bluuebunny/crossref_metadata_2025 huggingface dataset:
BODY WEIGHTS IN LAYSAN ALBATROSSES DIOMEDEA IMMUTABILIS
Authors: Fisher Harvey I.
Published: April 2008

Male Laysan Albatrosses are heavier (3300 gm.) than females (3000 gm.) upon arrival on Midway. This difference between the sexes persists except at egg‐laying and during certain periods of incubation.

Weights of males and females are essentially the same at egg‐laying, perhaps because of the presence of the 300 gm. egg in the female, but mostly because the males have lost weight in the pre‐egg phase.

Losses in weight during the long, continuous incubation spans are about 18–25% of the body weight. Males show a net loss of about 10% during the entire incubation period; there is no statistically significant change in the weights of the females.

Weights of both sexes decline in parallel from the end of incubation to mid‐May. Thereafter, they increase as attentiveness to the young is less and the parents have more time to forage at sea. Nevertheless, the body weights of both sexes at the end of the breeding season (July) are down 10–45%.

Decreased body weights of breeding birds cannot be attributed solely to the rigours of parental care; former breeders and juveniles not yet of breeding age show a similar decline in weight.

It is suggested that the normal pattern of yearly breeding by adult Laysan Albatrosses may be broken by failure to add weight (fat) before the breeding season. Former breeders consistently weigh 15–20% less than current breeders.

Nestlings normally show a gradual increase in body weight from hatching in late January until mid‐May, at which time they may be significantly heavier than either parent.

As a result of the increased energy requirements of locomotion and wing exercise and decreased food supplied by parents, nestlings lose about 30% of the May weight before they finally go to sea in Jufy

A possible “mutation” for small body weight is discussed.
COMMUNAL ROOSTING BEHAVIOUR OF THE AUSTRALASIAN HARRIER CIRCUS APPROXIMANS IN NEW ZEALAND
Authors: Gurr L.
Published: April 2008

The Australasian Harrier Circus upproximans habitually roosts communally in New Zealand but not in Australia. As many as 100 birds can occupy a roost in a small area of swamp. They start to assemble about one hour before dark and communal aerial displays in the vicinity of the roost are an integral part of the roosting behaviour. Roosts may be occupied all the year round, non‐breeding birds continuing to roost communally throughout the summer. In New Zealand the habit is neither connected with migration nor is it an anti‐predator device. It is considered that the abundance of food caused by the spread of introduced mammals and the large increase of habitat created by European settlement has built the harrier population up to such a size that the number required to elicit the response of communal roosting occurs at all times of year in most districts. Numbers within individual roosts fluctuate throughout the year and it is suggested that communal displays before roosting may provide the necessary feed‐back for the initiation of population adjustments.
THE BIRDS OF RODRIGUEZ, INDIAN OCEAN
Authors: Bourne W. R. P.
Published: April 2008

The present paper reviews several little‐known 18th century accounts of the sea‐bird fauna of Rodriguez, Indian Ocean. After a brief description of the history of the islands, early information on the sea‐bird colonies is summarized together with a reasoned interpretation of the species involved. Several species no longer known to breed bred in the 18th century. Subfossil petrel bones also indicate the existence of several species now absent, including the Mascarene PetrelPterodroma aterrima. These are described and figured. The scant evidence on sea‐bird breeding seasons suggests the existence of some out‐of‐season and staggered breeding. Finally, a few recent records of land‐birds are listed with some comment on the oriental origin and affinities of the species, and the need for measures to conserve the existing avifauna is stressed.
AUDITORY EXPERIENCE AND SONG DEVELOPMENT IN THE CHAFFINCH FRINGILLA COELEBS
Authors: Nottebohm Fernando
Published: April 2008

The present paper describes the results of experiments designed to evaluate the importance of auditory‐motor experience in the development of song in the Chaffinch. For this purpose a number of Chaffinches collected as nestlings or adults were deafened by extirpating the cochlea at different ages. Recordings of their song made subsequently provide the material on which the paper is based.

Since the results of the experiments can only be interpreted in the light of knowledge of normal song development, the latter is described from the observation of previous workers and from some new material.

Of the 20 males deafened, only three came into full song of their own accord; song was induced in the rest by the administration of testosterone phenylacetate or testosterone propionate. Songs of abnormal length were common among first‐year males though males deafened when two or more years old produced song of the normal length. The song of male Chaffinches deafened as adults, that is after they had produced full song for one or more breeding seasons, was infistinguishable from that produced by intact adult males. They even went through a “plastic” song stage in which some “intermediate” themes occurred. A first‐year male deafened when it had almost stabilized its song produced song that gradually deviated more and more from normal song. This indicates that the bird had not yet laid down a long‐term memory of its song independent of auditory feedback.

First‐year male Chaffinches deafened during early spring, mid‐winter and late sumer, respectively, show that the more they were deprived of the normal period of auditory‐motor experience, the simpler was the song they produced in their first spring. Thus, at the time of deafening they had acquired a particular auditory‐motor experience, and it is the type of element established up to that time that is incorporated into full song.

Male chaffinches brought into the laboratory as nestlings and deafened when three months old produced a virtually sfyctureless song, in which the only recognizable element was a sound reminiscent of the juvenile “chirrup”. The subsong and other calls of these birds were also highly abnormal. Song development in the Chaffinch clearly starts before song as such has made its appearance.

The available evidence suggests that the kind of song a male Chaffinch produces depends directly on its auditory‐motor experience before deafening. There is no indication that deafening achieves its effects on the resultant song by interfering with the hormonal substrate.

Relatively stable song end patterns develop in the absence of auditory feedback, so their occurrence does not necessitate the postulation of templates or preconceived patterns. Song development differs markedly from species to species.
STORM‐PETRELS OCEANODROMA SPP. IN THE INDIAN OCEAN
Authors: Bailey R. S. , Pocklington R. , Wrllrs P. R.
Published: April 2008

In the course of the International Indian Ocean Expedition two storm‐petrels, thought to be Oceanodroma matsudairae and O. monorhis, were encountered in the western Indian Ocean in some numbers. Two specimens of each species were collected, monorhis in the Arabian Sea, matsudairae off N.W. Australia. O. matsudairae, which had not been recorded before from these waters, appeafed to be concentrated within 5° of the equator and the birds probably belonged to the spring‐breeding population of Volcano Island. O. monorhis was found mostly in the Arabian Sea.

Bulweria bulwerii, for which there was but one certain Indian Ocean record, was also encountered several times.
THE IBIS
Authors: Ash J. S.
Published: April 2008

Some aspects of the weights of over 5,500 birds of 79 species, mostly migrants, captured in spring at an oasis on the northern edge of the Sahara, are discussed. Mean weights for five species were 26–44% below those of fat birds (those containing at least 30% lipid) weighed about the same time on the south side of the desert. Weights of fresh arrivals in Britain are higher than those in North Africa, but the differences are not great, suggesting that these have also made a long journey across Europe. Peak arrival times of day‐migrants differed from those of night‐migrants and the weights of some species varied with the time of day. There was no great advantage to migrants in remaining at the oasis; there were few weight changes greater than those normally occurring within an individual's daily range. Several species lost weight steadily during a cold spell, and many died. Male Swallows are heavier and larger than females, and in both sexes weight increases with wing‐length.
OBSERVATIONS ON THE LAVA GULL LARUS FVLIGINOSUS
Authors: Snow B. K. , Snow D. W.
Published: April 2008

Lava Gulls Larus fuliginosus live as scavengers and unspecialized predators along the shores of the Galapagos Islands. Although they concentrate locally at places where refuse is available, their breeding density is low: eight breeding pairs were found along a stretch of 35 miles of the coast of Indefatigable Island. The total (world) population is likely to be less than 300–400 breeding pairs.

Their low breeding density and small total population is attributed to the fact that they are confined to linear feeding grounds of limited extent, which provide a sparse food supply for much of the year.

Lava Gulls nest solitarily, usually in sheltered places near coastal lagoons; all the nests found were at least two miles from any other known site. The clutch consists of two eggs, incubation (one case) lasts 32–33 days, and the fledging period is about 60 days.

Breeding takes place throughout the year, with no apparent peak. Individual cycles of 9–12 months have been recorded.

Observations are given on behaviour and displays, and on the sequence of plumage change and moult in the first two years of life.
POLYMORPHISM IN RINGED PLOVERS
Authors: Smith N. G.
Published: April 2008

The rather similar ringed plovers Charadrius hiaticula and C. semipalmatus represent essentially allopatric, circumpolar populations which overlap in the breeding season only in a narrow zone in the eastern Canadian Arctic.

In eight fiords on eastern Baffin Island, semipalmatus was the more numerous by a factor of almost three. Both plovers occurred together, although not in equal numbers, in the same wide range of habitats.

Pair formation in both plovers apparently took place at the same time, but for more than half of the individuals, not in the same geographic area. The majority of the hiaticula individuals arrived after most semipalmatut, and the late arriving hiaticula appeared to be paired upon reaching Baffin Island. There was an overlap in their arrival times of about five days. Mixed hiaticula‐semipalmatus courtship groups occurred during this period. Pair forming activities of hiaticula and semipalmatus appeared similar but were not studied closely.

Analysis of the non‐overlapping territories of two populations suggested that the plovers did discriminate one type from the other for there was a tendency for unlike pairs to nest side by side. The significance of this odd pattern is not known.

Analysis of the mensural and plumage characteristics of adult plovers from the overlap zone seemed to indicate that gene flow between the two was absent and that they were behaving as distinct species. However, mixed pairs occurred in five out of eight fiords. Considering the populations of all fiords, the number of mixed pairs found (20) was significantly greater than theoretical expectation, which allowed for an occasional mixed mating since a choice of mate was not always possible.

All mixed matings produced mixed broods. The young were either hiaticula or semipalmatus. No intermediates occurred. Moreover, 10 pairs in which both birds were pheno‐typically “semipalmatus” produced both semipalmatus and hiaticula‐type chicks. No intermediates were detected. Egg and chick mortality probably prevented the detection of more such cases. All hiaticula x hiaticula matings produced only hiaticula‐type chicks. The inheritance data indicated that hiaticula and semipalmatus are morphs of a single polymorphic species.

If a switch gene is operating, it may have originally controlled only toe‐webbing, and the other differences may have accumulated as the result of geographic isolation. That differences in plumage pattern and body size are greatest where separation was probably longest supports this hypothesis.

One possible model considered semipalmatus‐type individuals to be either SS or Ss and hiaticula‐types to be ss. Accordingly, all semipalmatus‐types involved in mixed matings with hiaticula‐ types would have been Ss individuals because all such matings produced chicks of both types.

Circumstantial evidence suggested that during the last 80 years, the relative number of the two types in the overlap area has shifted in favour of the semipalmatus‐ type. This might have been the result of selective factors intrinsic to the polymorphism.
PREY TAKEN BY TAWNY OWLS DURING THE BREEDING SEASON
Authors: Southern H. N.
Published: April 2008

The diet of Tawny Owls during the breeding seasons 1949‐52 in Wytham Woods, near Oxford, was determined (a) from analysis of pellets collected, (b) from observation at night, by the use of a red floodlight, of prey brought to the nest and (c) from records of prey left in the nest made during daily visits to weigh the young.

Analysis of pellets showed an increase in the proportion of moles and beetles (mainly cockchafen) in the diet after the first week of May (the time when, on average, the young owls are about half grown) and a decrease in the proportion of mice and voles.

These changes were confirmed in a more emphatic way from observations of food being brought to the nest and from records of prey left in the nest.

This greater emphasis suggests that tho food brought to the young may differ from that which the adults eat themselves.

The fact that no moles were observed being brought to nests at night, wherean many were recorded as surplus prey in the nest, showed that diurnal hunting is regular during the breeding reaaon.

A true assessment of prey taken by Tawny Owls during the breeding season should be based both on analyeis of pellets cast by the adults and on records of food brought to the nest throughout 24 hours. Such records could best be obtained with an automatic camera and flash and a design of nest‐box which is described.
NEST PARASITISM AND DISPLAY OF CHESTNUT SPARROWS IN A COLONY OF GREY‐CAPPED SOCIAL WEAVERS
Authors: Payne Robert B.
Published: April 2008

Chestnut Sparrows Passer eminibey near Magadi, Kenya, built no nests of their own but usurped nests newly built by Grey‐capped Social Weavers Pseudonigrita arnaudi. The sparrows laid eggs and raised their own young in the appropriated nests. The sparrows were synchronized in their breeding with the social weavers but appeared to have a slightly later peak of breeding. Breeding of the sparrows may be stimulated by the sight of breeding activity of the social weavers. Breeding occurred in May and June at the end of a rainy season.

Male Chestnut Sparrows display at the nests with the wings raised. The display is given for several hours each day. Examination of nests built by the social weavers is an element of courtship display by the male sparrow.

In the subfamily Passerinae there is a greater difference in the form of the courtship display between the Chestnut Sparrow and other species of Passer than between nest‐building species of Passer and other genera. The display of Chestnut Sparrows is derived from the nest‐advertisement display of nest‐building Passer. Its exaggerated form may be an adaptation related to pair formation and intrapair sexual stimulation in the absence of male nest‐building behaviour.
OBSERVATIONAL LEARNING IN THREE SPECIES OF BIRDS
Authors: Alcock John
Published: April 2008

White‐throated Sparrows Zonotrickia albicollis, Fork‐tailed Flycatchers Muscivora tyrannus and Black‐capped Chickadees Porta atricapillus were placed in experimental situations where they could watch a trained companion uncover a hidden mealworm. After a period of watching its companion find the concealed mealworm, the observer bird was isolated visually from the other bird. While in isolation the observer birds approached, touched and pecked at a hidden food tray significantly more often than control birds which had not had an opportunity to observe a trained companion. However, the experimental birds failed to learn from observation alone how to uncover the concealed mealworm. But if rewarded in the presence of the companion bird (by taking a mealworm from it or by uncovering a mealworm as a result of local enhancement), then the observer bird frequently did come to find the prey in isolation. It is suggested that the interaction between observational learning and a bird's reinforced socially facilitated experience could assist in the development and expansion of a bird's behavioural repertoire.
BIRD MIGRATION OVER THE MALTESE ISLANDS
Authors: Lucca C. De
Published: April 2008

The present paper is based on data obtained during several years' observations and three recent surveys. Little has previously been published on migration through the Maltese Islands.

The geographical, vegetational and climatic factors of the islands are discussed in so far as they affect the migrants.

Visible migration is seen with anticyclonic weather and westerly winds. Birds are found grounded after night migration in cyclonic weather with southwesterly or easterly winds, much larger numbers and variety being seen with the latter. When there is a deterioration in the weather during the night, a large influx of birds is seen on the following morning, and in addition large flocks of migrating Turtle Doves are seen.

Several trans‐Saharan migrants may pass in smaller numbers during autumn than spring, but the difference may be more apparent than real because in early autumn the birds may depart after only a very short stay, and a few conspicuous species are absent or scarce. By contrast several species which winter north of the Sahara pass only or in much larger numbers during autumn, and these more than make up for those which are absent or rare.

There is no evidence from bird ringing that in spring Malta regularly gets birds from Tunisia, at any rate from that part covered by the ringing stations (Cap Bon, Enfidaville, Gabes). The migrants which pass through Malta probably originate from an area in North Africa around Tripoli and some way westwards of it. During autumn the bulk of recoveries is from eastern European countries with a smaller percentage from northern and central Europe.

Several species or groups of species are dealt with individually.

In the discussion stress is laid on the very close relationship between migration and weather, especially the wind component. The comparatively small numbers of birds seen at Malta probably form part of a larger movement travelling on a broad front. It is argued that the large “falls” of migrants in bad weather result from drift acting on a mass passing mainly to one side or the other of the islands. Since much larger densities are seen with easterly than with westerly winds, it follows, if the hypothesis of drift be correct, that the numbers of birds travelling to the east of Malta are larger than those to the west of it. Moreover, since day migrants are seen with westerly winds and the bulk of night migrants with easterly ones, it is inferred that day migrants normally pass to the west, and the bulk of night migrants to the east, of the Maltese Islands. A parallel is drawn between the autumn migration and the performance of racing pigeons which are flown from the north and NE at this season.
THE WINTER FEEDING ECOLOGY OF THE REDSHANK TRINGA TOTANUS
Authors: Goss‐Custard J. D.
Published: April 2008

The aim of the work was to find out how the Redshank which over‐winter on the Ythan estuary, Aberdeenshire, adapt their feeding activities to the short daylength in winter. To achieve this, the feeding behaviour and daily routine in winter were compared with those in autumn and spring.

Corophium volutator was the main prey on the estuary during the day. However, the temperature of the mud greatly affected the diet in the two areas where the feeding behaviour was studied in detail. At temperatures above 6°C, most of the biomass ingested consisted of Corophium. However, in one study area in one winter, Macoma balthica was taken more frequently at lower than at high temperatures. In the other area, Nereis diversicolor was taken more frequently at low than at high temperatures. These changes in diet appeared related to changes in the behaviour of the prey affecting their availability and not due to the birds changing their preference at low temperatures. The ingestion rate was not affected by the change in diet in the first area but decreased at low temperatures in the second. The sizes of Macoma and Nereis taken by the birds did not vary seasonally. The sizes of Corophium taken decreased in winter as a result of a reduction in the size of those present in the substrate. It was concluded that there was no evidence of Redshank increasing their ingestion rate in winter to compensate for the short daylength.

The proportion of the time spent feeding on the estuary in daylight was greater in winter than in spring. Redshank continued feeding at high water in the surrounding fields and on the estuary at night during the winter but not in either autumn or spring. During the winter they obtained less than 50% of their daily food requirements from the estuary in daylight, mainly because of the short daylength. Consequently, they had to collect the balance at night and at high water.

Seasonal changes in the numbers of Redshank were recorded. After an autumn decrease in numbers, no decrease in numbers could be detected during the winter. These findings are discussed in relation to the possible difficulties for Redshank in collecting their daily food requirements during the winter. The impact of the birds on their main estuarine prey Corophium is also discussed.
THE MECHANICS OF BIRD MIGRATION
Authors: Pennycuick C. J.
Published: April 2008

A theory is presented for calculating the relation between mechanical power required to fly and forward speed, for a bird flying horizontally. The significance of this for migration is explained, and quick methods are given (and summarized in the Appendix) for calculating key points on the curve.

Speed ranges and effective lift: drag ratios are calculated for a number of different flying animals.

Factors affecting migration range are discussed, and the effects of head‐ and tailwinds are considered. Still‐air range depends on effective lift: drag ratio, but not on size or weight as such.

The relation of power required to that available from the muscles is considered. Small birds have a greater margin of power available over power required than large ones, and tend to run their flight muscles at a lower stress, or lower specific shortening, or both. There is an upper limit to the mass of practicable flying birds, represented approximately by the Kori Bustard Ardeotit kori.

The effect of adding extra weight (food or fuel) is to increase both minimum‐power speed, and maximum‐range speed, in proportion to the square root of the weight, and to increase the corresponding powers in proportion to the three‐halves power of the weight.

Birds up to about 750 g (fat‐free) can double their fat‐free mass, and still have sufficient power to fly at the maximum‐range speed. Larger birds are progressively more severely limited in the maximum loads they can carry, and this reduces their range. Many large birds migrate by thermal soaring, thus economizing on fuel at the expense of making slower progress.

During a long flight both speed and power have to be progressively reduced as fuel is used up. A formula is given for calculating the still‐air range of a bird which does this in an optimal fashion. The only data required are the effective lift: drag ratio, and the proportion of the take‐off mass devoted to fuel.

Increase of height has no effect on the still‐air range, but the optimum cruising speed (and power) is increased. The optimum cruising height is reached when the bird can absorb oxygen just fast enough to maintain the required power. The optimum height increases progressively as fuel is used up.

No range is lost as a result of the work done in climbing to the cruising height.
FIELD NOTES ON SOME BIRDS FROM THE BOLIVIAN ANDES
Authors: Vuilleumier François
Published: April 2008

The paper includes data from Bolivia on fourteen rare or little known species of Andean birds. The display of Gallinago stricklandii is described; the ecology and distribution of Uropsalis segmentata, Aeronautes andecolus, Leptasthenura yanacensis, Asthenes pudibunda, Xolmis rufipennis, Oreopsar bolivianus, Oreomanes fraseri, Idiopsar brachyurus, and Compsospiza garleppi are outlined; the feeding behaviour of Chalcostigma olivaceum is described; the nests of Leptasthenura yanacensis, Schizoeaca harterti, Ampelion rubrocristatus, and Phrygilus plebejus are described (those of the first three species apparently for the first time). The species of Furnariidae that are known to breed with incompletely pneumatized skull are listed.
SYNCHRONY AND SOCIAL STIlMULATION IN COLONIES OF THE BLACK‐HEADED WEAVER PLOCEUS CUCULLATUS AND VIEILLOT'S BLACK WEAVER MELANOPTERYX NIGERRIMUS
Authors: Hall John Ruthven
Published: April 2008

The paper is concerned with the relative importance of environmental changes and social stimulation in bringing about synchronized social breeding in Ploceus cucullatus and Melanopteryx (Ploceus) nigerrimus. Field work was carried out in central Uganda.

Observations on a single colony of each species extending over a complete breeding period showed that breeding started abruptly with the arrival of a large number of males and the construction of new nests. The majority of females arrived later within a relatively short space of time. Subsequently the number of birds and the amount of activity declined gradually. Nests were repeatedly destroyed and reconstructed in the same positions. In P. cucullatus an entrance funnel was generally added only after occupation of the nest by a female.

Studies extending over a large number of colonies showed that main breeding seasons correspond approximately with the two rainy seasons each year. Isolated colonies may be active between seasons, however.

Nest‐building and breeding are highly synchronized within colonies. Uniform responses to rain may partly account for this synchrony, but fluctuations of activity in neighbouring colonies are relatively unsynchronized, suggesting that social stimulation is also an important factor. This is supported by direct observations of social interactions and by the fact that small colonies are relatively less successful than larger ones, apparently because the pair‐formation process may fail in the absence of sufficient social stimulation.
WEIGHTS OF SOME PALAEARCTIC WADERS WINTERING IN KENYA
Authors: Pearson D. J. , Phillips J. H. , Backhurst G. C.
Published: April 2008

Palaearctic waders were caught and weighed at Lake Nakuru in the Kenyan rift valley on 22 occasions in the non‐breeding season between March 1967 and May 1969. The weights of four species are presented:Curlew Sandpiper, Little Stint, Ruff and Marsh Sandpiper.

Winter weights were relatively low and varied little. It is thought that waders had very little fat reserve at this time.

The mean weights of early autumn samples tended to be higher than corresponding mean winter weights, and autumn populations included some markedly heavy birds.

An increase in the mean weight, and a dramatic rise in the maximum weights of each species occurred shortly before its main spring departure time. The great majority of waders apparently gained considerable weight before migration from the area in April and May.

The spring migration of waders from Kenya is briefly discussed.
NOTES ON THE BIRDS OF THE MOLLENDO DISTRICT, SOUTHWEST PERU
Authors: Hughes R. A.
Published: April 2008

An account is given of the geography and ecology of the Mollendo district, Southwest Peru, followed by a systematic list of the species recorded there over a period of 16 years' residence.

The following species are recorded, apparently for the first time, from the south coast of Peru:Pachyptila belcheri, P. desolata, Florida caerulea, Butorides striatus, Bubulcus ibis, Plegadis chihi, Himantopus himantopus, Micropalama himantopus, Chaetura pelagica, Petrochelidon pyrrhonota, Riparia riparia and Pheucticus chrysopeplus.
THE TIMING OF BIRDS‘ BREEDING SEASONS
Authors: Perrins C. M.
Published: April 2008

Examination of survival rdtes of nestlings and fledglings of some species show that there is a strong tendency for those young which are hatched earliest in the season to have the greatest chance of surviving to breed. Since natural selection so strongly favours parents who leave many surviving young, the question arises as to why other birds breed later than the date at which they could most successfully raise their young.

It is suggested that the food supply for the breeding females immediately prior to the breeding season may limit their ability to form eggs and the females may thus not be able to lay at the time which would result in young being in the nest at the best time for raising them, but as soon after this time as the female is able to produce her eggs. Not all species are likely to be prevented, by food shortage, from breeding at the best time for raising young and the groups of birds most likely to be affected are discussed.
TERRITORIALITY IN THE COMMON SHELDUCK TADORNA TADORNA
Authors: Young Colin M.
Published: April 2008

A population of Common Shelducks on the Ythan Estuary was studied intensively from December 1961 to August 1964, with special attention to territoriality and population regulation.

Many of the shelducks in this population establish mutually exclusive territories; the others (usually about one third of the population) remain together in a communal flock. Both members of territorial pairs take part in territorial defence.

Territory size is determined by the immediate topography of the area and by the limits of tolerance of the owner. The distribution of territories was found to be related to the distribution of Hydrobia ulvae, which is the staple item in the shelducks' diet.

Territories were usually occupied by the same birds year after year. The number of territories remained constant at 71 ± 1 throughout the three years of the study.

The first birds to return in the spring were not necessarily the first to take up their territories. Some territories were left unclaimed (at least for the greater part of the day) until the end of April. At no time were interlopers or neighbours ever seen trying to establish themselves in these unoccupied territories.

Territories from which both birds were experimentally removed were reoccupied by birds from the surplus flock, usually within a matter of days. When females of territorial pairs were removed, the surviving males invariably deserted their territories, but when the males were removed, the females remained on their territories and eventually acquired new mates.
THE SIGNIFICANCE OF CIRCADIAN BASED PHOTOSENSITIVITY IN THE HOUSE SPARROW PASSER DOMESTICUS
Authors: Murton R. K. , Lofts B. , Orr A. H.
Published: April 2008

Adult male House Sparrows, wild caught in December and January, were held on daily seven‐hour artificial photoperiods for 14 days beginning in late February, with the aviary lights arranged to switch‐on at 07.00 hrs. A control sample was then killed and the remaining birds divided into groups which received six hours of light daily (beginning at 07.00 hrs) plus one further hour of light given at variable times from the dawn. A further group received 16 hours of light given continuously (16L‐8D). Pooled plasma samples from these groups were assayed for luteinizing hormone (using a radio‐immunoassay technique) and the histological condition of all testes was examined.

Although all subjects received the same total amount of photostimulation only those given schedules simulating long days responded with testicular growth and spermatogenesis. It is argued that this was because light can only be effective if received during relatively restricted phases of a circadian‐based rhythm; only during these phases is the neuroendocrine apparatus sensitised to photostimulation.

Increase in size of the testis tubules and meiotic divisions of primary spermatocytes, leading to secondary spermatocyte production and increase in testis weight, were considered to be indicators of FSH activity. Using these criteria a curve of FSH activity could be drawn and be compared with the quantitative curve for LH levels obtained from the plasma assays (a comparable assay technique for FSH is not yet available). Although LH levels remained approximately the same in all groups, and this correlated with the histological and histochemical evidence, FSH activity was more pronounced in those groups given light flashes at increased intervals after the beginning of the dark period. Thus LH activity occurred in the absence of spermatogenetic development in those groups given “short‐day” schedules.

Birds kept on a 16L‐8D regime contained less plasma LH than anticipated and the possible existence of inhibitory mechanisms is discussed. It is feasible that when much FSH secretion begins LH production declines, but this explanation is speculative.

The temporal pattern of LH production was markedly different in Greenfinches (for which the experimental results are described elsewhere) than in the House Sparrows, and the discussion considers the reasons for these differences in terms of the ecological and ethological adaptations of the two species.
NOTES UPON A COLLECTION OF BIRDS FROM INDOCHINA
Authors: Dickinson E. C.
Published: April 2008

The rediscovery of some of the lost collection of Monsieur A. David‐Beaulieu from Laos is reported. Notes are given on 22 selected forms and a list is appended of the type specimens and topotypical material in the collection. One species, Acrocephalus concinnens, is reported from Indochina for the first time and several forms are reported or confirmed for the first time for either North or Central Laos.
OBITUARIES
Authors: MOREAU R. E.
Published: April 2008

The following autobiographical sketch was written by the late R. E. Moreau at the invitation of Dr. David Lack and was deposited at the Edward Grey Institute, Oxford, in 1966. By printing it in full we dispense with the need for a formal obituary, and instead have invited four ornithologists who knew Reg Moreau especially well to contribute their personal appreciations. These follow on pp. 557–564. Ed.
SOME OBSERVATIONS ON THE SPLENIUS CAPITIS MUSCLE OF BIRDS
Authors: Burton P. J. K.
Published: April 2008

A description is given of a modification of M. splenius capitis, best developed in the Apodiformes. In this order, the muscle originates on the opposite side of the midline from its insertion; the right and left muscles cross each other by means of interdigitating slips. This arrangement is termed the “cruciform origin”. A cruciform origin of simpler structure is also found in the Aegothelidae and Turnicidae, and similar tendencies on a smaller scale have been discerned in most orders. It is suggested that the cruciform origin in its extreme form increases the capacity for rapid and extensive head turning. The evolution and possible taxonomic significance of the cruciform origin are discussed, and problems for further investigation are suggested.
WEIGHTS OF SOME PALAEARCTIC MIGRANTS IN SOUTHERN UGANDA
Authors: Pearson D. J.
Published: April 2008

Between March 1966 and May 1968 Palaearctic passerines were mist‐netted in thick bush and lightly wooded savannah habitats near Kampala, on the northern shore of Lake Victoria. This paper reports weights of the seven principal species involved.

Most migrants appeared to be in a lean condition during the winter months, when weights were relatively low and varied little in each species. Birds were not particularly light on arrival. In fact, autumn Garden Warblers Sylvia borin and Willow Warblers Phylloscopus trochilus were sometimes markedly heavy, and for the former species there was some evidence that the individuals concerned were passage migrants. Autumn weights of Swallows Hirundo rustica, Reed Warblers Acrocephalus scirpaceus and Yellow Wagtails Motacilla flava were similar to those recorded in winter.

The mean weight of all species rose during late March or early April. Although most Garden Warblers and Willow Warblers trapped at the time of spring migration were within the normal winter weight range, many Acrocephalus warblers and the majority of Sand Martins Riparia riparia and Yellow Wagtails were rather heavy. Spring weights 40% or more above mean winter weight were not uncommon in the Sedge Warbler Acrocephalus schoenobaenus, but were recorded only occasionally in other species. Although most passerine migrants evidently left Kampala with substantial fat reserves, it was concluded that a considerable number of warblers departed at rather low weight.

High spring weights were mainly confined to a period of two or three weeks in each of the warbler species. Locally wintering Acrocephalus warblers must have attained full premigratory weights within three weeks, and a number of spring retraps showed substantial gains at minimum mean rates of between 0–1 and 0–35 g per day. Most heavy Garden Warblers were probably on passage.

Significant correlations between weight and wing‐length were obtained for all species investigated, regressions of weight on wing‐length being in the range 011‐0‐25 g/mm.

Spring weights are briefly compared with data from Nigeria, and the northward migration of passerines from Lake Victoria is discussed.
SEASONAL VARIATION IN METABOLIC FUNCTIONS OF BRAMBLINGS
Authors: Pohl Hermann
Published: April 2008

Seasonal variation in the rate of oxygen consumption during rest at different test temperatures and in the respiratory quotient (RQ) was observed in male Bramblings Fringilla montifringilla which had been caught as immature birds during autumn migration and kept under outdoor conditions for one year.

Resting oxygen consumption measured from +31o to – 4oC during one night was significantly lower in late April and October (migratory seasons) as compared to the preceding and the following December. Because of marked seasonal changes in body weight, the significance of differences in metabolic rate between different seasons was largely dependent on the manner of expressing the rate of oxygen consumption, either per bird or as the 0–67 power of body weight (“surface coefficient”).

The lower resting rate of oxygen consumption during the migratory seasons was interpreted as one possible factor responsible for allowing fat deposition by reducing total energy expenditure. This modification occurred only in birds kept under quasi‐natural conditions outdoors and not in birds which were kept in cages under constant conditions of light and temperature in the laboratory.
A NEW FAMILY OF HOATZIN‐LIKE BIRDS (ORDER OPISTHOCOMIFORMES) FROM THE EOCENE OF SOUTH AMERICA
Authors: Cracraft Joel
Published: April 2008

A new fossil genus and species, Onychopteryx simpsoni, is described for a proximal end of a tarsometatarsus from the lower Eocene (Casamayor Formation) of Argentina. Onychopteryx is considered most closely related to the Opisthocomidae but is sufficiently distinct to be placed in its own family, the Onychopterygidae. Onychopteryx indicates that the Opisthocomiformes had differentiated by the early Eocene and were present in South America at that time.
NESTING OF THE PURPLE‐THROATED CARIB HUMMINGBIRD
Authors: Wolf Larry L. , Wolf Janet S.
Published: April 2008

We present data on certain parts of the nesting biology of the Purple‐throated Carib Humming‐ bird Eulampis jugularis on the island of Dominica, British West Indies. We watched two nests with eggs and young and a single nest under construction. Incubation was in short periods averaging about six minutes. Females at both nests with eggs continued adding material to the nest until the end of incubation. We suggest that this common practice among hummingbirds may insure that a limited amount of energy at the time of initial nest‐building and egg‐production is optimally apportioned between the two activities. Brooding ceased in one nest when the young were about 13 days old. Feeding rates stayed relatively constant at one to two per hour throughout the nearly complete nestling period in one nest. Average time per feeding declined, apparently as the female‐young interaction became more efficient with maturation of the young. Nesting females foraged on both insects and nectar. We could not be sure what they were feeding the young. Defence of the nest varied with the position of the female and the type of intruder. The aggressive behaviour associated with defence varied according to the size and type of intruder.

We concluded that for the one nest of Eulampis for which we had the most complete data, had there been three young, the female would have been unable to provide sufficient food to nourish them. However, the universal clutch size of two and nearly universal promiscuity in humming‐ birds is strong evidence that factors other than the ability of adults to feed more than two young are important in determining clutch size.
GROWTH AND DEVELOPMENT OF NESTLING HEN HARRIERS
Authors: Scharf William C. , Balfour Edward
Published: April 2008

Nestling Hen Harriers Circus cyaneus in Orkney were weighed and measured during two nesting seasons.

The 501 weights and 390 longest primary measurements produce a composite record of growth for this species. The general shape of both weight and primary growth curves is sigmoid.

The primary feather growth can be measured at age seven and eight days after hatching and is less variable as an index of growth than is weight. The nestling period varies usually from 30 to 36 days, and age at first flight depends on the ratio of primary length to weight. Males usually fly before their heavier female siblings.

The asynchronous hatching produces a size‐rank between nestling Hen Harriers. The significance of the size‐rank to growth and mortality is discussed.

Sexual dimorphism develops at the nestling stage. Weights and measurements of males and females at different ages are tabulated.

Asynchronous hatching, and the influence of latitude differences on growth rate are briefly discussed.
OBSERVATIONS ON THE BREEDING BEHAVIOUR OF GREY AND RED‐NECKED PHALAROPES
Authors: Hohn E. Otto
Published: April 2008

Observations were made on Grey and Red‐Necked Phalaropes near Chesterfield Inlet, N.W.T., Canada, from the date of their local arrival, 13 June, until 21 July 1967.

The similarity of the colour of the Grey Phalarope nuptial plumage to that of dead seaweed among which the birds often feed is suggested as possibly relevant to the evolution of this plumage.

A mutual Head Up pre‐copulatory display, first given by the female, is described in Grey Phalaropes. It is suggested to have the function of assuaging fear in the prospective partner and to be a prelude of only the first copulation between any two birds. Other displays are described and figured.

Three full copulations, including their preliminaries, were observed in this species and two others in which the preliminary actions escaped observation. Three copulations took place on land and two on water. Of the three copulations observed with their preliminaries, two were initiated by some form of display by the female, and one, without any display, by the male. Eight attempted copulations were observed; all were initiated by males and all but one took place while the female was on land. One male which had just copulated was observed to attempt copulation with another female. In the course of three full or attempted copulations, another Grey Phalarope fluttered up against the mating pair.

All Grey Phalarope copulations took place in a collective feeding area; little intra‐species antagonism was seen and no evidence of territorial behaviour. All female Grey Phalaropes left the colony under observation on the night of 9–10 July; only two eggs had by then been laid in one nest and the female of one pair had not laid at all.

Six copulations and six attempted copulations were observed in Red‐necked Phalaropes; all took place on the water. Only in two of the copulations were the preliminaries observed; one was initiated by a display of the female, the other without any preliminary display by the male.

Preliminary observations suggest specific differences in rate of spinning and in the preferred direction of spin. The functions and factors associated with spinning are discussed. Accelerated spinning with reduced frequency of pecks at the water by both members of a pair of Red‐necked Phalaropes was observed once and may have been a form of display.

Head scratching, observed once in a Red‐necked Phalarope and several times in Wilson's, is by the direct method, supporting the view, based on the colour pattern of the downy young, that phalaropes are more akin to the sandpipers than to the avocets.
HANDEDNESS IN THE BROWN‐THROATED PARAKEET ARATINGA PERTINAX EST RELATION WITH SKELETAL ASYMMETRY
Authors: McNeil Raymond , Rodriguez José R. , Figuera Damelys M.
Published: April 2008

Observations on 56 specimens of Aratinga pertinax when bringing food to the beak prove that 28 birds were right‐handed while the other 28 were left‐handed. A biometric analysis reveals a slight departure from bilateral symmetry in hindlimb bones in close relationship with handedness. In the right‐handed birds, there is a significant predominance in the length of the right hindlimb as a whole and all right limb segments. The opposite holds true in left‐handed parrots (except for the femur). Right‐handed birds are in general more highly asymmetrical than left‐handed ones. There is a positive correlation between asymmetry of homologous segments of a pair of limbs and the asymmetry of the other segments of the same pair of limbs. The absence of significant negative correlations between bilateral differences of the different segments of a limb indicates that departures from bilateral symmetry tend to affect the limb as a whole, and thus is not in agreement with the rule of compensating variations.
TEMPERATURE RHYTHMS IN AFRICAN MONTANE SUNBIRDS
Authors: Cheke R. A.
Published: April 2008

The thermoregulation of Nectarinia tacazze, N. famosa, N. mediocris and Anthreptes collaris was studied at three localities in the Cherangani mountains, Kenya. Most of the experiments were conducted at an altitude of 3,350 m.

These sunbirds were found to have a diel temperature rhythm with ranges of 5o‐17oC, an adaptation for survival in the severe temperature regimes characteristic of high altitudes in Africa. The only other passerine birds in which regular temperature changes of this magnitude have been recorded are three members of the Hirundinidae.

For Zosterops senegalensis and male N. mediocris a significant difference was found between the weights of birds caught at 2,690 m and those from 3,350 m.