusual feeding babit of tbe Snowy Heron. Auk, ,53:203. Tinbergen, N. 1953 The Herring Gull’s world. Collins, I.ondon. White, S. R. 1946 Notes on the bird life of Australia’s beaviesL rainfall region. Emu, 46:81-122. HATIIEWAY SCHOOL OF CONSERVATION EDUCATION, MASSACHUSETTS AUDUBON SOCIETY, DRUMLIN FARM, SOUTH LINCOLN, MASSACHUSETTS, NOVEMBER 5, 19.58 DISPLAY BEHAVIOR OF BUFFLEHEAD, SCOTERS AND GOLDENEYES AT COPULATION BY M. T. MYRES The displays which occur in connection with the mating act have been described in but a few species of birds, and in fewer still has any attempt been made to relate these to, or distinguish them from, the other courtship displays. In a recent study (Myres, M. T., 1957 MS. An introduction to the behaviour of the goldeneyes: Bucephala islandica and B. clangula. M.A. Thesis, University of British Columbia ) it was shown that the pre- and post-copulatory displays of Barrow’s Goldeneye were almost indistinguishable from those of the Common Goldeneye. This was in marked contrast to those courtship displays which have a primarily pair-forming and pair-maintaining function, which were remarkably different in the two species- It is therefore of con- siderable interest to make further comparisons in the displays connected with copulation between other species of sea ducks (tribe Mergini* of the family Anatidae). Such a comparison is presented here between the only other member of the genus Bucephala [B. albeola, the Bufflehead ) and the two species of goldeneye already mentioned, and between two species of the genus Melanitla [M. deglandi, the White-winged Scoter, and M. perspicillata, the Surf Scoter ) and the Bufflehead. During the summer of 1957 I observed copulation of the Bufflehead on 12 occasions on Watson Lake, at 105 Mile, Cariboo Highway, in the Cariboo District of British Columbia. To my knowledge, the actions occurring at copulation have not been described previously for this species. On 103 Mile Lake, two miles away, I observed five instances of copulation in the White- winged Scoter. During the following winter, 1957—58, I saw copulation of the Surf Scoter on four occasions on salt water off Saltspring Island, B. C. The displays observed will be described for each species below, but a few remarks should be made regarding the manner of presentation. Capitalized words are names allotted to distinct displays. In a few instances names are given to displays, described elsewhere, of other speeies. To prevent unintended homologization of displays between species, different names are employed wherever possible, except when it is believed that two displays are without any doubt homologous. It will become clear in the course of the dis- cussion which displays, of the species described here, I believe to have had common origins. There may be instances where a name has been used, unavoidably, which is also used for a display in another species not discussed here. In such instances no homology should be understood, unless it has been clearly mentioned. * Classification follows P. Scoff, Key to the Wildfowl of the World. Severn Wildfowl Trust, Slim- bridge, Gloucestershire, England. Revised, 1951. 159 160 THE WILSON BULLETIN June 1959 Vol. 71, No. 2 In a few places it is stated that one display is more, or less, common than another. Because the number of separate copulations observed is only 21, and only one or two of these were recorded quantitatively by describing them onto magnetic tape, these assertions are not strictly objective. Rather they are subjective impressions received while watching the copulation sequence, in particular the course of the pre-copulatory display behavior. Bufflehead Copulation was observed 12 times between May 31 and June 16, 1957, as follows: May 31 (twice), June 1, 2, 3, 4 (three times), 5 (twice), 14 and 16. Most frequently the performance took place between 8:00 a.m. and midday, but on three of the 12 occasions it was seen in the evening. By June 16 many broods of downies were already on the lake, and I estimated that about half the broods subsequently present were there by that date. It is evident, for this and other reasons, that the females with whom males were seen to copulate were already well ahead with the incubation of their clutches by the first day in June. The female assumes a flattened pose on the water (Prone-posture), but it is unusual for the female to assume this for more than a few moments before the male mounts (this is in contrast to the two goldeneyes where the female may remain in the Prone-posture for as long as 20 minutes). The male swims around the female, or rests close by her on the water, performing the two main pre-copulatory displays. These are (1 ) a twitching of the water with his bill (Water-twitch), and (2) a preening movement over his back ( Preen-dorsally) : 1. The Water-twitch consists of dipping the hill to the water and then a slight sideways movement of the head, which is almost indistinguishable from a similar comfort movement. The movements may be distinctly separated by a pause, or by a Preen-dorsally, or they may be repeated one after the other in fairly quick succession. 2. In the Preen-dorsally it is impossible to be certain that the wing has been lifted in any way on some occasions, and indeed it probably is not lifted on all occasions. The hill must then come into contact with the feathers of the back or the upper side of the folded wing. On other occasions the wing is seen to be only slightly raised, and on one occasion the long scapulars were seen to he lifted more than the carpal joint so that a tiny spot of white appeared (from the secondary feathers or coverts). More often, however, the movement of the wing was just the lifting of a black shape above the back. In the Preen-dorsally the head may be swung around through an arc on the side toward the female, or on the side away from her. It seems likely that the indefinite lifting of the wing, and the variability as to which wing is concerned, may be an indication that the display is not as ritualized as in the surface-feeding ducks in which the colored specidum is flashed during this display — presumably most often in the wing which faces the female. K. Lorenz (1941. Jour. /. Ornithol., 89:194-294) states that in Aix galericulata this is invariably so in the Mock-preening display. In the Bufflehead the Preen-dorsally is elosely linked with the Water-twiteh, and the latter generally occurs before the former, just as a bird performing M. T. My res WATERFOWL DISPLAY BEHAVIOR 161 comfort-preening frequently dips his bill into the water in front of him. Undoubtedly the two displays originate from this comfort movement sequence. In the Bufflehead it was observed, however, that Water-twitching was more frequent than the Preen-dorsally (contrast White-winged Scoter). The unritualized form of these displays is also indicated by the fact that in the goldeneyes the supposed homologues of these movements (Jabbing and Wing-preen) are very highly ritualized: the Jabbing or Water-flicking of the goldeneyes is a frenzied series of movements and the Wing-preen is brief and momentary. Also in the goldeneyes they occur in a fixed sequence leading into the motor pattern of mounting itself — the Wing-preen never occurs, in fact, except as a preliminary motion at the beginning of the Steaming move- ment which, in goldeneyes, brings the male onto the back of the female. After a few moments, or a minute or two, of Water-twitch and Preen-dorsally display activity (the frequency of repetition is variable), the male suddenly moves toward the female and mounts. Generally he begins to move toward her from only a foot or so away, and the locomotory performance is not spectacular, but on one occasion it seemed that he made a slight rush over the water. On three occasions, out of eight in which the complete copulation sequence was observed, the wings were momentarily lifted off the back (Wing- flick) and snapped back into place about the time of intromission. This action has also been observed in goldeneyes and scoters. The tail is waggled from side to side during copulation. On dismounting the male continues to hold onto the head of the female with his bill, and the male and female rotate around each other for one or two full turns (Rotations). On three occasions, out of the 12, it appeared that the female was almost turned over onto her back as the male pulled at her head during the Rotations, and one of her legs was seen thrashing above the water behind her. As soon as he releases the female, the male almost at once begins to dip his head and the forepart of his body below the water, and to shimmer his wings in the water, as in normal comfort bathing (Bathing). The female also acts similarly, and then both birds stretch upward out of the water (Upward- stretch ) and flap their wings (Wing-flap), in a fashion identical with the comfort movements. However, this was only seen to occur on four of the 12 occasions. Twice the male made a shallow plunge below the surface first, as if the movement were an exaggeration of the first dip of the Bathing behavior. On no less than six occasions the male dived deeply (Plunge) coming up from one to 15 feet away from the point of diving- On four of these last occasions the male performed the Upward-stretch and Wing-flap immediately on sur- facing without prior Bathing, in another instance he performed Bathing, and in the sixth his actions were not recorded. On one of these six occasions the LIpward-stretch and Wing-flap were followed by more Bathing. In two of the 162 THE WILSON BULLETIN June 1959 Vol. 71, No. 2 12 instances the female, after she had performed some comfort movements at the end of copulation, performed a few of the neck-stretching and crouching movements which she generally performs when following a particular male away from a strange male or males (Following). On two occasions the first attempt at mounting did not result in a successful ejaculation, because the male slipped off the back of the female and performed Water-twitching move- ments again before mounting again. In one of these cases three attempts were made to mount in succession, and in another case the male appeared to give three Water-twitching movements, followed hy a single Preen-dorsally, while actually mounted on the back of the female. No Rotations were observed, nor did the male Plunge, after this but he did perform Bathing. The absence of the customary Rotations probably indicates failure to effect ejaculation, because in an unsuccessful copulation in Bucephala islandica the post-copulatory Rotations and Steaming displays were absent and tbe failure was followed by more pre-copulatory display actions, a successful copulation, and finally the normal post-copulatory displays (Myres, op. cit.) . White-winged Scoter Copulation was observed on five occasions: May 31 (once), June 2 (twice in succession), June 3 and 5 (once each). At this period many of the pairs (of which there were about 15 present on 103 Mile lake) , were not, apparently, incubating their eggs. They may also have been nonbreeding birds. The female assumes the Prone-posture from a position in which the head is elevated and forward, as in the “alarm” posture of this species. However, the Prone-posture is assumed only just before the male mounts. On three of the five occasions on which copulation was observed the female suddenly stretched her neck rigidly upward at an angle of 45 degrees forward as soon as the male caught hold of her head feathers on mounting. The same posture was observed when the female reappeared above the water after copulation. Three displays were observed in the male prior to copulation: (1) False- drinking, (2) Water-twitch, and (3) a Preen-behind-the-wing display (which is presumably the homologue of Preen-dorsally in Buffleheads ) . It should be mentioned here that during the winter of 1957-58 courtship behavior of this species was watched on a number of occasions. The main elements were the same as in the pre-copulatory behavior (namely the three displays men- tioned above) . This is the only species, of the ones reviewed here, in which this equivalence has been found. In the goldeneyes, Bufflehead and Surf Scoter the courtship displays of the pair-forming and pair-maintaining series differ quite markedly from the pre-copulatory displays. 1. False-drinking was performed by tbe male alone, or mutually by both male and female when it may be repeated a number of times. The display consists of dipping the bill to tbe water in front of the bird and a sudden elastic elongation of the neck forward and upward at an angle of about 75-80 degrees, until it is fully stretched and the head and neck appear to be larger than tbe rest of the body. Tbe neck relaxes and shortens, more slowly, immediately afterward. In the final stages of tbe pre-copulatory behavior, tbe False- drinking display may sometimes be less common tlian it is in the courtship behavior, this M. T. Myres WATERFOWL DISPLAY BEHAVIOR 163 was not consistently the case. 2. The Water-twitch was a dipping of the hill to the water, but with only a slight shake of the head. Generally the head was immediately lifted and swung round to the side, through 170 degrees, to the middle of the back and the Preen-hehind-the-wing took place. The Preen-behind-the-wing was sometimes more common than the Water-twitch (contrast Bnfflehead), but whenever the Water-twitch occurred it appeared always to be followed by a Preen-behind-the-wing. 3. The Preen-behind-the-wing takes three forms: (a) the scapulars and secondaries are lifted and held up for some movements which also exposes the white speculum, distinctive of this scoter. The preening movement may take place with the wing on the side toward the female, or on the side away from her. It often occurs when the male is some distance from the female; (b) the bill is thrust along the side of the body, or into tbe shoulder feathers, and the pink bill is then clearly visible against tbe black body plumage as the preening movement is made; and (c) the back feathers are nibbled. The white iris and white feathers around the eye are also most striking in both (b) and (c). Eventually the male mounts the female, hut there is a considerable period between the time the male covers the female and the Wing- flick. This move- ment was observed to occur once (or twice) in all five of the copulations observed. It was a vigorous movement, and made a sound as the wings beat the water. Upon dismounting, on two occasions the male was just holding on to the head of the female, but only a fraction of a circle (perhaps 20-30 degrees) was rotated. There was no post-copulatory display (contrast Surf Scoter), except that the male (upon slipping back into the water) flicked the tips of the primaries to rearrange the wings. The male was then in a hunched posture and drifted or swam slowly away from the female. The female also re- arranged her wings. Surf Scoter Copulation was observed on four occasions in midwinter on the sea off Saltspring Island, B. C.: December 29, 1957 (once), January 3, 1958 (twice in midafternoon) and January 5, 1958 (once in the afternoon). On all occasions there is no evidence to indicate that the birds involved were permanently paired. It would appear, by comparison with copulations of the White-winged Scoter observed on the breeding grounds, that the complete copulation display sequence was observed, despite the time of year. The Prone-posture resembles that of the goldeneye. The female lies flat with the neck below the water, and the hill curved upward. The longest time this was held was about two minutes in one of the copulations. The displays involved were extremely similar to those observed at copulation of the White-winged Scoter. The main pre-copulatory displays were the Water- twitch and the Preen-behind-the-wing, though these were not described in detail, while False-drinking was also observed. The male mounted the female slowly, as in the White-winged Scoter, and in every case the wings were eventually flicked, hut the movement was a single Wing-flick, not a double one. L'pon dismounting, however, there was 164 THE WILSON BULLETIN June 1959 Vol. 71, No. 2 a display not observed in the White-winged Scoter. This display (Chest-lifting) was seen on all four occasions as follows: As soon as the male slipped back into the water he threw his head back until it was over the middle of his back, which developed a 45 degree slope, and he thrust out his chest. Chest-lifting greatly resembles a display which is seen in a courting party. It is a sudden and brief movement. After Chest- lifting, no other movements by the male were observed. In one case the female did some unidentified movements afterwards, and then did the Upward- stretch and Wing-flap. There were unusual features about two of the copulations observed: (a) the third copulation occurred only a few minutes after the second, though it is not certain that the same male was involved in each case. The time was around 3:00 p.m. It was very mild, and drizzling at the time. A small party of Surf Scoters broke up, leaving two females and a male. The two females were tilting their bills upward repeatedly without lifting their heads, as in the Chin-lifting of Lesser Scaup (Aythyd af finis) . The male, between them, was performing the display in which he lifts the head and makes a scooping move- ment across the chest. The male also performed Water-twitches and Preens-behind-the-wing. Then he did some violent dipping, of the Bathing sequence, and one of the females assumed the Prone-posture. The male mounted her and copulation proceeded although the other female was almost touching them, (b) In the fourth and last copulation, the male mounted the female from in front, over her head. She quickly swung around beneath him, but there was ( as usual ) a considerable pause before he seized her head feathers. Discussion The displays occurring in the copulation sequence of the two genera Biicephala and Melanitta are listed and compared in Table 1. The pre- copulatory displays of the male Bufflehead consist of twitching the water with the bill, and making a preening-type movement in the dorsal region between the wings. Similar displays occur in the two scoters studied. In the two goldeneyes, by contrast, the predominant pre-copulatory displays of the male are stretching the wing and leg, and flipping water into the air with the bill. As I was more familiar with the goldeneyes I was not at first sensitive to the fact that Water-twitches and Preening-dorsally were indicative of copulation behavior in the Bufflehead. It seems to be significant that in Buffleheads the Water-twitch movement may he more frequent than the dorsal preening movement, whereas in the White- winged Scoter the preening movement is the more frequent pre-copulatory display. Whenever the Water-twitch did occur in the scoter it was generally followed immediately by a Preen-behind-the-wing. The twitching of the water with the bill before preening is, of course, a normal j)art of a comfort move- ment sequence in diving ducks, and it is most interesting that M. deglandi and B. albeola have diverged in the relative frequency with which they use these two movements in display. I find that Lorenz (op. cif.) also noted instances of variously ritualized linkages of two displays of the general courtship sequence M. T. Myres WATERFOWL DISPLAY BEHAVIOR 165 in some other clucks. In the Wood Duck (Aix sponsa) and the Mandarin Duck {Aix galericulata) of the tribe Cairinini, for example, the Mock-preening dis- play never occurs without the preceding “drinking” movement. In the Wood Duck “drinking” may occur at lower intensity by itself, but in the Mandarin Duck the two displays are absolutely linked. In the Gadwall (Anas strepera) Lorenz found, furthermore, that the two displays are equally firmly linked, but in the reverse order (Mock-preening is followed by “drinking”). Table 1 Distribution of M.\le Copulatory Displays in Melanitta AND BUCEPHALA^ M. perspicillata M. deglandi B. albeola B. islandica B. clangula Pre-copulatory False-drinking False-drinking Water-flip" Wing- and Leg-stretch Water-twitch Water-twitch Water-twitcb Note= Preen-behiiid- Preen-behiiid- Preen-dorsally" Note= wing wing Mounting Water-flick ( and Jabbing) " Wing-preen" Steaming Single Wing-flick Double Wing-flick Wing-flick ( ? ) Wing-flick Post-copulatory Rotations Rotations Chest-lifting Steaming Plunge or Bathing Bathing ? Rearrangement-of- wings“ Upward-stretch and Wing-flap^ Upward-stretch and Wing-flap® The displays in boldface are the most frequent displays in each species. - It should not be taken as certain that any of these displays are homologous until analytical ethological work has been conducted, but in the discussion it has been assumed that Water-twitch, Water-flick and Jabbing may be the same; that False-drinking and Water-flip are the same; and that Preen-behind-the-wing, Preen-dorsally and Wing-preen are the same. 3 Generally this is followed by a Tail-wag, but this was not specifically nofed in fhese displays, though it probably occurred. The Rearrangement-of-wings of M. deglandi may represent the settling of the wings after the Wing-flap which generally coincides with the Tail-wag. Preen-dorsally, or Preen-behind-the-wing, may well he homologous with the Mock-preening movements found in the general courtship displays of Aix and Anas, in which a colored speculum has been evolved, which emphasizes this (“morphological reinforcement”), and other movements (Lorenz, op. cit.; Tinbergen, N., 1952. Quart. Rev. Biol. 27: 24 and 27). In Anas discors, A. cyanoptera, A. querquedula and A. clypeata there is a further development. The secondary coverts are pale blue, and Lorenz (op. cit.) states that in A. querquedula the preening movement takes place on the outside ( instead of the inside) of the wing, and that the bill is actually directed at these coverts 166 THE WILSON BULLETIN June 1959 Vol. 71. No. 2 rather than the speculum. In only one of the three scoters are the secondaries differentiated and at variance in color from the rest of the black plumage of the wing. But display-preening is not absent in the two scoters studied merely because of this. Instead of plumage differentiation we find that the scoters have brightly colored bills (bright pink; white, orange and black; pale yellow or orange). It seems certain that the colored bill must be an alternative method of emphasizing the display movement. It really matters very little, so far as producing additional sign stimulation is concerned, whether this is done by preening specula (or coverts) Avhich are colored, or by a bill ( colored ) preening a uniformly dull wing. The Water-twitch of the Bufflehead is probably homologous with the Jabbing display of B. clangula or the Water-flicking behavior of B. islandica (Myres, op. cit.) which also occur in the pre-copulatory sequences. Jabbing in B. clangula immediately precedes the momentary Wing-preen display before mounting. But the Water-twitching movement of B. albeola was never a group of frenzied Jabbings as it is in B. clangula. The Wing-preen display of the goldeneyes is very rapid and, as a display, occurs only in the pre-coition sequence: in B. clangula it is a single momentary movement just as the pre- coition Steaming posture is assumed. In the Bufflehead and White-winged Scoter the movement is not unusually rapid, and so appears less ritualized. No Lalse-drinking, Wing- or Leg-stretching, or Steaming movements were observed in the pre-copulatory behavior of the Bufflehead. But Lalse-drinking ( comparable to Water-flip of the goldeneyes I occurs in the pre-copulatory display of the White-winged Scoter, though rather less frequently than the Preen-behind-the-wing or the Water-twitch. The post-copulatory displays are also interesting. Rotations do not occur in the White-winged or Surf Scoters at all. In the two goldeneyes they do not appear to differ at all from the Rotatory movements of Buffleheads. It is not clear to me yet which of the two sexes is providing the propulsive thrust, and which the drag, which results in circling of both birds over one spot. The pre-and post-copulatory Steaming displays of the two goldeneyes appear to be completely absent from B. albeola and the two scoters. In the Bufflehead a deep dive (Plunge) occurs on some occasions, which would appear to be an exaggeration of the preliminary plunges or dips which accompany Bathing. Bathing always occurs after copulation in the two goldeneyes, as well as in the Bufflehead, hut in the latter species was omitted when the Plunge occurred. The Plunge was followed directly hy the Upward-stretch and Wing-flap. Bathing and even the Upward-stretch and Wing-flap were absent in the post- copulatory sequence of the two scoters, and the only comfort action was a flicking of the tips of the primaries ( Rearrangement-of-wings) , which is possibly homologous with the final motions of closing the wings after the Wing-flap which completes the sequence in Bucephala. The only way in M. T. Myres WATERFOWL DISPLAY BEHAVIOR 167 which the Surf Scoter differs in copulatory behavior, qualitatively, from the White-winged Scoter is in having a distinct post-copulatory display (Chest- lifting ) . Whereas in the goldeneyes the female may be in the Prone-posture for a considerable time (as long as 20 minutes), in the Bufflehead and Surf Scoter the Prone-posture is assumed only a short while before the male mounts, and in the White-winged Scoter was observed only immediately prior to mounting, or as the male trod the female. There may be a correlation between the duration of soliciting by the female and the number and variety of displays in the male, e.g., the most are found in the long-soliciting goldeneyes, and the fewest in the White-winged Scoter. In the Bufflehead there were a few suggestions that, while mounted, the wings of the male Avere flicked. In goldeneyes the Wing- flick is a regular accompaniment of intromission. In all five instances of copulation in the White-winged Scoter a double Wing-flick was noted, and in all four instances a single Wing-flick was seen in the Surf Scoter. A major theoretical interest of the pre- and post-copulatory behavior of the ducks under discussion is that the displays involved are generally confined to the moments just before, and just after, the act of mating. They are generally confined to this moment in the reproductive cycle, and are rare in the more frequently described courtship behavior. Thus the Head-bobbing of the Buffle- head, which is the most well-known display of the male of that species, is absent completely from the copulation sequence. This rule applies fairly well also in the two goldeneyes. The Headthrow of B. clangula and Rotary-pumping of B. islandica, which are respectively the most frequently observed displays of these species, occur infrequently in the pre-copulatory behavior. In B. islandica it is possible to watch the Rotary-pumping display give way as the time for coitus approaches, to Water-flips and the Wing- and Leg-stretching displays indicative, in the male, of copulation. Ethologists are asked to realize the importance of the displays associated with copulation. These displays prove to be, in ducks, more conservative than the general courtship displays with pair-forming and pair-maintaining function. The copulation sequence may thus be of considerable importance in studies of the taxonomic relationships of species and genera. Thus, taking all displays into account, it is very hard to place the Bufflehead in the family tree, but considering only the displays of the copulation sequence it appears to be intermediate between the scoters and the goldeneyes. A much clearer picture will be established when descriptions of coitus are available for the other ducks comprising the tribe Mergini. Another interest of the displays occurring at copulation lies in the light they may throw on the successive evolution of courtship displays within a differentia- ting stock of animals. In the present case the developmental status of the Jabbing and Wing-preen displays of the Common Goldeneye, on the one hand. 168 THE WILSON BULLETIN June 1959 Vol. 71, No. 2 and the Mock-preening of Anas and Aix on the other, appears uncertain. The Water-twitch and Preen-dorsally, or Preen-behind-the-wing, displays appear less ritualized than either, but the direction in which evolution may have proceeded in regard to these displays is not yet clear. A comparative review of the evolution of courtship versus the copulation displays is planned. Acknowledgments I was supported by a C. I. L. Wildlife Conservation Fellowship during the time when these observations were being made. 1 wish to express my appreciation to Canadian Industries Limited for their interest in the broader aspects of the life and habits of waterfowl. Drs. M. D. F. Udvardy and B. Baggerman were kind enough to criticize the original manuscript. Summary The copulation of Bucephala albeola was observed 12 times, of Melanitta deglandi five times, and of M. perspicillata four times. The displays and actions employed are compared with those occurring at copulation in the two goldeneyes [Bucephala spp.). The Wing- and Leg-stretch display of the latter was completely absent from B. albeola and M. deglandi, in which the Water- twitch and the Preen-behind-the-wing predominated. Both these movements occur in association, however, in the normal comfort-preening sequence of ducks, and in similar (? non-homologous ) Mock-preening displays in the gen- eral courtship displays of members of both the Anatini and Cairinini. In the copulation behavior of goldeneyes they occur only in a momentary form just immediately prior to the exaggerated Steaming display which constitutes the approach to the female at mounting in these species. The post-copulatory Ro- tations, alone of all the displays, take exactly the same form in all three species of Bucephala. Rotations were not observed in scoters and the only difference between the two scoters in the displays occurring at copulation was in the ex- istence of a Chest-lifting display after coitus in the Surf Scoter. The post- copulatory Steaming of the goldeneyes is replaced in B. albeola by a Plunge movement on some occasions. This may be an exaggerated prelude to the bathing that occurs after coitus. Scoters lack Steaming displays and the White- winged Scoter merely rearranges the wings after dismounting. Ethologists, it is suggested, should j)ay more attention to the comparative aspects of copulation displays, since they are probably conservative. Taken with other differences in disjjlay between B. albeola and the goldeneyes, the jjossibility exists that B. albeola should not be placed in the same genus as the goldeneyes. The evolution of morphological reinforcement of the sign stimula- tory effects of motor patterns of display is discussed in reference to the spec- ulum of ducks in general, and to the colored bills of scoters in particular. DEPARTMENT OF ZOOLOGY, UNIVERSITY OF BRITISH COLUMBIA, VANCOUVER, BRITISH COLUMBIA, FEBRUARY d, 1 9.5d FOOD HABITS OF NESTING COOPER’S HAWKS AND GOSHAWKS IN NEW YORK AND PENNSYLVANIA BY HEINZ MENG Much has been written about the food habits of our birds of prey. Through crop and stomach content analyses it has been shown that most hawks and owls are beneficial to man’s interests and, therefore, are protected by many states. However, there is a notable exception — the accipiters. In only eight states are the accipiters fully protected. Five other states protect them except when they do damage to poultry, livestock, etc. Food habit studies always indicate that the large accipiters — the Cooper’s Hawk (Accipiter cooperii) and the Goshawk [Accipiter gentilis) — feed largely on poultry and game and, therefore, are unprotected. Accipiters are exceedingly wary, woods hawks and are seldom seen even in areas where they are abundant. Cooper’s Hawks and Goshawks are fast fliers and are seldom shot by hunters. The great majority of specimens available for food habit studies, therefore, come from game farms where they are caught in pole traps. Most of these hawks are young birds which have been attracted by the concentrations of game or poultry. Occasionally accipiters (as well as buteos) are shot from “kills” which prove to have been previously crippled or wounded game birds (McDowell and Luttringer, 1948). Analyses of the crop and stomach contents of this rather select group of hawks will naturally indicate a high percentage of poultry and game birds in their diet. Probably the best way to secure information about these hawks is to study their feeding habits during the nesting season. Nests are located early in the spring and studied throughout the breeding season. For the past ten years I have studied the food habits of nesting Cooper’s Hawks and Goshawks in New York and Pennsylvania. Pellets and remains of prey found in the nests and nest areas were collected and analyzed. Data were secured from 34 Cooper’s Hawk nests and 14 Goshawk nests. During the first three years of this period (1948-19.50) a study was made of the food consumed by 12 broods of Cooper’s Hawks. Each nest was visited four or five times a day from the hatching date until the hawks had left the nests. All of the pellets and remains of prey were collected and analyzed. Pellets found during one day were combined with the data of quarries observed in the nest on the previous day, in order to determine not only what species were preyed upon but also how many of each. Table 1 shows the kind and number of food items consumed by 42 young Cooper’s Hawks at 12 nests in the Ithaca, N.Y., region. In the Ithaca region the food of growing Cooper’s Hawks, as well as of the adults who partake of the prey brought to the young, consists of 18 per cent mammals and 82 per cent birds. The most important prey mammals are the 169 170 THE WILSON BULLETIN June 1959 Vol. 71, No. 2 Table 1 Food of Young Cooper’s Hawks at Ithaca, New York Species Number Birds Ring-necked Pheasant iPhasianus colchicus) 4 Spotted Sandpiper (Actitis maciilaria) 1 Rock Dove (Colitmba livia) 13 Mourning Dove {Zenaidura macroura) 5 Screech Owl iOlus asio) 1 Yellow-shafted Flicker iColaptes auratus) — 134 Pileated Woodpecker { Dryocopiis pileatus) 1 Red-headed Woodpecker ( Melanerpes erythrocephcdiis) 1 Yellow-bellied Sapsiicker iSphyrapicus variiis) 1 Hairy Woodpecker iDendrocopos villosus) 5 Blue Jay ( Cyanocitta cristata) 11 Catbird iDumeteUa carolinensis) 1 Robin ( Turdus migratoriiis) 79 Wood Thrush (Hylocichla mustelina) 7 .Starling iSturnus vulgaris) 241 Ovenbird i Seiurns aurocapillus) 5 Bobolink ( Dolichonyx oryzivorus) 1 Eastern Meadowlark (Sturnella magna) 118 Redwinged Blackbird (Agelaius phoeniceus) 3 Common Crackle (Qiiiscalus qidscula) 37 Brown-headed Cowhird ( iUoIothrus ater) 17 Scarlet Tanager (Piranga olivacea) 9 Rose-breasted Grosbeak ( Pheucticiis ludovicianus) 1 Rufous-sided Towbee i Pipilo erythrophthalmiis) 2 TOTALS 24 698 .Mammals Cottontail i Sylvilagus jloridanus) 6 Eastern Cliipmunk (Tamias siriatiis) 109 Gray Squirrel i Sciurus carolinensis) 4 Red Squirrel ( Tarniasciiirus hudsonicus) 36 TOTALS 4 155 TOTALS 28 — . 853 clii|)iiuink and the red scjuirrel, which together make up 94 per cent of the mammalian diet during the nesting season. The Starling, Yellow-shafted Flicker, L. Meadowlark, Robin, and Common Crackle together constitute 87 per cent of the avian diet, with the Starling being by far the most frequent item on the menu. Heinz Meng HAWK FOOD HABITS 171 L. L. Snyder ( 1937 ) examined 40 Cooper’s Hawks killed in Ontario during 1931 and 1932 and found Starlings in 17 of them. In a typical nest containing four young, an average of 266 prey items was brought to the nest during the first six weeks: 4 quarries per day during the first week, .5 per day during the second week, 7 per day throughout the third week, 9 per day during the fourth week, 7 each day during the fifth week and 6 per day in the sixth week. It takes an average of 66 prey items to raise a Cooper’s hawk to the age of six weeks. The females are about one-third larger than the males and require more food, so this figure would be slightly higher for the females and lower for the males. Fig. ]. Coo])er’s Hawk al nesi willi young. Most quarries are young animals that have not yet learned to he sufficiently wary, but occasionally adult birds are also brought in. These are probably caught while protecting their young. Like most predators the Cooper’s Hawk will take what is most abundant and easiest to catch. Sometimes even two- thirds-grown nestling birds are taken from their nests. On two occasions I saw a male, who does almost all of the hunting, bring two live nestling Scarlet Tanagers to its nest. 172 THE WILSON BULLETIN June 1959 Vol. 71, No. 2 There have been a few reports of Cooper’s Hawks taking young chickens during the nesting season, and if an individual male gets into this habit he may cause quite a loss to the owner. However, very few acquire this habit and most hawks tend to specialize on common wild birds or mammals that are available throughout the year. One Cooper’s Hawk nest that was studied intensively was within 300 yards of a large poultry range. Thousands of chickens could be seen from the nest, and they were sufficiently small so that the male could have easily killed and brought them to the nest, but not a single one was found in the nest, nor did the owner complain of having lost any. A similar incident in the case of a Goshawk nest in Nova Scotia was reported by A. C. Bent (1937:132—133). The nest was located one-half mile from a poultry yard that produced about 300 chicks. The farmers did not complain of losing a single bird all summer, nor had they seen any “hen hawks” about their premises. Time did not permit as intensive a study of the 14 Goshawk nests, but some rather interesting data were gathered. Nine of the nests were located in Wayne Co., Pa., three in Potter Co., Pa., and two in Chenango Co., N.Y. Each of the nests was visited several times during the nesting season, and once about a month after the young had left the nest. Pellets and remains of prey were gathered and analyzed (Table 2). Table 2 Analysis of Pellets and Prey Remains at Goshawk Nests Number of Species times found Birds Sparrow Hawk (Falco sparveriiis) 3 Ruffed Grouse {Bonasa umbellus) 5 Blue Jay {Cyanocitta cristala) 7 Common Crow" (Corvus brachyrhynchos) __ 83 Blackbird ( Eiiphagns, Qidscalus, Agelaius) 15 totals 7 - 113 Mammals Cottontail ( Sylvilagiis sp.l . .. . 7 Eastern Chipmunk (Tamias striatus) - 3 Cray Squirrel (Sciurus carolinensis) 4 Red .Squirrel {Tamiasciurus hudsonicus) 58 totals 4 72 totals 11 .. . — - 185 Heinz Meng HAWK FOOD HABITS 173 As can be seen from Table 2 the red squirrel and the Common Crow were the main food items of these 14 nesting pairs of Goshawks. Under one nest 24 crow legs and 15 humeri were found, and at another nest 3 crows were brought to the young while the writer was photographing the hawks from a blind. The remains of grouse were found only five times. The wing and leg bones of large birds are generally not swallowed by the hawks, and they can be found under the nests and in the nest areas. The humeri of crows and grouse are very similar in appearance, and very probably crow humeri have been mistaken for grouse hones in the past. In the area studied, crow humeri average 64 mm. in length and are straighter than grouse humeri, which average 57 mm. in length. Fig. 2. Goshawk al nest with young. In all of the Goshawk nest areas studied the grouse population was high, hut grouse appeared only five times in contrast to 83 crows. This suggests that the Goshawks do not select a particular area to nest in because of the high grouse population, as is often thought, but that they may even he instru- mental in increasing the numbers of grouse by removing numerous crows. Red squirrels, chipmunks, and crows destroy many grouse nests by feeding 174 THE WILSON BULLETIN June 1959 Vol. 71, No. 2 on the eggs and young, or, as in the case of the chipmunk, by pushing the eggs out of the nests. From the above data it can be seen that the Cooper’s Hawk and Goshawk are important predators of the Starling, Common Crow, red squirrel, and chipmunk. In view of these data it seems logical that these two accipiters should be protected along with the other birds of prey. Also, as long as even one species of hawk or owl remains unprotected all will continue to be shot. I feel that all birds of prey should be given protection, with the stipulation, as is found in Michigan’s law, that “a farmer or landowner may destroy hawks or owls on the land which he owns or occupies, which are doing real damage to poultry or other domestic animals” (Morrison, 1955). Literature Cited Bent, A. C. 1937 Life histories of North American birds of prey. U.S. Nat. Mas. Bull. 167. McDowell, R. D., and L. A. Luttringer 1948 Pennsylvania birds of prey. Pennsylvania Game Commission. 33 pp. Morrison, K. D. 1955 Bird protection laws show progress. Audubon Mag., 57:224. Snyder, L. L. 1937 The Starling in Ontario. Roy. Ontario Mus. Zool. Leaflet no. 4. STATE UNIVERSITY TEACHERS COLLEGE, NEW PALTZ, NEW^ YORK, DECEMBER 16, 1958 NOTES ON THE NESTING OE TURDUS LEUCOMELAS IN SURINAM BY F. HAVERSCHMIDT The Grey-headed Thrush ( Turdiis leucomelas) has a vast range in South America from Colombia eastward to the Guianas and southward to south- eastern Brazil, Matto Grosso and Peru. The representative in Surinam, T. 1. albiventer, is confined to Colombia, Venezuela and the region from the Gui- anas southward to the middle Amazon and Bahia. The upper surface of this thrush is brown, except the head which is dark greyish. The breast, abdomen and sides of the body are grey, the throat being broadly streaked with white. The axillaries and under wing coverts are bright rufous and the eyes are dark red. The sexes are indistinguishable in the field. The weights of specimens collected by me in Surinam are: 10 males, 55 to 76 grams (mean, 68), and 5 females, 67 to 75 grams (mean, 71) . In the coastal region of Surinam this is the commonest thrush, frequenting open forests and coffee plantations. It is now a common garden bird, breed- ing even in the middle of Paramaribo, but it also occurs in the sandy savannas further into the interior wherever there are scattered bushes or patches of forest. The local name in Surinam is “hoontjedief” (= thief of peas). Another thrush in the coastal and savanna area is Turdus nudigenis which is found in the same habitat hut it is definitely less numerous. Two other species, T. funiigalus and T. albicollis, are shy forest birds. Breeding season. — In the Penard Oological Collection from Surinam, now preserved in the Leyden Museum, the eggs of T. leucomelas are dated Janu- ary to June, but in my experience the breeding season begins at least two months earlier, in November and December. Thus, nesting seems to be con- fined to the short rainy season (from mid-November until mid-February), the short dry season (from mid-February until mid-April) and the long rainy season (from mid-April until mid-August ) . Breeding apparently does not take place in the driest months of the year (August to October) which may be due to the fact that at that time the ground is too hard and dry to provide sufficient food for the nestlings. That breeding does take place in the short dry season is not a contradiction of this rule since there is quite a lot of rain in this period, in most years. In fact, during the last several years this season was extremely wet. Fifteen nests in which incubation was in progress were distributed as follows: November, 1; December, 2; January, 1; Felv ruary, 1; March, 2; April, 4; May, 4. From December, 1951, until June, 1952, I was able to observe a pair that nested on a rafter near one of my windows, and which reared four broods in rather quick succession in the same nest. Though the birds were not marked 175 176 THE WILSON BULLETIN June 1959 Vol. 71, No. 2 I am certain that it was the same pair. Their history is as follows: Brood No. 1. Nest-building started on December 8, 1951. Incubation was seen for tbe first time on December 18, and feeding tbe nestlings on January 1, 1952. Two young left tbe nest on January 16 and one tbe following day. Brood No. 2. Repairing of the nest started on January 29. Incubation was seen on February 6, and feeding the nestlings on February 20. Three nestlings left the nest on March 6, 7 and 8, respectively. Brood No. 3. Repairing of the nest was seen on March 14, and incubation began on March 18. Two young left the nest on April 18 and 19. Brood No. 4. Repairing of the nest started on April 25. On April 30 it was still empty, but it contained 2 eggs on May 2 and 3 eggs on May 3. The eggs hatched on May 15. Two nestlings left the nest on June 1. In four broods a total of 10 young was reared. Nest and nest-building. — In the cultivated area the nest is very often made on rafters under wooden buildings. The nest is a typical thrush nest, and is lined with small, dry roots, therefore resembling the nest of the European Blackbird [Turdus inerula). I observed only one bird engaged in building, probably the female as is the rule among thrushes. Eggs. — As most nests are difficult to reach I have no records of clutch size apart from Brood No. 4 (3 eggs), but from the data in the Penard Collection it seems that a 3-egg clutch is the rule, and that 4 eggs may occur. The weights of three fresh and unblown eggs from Brood No. 4 were 6.2, 6.4 and 6.6 grams. In Brood No. 4 the eggs were laid daily. Incubation. — Invariably I saw only one member of the pair incubating, almost certainly the female, which is also the rule among thrushes. I never observed it being fed on the nest by its mate. The nest in which I observed four broods was on the rafter directly under aluminum plates of a loof on which the sun shone during practically the whole of the day. Under these circumstances the temperature at the nest was extremely high and the incu- bating bird spent most of the time not sitting in the nest but crouching on it, panting with an open bill. I was able to determine the incubation period only in Brood No. 4. The last egg was laid on May 3, when incubation started and all three eggs hatched on May 1.5, an incubation period of 12 days. On March 25, 1952, when the bird was incubating Brood No. 3, a female Glossy Cowhird (Molothrus bonariensis) appeared and inspected the rafter with the nest. Its appearance caused a great tnmidt among the thrushes which chased it away, both of them dive-bombing the cowhird which disappeared as fast as it could. It was certainly only searching for nests of the House Wren {Troglodytes niusculus) which is its usual host in Surinam and which regularly nests on rafters in the same situation as the thrushes. Other thrushes often took a hath in the gutter near the nest hut when coming too near it they were chased away by both birds of the nest. The nestling period. — The nestlings were fed by both parents and in prac- tically all cases with unrecognized animal food. Once an unidentified berry F. Haversclimidt TURDUS LEUCOMELAS 177 was brought to them. The excreta of the young were always taken away and dropped at some distance. I never saw them being swallowed. In the begin- ning of the nestling period the nestlings often were covered by the bird which had just fed them. The parent crouched over them exactly as during the incubation period. In Brood No. 4 this was seen for the last time on May 21, the nestlings then being seven days old. When both parents arrived at the same time with food one of them waited in the neighborhood of the nest until the other had fed the nestlings. I never noted that one of the birds passed the food to the other or that both were at the nest at the same time. One of them — certainly the male — often arrived singing in flight while carrying food in its bill. The same bird often uttered a few strophes after having fed the young. Both parents customarily perched on a piece of wood near the nest before alighting on it, and also after feed- ing. It was on this perch that I observed on March 5, 1952, (Brood No. 2) an interesting behavior. After having fed the nestlings one of the birds alighted as usual on the piece of wood when suddenly its mate with food in its bill alighted near it. The first one took fright by the sudden appearance of its mate and took a threatening attitude, flashing both wings, a movement by which the rufous axillaries and under wing coverts became very conspicu- ous. It was exactly the same attitude described and figured by Dilger (1956. Auk, 73:324) as “double wing flashing” in Catharus fuscescens, but I did not note down whether this thrush tilted one of its feet in this attitude like fuscescens. In only one case (Brood No. 4) was I able to determine the exact fledging period. The nestlings hatched on May 15 and left the nest after 17 days, on lune 1. The nestlings having left the nest, were fed for some unknown period, probably by the male only, at least in the latter part of this period, for repair- ing of the nest for the next breeding cycle started in the same period. In Brood No. 2 the young left the nest on March 6, 7 and 8. Two of them were still being fed on March 15, whereas the repairing of the nest started on March 14. Bathing. — Grey-headed Thrushes are very fond of bathing either by taking a shower bath in a tropical torrent or the usual hath while standing in a shallow pool of water. Sunbathing is also a regular habit in which the bird lies on its side on the ground with ruffled feathers and widely spread tail and widely open hill, one of its wings stretched to the utmost so that their underside is hit by the direct rays of the sun while it tilts over to the other side. P.O. BOX 644, PARAMARIBO, SURINAM, DECEMBER 9, 1956 NOTES ON CERTAIN GROUSE OF THE PLEISTOCENE BY ALEXANDER WETMORE IN the Ozark region of northwestern Arkansas in the spring of 1903, Mr. Waldo Conard, while searching for the site of an old lead mine, found a deposit of bones, some of which were sent to the American Museum of Natural History. Dr. Barnum Brown on behalf of that institution visited the area in the fall of 1903, and again in 1904, securing several hundred specimens. In his report (Brown, 1908) he identified 41 species of mammals, of which he named 19 as extinct species or subspecies new to science. Ten others were identified to genus or species, and in addition there was mention of amphibians, lizards, snakes and various bones of birds. Among the latter he listed the Turkey [Meleagris gaUopavo) with a query. The location, near the northern boundary of Newton County, was on a hill at 1030 feet elevation, a mile north of the Buffalo River, 4 miles west of the settlement known as Willcockson, and 15 miles south of the town of Harrison in Boone County. Some of the bird material later came to R. W. Shufeldt, who (1913, pp. 299- 301 ) verified Brown’s identification of the fragmentary material of the Turkey, and made additional rambling remarks under three headings, one marked ‘‘‘'Bonasa umbellus?,^'' and the other two headed “Bird ( indetermined ) ,” with reference under each to illustrations from photographs published in accom- panying plates. The supposed grouse bones were allocated tentatively, as he stated that he had no skeleton material of the Ruffed Grouse available for com- parison. In final comment {loc. cit., p. 300) he said, “If subsequently found to be another species of either Bonasa or Lagopus, I would suggest the specific name of ceres.” The records, except for the Turkey, have remained in this un- certain state until now. Recently John E. Guilday of the Carnegie Museum, through Dr. Kenneth C. Parkes of that institution, has requested assistance in the identification of grouse hones from a Pleistocene deposit in western Pennsylvania. To provide this information it has been desirable to make a firm determination of the earlier Arkansas grouse material, since the bones from Pennsylvania were similar in size. The Arkansas specimens, in the American Museum of Natural History, have been made available to me through the kindness of Dr. Edwin H. Colbert and Mrs. Rachel H. Nichols. Shufeldt’s material proves to represent an extinct species of Prairie Chicken, as indicated in the following allocation and discussion. T.vnipaiiuohus ceres (Shiifehll) Bonasa or Lagopus ceres Sluifeldl, Bull. Amer. Miis. Nat. Mist., vol. 32, art. 16, August 4, 1913, p. 300, PI. .55, figs. 18-20, PI. .56, figs. 45-72. Pleistocene (Conard Fissure): Four miles west of Willcockson. and one mile north of Buffalo River, northern Newton County, Arkansas. 178 Alexander Wetmore PLEISTOCENE GROUSE 179 Type. — Amer. Mas. of Nat. Hist., Dept, of Vert. Paleo. no. 12392. Characters. — Generally similar to the modern Lesser Paririe Chicken {Tympanuchus pallidicinctus IRidgwayl), but somewhat smaller; bill broader and somewhat stronger, as indicated by a fragmentary premaxilla; coracoid shorter but with shaft equally strong; scapula more slender; wing relatively smaller, as demonstrated by the indi- vidual elements as follows: humerus smaller, with head less bulbous, external condyle relatively smaller, entepicondyle slightly shorter, and opening for the pneumatic foramen a little smaller; ulna and radius definitely shorter, indicating a smaller middle segment of the wing; carpometacarpus slightly shorter and somewhat more slender; leg similar in length, but with the individual elements of femur, tihiotarsus and tarsometatarsus somewhat more slender. Measurements. — Following are pertinent measurements of complete elements of the skeleton, with similar data from two male and two female skeletons of Tympanuchus pallidicinctus for comparison. The modern Heath Hen (Tympanuchus cupido cupido) and the Greater Praririe Chicken (Tympanuchus cupido pinnatus [Brewster]) are de- cidedly larger. Total lengths Tympanuchus ceres Tympanuchus pallidicinctus Coracoid 45.2 45.3-48.8 Humerus 59.7-60.5 61.2-67.5 Ulna 55.9-56.3 58.3-65.6 Radius 47.7-50.2 53.2-58.6 Carpometacarpus 33.1-34.7 34.7-41.0 Femur (approximate) 65.0-66.8 62.0-67.0 Tihiotarsus 85.5-87.2 80.3-89.8 Tarsometatarsus 44.9-45.4 42.8-47.2 Remarks. — A part of the sternum comprising the anterior end of the carina is too fragmentary to afford usefid comparison. The scapida lacks the distal end of the blade. The greatest interest is found in the limb bones, as it is in these that the details attrib- uted to specific difference are indicated. The wing elements have been described suffi- ciently above. In tlie leg the femur, represented by six specimens, all nearly complete, shows no differences from modern Tympanuchus pallidicinctus in form. The tihiotarsus has the condyles relatively smaller, hut the measurements of total length, in the three specimens sufficiently complete to afford these data, fall within the limits shown by the two sexes of the living bird. The same is true in the total length of the two complete tarsometatarsi, hut the fossil hones are more slender than those of the living species. In summary, the skeletal elements indicate a bird slightly less in size than tlie modern Lesser Prairie Chicken, marked by heavier hill, and shorter, smaller wings, that stood about as tall as its living relative, hut with more slender legs. It appears to have been of related origin with T. pallidicinctus, hut not directly in the evolutionary line of that species. Dr. Brown in his original account ( 1908, p. 159) located the Conard Eissure site as “four miles west of Willcockson.” This is shown as a country settlement on the Harrison topographical sheet of 1905 of the U. S. Geological Survey, and is marked in some of the older atlases. It is not a post office, and is not found on newer maps. 180 THE WILSON BULLETIN June 1959 Vol. 71, No. 2 An important matter at the beginning of the examination of this Conard Lissure material was the determination of the characters found in the skeleton to separate the two currently accepted genera, T ympanuchus and Pedioecetes, since the general over-all appearance of the fossil placed it as a grouse of one of these two categories. I have had available in this study a series of 8 Ped- ioecetes phasianellus columbianus from Montana to represent that group, 4 T ymponuchus pallidicinctus, 2 of the recently extinct T ympanuchus cupido cupido from Massachusetts, and 3 Tympanuchus c. pinnatus from North Dakota. In life the modern species of Tympanuchus are marked by rounded tail, a prominent air sac bare of feathers on the sides of the neck (less evident in females), over which there is a tuft of elongated feathers in the male sex. Pedioecetes phasianellus has four central rectrices elongated to project prom- inently beyond the others, and lacks the bare area over the air sacs and the elongated neck feathers of the other group. Habitat and general habits are fairly similar in the two, and both gather in spring on display grounds where the males strut, posture and call. In detailed examination of the skeleton, ele- ment by element, beginning with the skull and continuing through sternum, pectoral girdle, wings, pelvis and posterior limb, I find that the only definite characters to separate the two groups of species appear in the pelvis. Details evident in other parts of the skeleton serve to identify species but are not valid to separate the two groups recognized as genera. In Pedioecetes phasianellus the posterior section of the sacrum, viewed from above, is only slightly narrowed posteriorly, and remains in close contact with the ilium to the posterior border of the pelvis. Viewed from the side the posterior end of the ilium is produced as a point. From this same view the ischium below, and particularly behind, the ilio-ischiadic foramen is decidedly broadened. Overhang of the free border of the ilium over the foramen in question is slight. (See Figs. 1-2.) In the forms of the genus Tympanuchus the posterior end of the sacrum, when viewed from above is narrowed, and does not extend to the end of the ilium (with or without an additional caudal element coalesced with it). Both internal and external angles of the posterior border of the ilium are rounded, and both, in this area, are free, the inner one from the posterior end of the sacrum, and the outer one from the projecting shaft of the pidiis. Viewed from the side the ischium is narrowed, with the outer margin of the post-acetahiilar portion of the ilium projecting above it as a pronounced overhang. (.See Figs. 3-4.) This projection is evident in both sexes hut usually is broader in males. There is enough of the sacrum preserved in the material of ceres to demon- strate that this species is a member of the genus Tympanuchus. The specimen forwarded by Mr. John E. Guilday found in Lloyd’s Rock Sinkhole, in tlie New Paris Sinkholes, one and one-half miles northeast of New Paris, Bedford County, Pennsylvania, collected September 21, 1958, is repre- sented by all of the important parts of the skeleton. While these bones were in mixed association, they appear to come from one individual, since there is no duplication among them, and the paired elements represent right and Alexander M^'etmore PLEISTOCENE GROUSE 181 Figs. 1-2. {above) Dorsal and lateral views of pelvis in the Sharp-tailed Grouse, Pedioecetes phasianellus columbianus (% natural size). Figs. 3-4. {below) Dorsal and lateral views of pelvis in the Greater Prairie Chicken, Tytnpanuchus cupido pinnatus (% natural size). 182 THE WILSON BULLETIN June 1959 Vol. 71, No. 2 left sides. The pelvis (and the other bones) indicate clearly that the bird is the Sharp-tailed Grouse ( Pedioecetes phasianeUus [Linnaeus] ) , this being the first Pleistocene record for the species in eastern United States. Mr. Guil- day interprets the considerable mammalian fauna with which the bird was found as a more boreal association than that of the present day in Bedford County. The presence of the grouse does not militate against this, as this spe- cies at present ranges north into northern Manitoba, northern Ontario, and Quebec. In modern times it bas not been found in the United States east of northern Michigan. The fossil is believed to date back to late Wisconsin time. There were a number of bones of the Ruffed Grouse [Bonasa umbellus) as- sociated with the other species, affording another Pleistocene locality for this wide-ranging species. Literature Cited Brown, B. 1908 The Conard Fissure, a Pleistocene bone deposit in northern Arkansas: with descriptions of two new genera and twenty new species of mammals. Mem. Anier. Mus. Nat. Hist., 9(pt. 4) :155-208. Shufeldt, R. W. 1913 Further studies of fossil birds with descriptions of new and e.xtinct species. Bull. Anier. Mus. Nat. Hist., 33 (art. 16) :285-306. SMITHSONIAN INSTITUTION, WASHINGTON 25, D. C., JANUARY 19, 1959 A PLEISTOCENE AVIEAUNA EROM ROCK SPRING, ELORIDA OCK Spring issues from a limestone bluff approximately 6 miles north of Apopka, Orange County, Florida, in the north-central portion of sec- tion 15, T. 20 S., R. 28 E. The fossils here reported were taken from Rock Spring Run within 200 yards of the source. The bone-bearing, argillaceous sands represent an old channel fill overlying the Ocala limestone, which is exposed in portions of the stream bed. Lateral erosion of the sands exposes the fossils. The bones are well mineralized and most are not waterworn. The frequent occurrence in association of bones from what appear to be the same individual indicates that the material has not been reworked and that the bones are the same age as the matrix. Pleistocene age of the site is indicated by the presence of mastodon {Mammut americanus), horse (Equus sp.), tapir [ Tapirus veroensis) , peccary { Platygonus sp. ) , and camel {Tanupolama mirifica ) in association with the bird material. H. James Gut (1939) discovered the site; John Mann, Jack Todd and, particularly, Gerald Lintner obtained additional specimens. This report is based on all the avian elements the four collected. The material is now in the collection of Pierce Brodkorh at the University of Florida. Avifauna The total number of bird hones available was approximately 1025, of which more than half were identifiable to species (Table 1). The 35 species and one additional genus determined make this locality one of the richer avian fossil deposits known. Four species are additions to the list of fossil birds of North America; four others are reported for the first time as fossils from Florida. Gavia immer was known previously as a fossil in North America only from the Pleisto- cene of California, although Brodkorh (1953:214) refers to an ulna from Lake Monroe, Volusia County, Florida, as “near immer.” Complete hones included in the 47 specimens from Rock Spring are three coracoids, two carpometacarpi, and one each of the fol- lowing: humerus, ulna, radius, femur, and tihiotarsus. The major portion of a cranium is also present. Among the 29 bones identified as Ardea herodias is an extremely large carpometa- carpus 116.4 mm. in length. Tlie length of the carpometacarpus in three A. occidentalis ranges from 96.4 to 100.9 mm.; in 33 A. h. herodias from 93.5 to 107.1 mm.; and in three A. goliath from 97.4 to 103.6 mm. (Adams, 1956 MS:70, 74, 75). The carpometacar- pus in five A. h. wardi ranges from 108.0 to 113.0 mm. I can detect no qualitative differ- ences between the fossil and A. herodias, and it seems likely that the fossil would fit within the range of a larger series of A. h. wardi. In addition to the four elements assigned to Nycticorax nycticorax is the distal 20 mm. of a right tarsometatarsus that differs in several characters. The trochlea for digit 2 does not protrude as far medially and posteriorly, and the trochlea for digit 4 is extended BY GLEN E. WOOLFENDEN 183 184 THE WILSON BULLETIN June 1959 Vol. 71, No. 2 distally, thus the three trochleae appear more equal and parallel than in other herons; also the metatarsal facet lies closer to the trochleae. Measurements of the fossil are as follows: width of shaft distal to metatarsal facet, 6.3 mm.; width through condyles, 10.3 mm.; distance from distal end to center of metatarsal facet, 11.4 mm. This ele- ment, which was compared with all North American herons and some extralimital forms, may represent an additional species. Ajaia ajaja was known previously as a fossil only from the Pleistocene of California. The Rock Spring deposit yielded the distal portion of a right tarsometatarsus. Of the 1025 bird bones 620 were those of ducks. I was able to assign approximately half of these to eight species. Aix sponsa is recorded on the basis of a complete right humerus. Shufeldt’s specimens of this species from Fossil Lake, Oregon, have been assigned to Spatula by Howard (1946:176). More recently. Pleistocene records of the species have been published for Ontario (Wetmore, 1958:9) and Kansas (Stettenheim, 1958:198). The Rock Spring specimen constitutes the first fossil record of this species from Florida. Mergus serrator, hitherto known as a fossil only from Oregon, is the most abundant bird in the Rock Spring deposit. Maxillae, mandibles, portions of the syrinx, as well as whole specimens of all the long bones are present. Aythya collaris was recorded from the Pleistocene of Crystal Springs, Florida, by Brodkorb (1956:158), but was published too late to be incorporated in the fossil check- list (Wetmore, 1956). A method of separating the humeri of the Anatinae from those of the Aythyinae, based on certain characters of the pneumatic fossa, became appar- ent while working on the duck material from Rock Spring. In the Anatinae the fossa is deeper and partially excavates the medial bar. The construction is such that the palmar surface of the bar is not completely visible. Further- more, the fossa usually possesses many bony struts. In the Aythyinae the pneumatic fossa is shallower, and the medial bar is essentially continuous with the shaft, exposing its palmar surface. Struts within the fossa are rare; in most cases the wall is solid. These characters enabled me to assign more than 100 specimens of river and diving ducks to their respective subfamilies; the specimens included several extralimital forms and all North American species with the exception of Anas diazi, Bucephala islandica, and Campto- rhynchus lahradoriurn. The humeri of two specimens of the Rosy-billed Pochard {Metopiana peposaca) of South America agree in all respects with those of the Anatinae. This deviation from what seems a reliable method of distinguishing the two subfamilies may be of phylogenetic significance, for Delacour and Mayr (194.5:25-26) consider Metopiana, along with Netta rufina and Aythya erythrophthalma, to “constitute a bridge between the river ducks and the more specialized pochards of the genus Aythya. . . .” Four bones in the collection belong to the order Charadriifornies. I was able to identify one of these to species and two to genus. A left tibiotarsns, lacking only the cnemial and rotnlar crests, is of Limnodromus scolopaceus. The element measures 60.0 mm. from distal condyles to proximal articulating surfaces. The same measurement taken from eight specimens of L. scolopaceus ranged from 55.4 to 65.4 mm.; seven specimens of Glen E. Woolfenclen PLEISTOCENE AVIEAUNA 185 L. griseus vary from 52.2 to 55.7 mm. Although L. griseus has been reported from the Pleistocene of California, this is the first record of L. scolopaceus as a fossil. The distal three-quarters of a left humerus and a fragment of the distal portion of a Table 1 Pleistocene Birds from Rock Spring, Florid.a. No. of No. of Species bones individuals Gavia immer. Common Loon 46 Podiceps auritus. Horned Grebe 1 Podilymbus podiceps. Pied-billed Grebe 18 Phalacrocorax auritus. Double-crested Cormorant 106 Anhinga anhinga. Anhinga 14 Ardea herodias. Great Blue Heron 29 Casmerodius albus. Common Egret 7 Nycticorax nycticorax. Black-crowned Night Heron 4 Botaurus lentiginosus. American Bittern 2 Ciconia maltha, extinct stork 2 Ajaia ajaja. Roseate Spoonbill — 1 Anas fulmgula. Mottled Duck 2 Anas acuta. Pintail 1 Anas carolinensis. Green-winged Teal 4 Anas discors. Blue-winged Teal 4 Aix sponsa. Wood Duck 1 Aythya collaris. Ring-necked Duck 3 Aythya affinis. Lesser Scaup 55 Mergus serrator. Red-breasted Merganser 226 Coragyps atratus. Black Vulture 1 Buteo jamaicensis. Red-tailed Hawk 1 Haliaetus leucocephalus. Bald Eagle 2 Pandion haliaetus. Osprey 11 Meleagris gallopavo. Turkey 10 Grus canadensis. Sandbill Crane 6 Aramus guarauna. Limpkin 40 Gallinula chloropus. Common Gallinule 1 Fulica minor, extinct coot 1 Limnodromus scolopaceus. Long-billed Dowitcher 1 Larus sp. undetermined gull 2 Ectopistes migratorius. Passenger Pigeon 1 Strix varia. Barred Owl 2 Megaceryle alcyon. Belted Kingfisher 1 Dendrocopos borealis. Red-cockaded Woodpecker 1 Corvus ossifragus. Fish Crow 1 Richmondena cardinalis. Cardinal 1 Totals 609 3 1 4 8 2 3 1 1 1 1 1 1 1 2 2 1 2 15 24 1 1 1 1 2 2 6 1 1 1 1 1 1 1 1 1 1 98 186 THE WILSON BULLETIN June 1959 Vol. 71, No. 2 left carponietacarpus are from a large gull, genus Larus. Tlie fossil humerus shows minor differences from humeri of one L. hyperboreus and of two L. manniis, particidarly in the region of the internal condyle and the entepicondyle. The fossil possibly represents an undescrihed species. Its measurements are: greatest width of the distal condyles, 20.5 mm.; least width of the shaft, 9.0 mm. The proximal portion of a left humerus of Megaceryle alcyon is the first fossil record of any member of the order Coraciiformes from North America. The bone agrees in all respects with that of the modern species. Dendrocopos borealis, hitherto unrecorded as a fossil, is included on the basis of a partial left humerus. The genus Dendrocopos has been recorded from the Pleistocene of Carpenteria, California, by Miller and DeMay (1942:121, 68). Four bones from Rock Spring are from passerine birds. Two were identified to species. Richmondena cardinalis, represented by a complete right carponietacarpus, was previ- ously unknown as a fossil. Corvus ossifragus, represented by a fragmentary coracoid, is recorded from several other Pleistocene deposits in Florida. Paleoecology Most of the species from the Rock Spring deposit normally occur in ripar- ian or aquatic situations. Certain of these, particularly Podilymbus podiceps, Anhinga anhinga, Anas discors, Aix sponsa, Aramiis guarauna, and GaUinuIo chloropus, are generally inhabitants of fresh water. Three species of ecto- thermal vertebrates, Rana catesheiana, Chelydra cf. serpentina, and Alligator mississipiensis, further substantiate a fresh-water environment at the time of deposition. Together with the fresh-w-ater species are three birds generally found on salt water in Florida. These are Mergus serrator, by far the most abundant species in the collection, Gavia imnier, and Podiceps auritus. The occurrence together of species generally associated with salt water with those associated with fresh water suggests that the sea was nearer to the spring than at present. The spring lies immediately east of the Pamlico shore line (MacNeil, 1950, map ) , and it seems likely that the bones w-ere deposited during Pamlico or post-Pamlico time. The Pamlico shore line represents a rise of the sea some 25 to 35 feet above its present level. This rise in sea level probably made Rock S])ring Run a sluggish depositing stream, possibly subjected to tidal flow'. Acknowledgments Specimens were borrowed from the Museum of Zoology, Univeisity of Michigan, through the courtesy of Robert W. Storer. Measurements of specimens of Limnodromus at the Museum of Vertebrate Zoology, Berkeley, were obtained through Frank A. Pilelka and William J. Hamilton III. Pierce Brodkorh assisted in determining certain elements and in preparation of the manuscript. 11. K. Brooks clarified geological aspects of the area, and Walter Auffenherg aided in the identification of the reptiles and amphibian. To these men I am grateful. Glen E. Woolfenden PLEISTOCENE AVIFAUNA 187 Eiterature Cited Adams, C. T. 1956 MS Comparative osteology and phylogeny of the family Ardeidae. (Ph.D. thesis, University of Florida.) Brodkorb, P. 1953 A review of the Pliocene loons. Condor, 55:211-214. 1956 Pleistocene birds from CiA'stal Springs, Florida. JFilson Bull., 68:158. Delacour, J., and E. Mayr 1945 The family Anatidae. Wilson Bull., 57 :3-55. Gut, H. J. 1939 Hitherto unrecorded fossil localities in south-central Florida. Proc. Florida Acad. Sci., 3:50-53. Howard, H. 1946 A review of the Pleistocene birds of Fossil Lake, Oregon. Pp. 143-195 in Carnegie Inst. Washington Publ. no. 551. MacNeil. F. S. 1950 Pleistocene shore lines in Florida and Georgia. Geol. Surv. Prof, paper 221-F, pp. 95-107. Miller, L., and I. DeMay 1942 The fossil birds of California. Univ. Calif. Publ. ZooL, 47 (4) :47-142. Stettenheim, P. 1958 Bird fossils from the late Pleistocene of Kansas. Wilson Bull., 70:197-199. Wetmore, a. 1956 A check-list of the fossil and prehistoric birds of North America and the West Indies. Smithsonian Misc. Coll., 131 (5) :1-105. 1958 Miscellaneous notes on fossil birds. Smithsonian Misc. Coll., 135(8) :1-11. DEPARTMENT OF BIOLOGY, UNIVERSITY OF FLORIDA, GAINESVILLE, FLORIDA, APRIL 8, 19.58 GENERAL NOTES The behavior of two captive ostriches at a burning leaf pile. — Two ostriches in the collection of the New York Zoological Society at Bronx Park have shown great interest in piles of leaves burning in their enclosure each fall. The two birds are exhibited with cranes and antelope on a large, enclosed, rolling meadow called “The African Plains.” A typical instance, recorded by movie camera and observer during the fall of 1958, occurred on the 3.7-acre African Plains Exhibit: a keeper ignited a pile of leaves about three feet in diameter and then retired. As he left, the ostriches approached the fire, the female leading, and, after several short pauses when the birds watched the fire closely, the female lowered her head and walked into the smoke directly before the burning leaves. The male continued to stand off, perhaps 15 feet away, watching. Flames could be seen plainly among the leaves as the female preened her neck, raised folded wings (over her back) , and lowered herself on her tarsi. The bird’s breast extended over the edge of the burning pile and smoke engulfed the forepart of her body. Glowing ashes and small flames were still visible very close to the bird. She kept her wings raised but waved them regularly in short movements over the back. The body plumage was moderately raised. Finally the bird lowered herself to her breast, protruding well into the smoking edges of the leaf pile, and continued to wave her wings. The neck was not extended nor was the mouth obviously open. When the female arose she preened her neck briefly and walked away from the smoking heap. The male approached her and began courtship display, eventually chasing her to the far end of the enclosure. The female performs most often at the burning leaf piles, though keepers report that the male indulges in exactly the same activity. I have not observed the male at the fire. While these performances have not been timed and the character of the fire has varied from time to time, the ostriches rarely spend more than two or three minutes at the leaf pile. Frequent keeper observations confirm that the male often displays to and chases the female when she arises from the leaf pile. Crowned Cranes and a European Crane in the same enclosure have not been observed at the leaf piles. The female ostrich iStruthio camelus australis Gurney) was received as an adult in 1947. The male (S. c. massaicus Neumann) was acquired as a half-grown bird in 1955. The motivation and degree of relationship of this behavior to anting, bathing, sunning, dusting or even smoke bathing is difficult to delineate. Smoke bathing as described by Ridley (1948. Brit. Birds, 41:83) for Jackdaws, White (1948. Brit. Birds, 41:244) for Herring Gulls, and Stevens (1948. Brit. Birds, 41:244) for the Black-headed Gull, for example, does not appear to be entirely of the same nature though it certainly may be related. Of course, the ostrich is a specialized form and differences in behavior may be expected. Ambient temperatures (fall) were usually low when the birds performed at the fire, but the female has performed on quite warm days. The birds’ attitude and movement at the fire is somewhat reminiscent of dust bathing with wing movements, perhaps, inhibited by the fire. It might be that anticipatory dust bathing is implied in the short wing movements. In this connection, however, the birds have not been seen dusting in unburned leaf piles, or ashes from burned piles, and not even in warm ash piles. Actual visible flame has been present, in most cases, when the birds have become interested in the heaps. Furthermore, the action of the female seems the result of strong motivation, for she may be counted upon to perform with fair regularity despite the presence of observers in places where the birds are not used to seeing visitors. We seldom see normal dusting in these two captive birds. Such dust bathing as 1 have noted in other specimens and would expect to be normal, resembled the dusting behavior of gallinaceous birds such as quail. Ostriches and rheas may get down in scrapes in sand or earth, work themselves 188 June 1959 Vol. 71, No. 2 GENERAL NOTES 189 over on one side, riib their necks upon the ground and throw, with their wings, considerable material over their hacks and through the plumage. This sort of dusling is an activity easily inhibited by the presence of observers. We cannot eliminate the learning factor in captive birds, or, for that mailer, in wild birds, and the possibility remains that the lack of some natural element in the birds’ wild environs may have provided a drive leading to artificial behavior. How- ever, this possibility does not provide an explanation for the observed behavior. The movement, posture and general attitude of the ostrich’s activity do not suggest rigid stereotypy or the “ecstasy” reported in some birds during anting and sunning. Whitaker (1957. W'^ilson Bull., 69:195-262) lists heat or the “thermogenic” element as “a probable factor in most anting situations,” and Lanyon’s (1958. Wilson Bull., 70:280) observations on meadowlarks seem to establish heat rather than light as the major factor in the sunning behavior of this species. We believe heat to be a major factor in the ostriches’ behavior, though their actions at the leaf pile did not resemble either of the two postures we have usually associated with ostrich sunning, and we know of no “anting” reports for ostriches. Ostriches, when sunning, may be seen standing with mouth partly open, plumage raised and wings slightly extended, or, occasionally, we see a bird resting upon its breast with wings partially extended on the ground and the head and neck folded over the back. The leaf pile activities of the ostriches do not conform with examples in Whitaker’s (Ibid.) anting compilation or with such anting behavior we have noted, either in an “active” or a “passive” sense. Of course, the limits of behavior termed anting, bathing, dusting, or sunning are arbitrary at best. Chisholm (quoted by Whitaker) summed it up nicely: “Smoke- bathing may in fact be complementary to water-bathing, sun-bathing and dust-bathing, and all four may well be allied to ‘anting’ with acids.” The Zoo Curator, working day-in and day-ont with live birds, has great opportunity to watch bathing, sunning and even anting activities in many diverse species, and soon may tend to think of these behavior patterns as points on a continuum. For example, we may suggest a very close connection between anting and sunning and, perhaps, we may think of these activities as the same basic response varied by position and focus of stimulus. Thus “active” anting may be a response to an extremely localized “thermogenic” stimulus, while sunning, involving, as Lanyon {Ibid.) says: “sudden warming of the bird’s immediate environment,” may be a more general reaction to a more diffuse heat source. Thus, a bird ants with a hot match stick but suns to hot air. Between these two peaks of behavior, but within the same range, may we not also situate passive anting involving postures and reactions intermediate between sunning and anting with modifications perhaps dependent upon the moderately localized stimuli of numbers of ants rather than the focused stimulus of a single ant or wad of ants. Furthermore, those who have watched a diverse collection of captive birds will be familiar with the similarity of bathing and dust-bathing in a number of transitional forms. Many will have observed certain birds of prey and pigeons assuming the same postures during rainfall as during sunning and noted that dusling is most frequently associated with a heat factor. At the Zoo we find our quail and pheasants dusting in the sunny parts of their cages, in places changing with the movement of the sun where there is heat. We have observed birds dusting on ant hills and in warm oily soil, all of which provide connecting links in the chain of relationships of these behavior patterns. This general synthesis presents a problem for study long overdue. — William G. Conway, New York Zoological Society, New York 60, New York, January 21, 1959. 190 THE WILSON BULLETIN June 1959 Vol. 71, No. 2 Strife over a nesting site between Downy and Red-headed Woodpeekers. — On April 24, 1956, a pair of Downy Woodpeckers [Dendrocopos pubescens) began construc- tion of a nest approximately 20 feet from ground level in a dead lombardy poplar in a woodlot in St. Paul, Minnesota. The woodlot, some 4.5 acres in extent, is composed primarily of boxelder (Acer Negiindo) and lomliardy poplar (Populus niger var. italica) with an understory of gooseberry {Ribes sp.), honeysuckle (Loiiicera sp.) and common lilac (Syringa vulgaris). The nest was successfully established and was occupied until May 18. On that date, at 2:30 p.m., a Red-headed Woodpecker (Melanerpes erythrocephalus) was first observed in the woodlot. This woodpecker flew to a poplar tree about 10 feet from the Downy Woodpeckers’ nest. It was immediately harassed by both Downys which flew close by in sweeping dives, emitting loud, scolding cries as they approached within four or five feet of the Red-headed Woodpecker. After several minutes of this fluttering, during which time the latter remained stationary, the Downys flew to nearby trees. One perched on either side of the Melanerpes, hut not between it and the nest. The Downys shook their heads vig- orously in an up-and-down motion in the direction of the intruder and continued their loud cries. The Red-headed Woodpecker seemed to ignore their defensive behavior and flew to the nest entrance. It began to enlarge the entrance hole immediately, and, after several min- utes, coidd place its head and shoidders within. At this point the owners’ display increased in intensity. They flew at the intruder with their fluttering dives, approaching more closely until they were diving to within six inches of their adversary. After several of these close dives, the Red-headed Woodpecker would leave the nest entrance momentarily and fly directly at the Downys. The latter would fly away at its approach, and were chased until they were 20 to 30 feet from the nest tree. The intruder would then return to the nest entrance and continue the enlarging process. The Downys came hack to within 10 feet of the nest tree, and resumed their fluttering dives, gradually working closer until they were again diving to witliin six inches of their adversary. At this point the intruder drove them away from tlie nest tree again and the entire process was repeated. This procedure took place four or five times from 2:30 p.m. to 3:50 p.m., at which time the Red-headed Woodpecker discontinued enlarging the entrance to the nest and flew out of sight toward the east. Immediately upon departure of the Red-head, the male Downy returned to the nest. He ajjpeared very cautious, and several times partially entered the nest before finally going inside. He then cleaned the nest of the debris caused by the enlarging processes. During tliis time his mate sat in a tree about three feet from the nest. After a period of about 10 minutes, tlie Red-headed Woodpecker returned to the nest. As he approached, the male Downy left the nest, possibly warned by his mate which emitted the chirping cry when their adversary came into view, and the entire process as outlined above was repeated. After approximately one-half hour of work on the nest entrance, during which the Downys were driven away several times, the Red-head again voluntarily left the nest, and flew directly to an oak tree approximately 400 feet east of the Downy Woodpeckers’ nest. It was met at the oak tree by its mate, which had not been noticed i)revimisly. Both then flew to the Downy Woodpeckers’ nest. During the Red-head’s absence, the male Downy Woodpecker had again cleaned the debris from the nest. However, at 4:45 p.m., when both male and female Red-headed Woodpeckers returned to the nest, the Downys left the area without an attempt to drive the intruders from the nest, and were not seen near the nest thereafter. It is not known if the Downys had a clutch of eggs in the nest, hut their long period of tenancy indicates that they ])rnhahly were in the process of incubation. The Red- .1 line 1959 Vol. 71, No. 2 GENERAL NOTES 191 headed Woodpeckers were still in possession of the nest during the first week in June when observations in the woodlot were terminated. A Downy Woodpecker nest, newly constructed, was found on May 24, approximately 450 feet from the other Downy nest. Since Downy Woodpeckers were not noticed using the woodlot previously, it is believed that this was a re-nesting attempt by the pair ousted by the Red-headed Woodpeckers. — R. G. Schwab and J. B. Monnie, Department of Entomology and Economic Zoology, University of Minnesota, St. Paul 1, Minnesota, June 24, 1958. Pilot black snake aiitl nesting Pileated Woodpeckers. — In May, 1957, I observed a pilot black snake (Elaphe obsoleta) which remained close to the nest of a pair of Pileated Woodpeckers (Dryocopus pileatus) over a period of five days. The nest was 40 feet from the ground in a dead stump in a swamp, near Seneca, Maryland, and contained small young, as judged by the behavior of the parents and the chrr notes which attended their visits. Pilot black snakes are effective predators of nestling birds. This fact may be illustrated by the following examples: 1) On June 15, 1952, I killed one of these snakes as it was leaving the nest of a Catbird { Dumetella carolinensis) . The snake’s stomach contained four well-feathered young catbirds. 2) Hoyt (1957. Ecology, 38: 246-256) cites the experience of Rhein, who took films of a pilot black snake as it climbed a tree trunk and entered the nest of a Pileated Woodpecker, from which it was later removed in the act of swallowing the well-developed young. Having seen Rhein’s film, 1 was startled on May 18 to discover that a 5-foot black snake was at a level with the nest of the Pileated Woodpeckers. The snake disappeared into a crevice behind and above the nest entrance. When its head reappeared in a small hole 10 minutes later, the male woodpecker also had its head out, directly below that of the snake. The two heads were about three feet apart. 1 now heard cuk, cuk's as the female Pileatetl Woodpecker alighted on a nearby tree, flew to the entrance, and then entered after her mate flew out. The snake withdrew from sight during this change-over. Two inches of its head and neck emerged from the same hole 15 minutes later, but the female woodpecker remained out of sight. I watched the nest hole for 30 minutes on May 19. The snake put its head out the small hole for a few minutes during this time. My next visit was on May 23. The sun was coming out after three days of cold, wet weather, and the pilot black snake was partly stretched on a broken limb where 1 had first seen it on May 18. On May 23 the male woodpecker had bis head and neck well out as if trying to see the snake a foot away and around the curvature of the stump. Neither animal appeared to be excited. The snake moved with great slowness, taking 28 minutes to descend to the ground where it disappeared in the vegetation before 1 could catch it. .Subsecpient observations indicated that the Pileated Woodpeckers were successful in raising their young. It was not apparent that the snake could have entered the nest hole of the Pileated Woodpecker. One or the other of the parent birds was always inside. This continuous attendance on small young is, in my experience, common to other species of woodpeckers. The situation is different when the young are more developed. Parent birds then spend more time collecting food and, in the case of Pileated Woodpeckers, the nest may be visited only at intervals of 30 to 60 minutes. The pilot black snake might be more dangerous at this later period which was, I believe, the one photographed by Rhein. One can only conjecture why the snake was in the stump. It may have been laying eggs, or simply resting over a periotl of cold weather without primary interest in the young Pileated Woodpeckers stirring within their nest a few feet away. — Lawhence Kilham, 7815 Aberdeen Road, Bethesda, Maryland, January 14, 1959. 192 THE WILSON BULLETIN June 1959 Vol. 71, No. 2 The plight of the bluebird in Michigan. — The plight of the Eastern Bluebird (Sialia sialis) over much of its range in eastern United States is rapidly becoming a matter of record (see Audubon Field Notes, Vol. 12, Nos. 3 to 6, 1958). To this 1 wish to append my meager Michigan data for the spring, summer, and fall of 1958. In April and May several people called me to ask what had happened to the bluebirds. People who had had bluebird tenants for many years had none this spring. A check of my own records showed that up to May 24 I had no Ingham County observations of this species; my only notebook enti7 was of a bird heard “warbling,” but not seen, on April 19, about 10 miles north of St. Johns in Clinton County. On May 24 six students and I took our annual May-day count in which we cover, in marathon fashion, all of the better knowm local birding spots. Increasingly conscious of the difficulty we might have in adding the bluebird to our list we covered many miles of promising habitat before getting our first and only record along a back road w'est of Lansing. Another segment of our searching party also located one bluebird. This west Lansing bird proved to be my only Ingham County record for 1958, but Mrs. Walter Halliday, who had been checking all spring on the disappearance of bluebirds from their former Okemos nesting sites, reported that she had finally located an occupied nesting box and that it produced young. Other local observers reported similar experiences, i.e., few or no bluebirds. Only four spring records were turned in for the Michigan Audubon Society’s Bird Survey report. During the summer session at our Gull Lake Biological Station I had difficulty finding bluebirds anywhere in the several counties covered on field trips. On June 28 I spotted one on a telephone wire on M-89 near Augusta (Kalamazoo County), but was not able to relocate it on several subsequent visits to that area. On July 25, however, w^e found a pair along a back road in Allegan County, near Fennville. In September Mrs. Wallace and I took a 12-day trip into the eastern part of the Upper Peninsula. Though well aware by then of the state-wide scarcity of bluebirds, I had some expectations of finding them assembling on roadside wires, as is their custom at that time of year. Our first two bluebirds were encountered on September 8 near Wolverine, 204 miles (by my odometer) north of East Lansing. Our next record was 10 days and approximately 1,000 miles later, when w’e located a group of six birds along a gravel road near Moran in Mackinac County. In six days of observations on fall migration at Whitefish Point, Chippewa County, where w'e recorded 77 species of birds betw'een September 11 and 17, we did not see or hear a single bluebird. We also made a cursoi^ check of the Gould City area (Mackinac County), where Dr. Karl Christofferson told us he had formerly seen large flocks (up to 75 in one count) in September and October. We found none in about 10 miles of slow’ driving (with frequent stops to look and listen) along back roads. At his station in Blaney Park, Dr. Christofferson had one pair of nesting bluebirds this summer in the 60 boxes he has provided for birds. Our only other bluebird record on this 1,668-mile trip, mostly in ostensibly favorable bluebird country, was of two birds perched on wires along U.S. 27 near Otsego Lake on September 19 — a total of 10 birds in three places in 12 days of observations. By contrast we counted 31 Sparrow Hawks (Falco sparverius) in about 15 different places (average of two per locality), mostly along roadside wires, as the bluebirds should have been. .Some of the reasons for the decline of the Eastern Bluebird over much of its former range are not hard to assess. It suffers from competition with more aggressive hole-nesting species, such as the Starling (Slurnus vulgaris) and the House Sparrow (Passer dornesticus) . Even native birds, such as Tree .Swallows (Iridoprocne bicolor) and House Wrens (Troglodytes aedon) , often win out in conflicts with bluebirds (Batts, 1958. Jack- pine Warbler, 36:138). Bluebirds are also subject to severe climatic changes — the un- June 1959 Vol. 71, No. 2 GENERAL NOTES 193 precedented winter of 1958 will go down in history as a disaster of major proportions for bluebirds and other insectivorous species that winter in the southern states. Many people suspect insecticides, but the evidence for this rests largely in the disappearance of the species from modern orchards, croplands, and roadsides in settled areas. Some bluebirds are showing up among the many victims of the ill-conceived fire-ant control program in the southeast; completion of the projected program, which comprises a large part of the Eastern Bluebird’s winter range, might well write the finish of this once familiar and much beloved bird. Perhaps the key to the whole problem lies in the wide- spread loss of favorable habitat, from all causes. In Michigan, at least, the bluebird now seems to be largely restricted to the jack-pine areas of northern counties and the more remote, abandoned or uncultivated farmlands. — George J. Wallace, Department of Zoology, Michigan State University, East Lansing, Michigan, January 17, 1959. The poisoning of meadowlarks with insecticides. — On March 6, 1958, Everett Woods, graduate student in the Department of Entomology, informed Dr. F. M. Baumgartner and me that meadowlarks were digging and eating freshly planted oat and barley seeds on a test plot at the Small Grains Laboratory. We thought it a good opportunity to test some candidate chemical bird repellents, so I went immediately to observe the plots. Twenty meadowlarks were feeding on the plots at that time. Closer observation on that date and on subsequent days revealed that the birds started by picking up scattered grain on top of the ground, digging up large pockets of grain where the planter had stopped at the end of the rows, and then starting down the rows digging up the seeds as they went. We made plans to spray the area with repellents, but adverse weather conditions all during March prevented us from doing it. The following day, seven dead Eastern and Western Meadowlarks