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1. Although the importance of adequate fat deposits for migrating birds has long been recognized, little is known about causes of intraspecific variation in the size of energy reserves. 2. We studied individual variation in visible fat reserves, body size, state of health and nutrition among autumn migrating Goldcrests Regulus regulus. 3. Birds showing signs of infectious/inflammatory diseases (high red blood cell sedi- mentation rate) or anaemia (low packed red blood cell volume) had significantly smaller fat stores than birds lacking these signs. However, no differences in fat reserves or health state were detected in relation to stage of post-juvenile moult. 4. These results suggest that the ability to deposit fat in the face of an energetically demanding migration may be affected by an individual's state of health.

We begin with two Roman stories—one ancient and now arcane, one modern and yet notorious. One recounts the heroism of a single man; the other convenes embassies from a majority of the world’s nations. Notwithstanding a bridge of more than two millennia, a common theme emerges from these two remote and seemingly dissimilar episodes—a lesson about the sanctity of promise-keeping between sovereign peoples. Be it the oath of a lone prisoner of war or a proud nation’s refusal to sign an international constitutive document, these diplomatic choices offer compelling evidence of how a people conceives of itself in relation to the other, as well as of its notions of justice and collective honor. Perhaps more than anything else, these shared values, these ideals, guide and inform every promise made— or not made—between peoples, and they dictate the manner in which that promise will be honored. To illuminate this point, I turn to the stories to which I have already alluded: the legendary faithfulness of

The female Goldcrest incubates alone and is not regularly fed by her mate. Incubation starts gradually already during the egg-laying period, and may be fully developed before the clutch is completed. From that time onward the hourly mean egg temperature remains remarkably constant, largely independent of time of day and weather conditions. The overall mean egg temperature, recorded during the continuous incubation period, was 36.54?C. The female regulated the temperature of the eggs by adjusting her attentive time. This is achieved by (1) varying the duration of the periods-off, which is inversely correlated with air temperature, and (2) varying the duration of the periods-on, which is less influenced by the weather conditions, but is significantly correlated with the time of day (light intensity), on average being shortest during the midday hours.

The material described in this paper is part of a collection obtained for the West Texas State College from a quarry in the Lower Pliocene beds of Donley County, Texas. This work was accomplished through the cooperation of the Works Progress Administration in 1936. The material presented is that of a small horse which was obtained from a quarry situated on the Grant property, two miles west of Goldston, and was collected by a paleontological party under the supervision of Mrs. Margaret Johnston.

I studied the foraging site shifts of tits and the goldcrest which were caused by the presence or absence of other species in flocks during the winter in northern Finland. Great tits occur only in forests near houses, and the crested tit avoided the foraging sites of the great tit in these forests. The willow tit avoided trees used by the crested tit when both were foraging together. In the best studied case, willow tits moved to outer and upper parts of spruce in the presence of great tits, which forage in lower and inner parts, but in the presence of crested tits, which prefer upper and outer parts of trees, willow tits moved to inner and lower sections of spruce. Using all the available comparisons in pine or spruce, species significantly avoided one another's foraging tree parts when together in the same flock. Foraging shifts seem to involve interference competition; social subordinates being more likely to change their foraging sites than social dominants. However, exploitative competition without aggression may be involved as a supplementary factor; avoidance was often mutual and social dominants sometimes appeared to avoid the foraging sites of the subordinate species in the encounter. Results strongly suggest that interspecific competition is currently, in ecological time, affecting the foraging behaviour of these coexisting birds.

A spruce beetle (Dendroctonus rufipennis) epidemic in southcentral Alaska has caused extensive mortality to spruce trees and a change in forest stand structure. Because a change in forest vegetation can influence composition and abundance of forest birds, we at- tempted to assess the type and magnitude of change in bird populations within 2 forest stands on the Kenai Peninsula that were undergoing differing levels of spruce beetle infestation. In addition, we compared bird populations occupying a salvage-logged forest site with those in the other forest stands. During our survey period (1994 to 1998), species composition and abun- dance of land birds differed across the sampled forest stands. Avian species diversity and rich- ness was greatest in the early successional stage of the logged forest and least in the heavily infested forest stand where many spruce trees killed by the spruce beetle had fallen to the ground. As predicted, ground nesting and foraging bird species increased where trees had fall- en or were removed. Conversely, the abundance of mature conifer forest birds, such as Town- send's warblers (Dendroica townsendi) and ruby-crowned kinglets (Regulus calendula) decreased in those forest stands that lost overstory structure. Townsend's warblers declined in abundance through time, potentially due to the loss of mature conifers for nest sites. Bird abundance was greater within the lightly infested stand in 1996, possibly due to immigration of birds from less suitable habitats. Because forest stand characteristics will continue to change through time fol- lowing the spruce beetle epidemic, we suggest that songbird communities will also remain dy- namic in response to changing habitats.

Increases in maximal capacity for thermogenesis (or Peak Metabolic Rate, PMR) are typically associated with winter acclimatization in passerines showing marked seasonal changes in cold tolerance. Thermogenic capacity also increases in spring migrant Warbling Vireos Vireo gilvus, a Neotropical migrant, relative to summer acclimatized individuals, but a similar increase does not occur in fall migrants. We tested whether migratory disposition was associated with variation in thermogenic capacity in another Neotropical migrant passerine, the Yellow Warbler Dendroica petechia, and in two passerine species migrating to mild temperate regions in winter, Yellow-rumped Warbler Dendroica coronata and Ruby-crowned Kinglet Regulus calendula. PMR was elicited by cold exposure in an atmosphere of 79% helium:21% oxygen during spring and fall migration for all species, and also during summer for Yellow Warblers. Yellow and Yellow-rumped Warblers both exhibited significantly higher thermogenic capacity in spring than at other seasons (23.3% greater than pooled summer and fall values in Yellow Warblers, 19.8% greater than in fall Yellow-rumped Warblers). For kinglets, males showed significantly higher PMR in spring than in fall (10.9%), but PMR did not vary seasonally in females. Thus, these species conform to a pattern of elevated thermogenic capacity in spring relative to other seasons, at least in the sex establishing breeding territories, suggesting that this may be a common pattern in migratory passerines. Mild temperate migrants migrate earlier in spring and later in fall than Neotropical migrants and, as a consequence, experience less variation in temperature between spring and fall migrations. Nevertheless, PMR varied similarly on a seasonal basis among Neotropical and mild-temperate migrants, despite the greater seasonal variation in temperatures encountered by Neotropical migrants. Moreover, ANCOVA on log PMR with log mass as a covariate did not demonstrate systematically lower PMR in Neotropical migrants than in mild temperate migrants for the species in this study, despite the differences in temperatures encountered during migration. This suggests that seasonal changes in PMR during migration are not associated with temperature acclimatization, but instead vary with other features of migratory patterns.

The species-confidence hypothesis asserts that birds prefer mates whose colors match those of their species and avoid potential mates whose colors are atypical of conspecifics. Earlier point-count research indicated this mate-choice hypothesis also may explain avian reactions to observer clothing color. In central Texas, during January and February 1993, we tested further whether the species-confidence hypothesis holds for reactions to observer clothing color by determining how close an investigator could get to individuals before they flushed (approach distance) and how long individuals remained visible near their initial flush point (detectability period). The same investigator experimentally wore or did not wear a hunter-orange vest, which some wildlife biologists wear as a safety precaution during hunting-season field studies. The vest did not affect approach distance for species with red or orange on their bodies (American robin [Turdus migratorius], P = 0.247; northern cardinal [Cardinalis cardinalis], P = 0.196; ruby-crowned kinglet [Regulus calendula], P = 0.434; red-bellied woodpecker [Melanerpes carolinus], P = 0.113). In contrast, approach distances for species without red or orange were longer when the vest was worn than when it was not worn (Carolina chickadee [Parus carolinensis], P = 0.032; northern mockingbird [Mimus polyglottos], P = 0.033; yellow-rumped warbler [Dendroica coronata], P = 0.001). Differences in detectability period between vest conditions depended on air temperature for American robins (P = 0.003) and on the variation in visibility within habitats for northern cardinals (P < 0.001). Detectability period was shorter when the vest was worn than when it was not worn for Carolina chickadees (P = 0.057) and yellow-rumped warblers (P = 0.060). Thus, for several species this mate-choice hypothesis seems to apply to garment color as well. Some species' reactions demonstrated that, if birds respond significantly to clothing color, important assumptions of distance-sampling techniques used to estimate avian richness, density, and abundance will be violated, and these parameters will be underestimated. Wildlife scientists will be more likely to draw valid inferences and recommend effective management practices from avian data gathered via distance-sampling methods if reactions to clothing color are precluded.

In this paper we analyse whether the abundance of breeding insectivorous birds decreases towards the South along the Iberian forests (as predicted by the model of Brown (1984)), and try also to relate these changes of abundance to several environmental features. Abundances of six foliage insectivorous passerines that are not tree-hole nesters, Troglodytes troglodytes (L., 1758), Erithacus rubecula (L., 1758), Sylvia atricapilla (L., 1758), Phylloscopus collybita (Vieillot, 1817), Regulus ignicapillus (Temminck, 1820), and Aegithalos caudatus (L., 1758) were recorded in fifty-eight large woodlands along a 850 km belt crossing the Iberian Peninsula. By means of simple, partial and stepwise multiple regression analyses bird abundances were related with distances to the north of each woodland and with the mean scores of climatic (mean temperature and precipitation), physiognomic (tree trunk densities under 20 cm diameter and over 30 cm) and floristic (conifer v. broadleaved tree species) variables. Five of the six species showed significant, negative correlations between their abundances and the distances of forests to the north, thus corroborating Brown's model. A. caudatus did not show, however, any clear pattern of abundance distribution. Simple correlation analyses showed also the importance of climatic and physiognomic variables in predicting bird abundance. When the problem of interaction between variables was solved, all the five species showed significant positive partial correlation with precipitation, although distance continued to be important for three species (T. troglodytes, R. ignicapillus and P. collybita), suggesting some additional role of this variable in the processes involved in the observed distribution. The importance of precipitation and distance to the north as predictors of abundance was also showed by the stepwise regression analysis. The mean variance explained by these models was around 30%, higher than or similar to that obtained in other studies performed at the local or intrahabitat level. This suggests the potential usefulness of multivariate approaches in studies of bird distribution undertaken on large scales.

(1) In coniferous forests in Central Sweden willow, (Parus montanus) and crested tits (P. cristatus) forage in the inner canopy while coal tits (P. ater) and goldcrests (Regulus regulus) forage on the outer, needled tree parts. (2) To test if interspecific competition affects foraging site selection of the two latter species, we reduced the numbers of willow and crested tits by more than half in three 40 ha study plots in the beginning of winter. (3) Later in winter, coal tits and goldcrests increased their foraging in inner canopy in the experimental plots in comparison with three control plots. (4) An experiment is powerful in excluding alternative explanations only if it is based on a sufficient number of repetitions. Observations within a plot may be dependent because they are derived from animals inhabiting the same environment. The simplest way around the problems is to use each plot as a single observation in test. Both coal tits and goldcrests exploited inner tree parts more in all of the three experimental plots than any of the three control plots, which alone is a significant difference. (5) The experiment indicates that interspecific competition affects foraging site selection of sympatric tits and goldcrests, as has been previously suggested by many nonexperimental studies.

0 WITH THE COMING of May, the planet Jupiter continues to be the most prominent star or planet visible in the evening sky. It is the first to appear in the northwest as the sky darkens after sunset. It then moves toward the western horizon to set-about four hours after sundown on May 1, two hours earlier on the 31st. Jupiter's position in the constellation of Gemini, the twins, is shown on the accompanying maps. These maps depict the sky as it looks about 11:00 p.m. (your own kind of daylight saving time) on May 1, 10:00 at mid-month, and 9:00 at the end. Among the stars, the most prominent is Arcturus, shown high in the south in Bootes, the herdsman. Below it is Virgo, the virgin, with Spica, another star of the first magnitude. Above and to the right of Virgo shines Leo, the lion, with a star of similar brightness, Regulus. Low in the southeast stands part of Scorpius, the scorpion. The star close to the horizon, named Antares, is also of the first magnitude. At such a low altitude, however, so much of its light is absorbed by the earth's atmosphere that it appears considerably fainter. In Gemini, where Jupiter now stands, is Pollux, another first magnitude star, and nearby are two others of the same degree of brightness. One is Capella, to the right in Auriga, the charioteer; the other is Procyon, toward the left in Canis Minor, the lesser dog. These stars shine brilliantly in the winter evening sky, but are not visible on summer evenings. To take their place, however, two stars are rising in the northeast that will become very prominent on summer evenings. One is Vega, in Lyra, the lyre; the other is Deneb, in Cygnus the swan Like Antares, which will also become more conspicuous in summer evenings, Deneb is considerably dimmed because it is so low on the horizon. High in the north shines Ursa Major, the great bear, which includes the familiar Big Dipper. Here are the two pointers, whose direction indicates the north star, Polaris, which is part of Ursa Minor, the little bear-and also of the Little Dipper.

The Comoedia sine nomine (sometimes cited as Columpnarium) is a seven-act play in Latin by an unknown author which survives in a single manuscript, Paris, Bibliotheque nationale de France, Lat. 8163.1 It is a most unusual classicizing adaptation of a plot which was very popular in the later Middle Ages, a combination of two widely used narrative motifs, the Flight from the Incestuous Father and the Falsely Accused Queen.2 Emile Roy in his 1902 edition assumed that the manuscript dated from the fifteenth century and was written in Italy, but in the view of Francois Avril of the Bibliotheque nationale, it was produced in the mid-fourteenth century at Avignon under Italian influence.3 I shall return later in this essay to the question of dating and provenance to argue that the text - or at least this particular manuscript of it - can be linked to Petrarch's circle in Avignon. It could of course have been composed considerably earlier than the surviving exemplar, but I believe that there are strong grounds for positing an Avignon provenance, and for speculating that although the plot is a well-known one, this particular version may be intended to allude to the papal schism.Plot and styleFirst I will consider the many ways in which the Comoedia is an unusual version of a popular, if disturbing, medieval narrative. The writer - or his source - has gone to a lot of trouble to rework the plot elaborately in classical terms, with a mish-mash of classical names.(I) The dying queen of the Carilli makes her husband King Emolphus swear only to marry a woman who looks exactly like her. He sends the court painters to travel the world and record possible candidates. (II) The people urge Emolphus to remarry; Princess Hermionides' nurse rashly remarks that her charge is the image of her dead mother. The king falls passionately in love with his daughter and decides to marry her. (Ill) Hermionides is horrified and wants to die. The nurse plots to save her: she persuades the king to delay the wedding until the gods have been placated, and escapes with the princess to Phocis. (IV) There they are taken in by Sophia, an old friend of the nurse and expert needlewoman. Hermionides is seen by the local king, Orestes, who falls madly in love with her. He sends Aphrodissa, a bawd, to negotiate for him, and they are secretly married.(V) Orestes' mother, Queen Olicomesta, is furious, as her son had foreseen. Orestes leaves for a tournament at Athens to pursue glory at Hermionides' urging, even though she is pregnant. (VI) When she bears a fine son, the messenger Epiphanius stays with Olicomesta en route to Athens, and while he is drunk the clever maid Pharia substitutes a letter announcing that the baby is an Ethiopian monster. This news makes Orestes sad, but he orders mother and child to be well looked after until his return. Again Epiphanius stops che'.i Olicomesta, and the letter is changed to order the killing of mother and baby. The faithful seneschal Coelius exposes the baby in a watertight cradle, and sends Hermionides into exile.(VII) The baby in its richly equipped cradle is found by Achironeus, a poor fisherman. He wants to adopt the child, but first consults the oracle of Apollo on Parnassus, after discussing the matter with his friend Amyclas. Their conversation is overheard by Orestes and his counsellor Regulus, who are on their way back from Athens, suspicious of recent events. Coelius too is suspicious and discovers the forged letter trick, which he reveals to Orestes and Regulus. Meanwhile Hermionides, wandering on Parnassus, meets a shepherd who urges her to consult the oracle. All the main characters then make for the oracle; Hermionides meets Achironeus the fisherman, hears his story, recognizes the baby as hers, and manages to recover him. The nurse, Orestes, and Coelius all overhear their conversation; Hermionides and Orestes are reunited. News arrives that Olicomesta and her maid are dead. The nurse announces that Emolphus is dead and that Hermionides has inherited the kingdom. …

Ecology -94". A cruise report. Swedish Polar Research Secretariat, Stockholm, pp. 311-316. Lundgren, B., Hedenstr6m, A. and Pettersson, J. 1995. Correlation between some body components and visible fat index in the Willow Warbler Phylloscopus trochilus (L.). Ornis Svecica 5: 75-79. Pettersson, J. and Hasselquist, D. 1985. Fat deposition and migration capacity of Robins Erithacus rubecula and Goldcrests Regulus regulus at Ottenby, Sweden. Ring. & Migr. 6: 66-76. Piersma, T., Bruinzeel, L., Drent, R., Kersten, M., Van der Meer, J. and Wiersma, P. 1996. Variability in basal metabolic rate of a long-distance migrant shorebird (Red Knot, Calidris canutus), reflects shifts in organ sizes. Physiol. Zool. 69: 191-217. , Cad6e, N. and Daan, S. 1995. Seasonality in basal metabolic rate and thermal conductance in a long-distance migrant shorebird, the knot. J. Comp. Physiol. B 165: 37-45. Scott, I. and Evans, P. R. 1992. The metabolic output of avian (Sturnus vulgaris, Calidris alpina) adipose tissue, liver and skeletal muscle: implications for BMR/body mass relationships. Comp. Biochem. Physiology 103A, 329-332. Summers, R. W. and Waltner, M. 1979. Seasonal variations in the mass of waders in southern Africa, with special reference to migration. Ostrich 50: 21-37. , Underhill, L. G., Clinning, C. F. and Nicoll, M. 1989. Populations, migrations, biometrics and moult of the Turnstone Arenaria i. interpres on the East Atlantic coastline, with special reference to the Siberian population. Ardea 77: 145-168. -, Underhill, L. G., Waltner, M. and Whitelaw, D. A. 1987. Population, biometrics and movements of the Sanderling Calidris alba in southern Africa. Ostrich 58: 24-39. Weber, T. P. and Piersma, T. 1996. Basal metabolic rate and the mass of tissues differing in metabolic scope: migration related covariation in Knots Calidris canutus. J. Avian Biol. 27: 215-224. Wilkinson, L. 1990. SYSTAT: The system for statistics. SYSTAT Inc., Evanston, IL.

Many studies indicate that interspecific competition restricts the use of foraging sites in mixed-species winter flocks of tits. However, predation is a strong mortality factor for members of the tit guild and predation risk may restrict the selection of foraging sites and organisation of the mixed-species tit flock. We evaluated pygmy owl (Glaucidium passerinum) predation can North European tits and goldcrests. A literature analysis of six areas showed clearly that pygmy owls feed more heavily on those species that forage on exterior tree parts (coal tit P. ater and golderest Regulus regulus)

We studied the abundance of arthropod food within spruce Picea abies in relation to the foraging site selection of tits Parus and the Goldcrest Regulus regulus in winter in Central Sweden. Arthropods, spiders in particular, were most abundant in upper tree parts and in the outer sections of branches. There was a high correlation between food abundance and bird density, based on proportional use of foraging sites over eight sections of spruce suggesting that food distribution is a major factor influencing the segregative distribution of the four bird species. However, the distribution of the bird species cannot be explained solely by food abundance. In outer tree parts there were fewer birds than expected from arthropod biomass. A possible explanation is that the risk of predation by Pygmy Owls Glaucidium passerinum is higher there, reducing the net benefit of foraging in the tree parts with highest food abundance. A further support for the impact of predation comes from the fact that it is the socially least dominant species, the Goldcrest and the Coal Tit P. ater, that use the outer tree parts. Crested Tits P. cristatus are highest in dominance rank, but they mainly forage in the inner tree parts. Willow Tits P. montanus are second in the dominance, but have the lowest food abundance in their foraging sites. Both interspecific competition over food, and the site-dependent risk of predation, seem to govern the ways in which the four bird species select their foraging sites in spruce in winter.

weather on incubation scheduling of the White-rumped Sandpiper (Calidris fuscicollis): A uniparental incubator in a cold environment. Behaviour 95: 261-289. Erckmann, W. J. 1981. The evolution of sex-role reversal and monogamy in shorebirds. Ph. D. Thesis, Univ. of Washington. Erikstad, K. E. 1986. Relationship between weather, body condition and incubation rhythm in Willow Grouse. Fauna norv. Ser. C, Cinclus 9: 7-12. Haftorn, S. 1978. Egg-laying and regulation of egg temperature during incubation in the Goldcrest Regulus regulus. Ornis Scand. 9: 2-21. 1979. Incubation and regulation of egg temperature in the Willow Tit Parus montanus. Ornis Scand. 10: 220-234. 1981. Incubation rhythm in the Great Tit Parus major. Fauna norv. Ser. C, Cinclus 4: 9-26. Johnsgard, P. A. 1981. The plovers, sandpipers, and snipes of the world. Univ. of Nebraska Press, Lincoln. KAlAs, J. A. 1986. Incubation schedules in different parental care systems in the Dotterel (Charadrius morinellus). Ardea 74: 185-190. and Byrkjedal, I. 1984. Breeding chronology and mating system of the Eurasian Dotterel (Charadrius morinellus). Auk 101: 838-847. Kendeigh, S. C., Dolnik, V. R. and Gavrilov, V. M. 1977. Avian energetics. In: Pinowski, J. and Kendeigh, S. C. (eds). Granivorous birds in ecosystems. Cambridge Univ. Press, pp. 127-204. Lofaldli, L. 1985. Incubation rhythm in the great snipe Gallinago media. Holarct. Ecol. 8: 107-112. Nethersole-Thompson, D. 1973. The Dotterel. Collins, London. Nielsen, B.-P. 1975. Affinities of Eudromias morinellus (L.) to the genus Charadrius L. Ornis Scand. 6: 65-82. Norton, D. W. 1972. Incubation schedules of four species of calidrine sandpipers at Barrow, Alaska. Condor 74: 164176.

Riparian forest strips are usually protected from logging for their buffer effect on aquatic habitats. However, their value to terrestrial wildlife is unknown. From 1989 to 1992, we compared bird abundance and species composition in 5 experimental riparian forest strips (20-m, 40-m, 60-m, and control [>300 m wide], intact strips, and 20-m-wide thinned strips), in boreal balsam fir (Abies balsamea) stands, for 3 years following clear-cutting. Bird densities increased 30-70% (P 0.05) thereafter to approximately pretreatment levels. The 20- and 40-m-wide riparian strips had highest mean bird densities, but also the fastest (P < 0.05) decreases thereafter. By the third year after clear-cutting, forest-dwelling species were less (P = 0.01) abundant than ubiquitous species in the 20-m strips. The golden-crowned kinglet (Regulus satrapa), Swainson's thrush (Catharus ustulatus), blackpoll warbler (Dendroica striata), and black-throated green warbler (D. virens) became nearly absent in 20-m strips. The removal of 33% of the trees in some 20-m strips resulted in a

In this note, we are mainly concerned with partial spreads U, V of PG(3, q) which cover the same points and have no line in common. Setting I Ul = I VI =t, we show that if t >q+ then t>max(q+2, 2q-2). Certain applications of this result to (0, 1) matrices and to translation planes are then discussed. 1. Summary. Our purpose is to describe a new result (Theorem 3) on the size of replaceable partial spreads in =PG(3, q), the 3 dimensional projective space over the finite field of order q=pS where p is a prime and s is a positive integer. The bound we obtain is "best possible" for q odd. It also represents somewhat of a breakthrough in the combinatorial theory of finite translation planes since, when applied to certain classes of such planes, it leads to an improvement of a well-known bound due to R. H. Bruck [1] (see Theorem 4). Furthermore, our result has a purely combinatorial interpretation in terms of (0, 1) matrices; this is discussed in ?5. Although we are dealing with very "modern" questions, our main tool is a classical theorem in solid geometry, namely the regulus theorem discussed below. By way of an example we shall also come across another hardy perennial-the Schlaffli double-six configuration. The proof in outline of the main result is a pleasant mixture of geometry and combinatorics. II1 order to exhibit this, we have attempted to keep this note accessible and self-contained. Thus we discuss below some geometrical background. We should mention that Theorem 3 can also be stated in purely affine or vector space language. How it can be proved, however, without reverting to the projective situation is far from clear. 2. Background in E. By a partial spread U of E =PG(3, q) we mean any nonempty family of pairwise skew lines of E. If every point P of E lies on some line of U we then refer to U as a full spread or, simply, a spread of E. Two partial spreads U, V of E are said to cover the same points provided the following holds: A point P of E lies on a line of U if and only if P lies on a line of V. A transversal of the partial spread Received by the editors October 20, 1972. AMS (MOS) subject classifications (1970). Primary 50D30, 05B25; Secondary 05B15, 50D30.

Changes in bird species richness, abundance, and guild structure were compared among young (42-75), mature (105-165), and oldgrowth (250-500+ years) and between winter and spring, for 2 years in Douglas-fir (Pseudotsuga menziesii) forests of the southern Washington Cascade Mountains. In winter, bird species richness, diversity, and abundance were all greater in oldgrowth than in younger stands. The most abundant species were the chestnut-backed chickadee (Parus rufescens), golden-crowned kinglet (Regulus satrapa), pine siskin (Carduelis pinus), and red crossbill (Loxia curvirostra). In spring, there were few differences in diversity and abundance along the stand age gradient. Species richness showed a slight increase from young to oldgrowth. The most abundant spring species were the winter wren (Troglodytes troglodytes), western flycatcher (Empidonax difficilis), varied thrush (Ixoreus naevius), hermit warbler (Dendroica occidentalis), and chestnut-backed chickadee. The Vaux's swift (Chaetura vauxi) exhibited the strongest association with oldgrowth in the spring. Seasonal changes in abundance were greater in young and mature stands than in oldgrowth. This pattern was most noticeable among permanent resident species. A more favorable microclimate and probably better foraging conditions in oldgrowth in winter may explain the observed seasonal patterns of abundance. J. WILDL. MANAGE. 51(3):586-595 Even though the importance of the breeding season has been strongly emphasized as shaping bird communities, the winter season may be equally critical (Fretwell 1972), especially in regions where large numbers of species occupy the habitat throughout the year. Seasonal population changes, particularly of permanent residents, may provide an indirect measure of habitat quality. Forests of different age may provide different levels of resources, and therefore, may vary in quality. The published accounts by Raphael (1984) and Raphael and Barrett (1984) provided comparable studies for late successional Douglas-fir forests in northern California. The purpose of our study was to document the seasonal changes in bird community structure within a sere of natural Douglas-fir forests and o speculate on the effects of forest management on bird communities during both the winter and breeding seasons. We express our appreciation to M. Q. Affolter, B. Booth, J. B. Buchanan, C. B. Chappell, M. This content downloaded from 157.55.39.123 on Tue, 18 Oct 2016 06:04:41 UTC All use subject to http://about.jstor.org/terms J. Wildl. Manage. 51(3):1987 BIRDS IN DOUGLAS-FIR * Manuwal and Huff 587 Emers, K. W. Hegstad, A. Hetherington, A. B. Humphrey, D. A. Leversee, R. W. Lundquist, J. M. Mariani, B. R. North, M. J. Reed, B. A. Schrader, and L. A. Willimont for assistance with the fieldwork. N. J. Manuwal, J. G. Dickson, R. W. Mannan, R. W. Lundquist, and J. B. Buchanan provided valuable comments on the manuscript. We thank J. M. Mariani for many long hours of data editing and calculation of detection rates for the winter 1984-85 data, and J. R. Osborne for his computer expertise. We thank U.S. For. Serv. personnel at the Wind River, St. Helens, Randle, and Packwood ranger districts and Mt. Rainier Natl. Park personnel for various assistance. We acknowledge the support of L. F. Ruggiero, A. B. Carey, and F. B. Samson. This study was funded by contracts PNW-83-219 and PNW-84-227 and is Contrib. 44 of the Old-growth Wild. Habitat Res. Pro