bluuebunny/crossref_metadata_2025 huggingface dataset:
THE FOOD AND FEEDING APPARATUS OF THE BLUE DUCK HYMENOLAIMUS
Authors: Kear J. , Burton P. J. K.
Published: April 2008

This paper describes a preliminary study of the feeding behaviour of the territorial Blue Duck. The bird is unusual in possessing lateral bill flaps and, in a number of head and skull characters, differs from a typical dabbling duck. Herbst's corpuscles are absent from the outer 60% of the width of the flaps and this is thought to indicate that any tactile function is subsidiary. It is tentatively suggested that an additional function is protective, and that the flaps cushion the jaw edges during vigorous food searching beneath stones on rocky stream bottoms. Food taken in summer was analysed from remains in droppings and from gut contents and was found to consist of aquatic insects, principally case‐living and free‐living caddis larvae, and algae. Some short‐term variation in the diet was noted. It is suggested, also tentatively, that the decline in Blue Duck numbers since the 19th century has been associated with the introduction of trout which are potentially direct food competitors. Further ecological research on this unique species is required.
PTERYLOGRAPHY, PLUMAGE DEVELOPMENT AND MOULT OF JAPANESE QUAIL COTURNIX C. JAPONICA IN CAPTIVITY
Authors: Summers D. D. B.
Published: April 2008

Japanese Quail were kept in small cages under controlled conditions of temperature and light, and their pterylography and moult are described. There are 10 primaries, 14 secondaries and corresponding numbers of greater upper and lower wing coverts. The alula has four feathers and the tail from five to six pairs of feathers. There is an apterium in the dorso‐pelvic tract similar to that in other quail genera. The arrangement of feathers in the ventral and cervical tracts appears to differ from that described for some North American quail.

The chicks hatch with a covering of natal down. Pre‐juvenile moult can be seen when the chicks are three days old. Juvenile body plumage is complete in about 30 days; the sides of the face, around the eyes, are the last places to acquire feathers. The tenth and last juvenile primary to grow is mature when the chicks are 41 days old.

The moult in which the juvenile plumage is replaced overlaps the post‐natal moult and in part of the ventral tract natal down is replaced by the first adult feathers. This makes it possible to sex the quail at 14 days old. The first adult moult is complete, in the body tracts, by the time the birds are five to six weeks old. The dropping of juvenile primaries commences at about three weeks old and ceases when about eight weeks old. Only from three to six primaries are replaced; most birds studied replaced five. The significance of this difference from other Galliformes is discussed; it is thought to be associated with the species' migratory behaviour. Quail which remained in the controlled laboratory environment did not undergo any further moult. All birds moulted when both temperature and light period were reduced and most birds moulted when the light period alone was reduced. Adult birds housed in small cages in an unheated, unlit shed underwent a complete moult between August and December in which all primaries were replaced. This moult took 8–14 weeks to complete.
A FIELD STUDY OF THE CALFBIRD PERISSOCEPHALVS TRICOLOR
Authors: Snow Barbara K.
Published: April 2008

The Calf bird Perissocephalus tricolor was studied in the Kanuku Mountains of southern Guyana for three months (January‐April 1970), during which time almost daily visits were paid to a lek of four adult males.

The adult males owned perches about 30 ft up in understorey trees, where they displayed and called throughout much of the day. Four immature males also visited the lek, particularly in the morning and evening. The immatures also wandered, feeding and occasionally calling together, over an area of forest of approximately 3 miles by half a mile. There was a hierarchy among the adult and immature males, the dominant males owning the most coveted perches at the lek.

The male's most far‐reaching call, the “moo call”, is a co‐operative advertising call, in that birds calling together adjust the timing of their calls so as to follow each other and not overlap. The adult males perform a number of silent agonistic displays on their lek perches. Periodically, adult and immature males and sometimes a female invade the vicinity of a lek perch, usually that of the dominant male. Once a female was briefly mounted by the dominant male on his lek perch during an invasion. On other occasions females visited the lek but no mating occurred.

The food of the males attending the lek was recorded by the daily collection of a total of 2,500 regurgitated fruit seeds (mostly drupes) from below the perches. Males also regularly take insects, but in smaller quantities.

Three nests were found. The nest is an extremely light structure built entirely of fine twigs. A single egg was laid in each nest. All the nests (and two old ones) were within half a mile of the lek. Two of the nests were only 5 yards apart and the eggs were laid in them within 10 days of each other.

The incubation period at one nest was 26–27 days and the fledging period approximately 27 days. The chick on hatching was covered in bright orange‐chestnut down. It was fed mostly on insects (predominantly Orthoptera) brought by the female in her beak. There was no evidence of a male attending the nest.

The Calfbird's nesting and lek behaviour is compared with that of other species of Cotingidae.
TERRITORY ESTABLISHMENT AND STABILITY IN McCORMICK'S SKUA
Authors: Young E. C.
Published: April 2008

This paper describes the way in which a new pair of McCormick's Skua became established in a vacant area in a breeding colony. The pair worked out from a central point to meet neighbouring birds on the original boundaries so that these became re‐established. Within three days of settling most of the vacant area was claimed and the pair was behaving as a recognised member of the breeding group. Eggs were laid in the first season.

Following comparison with other species it is proposed that the stability found in territory boundaries from year to year arises because territories becoming vacant are occupied by replacement pairs while neighbours are inhibited from encroaching on them.
HABITATS AND FEEDING STATIONS OF ST LUCIA FOREST BIRDS
Authors: Diamond A. W.
Published: April 2008

The habitats and feeding stations of birds in six types of forest, two mountain and four lowland, are described. Just over half the species occur in both lowland and mountain forest, about half the remainder being restricted to mountain and half to lowland forest. Endemic species, of which St Lucia has more than any other island in the Lesser Antilles, occur in a wide range of habitats, and their significance is discussed in relation to current theories of island biogeography.
THE ECOLOGY AND BEHAVIOUR OF THE LONG‐TAILED TIT
Authors: Gaston A. J.
Published: April 2008

The behaviour and ecology of a population of Long‐tailed Tits in Wytham Great Wood, Oxford, were studied between October 1970 and June 1971. Flocks were found to have a stable composition in autumn, and to occupy fairly discrete territories which they defended against other flocks.

In spring the population was reduced by about 50% and in the pre‐nesting period flocks formed only in cold weather or just before going to roost. These flocks occupied the same territories as the autumn flocks and the individuals composing them eventually nested within the flock territory.

Predation of nests was heavy, increasing to a peak in the first half of May. Only nine pairs out of 36 managed to rear young successfully. At six out of these nine nests, supernumerary birds helped to feed the young, but it seems unlikely that this increased their success, since all young hatched fledged successfully. The presence of supernumerary birds at the nest was accompanied by frequent hover‐displays by all the adults.

The distribution of nests in relation to habitat shows that there is a preference for scrub rather than mature woodland, although the latter is used extensively for feeding during the winter. There appears to have been a radical change in the height of nest‐sites in Wytham Great Wood between 1955–57 and 1971, and this is probably due to predation.
ON THE ORIGIN OF DIVERGENCE OF LEARNED SIGNALS (SONGS) IN ISOLATED POPULATIONS
Authors: Thielcke Gerhard
Published: April 2008

Short‐toed Treecreepers Certhia brachydactyla in Morocco sing very differently from European Short‐toed Treecreepers.

Short‐toed Treecreepers from Central Europe do not react to the playback of songs of North African Short‐toed Treecreepers. This result is statistically highly significant.

Treecreepers C. familiaris of Central Europe do not react to the playback of songs of North African Short‐toed Treecreepers or (some males) react just as little as they do to songsof Central European Short‐toed Treecreepers. This result is statistically highly significant.

Three hypotheses are examined as interpretations of these results: contrast reinforcement, loss of contrast and withdrawal of learning. The facts are best explained by withdrawal of learning. According to this hypothesis, Morocco was colonised by young European Short‐toed Treecreepers with a song that had not yet been fixed by learning. The founders of the new population evolved a divergent song, which has been transmitted by tradition ever since.
THE EFFECT OF EGG WEIGHT ON THE SUBSEQUENT GROWTH OF NESTLING GREAT TITS PARUS MAJOR
Authors: Schifferli L.
Published: April 2008

Eggs of known fresh weight were removed from Great Tit nests shortly before hatching and artificially incubated. Four to eight chicks were returned to each nest‐box on their hatching day and reared by foster parents. The effect of egg weight on subsequent growth was studied for 81 nestlings (13 broods), 50 of them (8 broods) up to the 17th day.

Hatching success of 275 eggs in the incubator was 67·6% and was not correlated with egg weight.

Egg weight had a significant effect on nestling weight up to the 14th day. Young hatched from lighter eggs grew more slowly at the beginning, but recovered before fledging. Mortality after fledging seemed not to be influenced by egg weight.

Maximum weight (mean 19 g) was attained between the 12th and the 17th day and was positively correlated with egg weight.

The effect of brood‐size (small in the experiments) on growth increased significantly with age. The range of egg weight for a nest had a significant effect on growth at the beginning, but a small and not significant effect after the 10th day.

The growth of each brood on any particular day was expressed as a deviation from mean growth. These growth deviations, plotted against date, were similar in all nests and were not correlated with any weather data.

The fledging success of 260 early broods was independent of egg weight, but it was positively correlated with egg weight in 78 late broods (data from 1965–71).

The ecological importance of egg weight at different times of the breeding season is discussed.
RAPTOR MIGRATION ACROSS THE STRAITS OF GIBRALTAR
Authors: Evans P. R. , Lathbury G. W.
Published: April 2008

The visible migration of birds of prey at Gibraltar is analysed from records kept throughout the spring passages of 1967–70 and the autumn passages of 1967–69. In early spring most visible passage is noted in the afternoons, whereas radar observations by Houghton (1970) indicate passage in the mornings. Later in the year an additional burst of visible passage sometimes occurs in the early morning, but it is concluded that most morning movements take place above visible range. Visible migration is recorded on most days of westerly wind during the migration seasons at Gibraltar. Passage is rarely seen when the winds are easterly. It is argued that under the latter conditions a strong upcurrent of air (standing wave) is formed over Gibraltar, and that this carries nearly all migrants above visible range.

Observations of visible passage elsewhere in the Straits suggest that, in spring, raptors of all species cross on a broad front from Tangier to Ceuta, except Honey Buzzards, which probably cross chiefly near Ceuta. In autumn, all species from northern Europe cross chiefly between Tarifa and to the east of Gibraltar, while birds from western Iberia probably cross mainly near Tarifa.

The periods of passage of the common migrant species are summarised.

On the basis of visual observations and published radar results, it is argued that raptors can compensate for lateral drift by the wind and so fly on chosen courses; but that in very strong cross‐winds, e.g. the easterly Levanters, they may have to let themselves be drifted off‐course.
POLYMORPHISM IN THE ARCTIC SKUA STERCORARIUS PARASITICUS IN ICELAND
Authors: Bengtson Sven‐Axel , Owen D. F.
Published: April 2008

A survey of the frequency of the dark and light colour forms of the Arctic Skuas breeding in Iceland provided evidence of a south‐north cline, the light form being more frequent in the north than in the south. In one area there were significantly more dark birds in 1971 than 30 years earlier, but in two other areas there was no evidence of a change in frequency. In northeast Iceland, where the light form is common, there was a statistical tendency towards unlike matings. It is suggested that the adaptive significance of the forms is to be sought in terms of facilitating departures from random mating, the genetic consequences of which are understood in general terms, although the ecological significance remains obscure.
A REANALYSIS OF NEST STRUCTURE IN THE WEAVERS (PLOCEINAE) USING NUMERICAL TAXONOMIC TECHNIQUES
Authors: Schnell Gary D.
Published: April 2008

Variables of nest architecture and construction behaviour of 62 species of ploceine finches studied by Crook (1963) were reanalysed using multivariate statistical techniques. Phenetic assessments were based on 38 two‐state characters for 48 OTUs. Product moment correlation coefficients and average distance coefficients were used as measures of similarity, and species were clustered using the unweighted pair‐group method with arithmetic averages. A three‐dimensional model was constructed of species plotted with respect to the first three principal components extracted from a matrix of correlations among characters. Principal component and factor analytic techniques were employed to determine trends in character variation.

The phenetic affinities expressed in the 3‐D model and two phenograms show many similarities to the phenetic groupings deduced by Crook. However, there were also some differences in interpretation. Crook's Modes C and D were shown as distinct clusters in my analyses, but Modes A and B did not separate completely. In particular, the globular nest of P. baglafecht of Mode A, Type IV, grouped with kidney‐shaped nests of species of Mode B, Type Va. The treatment of P. pelzelni, P. madagascariensis, and P. philippinus in my analysis differed somewhat from Crook's. The resulting cluster of F. sechellarum and M. malimbicus brought out some effects of standardising data on resulting interpretations of similarity.

Species within the subtypes of Crook usually remained close together, but the affinities between subtypes (and types) often differed between our studies. The results of factor and principal component analyses indicate that the main trends in character variation concern those traits found together in (a) M. rubriceps; (b) A. unicolor and Pa. superciliosus; (c) forest birds; and (d) non‐forest birds. These groups also are the main clusters. Differences in Crook's and my results are discussed and some of the advantages of utilising numerical techniques to describe similarity are mentioned.
SOCIAL BEHAVIOUR OF BREEDING WESTERN SANDPIPERS CALIDRIS MAURI
Authors: Holmes Richard T.
Published: April 2008

The behavioural interactions among breeding Western Sandpipers (Calidris mauri) are described, and interpreted in terms of their adaptive characteristics.

Upon arrival in early spring, males disperse onto territories through mutual antagonism. Territorial advertisement and maintenance is accomplished through display flights low over the ground, which are accompanied by soft buzzy vocalisations. These characteristics of display are related to the fact that this species occurs in dense, localised breeding populations, where longdistance communication is unnecessary.

Because densities are high and feeding often occurs in communal areas off territory, violations of territorial boundaries are frequent. The result is an extremely high intensity of interactions among individuals. Chasing and physical combat between males is frequent and generally un‐stereotyped. Birds nesting on territories away from the feeding sites often fly high above the other territories, and in doing so avoid being chased.

Western Sandpipers form monogamous pair‐bonds which are maintained until the young are ready to fly. The initial association of the pair is facilitated by a strong tendency to return to the previous site and by the advertisement of the males in which a specific vocalisation is given. Once the female is present on a male's territory, she is courted persistently by him and gradually begins to participate in his scraping displays. Pair‐bonds are re‐enforced by the close association of the pair during the pre‐nesting period and through a simultaneous preening display.

An hypothesis is developed that the participation of both sexes in incubation serves primarily as a means of pair‐bond maintenance, acting to keep both parents present until after the young hatch. At this time, their presence is needed to provide protection for the precocial young against predators.
NEST‐BUILDING BEHAVIOUR OF QUAKER PARROTS MYIOPSITTA MONACHUS
Authors: Harrison C. J. O.
Published: April 2008

An account is given of nest‐building by captive Quaker Parrots Myiopsitta monachus. Nests were made by thatching movements, twigs being inserted into a base by a sideways movement of the head. A downward slanting sheaf was formed around an internal cavity. The lip of the nest‐hollow was formed by pulling up and inserting the ends of some twigs. The cavity was shaped by chewing off projecting ends, and floored with chewed and shredded twigs.
PATTERNS OF GROWTH IN BIRDS. II. GROWTH RATE AND MODE OF DEVELOPMENT
Authors: Ricklefs R. E.
Published: April 2008

This analysis was initiated to examine the relationship between the rate of growth in birds and their development of mature function. The literature was surveyed for data on growth and development, and the growth curves of 81 species were chosen for the analysis. Growth curves of most species were fitted with the Gompertz equation, and the rate constants of the equation were used as an index of the growth rate. For those species whose curves were fitted better by other equations, with a slightly different form, appropriate conversion factors, derived in this paper, were employed.

Among species with similar modes of development, growth rate decreases with increasing body weight in an allometric manner, with slopes of –0.26 to –0.42, depending on the group. Between groups, the rate of growth in body weight was found to be closely associated with the rate of development of function, in particular, the acquisition of flight. Among those species that can walk at an early age, but acquire flight relatively late, the rate of growth depends primarily on the relative size of the musculature of the lower extremities.

Data are presented to refute the hypotheses that growth rate is adjusted to nestling mortality, or that the energy requirements of the young (and hence their growth rates) are balanced against brood size. It is concluded that most species grow at some physiologically maximum rate, but as yet it is not possible to distinguish between limitation of growth rate at the level of the organism or at the level of the tissue.
LEK BEHAVIOUR AND BREEDING OF GUY'S HERMIT HUMMINGBIRD PHAETHORNIS GUY
Authors: Snow Barbara K.
Published: April 2008

Guy's Hermit Phaethornis guy, a large forest hummingbird, was studied for 21/2 years in the Northern Range of Trinidad. Regular observations made at a lek of 16 males showed that leks are occupied from November until the beginning of July, and that individual birds retain their lek territories from year to year and use the same perches.

The usual song is a monosyllabic note regularly repeated, but the quality of the note varied between different leks and between different parts of a lek, and a few males had a disyllabic song. Young males join the lek between April and June and learn the song of their immediate neighbours. Their plumage, when they first join, is similar to a female's, with distinct pale super‐ and subciliary stripes. The acquisition of the dark head of the adult male probably takes four years.

Before they land on their lek perches, males perform an elaborate aerial display in which the red gape is flashed open and a loud tock is uttered. When males visit each other they rapidly change places on the lek perch, the airborne bird performing the tock‐display over the perched bird. A similar tock‐displaying with changing of place occurs when females visit males; twice these were seen to culminate in mounting. Periodically all males at the lek ‘false‐mate’ with a leaf or other piece of vegetation near their lek perches, after tock‐displaying above it. Young males false‐mate much more frequently than older males.

The breeding season lasts for eight months, the peak of breeding coinciding closely with the period when the two most important sources of nectar (Heliconia bihai and Pachystachys coccinea) are available. Males occasionally visit nests, and possibly assist in defending them. Undefended nests are quickly dismantled by other birds in search of nest‐material. Of 19 nests found before the clutch was complete, five (26%) were successful. The incubation period is 17–18 days, and the fledging period 21–23 days.
NOTES ON GEOGRAPHICAL VARIATION AND THE ANNUAL CYCLE IN PATAGONIAN POPULATIONS OF THE RUFOUS‐COLLARED SPARROW ZONOTRICHIA CAPENSIS
Authors: King James R.
Published: April 2008

Zonotrichia capensis australis inhabits Argentina from the northernmost limits of the Patagonian steppe south through Tierra del Fuego, and extends westward to the Pacific slope in southern Chile. At least part of the population has a north‐south migration along the Andean foothills of Argentina as far north as southwestern Bolivia. The breeding range of australis is bounded on the north and northwest by subspecies of Z. capensis (chilensis, choraules, and possibly hypoleuca) having conspicuous black lateral crown‐stripes. Topotypical australis (Tierra del Fuego) have plain grey crowns, but the frequency of black nuchal markings and faint lateral crown‐lines increases northward in the coastal populations. In inland populations (Andean piedmont) the frequency of black crown markings is apparently reversed, increasing southward. The size (wing‐length, tarsus, bill, and probably body‐weight) of australis decreases northward in both coastal and inland samples.

The nesting season of australis begins in late November and early December and extends to mid January and early February. Postnuptial moult begins from mid December to early January. Moult proceeds while the testes are apparently still functional. Postnuptial moult terminates from late January through mid March. There is no evidence in the current data of geographical trends in the chronology of nesting and postnuptial moult. The calendars appear to be about the same throughout the range of australis.

Postjuvenal moult begins about 4–5 weeks later than the onset of postnuptial moult and terminates in the latest birds in about mid March. Northward migration begins at about this time.
BREEDING NUMBERS AND REPRODUCTIVE RATE OF EIDERS AT THE SANDS OF FORVIE NATIONAL NATURE RESERVE, SCOTLAND
Authors: Milne H.
Published: April 2008

The total population of Eiders at the Sands of Forvie National Nature Reserve, Aberdeenshire, increased from about 3000 birds during 1961–63 to about 4800 birds in 1964–70. At the same time the estimated number of breeding pairs increased from about 1200 in 1961–63, to about 1800 in 1965–68 and to 2000 in 1970.

The mean size of completed clutches was 4.4; the number of eggs in a clutch showed a significant decline during the season from an average of 4.7 to 3.4 in most years. The overall hatching success was 63%, but there was a decline with season as a result of increased losses to predators.

In 1964 and 1969 laying was retarded, mean clutch‐size reduced, and the number of birds attempting to lay dropped by half, due to inclement weather just at the onset of laying. In 1969 the eggs produced were smaller than in other years, and hatching success was lower.

The female incubates without feeding, and is required to store sufficient energy, in the form of fat, to last her through the 26 days in addition to producing her clutch of eggs. An hypothesis is advanced which relates the feeding efficiency of the paired female immediately prior to laying to her egg production and incubating pattern, and which offers an explanation of the decline in clutch‐size and hatching success evident during the season.

In most years less than 5% of hatchlings survived to fledge; high survival was recorded in 1963, 1968 and 1970. Following the high production in 1963 the population increased in 1964 and the breeding stock in 1965 (females start to breed at two years old). The corresponding changes, following good breeding in 1968, were not so clearly detected because of unusually high adult mortality from oil pollution at the winter grounds in 1968 and the ‘late’ breeding year in 1969. The breeding stock in 1970, however, was higher than in any other year. This population continues to grow apparently as a result of its own reproductive output checked only by low productivity in most years and occasional high adult mortality.
APPENDIX
Authors: Gorman M. L.
Published: April 2008

The significance of habitat selection during nesting of the Eider Somateria mollissima mollissima
SPRING MIGRATION OF EIDERS SOMATERZA MOLLISSIMA IN SOUTHERN SCANDINAVIA
Authors: Alerstam Thomas , Bauer Carl‐Axel , Roos Gunnar
Published: April 2008

Eider migration in southern Scandinavia in spring 1972 was studied simultaneously at three radar stations and ten field observation sites. The Eiders winter in Danish and West German waters, from which they set out on spring migration on courses ranging from SE to NE; those from the northern part of the wintering area flew SE, those from the south NE, while birds wintering in between these geographical extremes set out on intermediate courses around E.

Radar showed that most Eiders fly over the island of Zealand and the peninsula of Skåne, but only exceptionally further north over Sweden. Few Eiders crossing land were registered by field observers and most evidently passed at high altitudes beyond the range of vision. After having crossed Skåne, on varying tracks both south and north of east, the Eiders descended and changed flight direction towards NE.

Some Eiders from the northern part of the wintering area circumnavigated Skåne, passing south along the Swedish coast of the Sound, crossing the very narrow peninsula of Falsterbo, and subsequently following the south coast of Skåne eastwards. Eiders from southern Denmark and Germany were often deflected eastwards along the south coast.

After having passed Skåne no significant land crossings were made. Upon reaching the province of Blekinge on a course towards NE, the Eiders were deflected E to ESE along the coast and later NNE along the west coast of Öland through Kalmar sound.

Approximately 350 000 ducks migrated during daytime of the study period, 250 000 crossing the land of Skåne while 100 000 passed along the south coast. Almost 300 000 migrated north in Kalmar sound, and 17 % of all Eiders passed east of Gland over the open sea.

Three distinct peaks of activity during the day were noted in Skåne. The first, at around sunrise, originated from birds resting in waters off Skåne. The second occurred about four hours later and probably consisted of birds which had departed from the wintering area in the early morning. A final peak at sunset was often recorded. Migration also took place during the night, but involved only one fifth of the total number.

From combined radar and field counts the total Baltic Eider population is estimated to have been 700 000–800 000 in spring 1972, indicating about 300 000 breeding pairs in the Baltic Sea.
THE VISIBLE MIGRATION OF RAPTORS OVER THE MALTESE ISLANDS
Authors: Beaman Mark , Galea Charles , Beaman Mark
Published: April 2008

Whilst the large migrations of raptors at the Bosphorus and at the Straits of Gibraltar have been documented in some detail, the movements which take place across the Mediterranean itself have been neglected. This paper reports observations of the visible migration of raptors over the Maltese Islands during 1969–73.

The largest numbers of raptors were recorded both in spring and autumn during contrary winds or overcast conditions. Normally very few were seen before the early afternoon at either season, in spite of the much shorter minimum sea‐crossing in autumn. Large passages occurred in winds with easterly or westerly components. It is therefore concluded that eastward drift does not greatly affect the numbers seen in Malta, as had been suggested by De Lucca (1969); rather that most influxes occurred in the late afternoon during unfavourable meteorological conditions. At other times most migration was probably above the visible range.

The number of raptors observed on passage in the Maltese Islands was small compared with movements at the Bosphorus or at Gibraltar. Nevertheless, the numbers of the narrow‐winged species (i.e., Ospreys, harriers and falcons) compare favourably with records at the narrow crossings. The only large soaring species commonly seen in Malta was the Honey Buzzard. Evidence is presented which suggests that the volume of Honey Buzzard migration across the central Mediterranean may be much larger than was formerly realized.
VOCALIZATIONS, SOCIAL ORGANIZATION AND BREEDING BIOLOGY OF THE TWITE ACANTHUS FLAVIROSTRIS
Authors: Marler P. , Mundinger P. C.
Published: April 2008

A seven‐week study of breeding Twites at the mouth of the Trondheim fjord revealed that they are double brooded. The second clutch is started while the first nestlings are still dependent on both parents. Males defend a moving area around the female which becomes focused on the nest during incubation. Adult vocalizations recorded and analysed fall into seven basic categories. We believe this represents the entire repertoire, which is rather small, and may correlate with the visually open habitat. Nine measures of the tup‐up‐up flight call reveal that calls of a male and female that are paired match closely and differ from those of other birds in the area. This is taken as evidence that the Twite flight call is modifiable by learning, as in some other cardueline finches.
SYSTEMATICS OF PARROTS
Authors: Smith G. A.
Published: April 2008

Parrots comprise such an homogenous and natural order of birds that it has proved difficult to find substantial characters with which to subdivide them further.

The classification, based largely on external morphology, which Salvadori proposed in 1891 has been the main source for almost all subsequent arrangements, which however, are inconsistent in the number of divisions and in the genera composing the divisions. The present paper is an attempt to reconcile the different arrangements by demonstrating instances of convergence and suggesting several additional features which may have use as systematic indicators.

The following anatomical, morphological and ethological characters are considered: tongue, hyoid bone, bill, intestine, gall‐bladder, carotid artery arrangements, neonate chick, furcula, skull rump feathers, exposed epidermis, irides, erectile feathers, sexual dimorphism, colour of immature males, copulatory patterns, epigamic and agonistic display, nesting, foliage‐bathing, rain‐bathing, bathing, sunning and head‐scratching; the evidence of hybridization is also discussed. Convergence is demonstrated in ground feeding forms for skull structure, loss of furcula and an indirect head‐scratching behaviour.

The following divisions are proposed: Platycercinae (Platycercini, Cacatuini, Nestorini, Strigopini); Loriinae (Loriini, Psittrichasini, Psittaculini, Micropsittini, Psittaculirostrini); Arinae (Arini); Psittacinae (Psittacini). Although this arrangement is very different in its larger groupings from any previous system, it very closely agrees with that of Salvadori in the number and in the constituent genera of the smaller groups.
BIRDS AS SCAVENGERS OF REFUSE IN UGANDA
Authors: Pomeroy D. E.
Published: April 2008

Refuse tips, abattoirs and fishing villages provide an important source of food for several species of large scavenging birds in Uganda. The most numerous are Marabou Storks, Hooded Vultures, Black Kites and Pied Crows. Estimates of the populations of these species are given for Kampala, several smaller towns in Uganda and Rwenzori National Park (where there is an important fishing industry).

Crows and kites are spread widely through Kampala and the population densities of both species exceed 12 km‐2 (the latter seasonally). On average there were about 200 Hooded Vultures at the Kampala abattoir and nearly as many Marabous at the refuse tips. Abattoirs and refuse tips in smaller towns often had proportionately higher populations of scavengers than Kampala.

The food consumption of these birds is calculated to be nearly 100 t per year in Kampala and 800 t per year in Rwenzori National Park. It is suggested that although man, through his various activities, provides most of the food for these scavengers, they are beneficial to him in the sense that the food which they eat might otherwise become a health hazard.
HABITATS OF THE LAND‐BIRDS OF VITI LEVU, FIJI ISLANDS
Authors: Gorman Martyn L.
Published: April 2008

The birds seen in 18 study areas covering the major habitats of Viti Levu are listed. The species show expansion of habitat and altitudinal range as compared to mainland species. The implications of future development of the forestry industry are discussed.
BREEDING BIOLOGY AND BEHAVIOUR OF THE GREY PHALAROPE PHALAROPUS FULCARIUS IN EAST SIBERIA
Authors: Kistchinski A. A.
Published: April 2008

Studies were made in 1970 in the Chukotski Peninsula, in 1971 in the delta of the Indigirka river and in 1972 in the delta of the Yana river. Grey Phalaropes inhabit polygonal and tussocky moss‐sedge tundra rich in swamps, lakes and (in June) temporary ponds. Population density in favourable habitats may reach 1–2 pairs ha‐1. Data on breeding chronology are presented, and various aggressive and courtship displays described. Most phalaropes seem to keep within a home range, sometimes large, during courtship time, but no defended territories and no forms of territorial behaviour exist. Many birds, both local nesters and wanderers, can feed on any pond. Sexual dimorphism is described. In 1970, three non‐breeding cock‐plumaged females were taken. Pairs are formed both before arrival and on the nesting grounds. All courtship displays are wholly or mostly initiated by females. In 1971, in the Indigirka delta, all the Grey Phalaropes were paired by 12 June, and stayed in pairs until the end of egg‐laying. In 1970, on the northern Chukotsk, phalaropes seemed to form no (or very few) permanent pairs. Throughout June, most birds occurred in mixed flocks constantly moving between lakes or ponds. Copulation seemed to be promiscuous within the local population; polyandry cannot be excluded in some cases. Pairs appeared to be created only for the time of egglaying; probably, the only biological role of pair‐formation is to find a male for incubating. Thus, a definite social system is not a species‐specific feature; it can vary depending on local and yearly situations, including probably sex ratio. Nests are usually situated in very wet places, sometimes on the water edge. They can be found as little as 3 m apart, but are usually 40–80 m apart, or further. Incubation begins after the second or third egg. After the end of egg‐laying, males drive females away from the nests, and pairs break up. Females and non‐breeders gather in flocks and move onto the lakes of maritime tundra, and later on to the sea. The composition of the flocks is not constant: they often join together or part. Brooding males feed near their nests, sometimes in groups; not unfrequently they join flocks of females and non‐breeders for some time. The normal average clutch‐size is c. 4 eggs; when nesting was delayed (in the central Indigirka delta in 1971) the average was 3–61. The loss of nests was great in 1971; numbers of young on 1–3 August was 10 times lower than adult numbers in June.
BREEDING OF THE ADÉLIE PENGUIN PYGOSCELIS ADELIAE AT CAPE BIRD
Authors: Spurr E. B.
Published: April 2008

Observations were made during four seasons (1967–68, 1968–69, 1969–70, 1970–71) on the breeding of Adelie Penguins at Cape Bird, Ross Island, Antarctica.

Breeding data from individuals were related to date of return, laying date, clutch‐size, nest location, and change of mate. Some females consistently laid near the mean date of laying, while others were consistently early or late layers. Laying date may be under direct genetic control, or may reflect feeding ability.

The mean clutch‐size was smaller in peripheral compared to central nests, and smallest of all in isolated nests. Clutches laid late in the season were smaller than those laid near the peak date, and small, late clutches were laid in peripheral rather than central nests. These differences may reflect age and/or feeding ability. Penguins that are better able to find food will return earlier, obtain central sites, and have larger clutches than those with a lesser ability.

The two main causes of egg and chick losses were predation and parental failure. Losses were highest in single‐egg clutches, at isolated and peripheral nests, and among eggs laid late in the season. These results may be partly related to the age and experience of the penguins. However, regardless of age, peripheral nesting and late laying were always disadvantageous.

The sex ratio of adults in the colonies was 117♂:100♀. This may be explained by the higher mortality of females. Some males could not find partners, but females that did not breed had probably been unable to obtain sufficient food for gonad development.

The return of penguins, incidence of non‐breeding, adult mortality, clutch‐size, and breeding success at Cape Bird were all markedly different in 1968–69 compared to the other three seasons studied. This season was marked by the persistence of sea‐ice along the northwestern shores of Ross Island. The low reproductive output in 1968–69 was thought to result from a shortage of food for egg‐laying and incubation.
PIRACY BY LAUGHING GULLS LARUS ATRICILLA: AN EXAMPLE OF THE SELFISH GROUP
Authors: Hatch Jeremy J.
Published: April 2008

In 1969, 1500 pairs of terns Sterna spp. and 50 pairs of Laughing Gulls Larus atricilla nested on Petit Manan Island, Maine, U.S.A. The gulls formed groups of up to eleven individuals to steal fish from the terns. The start of piracy coincided with hatching of the gull's eggs. Larger groups more often succeeded in stealing fish than smaller groups. Group formation cannot be ascribed to rarity of terns to chase, and is not due to shared advantage in fish seized or time spent chasing (hence energy expended). A sufficient explanation is the individual advantage to some gulls that join a small group at the expense of the initiator. Individual gulls are likely to follow different strategies. Chasing appeared to be more readily elicited by a chase in progress than by a tern carrying a fish.
BREEDING BIOLOGY OF THE BLACK‐BROWED ALBATROSS DIOMEDEA MELANOPHRIS AND GREY‐HEADED ALBATROSS D. CHRYSOSTOMA AT BIRD ISLAND, SOUTH GEORGIA
Authors: Tickell W. L. N. , Pinder R.
Published: April 2008

The two small albatrosses Diomedea melanophris and Diomedea chrysostoma were studied during five summers and one winter at Bird Island, South Georgia. Although superficially similar in habit small but consistent differences in breeding biology were demonstrated between the two species and may be related to differences in breeding frequency.

The breeding season of D. chrysostoma was longer than that of D. melanophris and each species favoured slightly different colony sites. The development time (incubation+fledging) of D. chrysostoma (213 days) was substantially longer than that of D. melanophris (184 days).

The eggs of D. chrysostoma were slightly larger than those of D. melanophris and there was marked difference in the behaviour of those breeding adults who lost eggs or chicks. D. chrysostoma departed to sea straight away whereas D. melanophris continued to visit the colony for some weeks before going.

Daily weighings of nestlings suggested that chrysostoma bring in less food per a given time than melanophris, and this may account for the longer fledgling period.
BIRDS OF THE UNDERSTORY OF LAKE‐SHORE FORESTS ON THE ENTEBBE PENINSULA, UGANDA
Authors: Okia Nathan O.
Published: April 2008

Monthly mist‐netting of low‐flying forest birds was conducted in three lake‐shore forests in southern Uganda from September 1970 to July 1972. It was found that the edge of the forest formed a distinct ecological barrier that was rarely crossed by species on either side of it. Catches were concentrated in the hours of daylight, in two peaks, a morning peak at 09.00 hrs and an afternoon peak at 16.00 hrs (sun‐time) for all birds combined, although there were slight species differences. Most bird species were found to be sedentary in a fixed home‐range, and covered lateral distances of up to c. 300 m. No movement between the different forests was recorded.

The most common birds such as bulbuls were often caught at heights between 0·6 and 1·8 m above the ground, but the upper limit of their vertical range was not determined. It is suggested that the bi‐modality of flight activity may be intrinsic, even though it may be correlated with such extrinsic factors as light and radiation. On a month to month basis, the numbers of birds caught reflected breeding and moult activity. This was best shown by the Pygmy Kingfisher, taken in higher numbers towards the end of the first rainy season when a majority of the birds caught were young and many birds were moulting the remiges. On the other hand higher numbers of Olive Sunbird were found during the second rainy season, again at a time corresponding to a general moulting of remiges. The bulbuls showed fluctuations in numbers caught that were matched by an equally fluctuating pattern of moult. The role of food as a possible limiting factor in bird breeding is discussed.
BREEDING BIOLOGY OF THE GREY‐FACED PETREL PTERODROMA MACROPTERA GOVLDI
Authors: Imber M. J.
Published: April 2008

The Grey‐faced Petrel is a non‐migratory winter breeder whose reproductive season occupies 9–10 months. Males spend more time in the burrows than females during the courtship period. Some females keep company with strange males, and may be fertilized by them, but subsequently share incubation with their mate of the previous year. The duration of the pre‐laying absence of females is about two months, and of the pre‐incubation absence of males about seven weeks. Since copulation is presumed to occur before this absence, these petrels seem to have evolved prolonged viability of the spermatozoa, though ovulation may take place some time before laying. Eggs are laid in late June or July but chicks are rarely reared from eggs laid after 14 July; effective laying thus lasts three weeks. The single egg is about 15·5% of the female's weight; she may be able to exert slight control over timing of oviposition. She may be required to incubate, if capable, for up to 14 days from laying but the male takes over, on average, after four days. There are three main incubation spells of 17 days' average duration, two by the male. These are of a duration such that there is usually a change‐over near hatching. Incubation lasts about 55 days. There is competition for burrows, resulting in two‐egg nests. Norway Rats take unattended eggs and young chicks and scavenge, but their predation (less than 10–35% of chicks per year) is not considered to be endangering the population. After initially more frequent feeds, chicks are fed approximately once a week by each parent. They do not become much heavier than adults and the growth rate is slow: about 120 days to departure.

The ability to begin breeding in winter, atypical of petrels in this region, may be facilitated by three factors: improved availability of food resulting from longer nocturnal feeding time and reduced inter‐specific competition; the ability to lay fertile eggs two months or more after copulation; and the brevity of the non‐breeding season due to the relative proximity of a sufficient food supply.
THE SOUTHWARD MIGRATION OF PALAEARCTIC BIRDS OVER NGULIA, KENYA
Authors: Pearson D. J. , Backhurst G. C.
Published: April 2008

Since 1969 remarkable numbers of night migrants have been attracted during misty conditions in November and December to three 1 kW floodlights at a game viewing lodge on the northeastern side of the Ngulia ridge, a small range of hills in the Tsavo National Park (West), southeast Kenya. The main species involved have been Palaearctic passerines, principally the Marsh Warbler Acrocephalus palustris, the Whitethroat Sylvia communis and the Sprosser Luscinia luscinia.

Data were collected at the Lodge in the late autumns of 1969–71, and in particular between November 1972 and early January 1973, when over 2500 Palaearctic passerines were caught and ringed. Large falls have depended on mist or rain during the latter part of the night, at any time during the month except around full moon. Highest numbers have occurred in late November and the first half of December. In 1973 falls continued into the second week of January. Grounded birds move on quickly, extremely few having been retrapped. During 1972–73, the species prominent in falls at the Lodge were abundant as transit migrants in Tsavo only from mid‐December to early or mid January, at which time retrap rates were highest. The high weights and considerable fat deposits of many birds caught suggested they were grounded some distance north of their destination. Forty‐two migrants analysed had a mean lipid content of 12·9% of their live weight; none was appreciably dehydrated. In 1972–73, highest weights were found at the beginning and end of the season.

Individual species are discussed, and in several cases their African status reviewed. Several species were encountered at Ngulia in numbers far larger than those previously reported from elsewhere in Africa. In 1972–73, for instance, over 1000 Marsh Warblers were caught and many thousands of others seen, hundreds of River Warblers Locustella fluviatilis occurred, and White‐throated Robins Irania gutturalis, Basra Reed Warblers Acrocephalus griseldis, Rufous Bush Chats Cercotrichas galactotes and Olive‐tree Warblers Hippolais olivetorum were caught regularly.

Most of the Basra Reed Warblers, Upcher's Warblers Hippolais languida and Olivaceous Warblers H. pallida, and many of the Whitethroats (apparently all of the eastern race icterops) handled during late December and early January were in fresh plumage, although these species are not known to moult north of the Sahara. They are presumed to have renewed their plumage in northeast Africa earlier in the autumn. In many Basra Reed Warblers and Whitethroats moult was only partly completed; in almost all such cases it was arrested.

Itinerancy south of the Sahara is discussed. It seems clearly established that a regular southward migration, in the usually accepted sense of the word, occurs across Tsavo, of Palaearctic species which have already been in tropical Africa up to three months. Most species involved in this migration cross the equator on a remarkably narrow front, and are rarely recorded in Kenya west of Nairobi.