THE SOCIAL BEHAVIOUR OF THE DUNNOCK PRUNELLA MODULARIS

Observations were carried out on a colour-ringed population of Dunnocks. During the winter, regular feeding groups formed at feeding sites, stable in composition, space and time. Dominance hierarchies formed and were weight related. Males were significantly heavier than females. The mean size of winter home-ranges was not significantly different from the mean size of breeding territories.
Three categories of breeding territory were established: solitary males, male-female pairs and pairs plus a male helper. There was one case of a bigamous male plus a helper. Pairs plus a helper had significantly larger territories than pairs alone; however, pairs raised significantly more fledglings. Five pairs produced a total of 23 fledglings, whereas four groups (pairs plus a helper) only produced seven fledglings.     

Family-based winter territoriality in western bluebirds, Sialia mexicana: the structure and dynamics of winter groups

Winter residency is characteristic of the majority of cooperatively breeding birds, but the composition and dynamics of winter groups have been examined in relatively few. In 1996-1998, we examined winter territoriality in the western bluebird, a year-round resident that shows a limited degree of helping behaviour in central coastal California, U.S.A. In spring, most western bluebirds breed as socially monogamous pairs, but a small proportion of pairs (3-16%) have additional breeding-age males helping at the nest, usually assisting parents or brothers. We found that year-round residents commonly wintered in family groups that defended territories similar to those used in spring. Winter groups had an even sex ratio and formed early in the autumn, when hatch-year birds dispersed. More females than males left their natal groups to be replaced by an influx of immigrant hatch-year birds. Winter groups typically consisted of breeders and one or two sons from the prior breeding season along with one or more immigrant females. A second period of dispersal occurred in spring when winter groups broke up and most birds other than the breeding pair left the winter territory. When they bred, yearling males and females often bred with unrelated individuals from their winter groups. Sons were more likely to remain on the study area as yearlings when they wintered with both parents than when they wintered with just one parent. We suggest that young males stay the winter due to benefits of remaining in family groups on mistletoe-based winter territories. Subsequent localized dispersal of sons then leads to opportunistic kin-based interactions later in life. Copyright 2001 The Association for the Study of Animal Behaviour.     

THE PROCESS OF COLONY FORMATION AMONG HERRING GULLS LARUS ARGENTATUS NESTING IN NEW JERSEY

We examined the pattern of colony occupation and egg-laying in five colonies of Herring Gulls nesting in New Jersey, U.S.A. Colonies formed from epicentres located in sparse bushes. The number of epicentres related to the number of birds nesting in the colonies. Colonies of over 250 pairs had more than one epicentre, whereas those with under 250 pairs had only one epicentre. Epicentres were not always in the geographical centre of the colonies. New territory-hunting pairs filled in the epicentre areas, and then nested outside these areas. The egg-laying pattern followed the settling pattern, but was more synchronous than the settling pattern. There was greater synchrony of egg-laying within sub-areas of the colonies than in the colonies as a whole. Further, synchrony correlated with the number of nests in sub-areas.     

Mutual benefits of associations between breeding and non-breeding White-fronted Geese Anser albifrons

The relationships between yearlings and adult pairs of White-fronted Geese Anser albifrons were studied during pre-nesting, laying and early incubation in the central Canadian Arctic. Prior to nesting, females of lone pairs spent 75–81% of their time feeding, while males spent only 42–47% of time feeding and 46–50% alert. In pairs with one or more associated yearlings, both females and males fed significantly more and spent less time vigilant. Yearlings spent significantly less time (59%) feeding when alone compared with 71–76% when with pairs. Associations between yearlings and paired adults were most frequent before adult females began prospecting for nest sites. No prospecting pairs were associated with yearlings. After the egg-laying period, groups of geese, predominantly yearlings, made distraction flights over humans and terrestrial predators approaching nests, in contrast to the more cryptic behaviour of nesting pairs. The presence of groups of geese associated with some nest sites suggests that continuing parent-offspring relationships may involve assistance with nest defence.     

Ostracism and indirect reciprocity: The reproductive significance of humor

Humor is hypothesized to be a social activity that alters the status of the humorist positively and that of the object or victim negatively. Of the two traditionally distinguished classes of humor, “ostracizing” humor singles out a victim, with others present or absent either incidental affiliates of the humorist (and one another) or unaffected. “Affiliative” humor, on the other hand, is focused on creating or maintaining group cohesiveness, with the identity of the victim more or less incidental.     

Does sex (female versus male) influence the impact of class attendance on examination performance?

The "conventional wisdom" is that grades are related to class attendance, i.e., students who attend classes more frequently obtain better grades and class attendance dramatically contributes to enhanced learning. However, the influence of sex (female vs. male) on this relationship is understudied. Furthermore, there have been several studies examining the impact of attendance on course grades that challenge the conventional wisdom. To address these issues, we determined the effect of class attendance on examination scores for female and male students enrolled in our undergraduate exercise physiology class of 51 students (20 female students and 31 male students). The experiment was designed not to interfere with the normal conduct of the course. Attendance was recorded in each class, and, although regular attendance was encouraged, it was not required and did not factor into the final grades. The final grade reflected the average days of attendance for female students only. Specifically, female students earning a grade above the class average attended 89 ± 4% of the classes; however, female students earning a grade below the class average attended only 64 ± 6% of the classes. In sharp contrast, there was no difference in the number of classes attended for male students earning grades above or below the class average (84 ± 3% vs. 79 ± 5%). Accordingly, some male students were absent frequently but scored above the class average, whereas other male students attended many classes but scored below the class average. Thus, the influence of regular attendance on examination performance is more important for female students than male students.     

Family-based territoriality vs flocking in wintering common cranes Grus grus

We describe winter territoriality in common cranes, Grus grus , a long-lived migrant species with long-lasting pair bonds and parental care extending throughout the winter. Cranes are territorial in the breeding season, and usually gregarious during migration and wintering. Only 2% of the families present in our study area were territorial, all other families foraged in flocks with immatures and adult pairs. Territorial pairs defended the same winter territory year after year, but only when they had offspring. They were gregarious otherwise. The average breeding success measured throughout several years was higher in territorial pairs. Winter territories were small (0.7 km² on average), but included a higher diversity of habitats than the areas visited by gregarious birds (11.7 km² on average). Adults of territorial families showed longer vigilance times, and lower food intake rates than did adults in flocks, which were compensated with a longer time spent foraging per day. The accumulated daily food intake did not differ between adults in flocks and in families. We suggest that winter territoriality is a facultative strategy, conditioned by parental experience and habitat availability.     

THE PRESENT AND PAST DISTRIBUTION OF THE BALD IBIS IN THE PROVINCE OF THE CAPE OF GOOD HOPE

Tarboton, W. R. 1981. Cooperative breeding and group territoriality in the Black Tit. Ostrich 52:216-225.

In a small, colour-ringed population of Black Tits Parus niger in central Transvaal, 11 of 19 observed breeding units comprised pairs with one to three helper-males. These pairs and groups defended permanent territories, the size of which correlated with the size of the group. There were significantly more territorial disputes during winter when less food was available than in summer. Breeding occurred in summer and the female alone built the nest, incubated the eggs and brooded the young while they were small. During this time she was fed by the alpha male and helper males, although before egg-laying the alpha male prevented helpers from courtship-feeding her. On average, unassisted pairs reared 0,88 young/season whereas pairs with helpers reared 1,55 young/season. However the feeding rate of nestlings of pairs with helpers was not higher than that of unassisted pairs and the number of young reared per group did not correlate with the number of helpers within the group.

The helper system in Black Tits was associated with a skewed sex-ratio (1,7:1 males: females) in the adult population and the data are consistent with the “hopeful reproductive” hypothesis for cooperative breeding.     

THE PELAGIC DISTRIBUTION OF THE SOOTY SHEARWATER PROCELLARIA GRISEA

The breeding distribution of the Sooty Shearwater and the dates of its breeding season are briefly reviewed.
Records from the Southern Ocean are summarised. It is concluded that they are accounted for by non-breeding birds feeding off the ice-edge in the Australian sector of the Antarctic during the latter part of the breeding season.
The great majority of Sooty Shearwaters spend the southern winter in the Pacific Ocean. Birds from the New Zealand colonies are probably mostly found on the feeding grounds off Japan: some may make a "circular" migration around the Pacific. Birds from the Cape Horn colonies spend the southern winter in the rich areas off the western coast of North America.
Some Sooty Shearwaters spend the southern winter off the South African coasts. A number of non-breeding birds remain there throughout the summer.
The Sooty Shearwaters "wintering" in the North Atlantic are probably numbered in tens of thousands only. The distribution of records is reviewed month by month and the records from Atlantic transects are summarised. The migrations in the North Atlantic are discussed in relation to prevailing meteorological and oceanographic conditions, and food supply. It is concluded that most Sooty Shearwaters in the North Atlantic make a "circular" migration, crossing the North Atlantic from west to east in June and July, and re-crossing about September further south in the northeast trades.     

THE PRODUCTION OF ANTIBIOTICS IN SOIL: II. PRODUCTION OF GRISEOFULVIN BY PENICILLIUM NIGRICANS

A study has been made of the conditions affecting production of griseofulvin by Penicilliiim nigricans in two types of soil, an acid, sandy podsol from Wareham Heath and a garden soil. The characteristic morphogenetic response of many fungi to low concentrations of griseofulvin was made the basis of a highly specific bioassay.
The essential prerequisites for production of griseofulvin in either soil were sterilization and enrichment with organic matter; no griseofulvin could be detected in autoclaved soil which had not been supplemented or in normal soil even when organically enriched. Garden soil was a better medium for growth of P. nigricans and production of griseofulvin than Wareham soil although this soil could be improved in this respect by liming.
The yield of griseofulvin was decreased in soil re-infected by other soil organisms, particularly by some which were known to produce antifungal antibiotics, e.g. Penicilliunr expansum, P. frequentons and two strains of Trichoderma viride. The antagonism shown to Penicilliunz nigricuns was not entirely a matter of antibiotic activity, as some fungi believed not to produce antifungal substances had an antagonistic effect. These were mostly fungi with a characteristically rapid growth rate, e.g. Mucor rarnmannianus and one strain of Trichoderma riride. In some cases Penicillium nigricans was itself antagonistic to other fungi irrespective of their ability to produce antibiotics or of their fast-growing habit.
The results were compared with those obtained from a previous study of the soil conditions affecting the production of gliotoxin by Trichoderma viride. A higher level of nutrient was required for the production of griseofulvin, and the effect of antagonism by other soil micro-organisms was more important than in the production of gliotoxin by T. viride in the soil.     

THE BIOLOGY OF OYSTERCATCHERS HAEMATOPUS OSTRALEGUS ON SKOKHOLM ISLAND, S. WALES

A population of about 50 pairs of Oystercatchers Haematopus ostralegus nesting on Skokholm Island, S. Wales, was studied between 1963 and 1965. Other information on Skokholm Oyster-catchers over the last 25 years was also analysed.
The adults were trapped, colour-banded and sexed by bill measurements. With few exceptions, birds kept the same mates and territories from one season to the next. Apparently the male is responsible for retaining the territory. Some Oystercatchers breed at three years but most do not do so until four or five. It seems that there is a high population pressure, preventing young birds from establishing themselves. The annual adult survival in the two years was 88% and 90% respectively.
The average clutch-size on Skokholm is known for many years, and varied annually between 2^.5 and 3.3. The number of c/4 varied greatly from year to year. There was a seasonal decline in mean clutch-size and also in egg and nest success. Predation, especially by Lesser Black-backed Gulls, was the main cause of egg loss.
In 1963, 36.7% of hatched chicks fledged and 59% in 1964. The larger clutches were more successful and produced more surviving young than did the more numerous smaller clutches. Early hatched young are more successful than later young.
The average yearly mortality of birds between fledging and breeding was 40%.     

FURTHER OBSERVATIONS ON THE BIOLOGY OF THE CABBAGE ROOT FLY, ERIOISCHIA BRASSJCAE BCHÉ

In 1951, eggs of Erioischia brassicae were first found in the field on 2 May, and the peak period of egg-laying occurred 19–31 May. This was up to a month later than in the period 1948-50.
The periodic removal and examination of the surface soil showed that eggs of E. brassicae were continuously present on the host plants from mid-June to early November. Plants under observation during this period showed an average of 285 eggs per plant and other plants exposed to attack from July to November showed an average of 162 eggs per plant. Peak periods of egg-laying, as indicated by numbers of eggs per plant per day, occurred in late June and early July, in mid-August and, to a less extent, in the first half of October. The plants showed no increase in the rate of infestation as the season advanced, although E. brassicae has a reproductive capacity of about 100 eggs per female and three to four generations a year.
The difference between the observed egg populations and pupal populations indicated that E. brassicae had a heavy mortality rate in its immature stages. The condition of puparia showed that the species was subject to a high degree of natural control, a fact for consideration when direct control measures are formulated.
Pupal diapause extending from October 1949 to May 1951 was observed in one specimen of E. brassicae and from October 1949 to August 1951 in one specimen of its Hymenopterous parasite, Trybliographa rapae Westw.
Tests with tar-oil winter wash showed that at a concentration of 1 1/4% it killed eggs of Erioischia brassicae and repelled gravid females for approximately a week. Laboratory tests with BHC indicated that it had no adverse effects on the eggs but was larvicidal.     

THE ECOLOGY AND BEHAVIOUR OF THE LONG-TAILED TIT

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.     

OBSERVATIONS ON THE BEHAVIOUR OF THE HAMERKOP SCOPUS UMBRETTA IN UGANDA

Hamerkops were studied in Uganda, mainly in the vicinity of Kampala, during January-August 1964. Behavioural observations were made of nest-building pairs, as well as of non-breeding birds.
Locomotion and feeding behaviour are described. Diving take-offs and landings, essential for entering or leaving a completed nest, are sometimes seen in other situations as well. Birds sometimes forage while on the wing, in addition to the more usual method while wading.
The most frequently seen comfort movements and maintenance activities are described. Hamerkops do not excrete onto their legs when over-heated as do the storks. The resting posture of sitting completely down on horizontal branches, which is common among Hamerkops, apparently is not known in any of the herons or storks.
Primarily hostile (Upright and Forward Threat) and primarily sexual ("Yip-purr", Nodding and False Mounting) social displays are described. During False Mounting, birds mount their partners repeatedly without making any attempt at copulation; reverse mountings, in which the other partner assumes the top position, are frequent.
The large, hollow nest and its construction are briefly described. During the 6–7 week building period at one nest, at least 8000 loads of material were added to the structure. Both members have an equal role in nest-building, and generally work independently of each other. They showed no stick-exchange displays as do herons and storks.
When all known aspects of the Hamerkop's behaviour are considered, there appears to be little similarity with either the herons or the storks. In fact, present behavioural evidence does not seem to indicate a particularly close relationship with any other birds so far studied.     

THE DISTRACTION BEHAVIOUR OF THE ARCTIC SKUA

Distraction displays of the Arctic Skua Stercorarius parasiticus were studied in the Faeroe Islands in colonial nesters and a solitary pair. There are aggressive and passive forms.
The aggressive flight against human intruders is common throughout the nesting cycle in the colony, but absent from the behaviour of solitary pairs. It is suggested that its development is correlated with an internal rhythm which requires a certain level of mutual stimulation not attainable by solitary or widely-scattered pairs. A highly formalized version of the attacking flight was employed against a sheep, in which the pair showed a marked tendency to coordinate their movements.
The lure display when eggs are fresh is markedly different from that employed nearer the hatching-period and afterwards. A courtship posture appears as a substitute activity in the early period, but only in the presence of the mate.
In the solitary pair development of the normal lure display was gradual, reaching its peak towards the hatching-period: there is a marked tendency for the pair to perform together, deriving mutual stimulation. It is suggested that this factor is important in the colony, where several perform together in scattered groups, in ensuring the earlier development (and therefore increased survival value) of the lure display. The birds' movements emphasize contrasts in the plumage coloration, and therefore the pattern may have greater biological advantage for colonies of predominantly light-phase birds in areas of fox predation.
The various patterns are described, and also variations incorporating false-brooding and drinking motions. The main components of the patterns are probably derived from the primitive food-begging of the chick, and elaborated with actions from courtship display.     

Body condition, territory ownership and age-related reproductive performance in Spruce Grouse Dendragapus canadensis hens

Adult Spruce Grouse Dendragapus canadensis hens show better reproductive performance (i.e. larger clutch size, earlier clutch initiation, higher frequency of renesting) than year-lings. Body and breast muscle weights, condition indices and relative body composition were compared between adult and yearling birds from northeastern Ontario, Canada, to determine whether differences in endogenous reserves mobilized for egg production and (or) territory ownership could explain these differences in reproductive performance. Adults and yearlings showed similar declines in body-weight, breast muscle weight and condition indices from the pre-laying to the post-laying period, but no significant interage differences emerged at any stage of the breeding season. Changes in body composition, especially gut structure, were similar in all birds; this result is consistent with a dietary shift in both age classes from a fibrous winter diet to more succulent foods in spring. Non-territory-holding (replacement) yearlings also had similar body-weights and breast muscle weights and were in similar condition to territory holders (residents) in the pre-laying period. My findings do not support the hypothesis that differences in body condition and territory occupancy can account for differences in age-related reproductive performance in Spruce Grouse.     

ESTIMATION OF BODY MASS IN THE SOUTHERN ELEPHANT SEAL, MIROUNGA LEONINA, BY PHOTOGRAMMETRY AND MORPHOMETRICS

A simple photographic technique was developed to indirectly estimate body mass data for southern elephant seal ( Mirounga leonina ) cows (postlactation), yearlings, and immature males and females. Regressions of mass on both photographic and morphometric variables (together and separately) yielded useful, predictable models. Using such variables, the best estimation of the actual mass was for postlactation cows, with a 95% confidence interval of ± 2.66% of the predicted body mass. Although combining photographic and morphometric variables produced the most reliable models specifically for cows and yearlings, the most practical model contained only the morphometric variables length and girth squared. Side area was the best correlated single photographic variable and this corresponded with other studies. Photogrammetry could be useful when animals cannot be sedated and are located on a flat surface, but it does require animals to be motionless when approached. Thus, the procedure may be more suited to bulls rather than other age classes and could have a role in studies where large numbers of mass estimations are rapidly required. If sedation is utilized in smaller animals, then the use of body length and girth is the most suitable indirect mass estimation technique to avoid the use of heavy weighing equipment.     

NOTES ON THE BIOLOGY AND ETHOLOGY OF THE NATAL ROBIN COSSYPHA NATALENSIS

A preference for bushy evergreen undergrowth determines both the local and the general distribution of Cossypha natalensis. The lack of such undergrowth makes equatorial rain-forests unsuitable. Tropical and subtropical evergreen forests provide excellent conditions from this point of view, and they are thus the main habitat type from which C. natalensis has secondarily extended into tropical and subtropical deciduous forests with evergreen undergrowth.
Adult birds remain in or close to their territories throughout the year. First-year birds undertake longer movements during the winter. Breeding territories are relatively small, from 2,500 up to (exceptionally) 10,000 square yards (2,100-8,400 sq. m).
Breeding begins in October. Both sexes build the nest, but only the female incubates. In southern Africa there is one brood a year, and the care of the offspring is protracted. The juvenile moult begins in the third and ends in the sixth month; adults have only one (post-breeding) moult a year.
The begging behaviour of the young is somewhat different from that of most other turdine birds, and is considered to be more primitive. The ontogeny of the adult displays is described as observed in young birds kept in captivity.
The development of vocal behaviour is described. Special attention is given to the different functional forms of the song, and to two of its special features, imitation and a tonal quality termed vox humana.     

FLORAL PIGMENTATION STUDIES IN THE GENUS GOSSYPIUM II CHEMOTAXONOMIC ANALYSIS OF DIPLOID GOSSYPIUM SPECIES

The chromatographic pigment arrays of nine diploid species (G. arboreum, G. anomalum, G. herbaceum, G. stocksii, G. sturtii, G. thurberi, G. gossypioides, G. raimondii and G. klotzschianum) were studied. Among the Old World cottons, G. sturtii of Australia was very different from the species analyzed. The two species of the Herbacea section (G. herbaceum and G. arboreum) were found to have very similar pigment arrays. Both G. anomalum and G. stocksii were more like the Herbacea species than any other species in the genus, but both G. anomalum and G. stocksii had unique pigment characteristics. Although the evidence obtained so far from pigmentation patterns suggests that some pairs of species are closely related, the pigment arrays do not support the classification of the New World diploids into more than one section. From analysis of pigments of interspecific hybrids and their parents, it was found that with a hybrid and one parent species the pigment array of the other parent species could be predicted. Using this approach, the pigment arrays of three New World diploid species were predicted.     

OBSERVATIONS OF THE MIGRATION OF RAPTORS AND OTHER LARGE SOARING BIRDS IN BULGARIA, 1975–1978

Observations are given, from the years 1975 to 1978, on the migrations of raptors and large soaring birds along the Bulgarian section of the Black Sea coast, with casual observations on passage in western and central Bulgaria. The winter status of pelicans, and of some raptors, is discussed.
The author's findings suggest that the main spring migration route follows the coast north from Burgas, rather than turning west there, as had been suggested.