THE BEHAVIOUR OF THE WILLOW WARBLER PHYLLOSCOPUS TROCHILUS IN CONTINUOUS DAYLIGHT

Willow Warblers Phylloscopus trochilus at Wytham, Oxford (51° 46' N., 1° 15' W.), start to sing around sunrise, in late April to early June. In the continuous daylight at Neiden, East Finnmark (69° 42' N., 29° 25' E.), they do not sing all the time, but in late June to late July start singing between 22.45 and 01.45 hrs., the start becoming progressively later as the season draws on. At Neiden, nest visits start some time after song (01.00–02.30), and this is probably also true at Wytham.
The influence of environmental variables on the starts of the two cycles is discussed. It is concluded that song starts at Wytham when light intensity has risen above a certain threshold level, and at Neiden, when it has reached a minimum value or has started to rise again. It is suggested that the Neiden birds react to the closest approximation of their light intensity cycle to that at dawn further south. The end of daily song at Neiden may be controlled by internal factors. It is suggested that the start of the Neiden nest-visit cycle is controlled by light intensity, but modified by temperature effects. The possibility that the environment affects the bird indirectly, via its brood or food, can be ruled out. The functional significance of the retention of activity lulls in the continuous daylight of the Arctic summer is discussed.
The daily song-starts of the Garden Warbler Sylvia borin , Brambling Fringilla montifringilla , and Yellowhammer Emberiza citrinella , follow the same pattern as those of the Willow Warbler. The Redwing Turdus musicus often has no daily song lull; its nest-visit lull begins and ends well before midnight. The significance of this is discussed.     

白头鹎方言的初步研究

对浙江省乘泗岛，普陀岛，温岭，长兴，杭州和龙游等６个地区白头鹎的鸣声进行了研究，发现它们鸣声主句的语调，音节数，持续时间，频谱特征和频率范围等均有差异，说明白头鹎鸣声中普遍存在“方言”，但它们作为同一个种在鸣声主句上有其共同特征：主要是鸣声多在１．５－３ｋＨｚ的低中频段内变化，单音节的鸣叫声等都极为相似。     

ABSOLUTE AND RELATIVE PITCH PRODUCTION IN THE SONG OF THE WHITE-THROATED SPARROW (ZONO TRICHIA ALBICOLLIS)

ABSTRACT

The songs of white-throated sparrows consist of 5 notes of very pure tonal quality. In ascending song, the pitch increases substantially from Note 1 to Note 2; whereas, in descending song, pitch decreases substantially from Note 2 to Note 3. Variability in the absolute pitch of each note is considerable among birds, but much less within individuals. Analysis of the major pitch changes in these songs shows that the pitch interval (ratio of the higher to the lower frequency), a measure of relative pitch constancy, predicts the frequency of the higher note in the pitch change more precisely than does the difference between the frequencies of the two notes, a measure of absolute pitch constancy. We conclude that white-throated sparrows produce relative rather than absolute pitch constancy during the major frequency changes in their songs and suggest that pitch interval may be an important cue in species recognition.     

Molecular evolution in space and through time: mtDNA phylogeography of the Olive Sunbird (Nectarinia olivacea/obscura) throughout continental Africa

This study constitutes the first investigation of the phylogeographic structure of a forest bird distributed throughout the montane and lowland forest biomes of Africa. The key objective was to investigate the importance of Pleistocene climatic cycles on avian diversification across Africa. The Olive Sunbird is a relatively large polytypic sunbird widely distributed throughout evergreen, montane and coastal forests in Africa. Recently, it was split into two species, the Eastern Olive Sunbird (Nectarinia olivacea) and the Western Olive Sunbird (Nectarinia obscura), based on morphological grounds. Analyses of a 395bp fragment of the mtDNA NADH subunit 3 gene with flanking tRNA sequences, from 196 individuals of N. olivacea and 86 from N. obscura indicate that genetic divergence levels are low (1.0-2.4%) across some 9000km, from Ghana in the northwest of Africa to KwaZulu-Natal in eastern South Africa. Neither currently recognized Olive Sunbird species were monophyletic using either parsimony or likelihood tree-building methods. [Formula: see text] (ST) values suggested that there was less variation partitioned among species than between most neighboring regions. Genetic diversity within the N. olivacea/obscura complex was dominated by three star-like phylogenies linked to each other by a single mutational step and two subnetworks (IV and V) separated from the core star-like phylogenies (subnetworks I, II, and III) by five to six mutational steps. The dominant evolutionary mechanism shaping genetic variation within the N. olivacea/obscura complex as identified by nested-clade analyses, appears to be one of range expansion possibly out of East Africa associated with a period of forest expansion during the mid-Pleistocene, some 1.1-0.7 million years ago. Mismatch profiles suggested that secondary contact has occurred between eastern and western lineages within the Ufipa Escarpment and possibly Zimbabwe, as well as between eastern lineages in the Kenyan Highlands and northern Eastern Arc Mts.     

High levels of gene flow among song dialect populations of the Puget Sound white‐crowned sparrow

Populations within a species can show geographic variation in behavioral traits that affect mating decisions or limit dispersal. This may lead to restricted gene flow, resulting in a correlation between behavioral variation and genetic differentiation. Populations of a songbird that differ in a learned behavioral trait, their song dialects, may also differ genetically. If song dialects function as mating barriers, evolutionary processes such as genetic drift should lead to divergence in allele frequencies among dialect populations. The Puget Sound white‐crowned sparrow (Zonotrichia leucophrys pugetensis) is an excellent study system with a well‐defined series of song dialects along the Pacific Northwest coast. A previous study found low genetic differentiation based on four microsatellite loci; however, available loci and analyses techniques have since dramatically improved and allow us to reassess gene flow in this species. We also add extra samples to fill in gaps and add a new level of analysis of geographic variation. Based on acoustic similarities, we group six song dialects into two geographically larger “northern” and “southern” song themes. One southern dialect is acoustically more similar to dialects in the north, which makes the genetic profile of birds singing this dialect particularly interesting. Traditional F‐statistics, analysis of molecular variance as well as Bayesian techniques confirmed the earlier result that geographic variation in song does not correlate with the neutral genetic structure of the sampled dialect populations. The song themes also did not differ genetically, and the origin of the extralimital northern‐theme dialect cannot be determined. We compare this result to findings in several other species and discuss how the timing of learning and dispersal allow vocalizations to vary independently of patterns of genetic divergence.     

3. THE GENERA TURDUS,GEOKICHLA, PSOPHOCICHLA,MONTICOLA AND COSSYPHA IN NYASALAND

Summary

Hanmer, D. B. 1981. Mensural and moult data of nine species of sunbird from Moçambique and Mala?i. Ostrich 52: 156–178.

Wing length, culmen length, weight and moult data are given for the Coppery Sunbird Nectarinia cuprea, Purplebanded Sunbird N. bifnsclata, Yellowbellied Sunbird N. venusta, Whitebellied Sunbird N. talatala. Grey Sunbird N. veroxii, Black Sunbird N. amethystina. Scarletchested Sunbird N. senegalensis. Collared Sunbird Anthreptes collaris and Violet-backed Sunbird A. longuemarei from Mopeia (Moçambique) and Nchalo (Mala?i). Moulting seasons, immature age at moult, the duration of primary moult, its relation to the breeding season, weight changes with moult, the breeding season, altitude and latitude, and the sequence and timing of moult in remiges and rectrices are discussed for all species except N. veroxii, N. amethystina and A. longuemarei. Softpart and plumage colour changes with age are discussed and some data are given on habits and migration.     

THE EFFECT OF TENSION OF DISSOLVED OXYGEN ON THE TOXICITY OF UN-IONIZED AMMONIA TO SEVERAL SPECIES OF FISH

The resistance to rapidly lethal concentrations of un-ionized ammonia ranging from about 2.0 to 8.8 p. p. m. N was determined for rainbow trout ( Salmo gairdnerii Richardson), perch ( Perca fluviatilis L.), roach ( Rutilus rutilus (L.)), and gudgeon ( Gobio gobio (L.)) in tensions of dissolved oxygen 53.4 and 96.7% of air-saturation value at 15.2°C.
The relation between concentration of un-ionized ammonia and period of survival from a few hours to 13 days was investigated for rainbow trout in two tensions of dissolved oxygen, 45.7 and 100.3% of air-saturation value, at 20.1°C.
Period of survival of all the species tested decreased with rise in concentration of un-ionized ammonia.
Decrease in tension of dissolved oxygen increased the toxicity of un-ionized ammonia to all species except gudgeon, for which there was no significant difference in period of survival at the two levels of oxygen.
The effect of oxygen tension on period of survival was greatest in the lowest concentrations of un-ionized ammonia.
Resistance of perch and roach to lack of oxygen was not significantly affected, but that of rainbow trout was reduced significantly, by the presence of a small concentration of ammonia (not toxic to trout within at least 13 days).     

Pitch-related cues in the songs of sympatric mountain and black-capped chickadees

Acoustic frequency (pitch) cues are known to be important in the recognition of conspecific song in a number of songbird species. Mountain chickadees (Poecile gambeli) and black-capped chickadees (Poecile atricapillus) are sympatric over parts of their ranges and their species-typical songs share many features. I examined the acoustic characteristics of song of these two congeners in a region of sympatry in southern Alberta, Canada. As reported for other populations in allopatry, black-capped chickadees emphasized relative frequency cues in song production. In particular, variation in the ratios between note frequencies was significantly less than variation in the note frequencies themselves. In contrast, songs of mountain chickadees did not have constant frequency ratios and contained an introductory acoustic element absent in black-capped chickadee song. Both species may rely on song note frequency or the presence of this introductory acoustic element when differentiating between conspecific song and heterospecific song. Song measures for chickadees in sympatry were similar to measures in allopatry, providing little evidence for character displacement in song production.     

Territorial song and song neighbourhoods in the Scarlet Rosefinch Carpodacus erythrinus

Throughout the range of the Scarlet Rosefinch, its territorial song consists of 3–9 (usually 4–5) elements, of which there are 5 different types. The differences lie in the way the pitch of the element changes in time (frequency "slope") and the width of the frequency band. Within a given type of song, the various elements can be present in almost any combination. Therefore, so many song types can be formed that the songs in even small parts of the species' area are clearly distinct from one another. Despite this capacity for variation, however, by chance identical songs may be sung in widely separated parts of the area, in some cases by different subspecies.
The species has not developed large-scale dialects or regiolects based on a song tradition acquired during an early imprinting phase. Scarlet Rosefinches tend to breed in small colonies, groups of up to about 15 pairs characterized by the same type of song (song neighbourhoods, formed by the development of a microlect).
Microlects develop by a founder effect. When males, near one-year old or older, join one another to form isolated colonies after arrival in the breeding region, they adopt ("learn") the song type that will eventually characterize the colony from the first male to arrive at the site. After the colony has been founded, in most cases each male uses only one type of song during a breeding season, with practically no variation of the temporal and frequency parameters.
Singing the same type of song, the members of a colony accept one another sufficiently to allow the breeding territories to be closely packed. It appears that a long-lasting capacity for acoustic learning, in combination with colony-like breeding and great ecological flexibility, has allowed the Scarlet Rosefinch to become the most successful species of the genus Carpodacus .     

两种米纹蝗雄性鸣声的比较研究(直翅目,蝗总科)

应用计算机技术分析了红足米纹蝗Notostaurus rubripes Mistshenko和小米纹蝗Notostaurus albicornis albicor-nis(Ev.)雄性的鸣声特征。这两种米纹蝗雄性呜叫声的脉冲组持续时间、脉冲组组份、脉冲组间隔、频率的主能峰以及呜叫行为均具有显著差异,可作为2种米纹蝗的分类依据。红足米纹蝗雄性鸣声的脉冲组间隔约为0．647s,每一脉冲组持续时间约为0．0673s,每个脉冲组有8个脉冲串,每个脉冲串仅有1个单脉冲,鸣声的主能峰频率约3．86～5．64kHz。小米纹蝗雄性鸣声的脉冲组间隔约0．529s,每一脉冲组持续时间为0．1185s,每个脉冲组有8个脉冲串,每一脉冲串有1～6个单脉冲构成,主能峰频率约8．10～9．24kHz。     

SONG INHERITANCE AND MATING IN A SONGBIRD WITH LOCAL DIALECTS

ABSTRACT

In this paper we document the pattern of geographic variation in song of the Corn Bunting in a marked population in Sussex. Song variation is best described as a system of local dialects with three song types in each dialect. We examine the inheritance of dialects from father to son; sons sing the same dialect as their nearest neighbour, rather than inheriting the dialect of the father. Therefore songs seem to be learned after dispersal. We also compare the dialects of mates and fathers of females: our results suggest that females do not rely on dialects when pairing. These results are discussed in the context of the current controversy surrounding other species with dialects and hypotheses relating dialects to the genetic structure of populations.     

THE INFLUENCE OF TEMPERATURE AND DAYLENGTH ON SPOTTED WILT VIRUS DISEASE OF TOMATO

The responses of young tomato plants to infection with tomato spotted wilt virus were studied at constant temperatures. The plants were grown in nutrient solutions and given three daylength treatments.
The length of the incubation period was positively correlated with temperature and a regression equation for this relationship is given. The calculated temperature at which this period becomes infinite is 6.7°C. The temperature coefficient ( Q ₁₀) varied from 1.7 to 2.9.
Dry-weight determinations were made of stems, leaves and roots. In healthy plants the leaf/stem ratio generally fell with rise of temperature and the shoot/root ratio rose. Infection changed these ratios, which is interpreted as indicating that it interfered with supplies of carbohydrate to the growing regions.
Systemic symptoms are described for plants raised at 11.4°, 18.3°, 23.9°, and 29.4°C.
Changes in daylength did not affect the systemic symptoms or incubation period. With a 9 hr. day at 29.4°C., the virus content of sap was significantly lower than with 12 or 15 hr., and with a 12 hr. day was significantly higher than with a 15 hr. day.     

Species-universal microstructure in the learned song of the swamp sparrow (Melospiza georgiana)

A swamp sparrow song is a 2-s string of about 10 identical syllables, each made up of two to five distinct notes. Naturally-occurring syllables are highly polymorphic. The development of syllable patterning is strongly influenced by imitation. Analysis of 452 songs indicates that, whether simple or complex, all syllables were assembled from the same species-universal set of note types, consisting of six basic categories. Two populations studied intensively, 1000 km apart, differed in the number of notes per syllable and the ordering of note types within a syllable. It appears that song dialects can be defined in the swamp sparrow by reference to these features. The process of song learning in the swamp sparrow thus consists of the selection of a particular number, timing and sequence of notes from a limited set of types. While some degree of selection of within-type note variants is possible, the structure of the major categories of swamp sparrow note types is in large degree genetically preordained.     

Patterns of Song across Natural and Anthropogenic Soundscapes Suggest That White-Crowned Sparrows Minimize Acoustic Masking and Maximize Signal Content

Soundscapes pose both evolutionarily recent and long-standing sources of selection on acoustic communication. We currently know more about the impact of evolutionarily recent human-generated noise on communication than we do about how natural sounds such as pounding surf have shaped communication signals over evolutionary time. Based on signal detection theory, we hypothesized that acoustic phenotypes will vary with both anthropogenic and natural background noise levels and that similar mechanisms of cultural evolution and/or behavioral flexibility may underlie this variation. We studied song characteristics of white-crowned sparrows (Zonotrichia leucophrys nuttalli) across a noise gradient that includes both anthropogenic and natural sources of noise in San Francisco and Marin counties, California, USA. Both anthropogenic and natural soundscapes contain high amplitude low frequency noise (traffic or surf, respectively), so we predicted that birds would produce songs with higher minimum frequencies in areas with higher amplitude background noise to avoid auditory masking. We also anticipated that song minimum frequencies would be higher than the projected lower frequency limit of hearing based on site-specific masking profiles. Background noise was a strong predictor of song minimum frequency, both within a local noise gradient of three urban sites with the same song dialect and cultural evolutionary history, and across the regional noise gradient, which encompasses 11 urban and rural sites, several dialects, and several anthropogenic and natural sources of noise. Among rural sites alone, background noise tended to predict song minimum frequency, indicating that urban sites were not solely responsible for driving the regional pattern. These findings support the hypothesis that songs vary with local and regional soundscapes regardless of the source of noise. Song minimum frequency from five core study sites was also higher than the lower frequency limit of hearing at each site, further supporting the hypothesis that songs vary to transmit through noise in local soundscapes. Minimum frequencies leveled off at noisier sites, suggesting that minimum frequencies are constrained to an upper limit, possibly to retain the information content of wider bandwidths. We found evidence that site noise was a better predictor of song minimum frequency than territory noise in both anthropogenic and natural soundscapes, suggesting that cultural evolution rather than immediate behavioral flexibility is responsible for local song variation. Taken together, these results indicate that soundscapes shape song phenotype across both evolutionarily recent and long-standing soundscapes.     

Cultural and genetic evolution in mountain white-crowned sparrows: song dialects are associated with population structure

Bird song often varies geographically within a species; when this geographic variation has distinct boundaries, the shared song types are referred to as song dialects. How dialects are produced and their adaptive significance are longstanding problems in biology, with implications for the role of culture in the evolution and ecology of diverse organisms, including humans. Here we test the hypothesis that song dialect, a culturally transmitted trait, is related to the population genetic structure of mountain white-crowned sparrows (Zonotrichia leucophrys oriantha). To address this, we compared microsatellite allele frequencies from 18 sample sites representing eight dialect regions in the Sierra Nevada. Pairwise genetic distances were not significantly correlated with geographic distances either within or between dialects, nor did dialect groups form distinct genetic groups according to neighbor-joining or UPGMA analysis, and most variation in allele frequencies occurred among individuals rather than at higher levels. However, most of the remaining variation was attributable to differences among, rather than within, dialect regions, and this among-dialect component of variance was statistically significant. Moreover, when controlling for the effect of geographic distance, song dissimilarity and genetic distance between site pairs were significantly correlated. Thus, song dialects appear to be associated with reductions in, but not strict barriers to, gene flow among dialect regions.     

MOULTING RHYTHM IN THE ALIENICOLAE OF APHIS FABAE SCOP. (HEMIPTERA: APHIDIDAE) IN THE FIELD

In a natural population of alienicolae of Aphis fabae Scop, on field beans in July 1952, the frequency of moulting of the last larval instar into the alate form was usually relatively high between about 04.00 and 08.00 hr. G. M. T. This high rate was followed by a decline to a lower fluctuating rate for the rest of the day. The moulting rate at night was usually very low.
The high rate of moulting in the morning, just as the temperature is rising, may be due to acceleration of nymphal development which leads to a synchronization of moulting, much as teneral development of alatae, if accelerated, produces flight peaks during the day (Johnson, Taylor & Haine 1957): data on the relations of moulting and nymphal development to temperature are, however, insufficient for making a complete analysis along these lines.
Changes in moulting rate during the rest of the day are correlated with temperature and with time, both independently. A rise of 1°C. ambient temperature is associated with an 11.6% rise in moulting rate: a fall of 1°C. with a drop of 10.5% and a lapse of 1 hr. in time by a 5.4% drop in the rate. Sunshine and humidity show no simple correlation with moulting rate.     

Cultural Evolution of Puget Sound White-Crowned Sparrow Song Dialects

The songs of male Puget Sound white‐crowned sparrows currently form about 12 dialects along the Pacific Northwest coast. In his survey of 1970, Baptista (Condor 1977; 79: 356–370) defined six of the dialects based on the song's terminal trill because most males at each locality shared the simple syllables (SSs) in this trill. The complex syllables (CSs) in the song's introduction varied among males at a locality, and were often shared among localities. From 1997 to 2004 we revisited nine of the sites Baptista studied to determine whether the SSs and CSs had changed over the 30‐yr interval. Using Baptista's catalogs of SS and CS types as bases for comparison, we found that the relative proportions of CS types changed significantly more over time than did the proportions of SS types. These results suggest that SSs and CSs evolve independently. Observations were also made on the developmental mechanisms that either produce diversity or maintain uniformity in song phrases. In a survey of 670 field‐recorded songs, unique improvizations occurred significantly more often in CSs than in SSs. In a laboratory experiment using hand‐reared males and multiple song tutors, males were significantly more accurate in imitating SSs than CSs. In choosing their final song to keep from their overproduced repertoire, yearling males tended to retain the song type that matched the SSs in the song played back to them. We conclude by discussing how differences in the functions served by these two song phrases may have led to their different rates of cultural evolution.     

杭州市区白头鹎鸣声的微地理差异

2002年5—8月,对中国东部浙江省杭州市区的白头鹎鸣声的微地理差异进行研究。在约60 km2的 研究区内,选择8个调查点(4个城区,4个丘陵山地),录制了80个雄性白头鹎的511个鸣声样本,并随机选 取每一调查点的20个鸣声样本进行分析。其结果显示,白头鹎在杭州市区至少有8种微地理鸣声方言,每个微 地理鸣声方言都有一典型鸣句;它们在听觉上、波形结构、音节组成、音节频谱特征等方面均不相同。有的一 路之隔的相邻微地理鸣声方言之间存在明显差异;部分区域出现鸣声混合现象;有的个体还具有“多语”功 能。白头鹎鸣声产生微地理差异的原因可能与鸟类个体的扩散和城市中鸟类栖息地的人为改变有关。     

Song overproduction, selective attrition and song dialects in the white-crowned sparrow

Male Puget Sound white-crowned sparrows, Zonotrichia leucophrys pugetensis, form large vocal dialects along the Pacific northwest coast of North America. Most adult males sing a single song dialect throughout their lives. To determine how dialects are maintained in this species, I studied two populations at the Columbia River mouth in a contact zone between two dialects. Singers of each of the two dialects clustered together in space, forming local song 'neighbourhoods'. Two hypotheses for the maintenance of dialects were tested. The late acquisition hypothesis predicts that yearling or adult male immigrants memorize their song from the territory neighbours they settle next to. The selective attrition hypothesis predicts that males memorize a variety of dialects early in life, overproduce song dialects upon arrival, and later selectively retain the one prelearned dialect that best matches what their neighbours sing. In 1997 and 1998, 35-40% of new territory occupants sang two dialects upon arrival in April, and then over the course of days to several weeks, discarded one dialect from their repertoire. Fourteen of 16 (88%) kept as their adult song the dialect that matched the dialect sung by the majority of their neighbours. No male added a new dialect to his repertoire after arrival, nor did males alter their retained dialect to more closely resemble their neighbours' songs. New arrivals that overproduced dialects upon arrival were significantly more likely to match their neighbours' dialect than males that did not overproduce upon arrival. In a playback experiment, males in the overproduction stage engaged in matched countersinging to the dialect played to them. These observations and the experiment support the selective attrition hypothesis: males visit and memorize a variety of dialects, probably in their hatching-year summer, overproduce dialects upon arrival the next spring, and then selectively retain the one dialect that matches the local song culture. Vocal plasticity late in life is not the result of a late sensitive phase for song memorization, but rather results from behavioural selection operating on a pre-existing repertoire of song dialects. Copyright 2000 The Association for the Study of Animal Behaviour.     

THE BREEDING BIOLOGY OF THE BLACK-FACED DIOCH QUELEA QUELEA IN NIGERIA

A study of the breeding biology of Quelea quelea in Nigeria, and particularly at a large breeding colony near Lake Chad, showed that losses of eggs and young were extremely small. 95% of eggs laid hatched successfully, and 87% give rise to fledglings. Nestling deaths were density-dependent and apparently due to starvation.
The incubation period was 10 days or less. By day, eggs were heated to 34°- 37° C. by the sun; at night the females incubated. The nestlings were initially fed mainly on insects, their diet gradually changing to one of seeds—mostly of the grass Echinochloa pyramidalis . The deep body temperatures of young birds were determined. It is suggested that the nestlings left the nest after, on average, 11¹/₂ days to escape intolerable temperature conditions in the nest.
Fat reserves were accumulated by nestlings and fledglings, and were utilized when the young became independent. The adults put on fat during the incubation period and lost it during the time spent feeding nestlings.
It is concluded that the most common clutch-size of Q. quelea , which is everywhere three, corresponds to the largest number of young the parents can normally nourish. This conforms to Lack's theory on the significance of clutch-size, and gives no support to Skutch's opinion that the theory does not apply to tropical birds.